JP2019162091A - Carbon dioxide stabilizing device and fuel production system - Google Patents

Abstract

To provide a carbon dioxide stabilizing device capable of efficiently stabilizing carbon dioxide and a fuel production system using the same.SOLUTION: According to an embodiment, there is provided a carbon dioxide stabilizing device comprising a nonaqueous phase, an electroconductive carrier, an enzyme material, and a water phase. The nonaqueous phase includes an ionic liquid. Carbon dioxide is supplied to the nonaqueous phase. The electroconductive carrier is installed to contact the nonaqueous phase. The enzyme material is carried to the electroconductive carrier. The enzyme material catalyzes a reduction reaction of carbon dioxide supplied to the nonaqueous phase or a reduction product thereof. The water phase includes an extract including water. A reaction product of the reduction reaction is supplied to the water phase.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a carbon dioxide fixing device and a fuel production system.

Coal consumption, which continues to increase year by year, brings about an increase in the concentration of carbon dioxide (CO ₂ ) in the atmosphere, which is a major cause of global warming. In nature, approximately 100 billion tons of CO ₂ is converted into biomass annually by photosynthesis. However, as a result of since the industrial revolution CO ₂ emissions have continued to increase year by year, is only the photosynthesis of the natural world, the discharge rate of the CO _2, the rate of conversion of CO ₂ into biomass is becoming no longer keep up.

Therefore, as one of the countermeasures against global warming, there has been a need to capture and store CO ₂ which is the cause gas.

Until now, chemical absorption separation of CO ₂ by inorganic chemicals (for example, alkaline solutions such as amines), physical absorption separation of CO ₂ by absorption liquids such as methanol and polyethylene glycol, membranes such as polymer membranes and ceramic membranes separation of CO ₂ by the separation method, a physical absorption separation of CO ₂ by absorption material of a porous, such as a zeolite or activated carbon, to compress the CO ₂ (compression), such as buried underground or submarine, are taken various measures method ing. In CCS technology (CCS: Carbon Dioxide Capture and Storage), for example, technology for separating and recovering CO ₂ generated from thermal power plants, transporting it, and storing it underground or on the seabed Is promoted. However, there are problems such as cost for separating and recovering CO ₂ .

In addition, the methods for separating and recovering CO ₂ , such as physical absorption separation using an absorption liquid or an absorbent material, membrane separation method, CO ₂ compression and sequestration, have various limitations as follows:
(1) Applicable only to low-pressure gas (2) Use of corrosion-resistant reaction vessel is required (3) Thermal energy is required (4) Hydrogen gas needs to be separated (5) Energy to separate oxygen (6) Desulfurization is required.

On the other hand, in recent years, in addition to preventing global warming, the next step aimed at realizing a sustainable society is not only to capture and store CO ₂ , but also to actively use useful materials such as chemical fuel and biomass from CO _2. The development and establishment of bioprocesses such as biorefinery to be converted and CO ₂ fixation are becoming necessary.

In recent years, ionic liquid gelation and film formation techniques capable of absorbing and separating CO ₂ with high efficiency have been established. On the other hand, active research has been actively conducted to convert captured CO ₂ into a useful fuel by using both types of conversion methods, electrochemical conversion and photochemical conversion. As an electrochemical conversion method, for example, by using a material in which spiked graphene is modified with spherical copper nanoparticles as an electrode and catalyst without using noble metals or rare metals, it is higher than carbon dioxide under normal temperature and pressure conditions. It has been reported that ethanol can be produced with high selectivity and high Faraday efficiency. This method is a very attractive chemical fuel production method because it can produce chemical fuel using electrical energy obtained by wind power generation, solar power generation, etc., and needs for energy conversion and storage. Therefore, it is a manufacturing method that has received much attention. However, CO ₂ is not very soluble in water and it is difficult to produce high-concentration ethanol. Moreover, when converting from CO ₂ to a fuel such as methanol using an electrochemical conversion method, a large overvoltage is required. In addition, the electrochemical method has problems such as many by-products.

The enzyme conversion method has recently attracted attention as one of clean and highly efficient fuel production methods that can selectively convert CO ₂ into fuel under mild conditions. In addition, the fuel conversion method from CO ₂ using an enzyme utilizes a direct electron transfer to an enzyme, which is a kind of molecular electrode (electro) catalyst, and thus has a smaller overvoltage than an inorganic catalyst such as a metal catalyst. Since it can be used, it is a more preferable conversion method. However, current enzyme conversion methods have problems such as the loss of intermediate products in the production of fuel (methanol) by a multistage enzyme reaction. In addition, the purity and concentration of methanol produced are low, and there are various problems such as enzyme deactivation and outflow. As one of these root causes, it is conceivable that CO ₂ which is a raw material for producing fuel has low solubility in an aqueous solution which is a reaction solvent, as in the electrochemical method.

International Publication No. 2015/097020 US Pat. No. 6,440,711 JP 2012-21216 A Special table 2012-512326 gazette

"High-Selectivity Electrochemical Conversion of CO2 to Ethanol using a Copper Nanoparticle / N-Doped Graphene Electrode", Yang Song, et al. Chemistry Select, 2016, 1, 1-8. "Methanol Production via Bioelectrocatalytic Reduction of Carbon Dioxide: Role of Carbonic Anhydrase in Improving Electrode Performance", Paul K. Addo, et al., Electrochemical and Solid-State Letters, 2011, 14 (4) E9-E13. “Reversible Interconversion of Carbon Dioxide and Formate by an Electroactive Enzyme”, Torsten Reda, et al, Proc. Natl. Acad. Sci. U.S.A. 2008, 105, 10654-10658. “Reversible Interconversion of CO2 and Formate by a Molybdenum-Containing Formate Dehydrogenase”, Arnau Bassegoda, et al. J. Am, Chem. Soc. 2014, 136, 15473-15476. “Electrochemical Reduction of Carbon Dioxide to Methanol by Direct Injection of Electrons into Immobilized Enzymes on a Modified Electrode”, Stefanie Schlager, et al., ChemSusChem 2016, 9, 631-635.

  An object of this invention is to provide the carbon dioxide fixing apparatus which fixes a carbon dioxide with high efficiency, and a fuel production system using the same.

  According to the embodiment, a carbon dioxide immobilization apparatus including a non-aqueous phase, a conductive carrier, an enzyme body, and an aqueous phase is provided. The non-aqueous phase contains an ionic liquid. Carbon dioxide is supplied to the non-aqueous phase. The conductive carrier is placed in contact with the non-aqueous phase. The enzyme body is supported on a conductive carrier. The enzyme body catalyzes the reduction reaction of carbon dioxide or its reduction product supplied to the non-aqueous phase. The aqueous phase contains an extract containing water. The reaction product of the reduction reaction is supplied to the aqueous phase.

1 is a schematic diagram of an example carbon dioxide immobilization device according to an aspect of an embodiment. FIG. Schematic of another example of a carbon dioxide immobilization device according to an aspect of the embodiment. Schematic of an example carbon dioxide immobilization device concerning other modes of an embodiment. Schematic of another example of a carbon dioxide immobilization device according to another aspect of the embodiment. Schematic of the modification of the carbon dioxide fixing device shown in FIG. Schematic of another modification of the carbon dioxide immobilization apparatus shown in FIG. Schematic which shows the carbon dioxide fixing device of another example which concerns on the other aspect of embodiment. Schematic which shows another example of the carbon dioxide fixing apparatus which concerns on the other aspect of embodiment. Schematic which shows the state in the middle of manufacture of an example of the member contained in the carbon dioxide fixing device shown in FIG. The schematic diagram of the carbon dioxide immobilization device of another example concerning the mode of an embodiment. Schematic of the single cell which comprises the stack type carbon dioxide fixing device of an example concerning an embodiment. Schematic of an example stack type carbon dioxide immobilization device concerning an embodiment. 1 is a scheme showing an example fuel production system according to an embodiment.

  Embodiments will be described below.

(First embodiment)
According to the first embodiment, a carbon dioxide immobilization apparatus including a non-aqueous phase, one or more conductive carriers, one or more enzyme bodies, and an aqueous phase is provided. The non-aqueous phase contains one or more ionic liquids. The conductive carrier is placed in contact with the non-aqueous phase. The enzyme body is supported on a conductive carrier. The aqueous phase contains an extract containing water.

  The non-aqueous phase and the aqueous phase are in contact via, for example, one or more porous membranes or separators. Alternatively, the non-aqueous phase and the aqueous phase may be in direct contact.

Carbon dioxide (CO ₂ ) is supplied to the non-aqueous phase in the carbon dioxide fixing device according to the embodiment. By using an ionic liquid as the non-aqueous phase medium, CO ₂ can be selectively and efficiently absorbed into the non-aqueous phase.

  The supply source of carbon dioxide is, for example, a gas containing carbon dioxide. The supply source of carbon dioxide is not particularly limited as long as it is a gas containing carbon dioxide. For example, atmospheric gas, gas generated in a thermal power plant, exhaust gas, gas from dry ice, gas from a carbon dioxide gas cylinder, or the like can be used as a carbon dioxide supply source.

  The carbon dioxide immobilization apparatus according to the embodiment can further include a mechanism for bringing the gas containing carbon dioxide into contact with, for example, a non-aqueous phase. Alternatively, for example, in the apparatus, the non-aqueous phase may be exposed to the atmosphere. Thus, the design of the carbon dioxide immobilization apparatus can be appropriately set according to the source of gas containing carbon dioxide as a reactant.

  The carbon dioxide immobilization apparatus can also include a mechanism for supplying a gas containing carbon dioxide to the non-aqueous phase in a state where the gas is pressurized to a pressure higher than normal pressure (0.1 MPa = 1 atm), for example. By increasing the pressure of the gas, and hence the pressure of carbon dioxide, the supply rate of carbon dioxide to the non-aqueous phase can be improved.

  The conductive carrier is placed in contact with the non-aqueous phase in the carbon dioxide fixing device. The conductive carrier can be provided on the surface of the non-aqueous phase, for example. Alternatively, the conductive carrier may be present in the non-aqueous phase. The non-aqueous phase may be a liquid or a gel. The conductive carrier carries one or more enzyme bodies. Although details will be described later, the loading of the enzyme body by the conductive carrier includes, for example, modification of the conductive carrier by the enzyme, inclusion of the enzyme by the conductive carrier, introduction of the enzyme into the conductive carrier, and the like. The introduction of the enzyme into the inside of the conductive carrier includes, for example, confining the enzyme inside the network structure of the lattice-like conductive carrier.

  Each of the one or more enzyme bodies carried by the conductive carrier includes at least one enzyme. Although details will be described later, carbon dioxide supplied to the non-aqueous phase is reduced by an enzyme reaction catalyzed by the enzyme body. For example, fuel is generated by an enzyme reaction that is a reduction reaction. The enzyme reaction catalyzed by the enzyme body includes a reduction reaction for reducing carbon dioxide. Therefore, the part containing the enzyme body in the carbon dioxide immobilization apparatus can also be called a carbon dioxide reduction reaction part.

  Also, the enzymatic reaction that reduces carbon dioxide can be a multi-stage reaction. In this case, the enzyme body which catalyzes the enzyme reaction which further reduces the reduction product of carbon dioxide is included. Through multiple stages of reduction reactions (enzymatic reactions), carbon dioxide can be reduced to the final product. The final product can be a fuel such as methanol, for example.

  The reaction product produced by the reduction reaction is supplied to the aqueous phase. The extract contained in the aqueous phase selectively extracts the reaction product. According to an example, the aqueous phase extraction liquid selectively extracts and recovers the final product in the multi-stage enzymatic reaction of carbon dioxide. Therefore, the water phase can be called a fuel recovery unit in the carbon dioxide fixing device.

  The carbon dioxide immobilization apparatus according to the embodiment can include a carbon dioxide reduction reaction unit that generates fuel by reducing carbon dioxide as described above, and a fuel recovery unit that recovers the generated fuel. The carbon dioxide immobilization apparatus according to the embodiment can also be called a fuel production apparatus.

  The fixation of carbon dioxide here means conversion of carbon dioxide into a carbon compound (conversion) by a chemical reaction. This includes carbon dioxide reduction. Carbon dioxide, which is a gas causing global warming, can be reduced by converting it into a gas, liquid, or solid carbon compound by a chemical reaction. Further, as the carbon compound, for example, carbon dioxide can be used as a resource by obtaining a useful substance such as fuel.

  In the carbon dioxide immobilization apparatus according to the embodiment, a site for supplying a reactant (carbon dioxide or a reduction product thereof) and a site for collecting the reaction product (a carbon compound that is a reduction product of carbon dioxide) are: It is divided into a non-aqueous phase and an aqueous phase. Therefore, the reaction product is difficult to mix with the reaction product, and the reaction product can be recovered with a small amount of impurities.

  In the carbon dioxide immobilization apparatus according to the embodiment, since the aqueous phase extracts a reaction product (for example, fuel) from the reaction field, the equilibrium of the enzyme reaction of fuel generation can be shifted to the reaction product side. . Moreover, since the aqueous phase extracts the reaction product, the loss of the reaction product is reduced. As a result, the yield of the produced reaction product (for example, fuel) can be increased.

As described above, the carbon dioxide immobilization apparatus according to the embodiment can efficiently fix carbon dioxide or a reduction product thereof to, for example, a reaction product such as methanol, thereby fixing carbon dioxide. Demonstrate high performance. Therefore, CO ₂ emission can be suppressed, and at the same time, a compound useful as a fuel can be produced.

  According to the first aspect of the carbon dioxide immobilization apparatus according to the embodiment, the enzyme body can include a first enzyme body, a second enzyme body, and a third enzyme body. Further, in this aspect, the non-aqueous phase can include a first non-aqueous phase, a second non-aqueous phase, and a third non-aqueous phase. Furthermore, the conductive carrier can include a first conductive carrier, a second conductive carrier, and a third conductive carrier. In this embodiment, the aqueous phase can include a first aqueous phase, a second aqueous phase, and a third aqueous phase. That is, the carbon dioxide immobilization apparatus of this aspect can include a plurality of conductive carriers, can include a plurality of non-aqueous phases, and can include a plurality of aqueous phases.

  The first enzyme body catalyzes a first reduction reaction that reduces carbon dioxide to produce a first reaction product. According to one example, the first reaction product is formic acid.

As used herein, formic acid is any of formate anion (HCOO ⁻ ), formic acid (formic acid: HCOOH) in which a proton is bonded to the formate anion, and formate (formate salt) in which a cation is bonded to the formate anion. Means a form. In the following description, formic acid also includes any of the above forms. Also, other compounds include any form such as anion, acid, and salt.

  The first conductive carrier carries the first enzyme body. The 1st enzyme body currently carry | supported by the 1st electroconductive support | carrier acts as a reproducible catalyst. The first conductive carrier is placed in contact with the first non-aqueous phase.

  The second enzyme body catalyzes a second reduction reaction that reduces the first reaction product to produce a second reaction product. According to one example, the second reaction product is formaldehyde. The second conductive carrier carries the second enzyme body. The 2nd enzyme body currently carry | supported by the 2nd electroconductive support | carrier acts as a reproducible catalyst. The second conductive carrier is placed in contact with the second non-aqueous phase.

  According to an example in which the third enzyme body catalyzes a third reduction reaction that reduces the second reaction product to produce a third reaction product, the third reaction product is methanol. The third conductive carrier carries the third enzyme body. The third enzyme body supported on the third conductive carrier serves as a reproducible catalyst. The third conductive carrier is placed in contact with the third non-aqueous phase.

  Carbon dioxide is supplied to the first non-aqueous phase. The carbon dioxide supplied to the first non-aqueous phase is reduced to the first reaction product by the first reduction reaction.

  The first reaction product is supplied to the first aqueous phase. The first aqueous phase supplies the first reaction product to the second non-aqueous phase.

  The second non-aqueous phase is supplied with the first reaction product. The first reaction product supplied to the second non-aqueous phase is reduced to the second reaction product by the second reduction reaction.

  The second aqueous product is supplied with the second reaction product. The second aqueous phase supplies the second reaction product to the third non-aqueous phase.

  The third non-aqueous phase is supplied with the second reaction product. The second reaction product supplied to the third non-aqueous phase is reduced to the third reaction product by the third reduction reaction. The third reaction product generated by the third reduction reaction is supplied to the third aqueous phase.

  A third reaction product is supplied to the third aqueous phase. As described above, the third reaction product is obtained.

  In this embodiment, carbon dioxide is reduced to a final product (fuel) by a three-stage enzyme reaction catalyzed by the first to third enzyme bodies. That is, the first reaction product and the second reaction product are intermediate products of a three-stage reaction, and the third reaction product is a final product.

  Each of the first to third conductive carriers can contain (carry) one or more kinds of enzyme bodies. The first to third conductive carriers may be different from each other in the kind and number of enzyme bodies contained in them or may be the same.

  Each of the first to third non-aqueous phases can contain one or more ionic liquids. The types of ionic liquids contained in the first to third non-aqueous phases may be different from each other or the same. In addition, one or more conductive carriers may be in contact with each of the first to third non-aqueous phases. The first and third non-aqueous phases may be different in the kind and number of conductive carriers in contact with them or may be the same. Further, as will be described later, one conductive carrier can be in contact with two or more of the first to third non-aqueous phases.

  In this aspect, since the first reaction product is selectively extracted by the extract contained in the first aqueous phase, the equilibrium of the first reduction reaction can be shifted to the first reaction product side. Further, the first reaction product as a substrate is supplied from the first aqueous phase to the second non-aqueous phase, and the second reaction product is selectively selected by the extract contained in the second aqueous phase. Therefore, the equilibrium of the second reduction reaction can be shifted to the second reaction product side. The second reaction product as a substrate is supplied from the second aqueous phase to the third non-aqueous phase, and the third reaction product is selectively extracted by the extract contained in the third aqueous phase. Therefore, the equilibrium of the third reduction reaction can be shifted to the third reaction product side.

  Thus, since the equilibrium of the three-stage reaction for reducing carbon dioxide to the third reaction product, which is the final product, can be shifted to the final product side in each reaction stage, the final product can be obtained with high yield. The product can be recovered. In addition, since the reaction product (carbon dioxide) and the intermediate product (first and second reaction products) are difficult to be mixed into the final product (third reaction product), a highly purified final product is obtained. be able to. Further, at each stage where the intermediate product is generated (first reduction reaction, second reduction reaction), the first aqueous phase and the second aqueous phase are the respective intermediate products, that is, the first reaction product. Since the product and the second reaction product are recovered, the loss of the intermediate product is suppressed.

  Further, in the modified example of the first aspect, for example, a two-stage enzyme reaction in which carbon dioxide is reduced to the final product in two stages can be employed instead of the three-stage enzyme reaction. In this case, the non-aqueous phase includes a first non-aqueous phase and a second non-aqueous phase. Carbon dioxide is supplied to the first non-aqueous phase, and a first reaction product is generated by a first reduction reaction that reduces the carbon dioxide. A first reaction product is supplied to the second non-aqueous phase, and a second reaction product is generated by a second reduction reaction that reduces the first reaction product. The second reaction product generated by the second reduction reaction is supplied to the aqueous phase.

  In this variation, only the first reaction product is an intermediate product. The second reaction product is a final product. Therefore, the second reaction product is extracted and recovered by the extract contained in the second aqueous phase. Except for this point, the configuration of this modified example is the same as that of the first embodiment, and thus the description thereof is omitted.

  Moreover, the reaction which reduces carbon dioxide as needed can also be made into the multistage reaction containing four or more steps. Depending on the number of reaction stages included in the multistage reaction, the numbers of the conductive carrier, the non-aqueous phase, and the aqueous phase can be appropriately changed. Furthermore, if necessary, a substrate other than carbon dioxide and an intermediate product (reduction product of carbon dioxide) may be included in each non-aqueous phase.

  The carbon dioxide immobilization apparatus of the first aspect can be configured in either a flow type or a batch type.

  In the flow type form, each of supply of carbon dioxide to the first non-aqueous phase, supply of reaction products to the subsequent aqueous phase, and supply of reaction products from each aqueous phase to the subsequent non-aqueous phase Is performed continuously.

  In the batch mode, the reaction product is supplied discontinuously from at least each aqueous phase to the subsequent non-aqueous phase. For example, when a three-stage reaction is employed, after the first reaction product generated by the first reduction reaction is supplied to the first aqueous phase, the first reaction product is converted into the first aqueous phase. It is temporarily stored in the recovered state. Similarly, the second reaction product generated by the second reduction reaction is temporarily stored in the second aqueous phase after being supplied to the second aqueous phase. In order to obtain a batch type, for example, a mechanism for controlling the flow of the extract can be provided in each of the first aqueous phase and the second aqueous phase.

  According to the second aspect of the carbon dioxide immobilization apparatus according to the embodiment, the enzyme body can include a first enzyme body, a second enzyme body, and a third enzyme body. Further, the non-aqueous phase can include a first non-aqueous phase, a second non-aqueous phase, and a third non-aqueous phase. Furthermore, the conductive carrier can include a first conductive carrier, a second conductive carrier, and a third conductive carrier. That is, the carbon dioxide immobilization apparatus of this aspect can include a plurality of conductive carriers and can include a plurality of non-aqueous phases. Carbon dioxide is supplied to the first non-aqueous phase. Carbon dioxide supplied to the first non-aqueous phase is reduced by the first reduction reaction, and a first reaction product is generated. The second non-aqueous phase is supplied with the first reaction product. The 1st reaction product supplied to the 2nd nonaqueous phase is reduced by the 2nd reduction reaction, and the 2nd reaction product is generated. The third non-aqueous phase is supplied with the second reaction product. The 2nd reaction product supplied to the 3rd nonaqueous phase is reduced by the 3rd reduction reaction, and the 3rd reaction product is generated. The third reaction product produced in the third non-aqueous phase is supplied to the aqueous phase.

  In this embodiment, carbon dioxide is reduced to a final product (fuel) by a three-stage enzymatic reaction in the first to third non-aqueous phases. That is, the first reaction product and the second reaction product are intermediate products of a three-stage reaction, and the third reaction product is a final product.

  Each of the first to third conductive carriers can contain (carry) one or more kinds of enzyme bodies. The first to third conductive carriers may be different from each other in the kind and number of enzyme bodies contained in them or may be the same.

  In the carbon dioxide immobilization apparatus of the second aspect, the first reaction product generated by the first reduction reaction is directly supplied to the second non-aqueous phase. In addition, the second reaction product generated by the second reduction reaction is directly supplied to the third non-aqueous phase.

  In this way, the intermediate product (first reaction product, second reaction product) in the multistage reaction for reducing carbon dioxide is converted into the subsequent non-aqueous phase (second non-aqueous phase, third non-aqueous phase). When supplying to (phase), do not go through the water phase. Therefore, the loss of the intermediate product can be reduced.

  Moreover, in the modified example of the second aspect, for example, a two-stage enzyme reaction that reduces carbon dioxide to a final product can be employed instead of the three-stage enzyme reaction. In this case, the non-aqueous phase includes a first non-aqueous phase and a second non-aqueous phase. Carbon dioxide is supplied to the first non-aqueous phase, and a first reaction product is generated by the first reduction reaction. The first reaction product is supplied to the second non-aqueous phase, and the second reaction product is generated by the second reduction reaction. The produced | generated 2nd reaction product is supplied to an aqueous phase.

  In this variation, only the first reaction product is an intermediate product. The second reaction product is a final product. Therefore, the second reaction product is extracted and recovered by the extract contained in the second aqueous phase. Except for this point, the configuration of this modified example is the same as that of the second aspect, and thus the description thereof is omitted.

  Similarly to the first aspect, the reaction for reducing carbon dioxide as required can be a multi-stage reaction including four or more stages. Depending on the number of reaction stages included in the multistage reaction, the numbers of the conductive carrier, the non-aqueous phase, and the aqueous phase can be appropriately changed. Furthermore, if necessary, a substrate other than carbon dioxide and an intermediate product (reduction product of carbon dioxide) may be included in each non-aqueous phase.

  Next, details of the non-aqueous phase, the conductive carrier, and the aqueous phase in the carbon dioxide immobilization apparatus according to the embodiment will be described.

<Non-aqueous phase>
The non-aqueous phase contains an ionic liquid.

As the non-aqueous phase medium, it is desirable to use materials having the following characteristics:
(1) High ability to absorb and separate CO ₂ (2) Low vapor pressure (3) High thermal stability (4) High conductivity (5) Wide potential window (6) Chemical stability High (7) Can be used as a protein stabilizer.

  Although it will not specifically limit if it is a non-aqueous phase material which has said main characteristic, It is desirable to use an ionic liquid as a medium of a non-aqueous phase. An ionic liquid has a low vapor pressure (close to zero), a wide potential window, and absorbs a specific substance such as carbon dioxide well, has high thermal stability, and high conductivity. It is desirable to use it as a phase medium.

An ionic liquid having high CO ₂ solubility can absorb a large amount of carbon dioxide. For example, by using such an ionic liquid as a non-aqueous phase medium, CO ₂ can be efficiently supplied to the non-aqueous phase. Since the enzyme body carried by the conductive carrier in contact with the non-aqueous phase becomes a place for CO ₂ reduction reaction, CO ₂ that is a reactant is efficiently supplied to the enzyme body, so that the CO ₂ solubility is high. It is desirable to use an ionic liquid as a medium. When an ionic liquid is used as a non-aqueous phase medium, the amount of CO ₂ absorbed increases with increasing pressure. For example, 1% if pressurized to _{0.1MPa (CO 2 mole% in ionic} liquid) or more, the use of _{60% (CO 2 mole% in} ionic liquid) ionic liquid capable of absorbing CO ₂ in the above case where pressurized to 6MPa Is desirable.

  As described above, the ionic liquid has high conductivity, and both ionic conductivity and electronic conductivity are excellent. Since excellent ion conductivity and electron conductivity are advantageous for the catalytic efficiency of the enzyme, a product (for example, fuel) can be produced quickly and efficiently.

  The ionic liquid is also called a designer liquid, and the characteristics can be freely designed (designed) by appropriately selecting the anion and cation according to the application.

  Representative cations of the ionic liquid include, for example, imidazolium, ammonium, phosphonium, pyridinium and the like.

Other representative cations of ionic liquids include, for example, 1-methyl-3-alkylimidazolium, 1,3-bis [3-methylimidazolium-1-yl] alkane, poly (diallyldimethylammonium), metal (M ⁺ ) tetraglyme, pyrrolidinium Etc.

Representative anions of ionic liquids include, for example, bis (trifluoromethanesulfonyl) imide ([Tf ₂ N] ^- , [TFSI] ^- , or [TFSA] ^- ), tetrafluoroborate ([BF ₄ ] ^- ), hexafluorophosphate ([PF ₆ ] ^- ), Dicyanoamine ([DCA] ^- ), etc.

Other typical anions of ionic liquids include, for example, halides, formate, nitrate, hydrogen sulfate, heptafluorobutyrate, thiocyanate, tris (pentafluoroethyl) trifluorophosphate, dicyanamide, poly (phosphonic acid), tetrachloroferrate, trifluoromethanesulfonate ([TfO] ⁻ ), etc. Is mentioned.

  Ionic liquids can be roughly divided into nonpolar ionic liquids and polar ionic liquids. In general, the nonpolar ionic liquid is a hydrophobic ionic liquid, and the polar ionic liquid is a hydrophilic ionic liquid.

  On the other hand, hydrophilic polar ionic liquids can be further classified into protic ionic liquids and aprotic ionic liquids. The polar ionic liquid can also be used as a core solution of reverse micelles formed with a hydrophilic solvent. In addition, it is known that Nafion (registered trademark), which is a material that is not an ionic liquid, can be used as a proton exchange membrane (PEM; Proton Exchange Membrane), but by making the protic ionic liquid into a gel (membrane), Similarly, it can be used as a proton exchange membrane (PEM). The aprotic ionic liquid can be used as a protein (enzyme) refolding agent and a heat stabilizer.

  Thus, the ionic liquid can be properly used depending on its characteristics.

Among ionic liquids, it is desirable to use imidazole-based ionic liquids. The imidazole-based ionic liquid or gel thereof can absorb CO ₂ with high selectivity and has high conductivity.

Among hydrophobic ionic liquids, for example, it is particularly desirable to use imidazole-based 1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide (EMIMBTI), which has excellent CO ₂ absorption characteristics.

There are many EMIMBTIs including official names, aliases, and abbreviations. For example, 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) amide, 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide [1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide], 1-ethyl-3 It is also called -methylimidazolium bis (trifluoromethanesulfonyl) imide. Abbreviations include EMIMIm, [emim] [(CF ₃ SO ₂ ) ₂ N], [emim] [TFSI], EmimTFSI, EMIMTFSI, EmimNTf ₂ , EmimTf ₂ N, Emim TFSI, Emim NTf ₂ , Emim Tf ₂ N, [ C ₂ mim] [NTf ₂ ], BMIM-NTf ₂ , [C ₂ mIm ⁺ ] [TFSI ⁻ ], [C ₂ C ₁ im] [NTf ₂ ] and the like are also described. To avoid confusion, the molecular structure is shown below.

Two or more kinds of ionic liquids can be mixed and used in consideration of absorption characteristics for CO ₂ and costs, toxicity, viscosity, conductivity, and the like. For example, by mixing and using an ionic liquid having good absorption characteristics for CO _{2 and} an ionic liquid having lower toxicity and lower cost than these, the purpose of reducing the cost of materials and reducing toxins can be achieved.

  In addition, since the aprotic ionic liquid in the polar ionic liquid can be used as a heat stabilizer for proteins, the polar ionic liquid is mixed with the nonpolar ionic liquid as a non-aqueous phase. Can be used.

  In addition, the cathodic limit of the ionic liquid depends on the characteristics of the cation, and when the cation contains an electron withdrawing group, the cathode limit increases. Therefore, it is desirable to select an ionic liquid from ionic liquids that absorb carbon dioxide well and contain cations containing electron-withdrawing groups.

The ionic liquid further includes, for example, 1-methyl-3-propyl-methylimidazolium dihydrogen phosphate (PMIH ₂ PO ₄ ), polybenzimidazole (PBI), 1-octyl-3-methylimidazolium bis (trifluoromethanesulfonyl) amide, [C ₈ mIm ⁺ ]. ^{[TFSA -] (TFSA - =} (CF 3 SO 2) 2 n -), 1-alkylimidazolium bis (trifluoromethanesulfonyl) amide, [C n ImH +] [TFSA -] (n = 4 or 8), triethyl sulfonium bis ( trifluoromethylsulfonyl) imide (TSBTSI), 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim] [PF ₆ ]), 1-butyl-2,3-dimethylimidazolium bis (trifluoromethylsulfonyl) imide ([bmim] [Tf ₂ N]) , Octyl-3-methylimidazoliumhexafluorophosphate ([omim] [PF ₆ ]), 1-decyl-3-methylimidazolium bis (trifluoro-methylsulfonyl) imide ([dmim] [Tf ₂ N]), 1-butyl-3-Methylimidazolium tetrafluoroborate ( [bmim] [BF ₄ ]), 1-dodecyl-3-methylimidazolium chloride ([dmim] [Cl]), 1-Methyl-3-octylimidazolium chloride (MOImCl), [C ₂ mim] [NTf ₂ ], [C ₆ mim] [NTf ₂ ], [C ₈ mim] [NTf ₂ ], [C ₆ F ₉ MIM] [NTf ₂ ], 1-butyl-3-methyl imidazolium bis [(trifluoromethyl) sulfonyl] imide, [C ₄ mim] [NTf ₂ ], [C ₄ mim] [PF ₆ ], [Bmim] [PF ₆ ] (BMIM-PF ₆ ), [bmmim] [PF ₆ ], [C4mim] [TFSI], IL [C ₈ mim] [Tf ₂ N] (1-octyl-3-methylimidazolium bis (trifluoromethylsulfonyl) amide), IL ₂ (1-ethyl-3-methyl-imidazolium bromide, [ emim] [Br]), 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([emim] [Tf]), 1-ethyl-3-methylimidazolium tetra-fluoroborate ([emim] [BF ₄ ]), [emim] [AlCl ₄ ], [Emim] [H _2,3 F _3,3 ], [emim] [CH ₃ CO ₂ ], [emim] [CF ₃ SO ₃ ], [emim] [(C ₂ F ₅ SO ₂ ) ₂ N ], [Emim] [(C ₂ F ₅ SO ₂ ) ₂ C], [emim] [TFA], [emim] [Ac], 1-butyl-3-methylpyridinium tetrafluoroborate ([bmpyri] [BF ₄ ]), 1-butyl-3-methylpyrrolidinium tetrafluoroborate ([bmpyrro] [BF ₄ ]), [bmim] [BF ₄ ], 1-ethyl-3-methylimidazolium chloride ([emim] [Cl]), [emim] [Tf ₂ N ], [C ₄ mim] [AC], [P ₆₆₁₄ ] [Pro], [P ₆₆₁₄ ] [Ala], [P ₆₆₁₄ ] [Gly], [MTBDH] [TFE], [C ₂ mim] [DCA] _{, [C 2 mim] [Tf} 2 N], [C 2 mim] [TfO], be used as the [C ₂ mim] [TCB] It can be.

Other ionic liquids that can be used include, for example, N- (2-Methoxyethyl-N-methylpyrrolidinium tetrafluoroborate (MEMPBF ₄ ), N- (2-Methoxyethyl-N-methylpyrrolidinium bis (trifluoromethanesulfonyl) imide (MEMPTFSI), N , N-Diethyl-N-methyl-N- (2-methoxyethyl) ammonium tetrafluoroborate (DEMEBF ₄ ), N, N-Diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide (DEMETFSI), N, N, N-Trimethyl-N-propylammonium bis (trifluoromethanesulfonyl) imide (TMPA TFSI), N-Methyl-N-propylpiperidinium bis (trifluoromethanesulfonyl) imide (PP13 TFSI) and the like can be mentioned.

  The ionic liquids described above are different in display and symbols as in EMIMBTI, but may have the same molecular structure. In addition to the ionic liquid shown above, a new ionic liquid can be synthesized as necessary.

Further, it is known that CO ₂ is physically absorbed by an imidazole ([Emim] ⁺ ) series ionic liquid depending on pressure.

For example, in the case of [emim] [TFSA], [emim] [BETA], [emim] [NFBS], [emim] [BF ₄ ], which are examples of imidazole-based ionic liquids, At a pressure (0.1 MPa = 1 atm), the solubility of CO ₂ in these ionic liquids is about 0.1 mole fraction or less to 0.2 mole fraction or less. On the other hand, these ionic liquids exhibit a CO ₂ solubility of a mole fraction of 0.3 or more and 0.6 or more under a pressure condition of 40 ° C. (313 K) and 6 MPa (= 60 atm). Depending on the type of imidazole ionic liquid, for example, when the pressure is increased from normal pressure to 6 MPa at 40 ° C. (313 K), the solubility of CO _{2 in the} ionic liquid is greatly increased (for example, 3 times to 4 times).

Thus, when the temperature is constant, the amount of CO ₂ absorbed by the ionic liquid increases as the pressure of the supplied CO ₂ increases.

The gas-liquid critical point of CO ₂ has a temperature of 31 ° C. and a pressure of 7.4 MPa. If the CO ₂ is supplied to the ionic liquid used in the medium of the non-aqueous phase as a gas, it is preferable to supply the CO ₂ under conditions CO ₂ is not a supercritical fluid. As temperature or pressure rises from the gas-liquid critical point, CO ₂ can become a supercritical fluid. For example, if the pressure is 7.4 MPa or less under the temperature condition of 31 ° C., CO ₂ can be supplied as a gas to the non-aqueous phase.

On the other hand, the solubility of CO _{2 in} an ionic liquid also depends on the temperature. In general, the solubility of CO _{2 in} ionic liquid decreases with increasing temperature. Therefore, it is desirable to control the temperature optimally according to the activity characteristics of the enzyme at each temperature.

The solubility of CO _{2 in} an ionic liquid is also affected by cationic species and anionic species. There is a tendency that the effect of anionic species is greater than the effect of cationic species on CO ₂ solubility in ionic liquids.

As a specific example, in the case of an ionic liquid having the same Bmim cation, CO ₂ is well absorbed by the following anion sequence.
^{_{NO 3 - <DCA - <BF}} 4 - <PF 6 - <TfO <TFSA

In the case of an ionic liquid having the same Emim cation, CO ₂ is well absorbed by the following anion sequence.
^{_{DCA - <BF 4 -, PF}} 6 - <NFBS <TFSA <BETA

One of the reasons why CO ₂ solubility in an ionic liquid depends on the cationic and anionic species of the ionic liquid is the presence of an unoccupied space dispersed in the ionic liquid. An unoccupied space regularly dispersed in the ionic liquid is used as a space for accommodating CO ₂ molecules. When CO ₂ is absorbed into this unoccupied space, the unoccupied space expands with the displacement of cations and anions in the ionic liquid.

There is a tendency that the proportion of the unoccupied space in the ionic liquid tends to increase as the ionic liquid has a weaker cation and anion attracting force (cohesive force). The more unoccupied space in the ionic liquid, the more CO ₂ is absorbed.

Many imidazole-based ionic liquids absorb CO ₂ by physical absorption based on the above-described principle.

Therefore, in the embodiment, different ionic liquids can be appropriately mixed and used as necessary based on the absorption characteristics of the ionic liquid having the same Emim cation with respect to CO ₂ .

In the case of an ionic liquid having the same Emim cation, the longer the perfluoroalkyl chain, the greater the effect of improving the solubility of CO ₂ . Therefore, in consideration of this effect, an ionic liquid perfluoroalkyl chain may be appropriately designed and synthesized.

Examples of ionic liquids that physically absorb carbon dioxide include [C ₄ mim] [Nf ₂ T], [C ₄ mim] [PF ₆ ], [C ₄ mim] [BF ₄ ], [C ₈ mim An ionic liquid such as [Nf ₂ T] or [C ₂ mim] [eFAP] can be used.

On the other hand, chemical absorption of CO ₂ by an ionic liquid can be performed using an ionic liquid such as an Amine-based ionic liquid or an Amino acid-based ionic liquid.

Examples of ionic liquids that chemically absorb carbon dioxide include [P ₆₆₁₄ ] [Pro], [P ₆₆₁₄ ] [Ala], [P ₆₆₁₄ ] [Gly], [MTBDH] [TFE], [N ₁₁₁₄ ] [Tf ₂ N] and [MTBDH] [Im] can be used.

In addition, in the case of a hydrophobic ionic liquid, since the solubility of water in the ionic liquid is low, the influence of water is small. In addition, when an ionic liquid is used, the following advantages can be mentioned regardless of hydrophobicity or hydrophilicity:
1) Volume expansion due to gas absorption is small 2) Chemical stability in a wide temperature range 3) Nonflammability, so there is little risk of causing accidents.

In order to improve the CO ₂ sequestration effect or to prevent problems such as leakage or outflow of the ionic liquid, it is further desirable to immobilize the ionic liquid with an immobilization support. For example, an ionic liquid can be immobilized by forming an ionic liquid film on a carrier material.

  As the ionic liquid immobilization carrier, a carrier material such as a porous membrane, a porous monolayer material, zeolite, a silica glass membrane, and a polymer can be used.

  When a polymer is used as an immobilizing carrier for an ionic liquid, a polymer / ionic liquid composite membrane, polymer / ionic liquid fiber, or other polymer / ionic liquid can be obtained by casting, electrospinning, or suction. A composite material can be made. As the polymer, for example, poly (vinylidene difuoride) (PVDF), poly (vinylidene difuoride) -hexafluoropropylene (PVDF-HFP), or the like can be used.

Also, a polymer / ionic liquid film can be formed on the surface of the electrode by dissolving the polymer material and the ionic liquid material with a solvent and spraying the material on the porous electrode material. As described above, the ionic liquid can be used while being fixed in the form of a membrane or a fiber, so that leakage of the ionic liquid due to absorption of CO ₂ due to pressurization can be prevented.

  As a carrier material for producing the ionic liquid film, for example, a hydrophobic polymer material or a hydrophilic polymer material can be used. As the hydrophobic polymer material, for example, polyvinylidene fluoride (PVDF) can be used. As the hydrophilic polymer material, for example, polyethylene (PE), polytetrafluoroethylene (PTFE), polyvinyl alcohol (PVA), or the like can be used. Alternatively, a mixture of hydrophobic and hydrophilic polymer materials can be used. When mixed and used, for example, PVDF and PTFE can be mixed and used.

In addition to a polymer material, an anodic alumina nanoporous film, porous TiO ₂ , mesoporous carbon, or the like can be used as a carrier material that can use an ionic liquid as a film.

  The ionic liquid can also be gelled with a gelling agent into an ion gel, also called an ionogel. An ion gel film can be formed by further forming an ion gel. As a gelling agent, for example, gelatin, MOGs, or hydroxypropyl methylcellulose (HPMC) can be used.

  Ionic liquids can also be used as polymerized ionic liquids by polymerizing. A polymer (ionic liquid) film can be formed by further forming polymerized ionic liquids.

In addition, a porous ionic liquid structure having a porous structure can be used as the ionic liquid. The porous ionic liquid structure is obtained by, for example, performing cross-linking of the ionic liquid in a condition where a template made of TiO ₂ or the like exists, and subsequently removing the template (for example, etching, replacement removal, etc.). Can be made. In addition, the porous ionic liquid structure can be produced even under mold-free conditions. The porous ionic liquid structure that can be used in the embodiment is preferably a porous ionic liquid structure that can absorb CO ₂ well, and the type thereof is not particularly limited.

  When an ionic liquid is used as the non-aqueous phase medium, a permeation-separation membrane (for example, described later) is provided between the non-aqueous phase containing the ionic liquid and the aqueous phase for the purpose of preventing the ionic liquid from flowing into the aqueous phase. It is desirable to provide a separator.

  For example, a supporting salt may be added to the non-aqueous phase as an electrolyte. Examples of the supporting salt include KCl, Tetrabutylammonium perchlorate (TBAP), solid polymer electrolyte, and the like.

  Note that some ionic liquids included in the non-aqueous phase can themselves have a function as an electrolyte. In that case, the addition of a separate electrolyte can be omitted.

<Conductive carrier>
The conductive carrier is placed in contact with the non-aqueous phase. The conductive carrier can be, for example, a sheet-like or plate-like conductive material provided on the surface of the non-aqueous phase. Alternatively, the conductive carrier can be, for example, a particulate conductive material dispersed in a non-aqueous phase. In addition, for example, a conductive carrier made of a porous material can be used, and at least a part of such a porous conductive carrier can be filled with a non-aqueous phase.

  The conductive carrier carries an enzyme body. The enzyme contained in the enzyme body is preferably in ohmic contact with the conductive carrier, but is not particularly limited as long as electrons can be supplied to the redox active site of the enzyme through other molecules.

  As other molecules, for example, alkanethiol containing an amino group or a carboxyl group terminal can be used. The thiol group of alkanethiol is, for example, self-assembled monolayer membrane (SAM membrane) when the alkanethiol is self-orientated and aligned by van der Waals force of alkyl group when bonded to gold. Form. Since the enzyme can form an amide bond with the alkanethiol, the enzyme can be immobilized on the surface of a conductive carrier such as gold via the alkanethiol.

  Alternatively, the enzyme can be immobilized via a linker on the surface of a conductive carrier made of carbon material such as graphene or carbon nanotube, or gold. In this case, the linker becomes another molecule as an electron supply path to the above-described redox active site. The molecule serving as the linker is not particularly limited as long as it can fix the enzyme to the conductive carrier.

When a carbon material is used as a conductive carrier, the carbon material can be subjected to treatments such as UV / O ₃ treatment, plasma treatment, and chromic acid treatment. By treatment, some carbon atoms can be converted to carboxyl groups. The enzyme can be fixed to the carbon material by the amide bond between the amino group contained in the enzyme and the carboxyl group contained in the carbon material.

  Alternatively, when a carbon material is used as a conductive support, the carbon material is first treated with a mixed acid (a mixture of concentrated nitric acid and concentrated sulfuric acid) to form nitro groups on the surface of the carbon material. Thereafter, the nitro group is reduced to an amino group. In this case, the enzyme can be fixed to the carbon material by an amide bond between the carboxyl group contained in the enzyme and the amino group contained in the carbon material.

  The conductive carrier can be, for example, an electrode. Alternatively, the conductive carrier can be a conductive material separate from the electrode, such as metal particles, graphene, nanowires, carbon nanotubes (CNT), carbon nanophones, and the like. As the metal particles, for example, particles made of metal such as gold, silver, platinum, copper, or alloy particles containing these metals can be used. When a conductive material separate from the electrode is used as a conductive carrier that supports the enzyme body, it is desirable that the conductive carrier be placed in ohmic contact with the electrode. For example, the conductive carrier can be dispersed in the vicinity of the electrode so that electrical contact can be obtained between the particulate conductive carrier and the electrode. Alternatively, for example, the electrode surface can be modified with a conductive carrier.

  Electrons are supplied from the conductive carrier to the enzyme body supported on the conductive carrier. The enzyme body directly receives electrons from the conductive carrier by interfacial electron transfer (IET). Specifically, when the electrode is used as a conductive carrier, electrons move directly from the electrode to the enzyme body. When a conductive carrier separate from the electrode is used, electrons moved from the electrode to the conductive carrier move directly from the conductive carrier to the enzyme body.

Enzymes are also a type of molecular electrocatalysts, so they can accept electrons directly from the electrodes. That is, by applying a little overvoltage η, electrons are transferred directly to the active site of the oxidized enzyme (E _ox ) in the enzyme body through electron transfer at the interface between the electrode and the enzyme body, and the reduced enzyme (E _red ) is given. Can be reduced. The reduced enzyme functions as a molecular electrode catalyst in a reduction reaction that reduces carbon dioxide or a reduction reaction that further reduces a reduction product of carbon dioxide. Specifically, the reducing enzyme donates an electron used for reducing the substrate of the reduction reaction, and the reducing enzyme itself is oxidized to the oxidizing enzyme. The oxidized enzyme is reduced again to the reduced enzyme by electron transfer from the electrode. By regenerating the reduced enzyme, it can repeatedly serve as a molecular electrode catalyst for reducing carbon dioxide to fuel.

  Here, the reduction of the enzyme by directly receiving electrons from the electrode by the electron transfer at the interface is referred to as the reduction of the enzyme by the direct electron transfer. On the other hand, when an enzyme does not receive electrons directly from an electrode but is reduced by receiving electrons via a coenzyme or a mediator, it is called enzyme reduction by indirect electron transfer.

  When utilizing the reduction of an enzyme by direct electron transfer, the enzyme reaction (reduction reaction) does not require a coenzyme or a mediator, and thus is not limited by the diffusion rate of the coenzyme or the mediator. The rate of the enzymatic reaction that utilizes the reduction of the enzyme by direct electron transfer depends only on the electron transfer rate.

  Also, coenzymes and mediators are expensive. In addition, when the coenzyme or mediator is water-soluble, there is a concern that the coenzyme or mediator will flow out into the aqueous phase. When the coenzyme or mediator flows into the aqueous phase, not only does the coenzyme or mediator have a loss in price, but the enzyme reaction is delayed, resulting in a reduction in production efficiency of the reaction product. In addition, the depletion of coenzymes due to consumption and loss leads to termination of the enzyme reaction.

  Since the reduction of the enzyme by indirect electron transfer has the above-mentioned limitations, it is desirable to employ the reduction of the enzyme by direct electron transfer without using a coenzyme or a mediator. That is, it is desirable that the carbon dioxide immobilization apparatus according to the embodiment does not include any of the coenzyme and the mediator. Moreover, since there is no possibility that the coenzyme and the mediator are mixed in the reaction product, a reaction product with high purity can be obtained.

  For example, an electrode that exchanges electrons directly with an enzyme that is a molecular electrode catalyst without using a coenzyme or a mediator is regarded as a cathode electrode. The cathode electrode itself may be a conductive carrier that supports the enzyme body. Alternatively, the cathode electrode can be an electrode that is in ohmic contact with the conductive support.

The interfacial electron transfer rate between the enzyme and the cathode is affected by the following:
(1) Distance between the redox center in the enzyme and the electrode (2) Ease of electrons in the electron transfer path (3) Reorientation energy related to redox of the enzyme.

  Therefore, it is desirable that the distance between the redox center in the enzyme contained in the enzyme body and the electrode is short.

  When a conductive carrier separate from the cathode electrode is used, for example, a material having high conductivity between the conductive carrier and the cathode electrode, for example, gold nanoparticles, silver nanoparticles, platinum nanoparticles, copper nanoparticles It is desirable to intervene graphene, nanowires, carbon nanotubes (CNT), carbon nanophones, and the like. By doing so, it is possible to more easily realize supply of electrons to the redox center in the enzyme.

  A semiconductor material can also be used as the conductive carrier. When a semiconductor material is used, it is desirable to use it in combination with a light source so that electrons can be provided by light irradiation. For example, when a semiconductor material is used as the anode electrode, electrons generated by irradiating the anode electrode with light can be provided to the redox center in the enzyme via the cathode electrode. Alternatively, when a semiconductor conductive carrier is used as the cathode electrode, electrons generated by light irradiation can be provided to the redox center in the enzyme. The electrons generated by light can be provided to the redox center in the enzyme in combination with, for example, electrons provided by an electrical control unit described later.

  Furthermore, it is desirable that the reorientation energy related to the redox of the enzyme is small. For this reason, it is desirable to use a method in which an enzyme body is supported on a conductive carrier, for example, a method for modifying the enzyme, in which the reorientation energy of the enzyme can be kept small.

  The conductive carrier carrying the enzyme body can be obtained, for example, by the following method. For example, the enzyme body can be directly modified to the conductive carrier by physical or chemical methods (interactions).

  In the case of a physical method, for example, the enzyme body can be directly modified to the conductive carrier by physical adsorption of the enzyme body to the surface of the conductive carrier.

  Enzyme modification to a conductive carrier by physical adsorption has the advantage that the interaction between the enzyme and the conductive carrier is weak, so that there is little change in the high-dimensional structure of the enzyme and the activity of the active site of the enzyme is maintained. On the other hand, the enzyme may be detached from the conductive carrier depending on environmental conditions such as a solvent, ionic strength, and temperature.

  In addition, binder (for example, epoxy-resin), Nafion (registered trademark), polymer material (for example, polyvinyl carbonate (PVC), PVA, conductive polymer, etc.), Carbon wax, mineral oil, carbon paste oil base, ion It is also possible to physically modify the enzyme body to a conductive carrier through a material such as a liquid, gel, or solid electrolyte. In this method, in order to promote the electron donation to the active site of the enzyme more smoothly, a material having excellent electron conductivity, for example, CNT, graphene, metal nanoparticles, metal fine particles are mixed with the above materials, It is desirable to use it for modification of an enzyme body.

  By conducting enzyme immobilization on a conductive carrier using a polymer material, a conductive carrier carrying an enzyme can also be obtained. For example, using a monomer solution containing an enzyme body, the enzyme body can be modified into a conductive carrier together with the electropolymerization of the monomer.

  Using the physical methods described above, enzyme bodies can be transformed into, for example, electrode substrates, carbon paper, carbon fibers, carbon nonwoven fabrics, carbon cloth, carbon felt, foamed graphene (graphene foams with continuous 3D) network), and can be modified to the surface of a conductive carrier made of a material such as a porous conductive material. In this method, metal nanoparticles, a surfactant, and the like can be appropriately introduced between the conductive carrier and the enzyme body. For example, the denaturation of the enzyme can be prevented by introducing a surfactant. Moreover, the cell or microorganism containing an enzyme can also be directly modified to a conductive carrier.

  Moreover, the enzyme body can be included in a net-like or cloth-like conductive carrier by using an entrapment method.

  The electron transfer rate is affected by factors such as the electron transfer distance between the enzyme and the conductive carrier, and the electrical resistance of the material used to modify the enzyme body. Therefore, it is desirable that the physical distance between the enzyme and the conductive carrier is as short as possible. For example, as described above, a surfactant can be introduced between the conductive carrier and the enzyme. Further, as described later, the enzyme body may contain a surfactant. In view of the fact that a surfactant can be located between the enzyme and the conductive carrier, it is desirable to select a surfactant with a hydrocarbon chain as short as possible.

  In the case of a chemical method, for example, the enzyme can be modified to the conductive carrier by ionic bond or covalent bond. When modifying an enzyme body to a conductive carrier by ionic bonding, pay attention to the influence of pH and ionic strength. On the other hand, when the enzyme body is modified on the electrode by a covalent bond, the interaction between the enzyme body and the conductive carrier is strong, and the enzyme body can be easily detached from the conductive carrier even in environmental conditions where high concentrations of salts and substrates are present. Never leave. Therefore, it is desirable to use supply coupling.

[Cathode electrode, Anode electrode]
For example, a pair of electrodes called a cathode and an anode are installed in the non-aqueous phase. These cathode and anode can be contained, for example, in a non-aqueous phase medium (ionic liquid). A porous electrode can be used for each of the cathode and the anode. In such a case, these electrodes can also function as a porous membrane. For example, the electrodes can be installed at the interface between the gas phase and the non-aqueous phase, or at the interface between the non-aqueous phase and the aqueous phase. .

  The anode electrode can function as a counter electrode with respect to the cathode electrode.

  Further, a pair of electrodes, that is, a larger number of electrodes than two electrodes can be used. Of the plurality of electrodes, the same electrode can serve both as a cathode electrode and as an anode electrode. For example, the same electrode can function as a cathode electrode in one mode of operation and an anode electrode in another mode of operation.

  You may use the electrode containing an enzyme body as a cathode electrode. Alternatively, an electrode including an enzyme / conductive carrier (a conductive carrier on which an enzyme is supported) may be used as a cathode electrode. That is, the cathode electrode can function as an electrode for direct electron transfer to the molecular electrode catalyst.

  When non-porous electrodes are used as the cathode electrode and the anode electrode, the cathode is placed at a position where diffusion of substrates and intermediate products, fuel, proton ions, etc. of the enzyme reaction in the non-aqueous phase and the aqueous phase is not hindered. It is desirable to install an electrode and an anode electrode, respectively. On the other hand, when the cathode electrode and the anode electrode can function as a porous film, the position where the cathode electrode and the anode electrode are installed is not particularly limited.

  For example, the cathode electrode can be installed between the non-aqueous phase and the aqueous phase. For example, an anode electrode can be installed between the gas phase and the non-aqueous phase. Furthermore, for example, the non-aqueous phase can be divided into a plurality of regions by installing a plurality of cathode electrodes in the non-aqueous phase. For example, when the aqueous phase is a proton source, the cathode electrode carrying the enzyme body is placed between the non-aqueous phase and the aqueous phase as a porous membrane so that protons can be efficiently supplied to the enzyme body. The reaction can be promoted.

  Further, at least a part of the porous electrode can be impregnated with a non-aqueous medium, that is, an ionic liquid. Regardless of the position where the electrode is placed, the porous electrode can be impregnated with the ionic liquid.

  The material of the cathode electrode and the anode electrode may be selected from conductive materials, and the materials are not particularly limited. For example, commercially available carbon, carbon cloth, carbon fiber, carbon nonwoven fabric, carbon paper, carbon felt, carbon nanofiber nonwoven fabric, foamed graphene (for example, graphene foam having a continuous three-dimensional network; graphene foams with continuous 3D networks).

  Foamed (foamed) graphene can be made, for example, by first forming a graphene layer on a nickel foam by chemical vapor deposition (CVD) and then removing the nickel base. Foamed graphene has many pores, so that a non-aqueous phase medium (ionic liquid) can penetrate into the inside. Foamed graphene further has advantages such as being robust and flexible and easy to handle.

  In addition, a composite electrode material including a thin piece of graphene or a carbon nanotube can be used. An electrode using these materials can also function as a porous film. When one side of the electrode that also serves as the porous membrane is exposed to a gas phase such as the atmosphere, for example, in order to promote the supply of carbon dioxide to the non-aqueous phase, a gas diffusion layer is formed on the surface exposed to the gas phase. May be provided. The gas diffusion layer is a dense layer (Micro Porous Layer) mainly made of carbon and a water-repellent material.

  Metal material electrodes can also be used as the cathode and anode electrodes. For example, an electrode containing platinum, gold, or silver can be used. On the other hand, it is desirable to use a titanium electrode from the viewpoint of cost.

  The cathode electrode and the anode electrode are appropriately processed and used, for example, in a flat plate shape, a rod shape, a net shape, a wire shape, a foam shape, a cloth-form, etc. according to the installation position and application of the electrode. can do.

[Reference electrode, pseudo reference electrode]
In addition to the cathode electrode and the anode electrode, a three-electrode system can be designed by further providing a reference electrode or a pseudo reference electrode in the non-aqueous phase. Alternatively, in addition to the cathode and the anode, a four-electrode system can be designed by further providing reference electrodes (two in total) or pseudo reference electrodes (two in total) corresponding to the cathode and the anode, respectively. . By using the reference electrode or the pseudo reference electrode, the voltage can be controlled more accurately. Therefore, an enzyme reaction (reduction reaction) can be efficiently advanced. The reference electrode and the pseudo reference electrode can be installed at any location in the non-aqueous phase, but it is desirable to provide them between the cathode electrode and the anode electrode.

  Or you may install a reference electrode and a pseudo reference electrode in the arbitrary places in a water phase. In view of advantages such as ease of maintenance, it is desirable to install a reference electrode or a pseudo reference electrode in the aqueous phase. In addition, when the reference electrode is installed in the aqueous phase, it is not necessary to use a reference electrode for an organic solvent.

  When the carbon dioxide fixing device is set to a constant current, it is desirable that the current value and the product concentration (for example, fuel concentration) are stabilized by appropriately installing the reference electrode and the pseudo reference electrode as described above. In addition, when a constant voltage is set, a stable applied potential value can be maintained, and a high-purity product (fuel) is obtained, which is desirable.

  Examples of the reference electrode and pseudo reference electrode include platinum, platinum black, palladium, silver, silver / silver chloride (Ag / AgCl) electrodes, gold, and carbon electrodes.

  The reference electrode and the pseudo reference electrode are used by appropriately processing, for example, a flat plate shape, a rod shape, a net shape, a wire shape, a foam shape, or a cloth-form according to the installation position and application. can do.

[Enzyme]
The enzyme body carried on the conductive carrier contains one or more kinds of enzymes. The enzyme body may be a single enzyme. Alternatively, the enzyme body includes an immobilized enzyme. Here, the enzyme immobilization means that the enzyme is bound to the immobilization carrier by the carrier binding method, the enzyme is encapsulated in a polymer gel or a microcapsule by a comprehensive method, and the enzymes are bound by a crosslinking method. including. An enzyme body obtained by immobilizing an enzyme is, for example, a support comprising a molecular assembly formed by a dispersant and an enzyme, a microcapsule containing the enzyme, a polymer material, and the like. And a complex containing an enzyme supported or encapsulated. Furthermore, cells or microorganisms containing enzymes can also be used as the enzyme body.

  The enzyme body is supported on a conductive carrier. The form of the enzyme body supported by the conductive carrier is as described above.

  The conductive carrier contains one kind of enzyme body, and each enzyme body may contain two or more kinds of enzymes. Or the electroconductive support | carrier may contain the multiple types of enzyme body from which the kind of enzyme differs. In this case, each enzyme body may contain only one type of enzyme or two or more types of enzymes.

  In addition, when the conductive carrier includes a plurality of types of enzyme bodies having different types of enzymes, a part of the reaction product generated by the enzyme reaction in one enzyme body is converted into the enzyme reaction in the other enzyme body. May be a substrate for Chemical substances are exchanged quickly between individual enzyme bodies contained in the same system. Therefore, the reaction product produced by the enzyme reaction in one enzyme body quickly moves to the other enzyme body, where it participates in the enzyme reaction as a substrate.

  By setting the place where the enzyme reaction is performed in a non-aqueous solvent, it is possible to prevent the generation of viruses, molds, bacteria, algae and the like. From this point of view, the enzyme body is surrounded by the non-aqueous phase medium by, for example, immersing or burying the conductive support in the non-aqueous phase or impregnating the non-aqueous phase medium with the conductive support. Is desirable.

In addition, when the enzyme body obtained by immobilizing the enzyme is used, the following properties are expressed, which is desirable:
(1) A high concentration substrate (for example, carbon dioxide or a reduction product thereof) can be used.
(2) The stress resistance of the enzyme is improved.
(3) Separation of the enzyme (enzyme) and the product is facilitated.
(4) Repeated use of the enzyme is facilitated.

(enzyme)
The enzyme that can be included in the enzyme body is not particularly limited as long as it is an enzyme that catalyzes a reaction that reduces carbon dioxide when a single enzyme is combined or a combination of a plurality of enzymes to generate fuel. Enzymes that can be used include, for example, an enzyme that functions as a catalyst for an enzyme reaction that reduces carbon dioxide to produce an intermediate product, a reaction product derived from carbon dioxide (for example, the above-mentioned intermediate product of carbon dioxide as an intermediate product). An enzyme that functions as a catalyst for an enzyme reaction using a reduction product as a substrate, an enzyme that captures carbon dioxide, and the like.

Specific examples of enzymes include formate dehydrogenase (FDH), metal-dependent formate dehydrogenase, tungsten-containing formate dehydrogenase enzyme (FDH1), formaldehyde dehydrogenase (F _ald DH), alcohol dehydrogenase (ADH), carbon monoxide dehydrogenase (CODH). ), Oxidoreductase-dehydrogenase such as carbonic anhydrase and molybdenum-containing formate dehydrogenase (Mo-FDH). An example is remodeled nitrogenase, which is an enzyme that reduces carbon dioxide to methane.

  In addition, it is possible to use an enzyme for converting carbon dioxide into a useful substance having higher added value in addition to fuel by a multistage enzymatic reaction.

  Depending on the type, the enzyme can exhibit catalytic activity even under high pressure. For example, some enzymes can function under pressures of 200 MPa. For different types of enzymes, there may be a pressure at which the reaction rate of the reaction catalyzed by the enzyme is maximized under certain conditions (other than pressure), that is, an optimal pressure. For example, under a certain condition (a condition other than pressure), the reaction rate increases as the pressure is increased, and the reaction rate becomes maximum when the optimum pressure is reached. Under pressures higher than the optimum pressure, the reaction rate decreases. For example, the enzyme is generally denatured under a pressure of about 400 MPa or higher and may not maintain its function.

As described above, the CO ₂ solubility of the ionic liquid improves with increasing pressure. Therefore, it is preferable to use an enzyme that exhibits catalytic activity even under conditions where the pressure is increased to promote CO ₂ absorption into the non-aqueous solvent. Specifically, the enzyme included in the enzyme body is preferably one that maintains the function of catalyzing the reduction reaction of CO ₂ or the reduction product of CO ₂ even under a pressure of 400 MPa. For example, it is more preferable to use an enzyme that retains activity in the range of 0.1 MPa (normal pressure) to 7.4 MPa at room temperature (298 K) to 304 K.

(Dispersant)
An emulsifier can be used as a dispersant. An emulsifier is an amphiphilic molecule having a hydrophilic group and a hydrophobic group. The type and combination of the emulsifiers used in the embodiment are not particularly limited as long as a stable molecular assembly can be formed using the emulsifiers. Examples of emulsifiers include lipids and boundary lipids, sphingolipids, fluorescent lipids, cationic surfactants, anionic surfactants, ampholytic surfactants, zwitterionic surfactants. , Nonionic surfactants, sugar surfactants, synthetic polymers, natural polymers such as proteins, and the like can be appropriately selected and used.

  As the zwitterionic surfactant, for example, N-dodecyl-N, N-dimethyl-3-ammonio-1-propanesulfonate (SB-12) can be used.

(Molecular assembly)
In non-aqueous solvent, almost spherical reversed micelle or string-like reversed micelle by liposome, or liposome, vesicle, microemulsion, large emulsion, bicontinuous microemulsion, monodispersed single emulsion, double emulsion, multiple layers Any one or more molecular aggregates of the emulsion can be formed.

  The enzyme body may be obtained by immobilizing an enzyme on such a molecular assembly. For example, as an example of a molecular assembly, a substantially spherical reverse micelle formed by a dispersant in a non-aqueous solvent can hold a predetermined amount of water as a water pool at the center. By incorporating the enzyme into the reverse micelle water pool, the enzyme can be immobilized. Immobilizing the enzyme in this way is also referred to as solubilization of the enzyme in the water pool. In the enzyme body, the water pool is used as an enzyme reaction field catalyzed by the enzyme.

  A reverse micelle is formed as follows, for example. When an emulsifier is added to a non-aqueous solvent such as an ionic liquid and the emulsifier concentration reaches the critical micelle concentration (Critical Micelle Concentration; CMC), the hydrophilic and hydrophobic groups of the emulsifier face inward and outward respectively, Surrounding substantially spherical reverse micelles can be formed.

  Further, by increasing the concentration of the emulsifier, the reverse micelles that are spherical can be grown to form reverse string micelles that are stretched in a string shape. The water in the center of the reverse string micelle serves as a reaction field for the enzyme reaction as in the reverse micelle. Moreover, the non-aqueous solvent containing an enzyme body can be gelatinized by using a reverse string micelle as an enzyme body. Details of the gelation of the non-aqueous solvent will be described later.

  Further, instead of the emulsifier, for example, a surfactant such as sodium 1,2-bis (2-ethylhexylcarbonyl) -1-ethanesulfonate (Aerosol OT; AOT) is added to the non-aqueous solvent to reverse micelles and reverses. String-like micelles can be produced. When the concentration of AOT in the non-aqueous solvent is increased, reverse string micelles can be formed. Furthermore, when the concentration of AOT is continuously increased, the reverse string micelles are entangled with each other and the entire non-aqueous solvent is gelled.

  In addition, as other molecular aggregates, for example, monodisperse single emulsions (W / O single emulsions such as liposomes, vesicles, microemulsions, large emulsions, bicontinuous microemulsions, water-in-oil emulsions, etc. formed by a dispersant). A dispersion emulsion), a double emulsion (W / O / W type double emulsion), or a multilayer emulsion can be used. These molecular assemblies may contain an aqueous solvent as an inner aqueous phase that can be used as a water pool.

  Moreover, the aqueous solvent which a molecular assembly can contain as an internal aqueous phase may contain the polar ionic liquid as mentioned above, for example. For example, an ionic liquid (IL + W) / O microemulsion (water-in-oil emulsion), reverse micelle [(IL + W) / O], or reverse string-like reverse micelle formed in a non-polar ionic liquid ) And a water solvent (W), a mixture of a polar ionic liquid (IL) and a water solvent (W) can be used as the internal phase (IL + W) of the mixed solvent.

In the water pool, the water existing around the hydrophilic group of the molecule of the dispersing agent or the protonic ionic liquid (PIL) in a state where the molecular motion is constrained by the ion-dipole interaction is referred to as bound water. Called. On the other hand, the water present in the center of the water pool is free water in a state substantially similar to bulk water. There is a rapid exchange between free water and bound water. Free water increases with increasing water content ω _o . The water content ω _o is obtained by the following formula.

Here, [H ₂ O] is the molar concentration of water, and [S] is the molar concentration of the dispersant (S).

  Further, the radius (Rw) of the water pool is obtained by the following formula.

When protic ionic liquid (PIL) is used as the ionic liquid, PIL also serves as a co-surfactant and contributes to the formation of reverse micelles or microemulsions (water-in-ionic liquid type; W / IL) It will be. Therefore, it is also necessary to consider the amount of PIL used to form reverse micelles or microemulsions (W / IL). In general, the water content ω _o increases as the PIL amount increases at a constant surfactant concentration [S].

By appropriately adjusting the water content ω _o , the size of the water pool can be adjusted appropriately. However, when a solvent such as a polar ionic liquid coexists in the water pool, the water content ω _o may deviate from the above formula.

  The above-described molecular aggregates such as reverse micelles, reverse string micelles, liposomes, vesicles, microemulsions, large emulsions, W / O monodisperse emulsions, or W / O / W double emulsions are further gels or polymer materials. Can be coated.

  In addition, molecular aggregates such as reverse micelles, liposomes, vesicles, microemulsions, large emulsions, W / O monodispersed emulsions, or W / O / W double emulsions coated with gel or polymer are regarded as microcapsules. be able to.

  In order to promote the stability of molecular aggregates and direct electron transfer to enzymes in enzyme reactions, graphene oxide, carbon nanotubes, graphene, carbon nanophones, silica nanoparticles, silver nanoparticles, gold nanoparticles, palladium nanoparticles, One or more types of copper nanoparticles, semiconductor nanoparticles, and mesoporous materials can be dispersed inside, on the surface, or around the molecular assembly. Here, the inside of the molecular assembly is, for example, a water pool such as a reverse micelle, or the center of a reverse string micelle. Of these, when graphene oxide, carbon nanotubes, graphene, carbon nanophones, silver nanoparticles, gold nanoparticles, palladium nanoparticles, and copper nanoparticles are dispersed, high electronic conductivity and ion conductivity, as well as molecular assembly The effect of improving the stability of the body can be obtained. On the other hand, when silica nanoparticles, semiconductor nanoparticles, and mesoporous materials are dispersed, an effect of improving the stability of the molecular assembly can be obtained.

  Also, one or more types of semiconductor nanoparticles can be dispersed inside, on the surface, or around the molecular assembly. When semiconductor nanoparticles are dispersed, the effect of improving the stability of the molecular assembly can be obtained, and electrons generated by light irradiation can be directly provided to the enzyme.

  Care is taken not to short-circuit a pair of electrodes (cathode electrode, anode electrode, reference electrode, or pseudo reference electrode) provided in the non-aqueous phase with these materials. For example, short-circuiting of the electrodes can be prevented by dispersing the material inside the molecular assembly or arranging the electrodes sufficiently apart. In addition, it is preferable to reduce the size of the material in order to prevent short-circuiting of the electrodes.

(Micro capsule)
The microcapsule according to the embodiment is obtained, for example, by encapsulating a core portion including minute nuclei (solid, liquid, gas) with a porous wall film and having a size ranging from nanoscale to millimeter scale. Point to. The microcapsules in the enzyme body have effects such as prevention of enzyme denaturation and inactivation, isolation from non-aqueous solvents, storage, and concealment.

  The core part of the microcapsule according to the embodiment is used as a field for enzyme reaction. Furthermore, the microcapsule can quickly take in the components related to the enzyme reaction such as a substrate, water, and an intermediate product into the core, and can quickly release the reaction product of the enzyme reaction from the core.

  As the material of the wall film of the microcapsule, that is, the shell, a hygroscopic polymer material or other polymer material that can be used as, for example, an immobilization carrier can be used. That is, the wall film of the microcapsule may be any one of a wall film made of a hygroscopic polymer material or a polymer material, an organic wall film, an inorganic wall film, or an inorganic / organic hybrid wall film.

  When an electron is given to an enzyme by direct electron transfer, it is desirable to disperse a highly conductive nanomaterial or semiconductor nanomaterial in these wall films as in the above-described molecular assembly.

  Microcapsules can generally be made by three major techniques: chemical techniques, physicochemical techniques, and mechanical and physical techniques. Among these techniques, interfacial polymerization method of chemical technique, in-situ polymerization method, submerged curing coating method, and submerged drying method of physicochemical technique, etc. There is a way.

  The microcapsule according to the embodiment can be produced by the above-described method, and can be produced by using, for example, a double emulsion produced by a two-stage emulsification method, a film milk method, or a one-stage emulsification method as a template. In particular, microcapsules obtained by using a double emulsion prepared by a one-step emulsification method as a template have few impurities in the core material, few variations in the particle size, number of cores, and core particle size, and maintain high activity. It is desirable because the enzyme can be encapsulated in the core.

  Alternatively, microcapsules can be produced by photopolymerization of a dispersant using reverse micelles, vesicles, or double emulsions formed with a reactive dispersant.

  A substance in which an enzyme is held in a microcapsule can be used as an enzyme body. Such an enzyme body can be obtained, for example, by producing a microcapsule so that the enzyme is encapsulated in the produced microcapsule when the microcapsule is produced by the above-described method. Moreover, you may hold | maintain the cell and microorganisms mentioned later in a microcapsule instead of an enzyme. Microcapsules (enzyme bodies) encapsulating the enzyme thus obtained may be immersed in an aqueous solvent so that the core or wall membrane contains moisture.

(Cells and microorganisms)
As the enzyme body, cells or microorganisms containing the enzyme can be used. Cells and microorganisms can be used alone as enzyme bodies. Alternatively, cells or microorganisms immobilized by a carrier binding method or a comprehensive method can be used as the enzyme body.

  Alternatively, cells or microorganisms may be coated with a gel or polymer material containing a highly conductive nanomaterial or semiconductor nanomaterial to form an enzyme body. Details of gels and polymer materials that coat cells and microorganisms will be described later. When cells or microorganisms are coated with a gel, an extracellular matrix protein (Extracellular Matrix protein: ECM protein) or an extracellular matrix, Fibronectin (FN) can also be coated together with the gel.

  Naturally occurring cells and microorganisms contain various enzymes, some of which contain enzymes or combinations of enzymes that are useful for fixing carbon dioxide or converting it to fuel. By selecting cells or microorganisms having an appropriate combination of enzymes, they can be used as the enzyme bodies of the embodiments. Moreover, the cell which can be used for embodiment can be cells other than microorganisms, for example, an animal cell and a plant cell. Further, instead of the above microorganisms and cells, a group of organisms collectively called algae using light such as sunlight or artificial light as an energy source can be used.

  Cells and microorganisms that have been killed without proliferation can be used. A microorganism in such a dead state is said to be in a quiescent state, and a microorganism in which such a microorganism is immobilized is referred to as an immobilized quiescent cell.

(Support)
As the support on which the enzyme is immobilized, for example, powdered or porous beaded chitin, chitosan (for example, Chito Pearl BCW3010 manufactured by Fujibo), xylan, κ-carrageenan and other polysaccharides can be used. As the support, for example, porous glass, polylactic acid, alumina, silica gel, and celite can be used. In addition, for example, polysaccharide derivatives such as cellulose, dextran, and agarose can also be used as the support.

  The shape of the support is not particularly limited, and may be a shape other than the above powder and porous beads. For example, in the case of cellulose, in addition to the form as cellulose powder, it can be used as a non-woven fabric. As the support, for example, cellulose powder, cellulose nanofiber (CNF), cellulose nanocrystal (CNC), chitin nanofiber, or chitosan nanofiber can be used. A typical CNC has a width of about 4 nm to 100 nm and a length of about 5 μm, and a typical CNC has a width of about 10 nm to 50 nm and a length of about 100 nm to 500 nm. Have Further, for example, [BiNFi-s], which is a nanofiber derived from cellulose, chitin, and chitosan manufactured by Sugino Machine, may be used. “BiNFi-s” has a diameter of about 20 nm and a length of several μm.

  Further, a polymer material can be used as the support. As polymer materials (polymer materials) that can be used as a support, there are materials made from natural polymers or synthetic polymers.

  Examples of natural polymers include starch-based (starch-acrylonitrile graft polymer hydrolyzate, starch-acrylic acid graft polymer, starch-styrene sulfonic acid graft polymer, starch-vinyl sulfonic acid graft polymer, starch-acrylamide graft. Polymers), cellulose (cellulose-acrylonitrile graft polymer, cellulose-styrene sulfonic acid graft polymer, crosslinked carboxymethyl cellulose), other polysaccharides (hyaluronic acid, agarose), protein (collagen, etc.), etc. Can be used.

  A polymer material made from a synthetic polymer is excellent in terms of mechanical strength and chemical stability. Synthetic polymers include, for example, polyvinyl alcohol (polyvinyl alcohol cross-linked polymer, PVA water absorption gel, freeze / thaw elastomer, etc.), acrylic (sodium polyacrylate cross-linked, sodium acrylate-vinyl alcohol copolymer, polyacrylonitrile) Saponified polymers), other addition polymers (maleic anhydride polymers, vinylpyrrolidone copolymers, etc.), polyethers (polyethylene glycol-diacrylate cross-linked polymers, etc.), condensation polymers (esters) Polymer, amide polymer) and the like can be used.

  The above-described polymer material can be used by appropriately processing into various shapes such as powder, bead, fiber, film, and non-woven fabric depending on the application.

  Using the above support as an immobilization carrier, for example, by modifying the enzyme to a support by a carrier binding method (physical adsorption method, ion binding method, covalent bond method), dispersing the enzyme on the support, Make it. Alternatively, for example, a lattice-shaped support is used and modified with an enzyme by a comprehensive method (lattice type), or the enzyme is dispersed in the network structure of the support to produce an enzyme body. .

  As a support on which the enzyme is immobilized, a polymer gel (polymer gel) may be used. Examples of such gels include Metrogel (MeTro Hydrogel; registered trademark), gelatin methacrylate (GelMA) hydrogel, gelatin, alginic acid hydrogel, sodium polyacrylate gel, mebiol gel (Ikeda) made of a protein called tropoelastin. Mebiolgel), room temperature solidified / stretchable hydrogel AQUAJOINT (registered trademark; trade name, manufactured by Nissan Chemical Industries, Ltd.), silica gel, agar, κ-carrageenan, polyacrylamide gel can be used. .

  An enzyme body is prepared by dispersing and modifying an enzyme in the above gel by, for example, a binding method (physical adsorption method, ion binding method, covalent bonding method), or by encapsulating the enzyme in a gel by an inclusion method. be able to.

[Porous membrane]
A porous membrane can be provided between the gas phase and the non-aqueous phase, or between the non-aqueous phase and the aqueous phase. Moreover, the non-aqueous phase can be divided into a plurality of non-aqueous phases by installing a porous membrane in the non-aqueous phase.

  As described above, a porous cathode electrode or an anode electrode may be used as the porous film, but a porous film separate from the cathode electrode and the anode electrode may be used. In this case, an inorganic or organic material such as glass, ceramics, or a polymer can be used as the material for the porous film, in addition to the electrode material described above.

  Further, it can be appropriately modified with a water repellent film, a hydrophilic film, a modified film, metal nanoparticles or the like at an appropriate position on the surface of the porous film. When the cathode electrode and the anode electrode also serve as a porous film, these electrodes may be similarly modified with a water repellent film, a hydrophilic film, a modified film, metal nanoparticles, or the like.

  When a porous membrane is installed between the aqueous phase and the porous membrane facing the aqueous phase, a permeation-separation membrane, a proton exchange membrane (PEM) or a Protic ionic liquid membrane is further provided. Also good.

<Water phase>
The carbon dioxide immobilization apparatus according to the embodiment includes an aqueous phase including an extract containing water.

  The extract can contain a buffer. The type and concentration of the buffer can be appropriately selected depending on the type of reaction system. An appropriately conditioned buffer can serve as a proton source for the reduction reaction.

  The extract is not particularly limited, and an aqueous solution that can rapidly extract the reaction product can be used as the extract. As the extract, it is desirable to use an aqueous solution capable of continuously supplying protons to the non-aqueous phase.

<Separator>
The carbon dioxide immobilization apparatus according to the embodiment may further include a separator. The location where the separator is installed can be changed according to the design of the apparatus. For example, it is possible to install a separator between a non-aqueous phase and an aqueous phase, or to install a separator adjacent to an electrode that also serves as a porous membrane. It is not limited to.

  The separator is preferably selected from materials that can selectively permeate the substrate and fuel. The separator is preferably selected from insulating materials.

  A separator can be selected from a stand-alone type and a composite type. For example, a composite separator that is modified with a porous membrane and integrated with the porous membrane can be used. Alternatively, a single separator that is not integrated with the porous membrane can be used.

  For example, when the separator is installed between the gas phase and the non-aqueous phase, carbon dioxide is selectively permeated, and an intermediate product (for example, formic acid or formaldehyde) or a final product (for example, fuel such as methanol). ), For example, a hydrophobic separator can be used.

  On the other hand, when the separator is installed, for example, between the non-aqueous phase and the aqueous phase, for example, the movement of proton ions from the aqueous phase to the non-aqueous phase and the diffusion and extraction of fuel from the non-aqueous phase to the aqueous phase In view of the above, it is desirable to select from proton exchange membranes and hydrophilic materials.

  The separator can be selected from polymer membranes. As the polymer film, a polymer film composed of a homogeneous film, a composite film, and an asymmetric film can be selected. A Nafion (registered trademark) membrane can also be used as a separator. In particular, it is desirable to use a permeation-separation membrane that selectively allows water, reaction products, and ions to pass therethrough and does not pass enzymes, enzyme bodies, ionic liquids, and the like.

  The thickness of the separator can be appropriately selected according to the permeation rate of carbon dioxide in the gas phase and the permeation rate of ions and molecules in the non-aqueous phase or the aqueous phase.

  Below, the example of the concrete structure of the carbon dioxide fixing device which concerns on embodiment is demonstrated, referring drawings. In addition, the same code | symbol shall be attached | subjected to a common structure through embodiment, and the overlapping description is abbreviate | omitted. Each figure is a schematic diagram for promoting the explanation of the embodiment and its understanding, and its shape, dimensions, ratio, etc. are different from the actual apparatus, but these are the explanations described above and known techniques. The design can be changed as appropriate.

  In FIG. 1, the schematic of the carbon dioxide fixing device of an example which concerns on the 1st aspect of embodiment is shown. The carbon dioxide immobilization apparatus shown in the figure is an example of a carbon dioxide immobilization apparatus that reduces carbon dioxide to a final product through a three-stage enzyme reaction.

  A carbon dioxide immobilization apparatus 100 shown in FIG. 1 includes a first block 110, a second block 120, and a third block 130.

  The first block 110 includes a first cell body C1 that accommodates the gas phase 111, the non-aqueous phase 112, and the aqueous phase 113 or has a space in which they are accommodated. The 2nd block 120 contains the 2nd cell main body C2 which accommodates the space which accommodates the supply water phase 123a, the non-aqueous phase 122, and the extraction water phase 123b, or accommodates them inside. The third block 130 includes a third cell main body C3 that houses the supply aqueous phase 133a, the non-aqueous phase 132, and the extracted aqueous phase 133b, or has a space in which they are contained.

  Here, the non-aqueous phase 112 of the first block 110, the non-aqueous phase 122 of the second block 120, and the non-aqueous phase 132 of the third block 130 are respectively a first non-aqueous phase and a second non-aqueous phase. It can be regarded as an aqueous phase and a third non-aqueous phase.

  Further, the water phase 113 in the first block 110 and the supply water phase 123a in the previous stage of the second block 120 can be considered together as the first water phase. The extracted aqueous phase 123b in the subsequent stage of the second block 120 and the supply aqueous phase 133a in the preceding stage of the third block 130 can be considered as the second aqueous phase. The extracted aqueous phase 133b in the subsequent stage of the third block 130 can be regarded as the third aqueous phase.

  More specifically, in the first block 110 of the carbon dioxide immobilization apparatus 100, the gas phase 111 containing carbon dioxide, the non-aqueous phase 112 containing ionic liquid, and the first reaction product 15 from the non-aqueous phase 112. The aqueous phase 113 containing the extraction liquid for extracting the water is accommodated in the first cell body C1.

  In the first block 110, the cathode electrode 115 and the anode electrode 114 are provided in contact with the non-aqueous phase 112. The cathode electrode 115 and the anode electrode 114 are electrodes made of a porous material. The enzyme body 11 is supported on the cathode electrode 115. The carrying form of the enzyme body 11 is schematically shown.

  The first block 110 further includes an electrical control unit 151. The electrical control unit 151 may be a cell voltage control unit that controls a voltage (or potential) applied to the cathode electrode 115 and the anode electrode 114. Alternatively, the electrical control unit 151 may be a current control unit that controls a current flowing between the cathode electrode 115 and the anode electrode 114. The electrical control unit 151 may include a mode that functions as a cell voltage control unit and a mode that functions as a current control unit.

  The cathode electrode 115 is, for example, a cathode (cathode) and is also disposed between the non-aqueous phase 112 and the aqueous phase 113 and functions as a porous film. The anode electrode 114 is, for example, an anode (anode), and is installed between the gas phase 111 and the non-aqueous phase 112 to function as a porous film. The cathode electrode 115 and the anode electrode 114 divide the internal space of the first cell body C1 into three chambers: a chamber for the gas phase 111, a chamber for the non-aqueous phase 112, and a chamber for the aqueous phase 113. Partitioning.

  The cathode electrode 115 shown in FIG. 1 is installed between the non-aqueous phase 112 and the aqueous phase 113, but can be installed at any other location in the non-aqueous phase 112. For example, it is desirable to install the cathode electrode 115 in the vicinity of the interface between the non-aqueous phase 112 and the aqueous phase 113 so as not to contact the aqueous phase 113. Similarly, the anode electrode 114 can also be installed at any location in the non-aqueous phase 112. When the anode electrode 114 is installed between the non-aqueous phase 112 and the gas phase 111, a part of the anode electrode may be exposed to the gas phase. Moreover, the cathode electrode 115 and the anode electrode 114 can each impregnate a part of the non-aqueous phase 112.

  The first block 110 includes a reference electrode 116 in addition to the cathode electrode 115 and the anode electrode 114. FIG. 1 shows an example in which a reference electrode 116 is provided in the aqueous phase 113 to form a three-electrode system. The position where the reference electrode 116 is installed is not limited to the position shown in the figure. For example, the reference electrode 116 can be installed at an arbitrary position in the aqueous phase 113. Alternatively, the reference electrode 116 may be set at an arbitrary position in the non-aqueous phase 112. However, care should be taken that the reference electrode 116 does not contact the cathode electrode 115 or the anode electrode 114.

  When the reference electrode 116 is provided in the aqueous phase 113, it may not be considered. However, when the reference electrode 116 is provided in the non-aqueous phase 112, for example, a reference electrode for an organic solvent is preferably used as the reference electrode 116.

  A four-electrode system may be designed by using two reference electrodes. For example, two reference electrodes can correspond to the cathode electrode 115 and the anode electrode 114, respectively. Alternatively, the reference electrode may be omitted and a two-electrode system may be designed.

  In the case of the two-electrode system, the cell voltage control unit (electric control unit 151) controls the voltage applied to the electrodes. On the other hand, for example, in the case of a three-electrode system, the cell voltage control unit controls the potential applied to the electrodes.

  A pseudo reference electrode may be used instead of the reference electrode. Since the design of the pseudo reference electrode such as the position where the pseudo reference electrode is installed can be the same as the design of the reference electrode, the details are omitted.

The enzyme body 11 shown in FIG. The enzyme 12 catalyzes a reaction for reducing the carbon dioxide (CO ₂ ) supplied to the non-aqueous phase 112 to the first reaction product 15.

  The carbon dioxide contained in the gas phase 111 is selectively absorbed by the ionic liquid contained in the non-aqueous phase 112, whereby the carbon dioxide is supplied to the non-aqueous phase 112. Carbon dioxide is reduced to the first reaction product 15 by the catalytic action of the enzyme 12 of the enzyme body 11. The cathode electrode 115 donates electrons to the enzyme 12 and reduces the oxidized enzyme of the enzyme 12 that is oxidized when the carbon dioxide is reduced to the reduced enzyme of the enzyme 12.

  Next, the generated first reaction product 15 is extracted by the extract in the aqueous phase 113. Thereafter, the first reaction product 15 is introduced into the second block 120. Alternatively, for example, when the first reaction product 15 itself, which is an intermediate product, is a useful substance, the first reaction product 15 can be recovered and used in the aqueous phase 113. In addition, when collect | recovering the 1st reaction product 15, you may provide the extraction port for taking out a collection | recovery, for example in the part adjacent to the water phase 113 of the cell main body C1 (illustration omitted).

The flow rate of the gas phase is determined by the air flow control valve 53 installed in the gas inlet (CO ₂ inlet) 51 and the gas outlet (CO ₂ outlet) 52 or the gas inlet path connected to the gas inlet 51. It can be controlled by a pump (not shown) installed in

  Further, for example, the pressure of the gas phase 111 can be controlled by controlling the air flow control valve 53 or a pump installed in the gas introduction path. By increasing the pressure of the gas phase 111, the supply of carbon dioxide to the non-aqueous phase 112 can be promoted.

  In the carbon dioxide immobilization apparatus 100 shown in FIG. 1, the gas phase 111 is accommodated in the first cell main body C1, but the first cell main body C1 does not accommodate the gas phase 111. You can also. For example, in the carbon dioxide immobilization apparatus 100, the non-aqueous phase 112 may be in contact with the air directly or via the porous anode electrode 114 or other porous membrane.

  The flow rate of the extract in the aqueous phase 113 is set in the liquid flow control valve 57 installed in the extract introducing port 55 and the extract extracting port 56 or in the external flow path 54 connected to the extract introducing port 55. It can be controlled by a pump (not shown).

  In the second block 120 of the carbon dioxide fixing device 100, a supply aqueous phase 123a into which the aqueous phase 113 from which the first reaction product 15 has been extracted is introduced, a non-aqueous phase 122 containing an ionic liquid, and a non-aqueous phase. An extracted aqueous phase 123b containing an extraction liquid for extracting the second reaction product 25 from 122 is accommodated in the second cell main body C2. Note that the ionic liquid contained in the non-aqueous phase 122 of the second block 120 may be the same as or different from the ionic liquid contained in the non-aqueous phase 112 of the first block 110. Good.

  In the second block 120, the cathode electrode 125 and the anode electrode 124 are provided in contact with the non-aqueous phase 122. The cathode electrode 125 and the anode electrode 124 are electrodes made of a porous material. The enzyme body 21 is supported on the cathode electrode 125. The carrying form of the enzyme body 11 is schematically shown.

  The second block 120 further includes an electrical control unit 152. The electrical control unit 152 may be a cell voltage control unit that controls a voltage (or potential) applied to the cathode electrode 125 and the anode electrode 124. Alternatively, the electrical control unit 152 may be a current control unit that controls a current flowing between the cathode electrode 125 and the anode electrode 124. The electrical control unit 152 may include a mode that functions as a cell voltage control unit and a mode that functions as a current control unit.

  The cathode electrode 125 is, for example, a cathode (cathode) and is installed between the non-aqueous phase 122 and the extraction aqueous phase 123b and functions as a porous membrane. The anode electrode 124 is, for example, an anode (anode) and is disposed between the supply aqueous phase 123a and the non-aqueous phase 122 and functions as a porous film. Further, the cathode electrode 125 and the anode electrode 124 also serve as a support substrate for the non-aqueous phase 122. The cathode electrode 125 and the anode electrode 124 include three chambers in the internal space of the second cell body C2, that is, a chamber for the supply aqueous phase 123a, a chamber for the non-aqueous phase 122, and a chamber for the extraction aqueous phase 123b. It is divided into and.

  The cathode electrode 125 and the anode electrode 124 shown in FIG. 1 are installed between the supply aqueous phase 123a and the non-aqueous phase 122 and between the non-aqueous phase 122 and the extraction aqueous phase 123b, respectively. And the anode electrode 124 can be installed at any other location in the non-aqueous phase 122. For example, it is desirable to install the cathode electrode 125 in the vicinity of the interface between the non-aqueous phase 122 and the extracted aqueous phase 123b so as not to contact the aqueous phase. Similarly, the anode electrode 124 can also be installed at any place in the non-aqueous phase 122. For example, it is desirable to install the anode electrode 124 in the vicinity of the interface between the non-aqueous phase 122 and the supply aqueous phase 123a so as not to contact the aqueous phase.

  The second block 120 includes a reference electrode 126 in addition to the cathode electrode 125 and the anode electrode 124. Since the design of the reference electrode 126 in the second block 120 such as the position where the reference electrode 126 is installed can be the same as the design of the reference electrode 116 in the first block 110, the details are omitted.

  In the case of a two-electrode system, the cell voltage control unit (electric control unit 152) controls the voltage applied to the electrodes. On the other hand, for example, in the case of a three-electrode system, the cell voltage control unit controls the potential applied to the electrodes.

  A pseudo reference electrode may be used instead of the reference electrode. Since the design of the pseudo reference electrode such as the position where the pseudo reference electrode is installed can be the same as the design of the reference electrode, the details are omitted.

  When the extract containing the first reaction product 15 is introduced from the aqueous phase 113 of the first block 110 into the supply aqueous phase 123a of the second block 120, the ionic liquid contained in the non-aqueous phase 122 causes the first By selectively extracting the reaction product 15, the first reaction product 15 is supplied to the non-aqueous phase 122. The first reaction product 15 is reduced to the second reaction product 25 by the catalytic action of the enzyme 22 of the enzyme body 21. The cathode electrode 125 donates electrons to the enzyme 22 and reduces the oxidized enzyme of the enzyme 22 to the reduced enzyme of the enzyme 22.

  Next, the produced | generated 2nd reaction product 25 is extracted with the extract in the extraction water phase 123b. Thereafter, the second reaction product 25 is introduced into the third block 130. Alternatively, for example, when the second reaction product 25 itself, which is an intermediate product, is a useful substance, the second reaction product 25 can be recovered and used as it is in the extracted aqueous phase 123b. In addition, when collect | recovering the 2nd reaction product 25, you may provide the extraction port for taking out a collection | recovery, for example in the part adjacent to the extraction water phase 123b of the cell main body C2 (illustration omitted).

  Similar to the first block 110, the flow rate of the extraction liquid in the supply water phase 123 a and the extraction water phase 123 b of the second block 120 is the external flow connected to the liquid flow control valve 57 and the extraction liquid inlet 55. It can be controlled by a pump (not shown) installed in the passage 54.

  In the third block 130 of the carbon dioxide immobilization apparatus 100, a supply aqueous phase 133a into which the extracted aqueous phase 123b of the second block 120 from which the second reaction product 25 has been extracted is introduced, and a non-aqueous solution containing an ionic liquid. The phase 132 and the extraction aqueous phase 133b containing the extraction liquid for extracting the third reaction product 35 from the non-aqueous phase 132 are accommodated in the third cell body C3. The ionic liquid contained in the non-aqueous phase 132 of the third block 130 is transferred to the ionic liquid contained in the non-aqueous phase 112 of the first block 110 and the non-aqueous phase 122 of the second block 120. It may be the same as or different from the ionic liquid contained.

  In the third block 130, the cathode electrode 135 and the anode electrode 134 are provided in contact with the non-aqueous phase 132. The cathode electrode 135 and the anode electrode 134 are electrodes made of a porous material. An enzyme body 31 is carried on the cathode electrode 135. The carrying form of the enzyme body 31 is schematically shown.

  The third block 130 further includes an electrical control unit 153. The electrical control unit 153 may be a cell voltage control unit that controls a voltage (or potential) applied to the cathode electrode 135 and the anode electrode 134. Alternatively, the electrical control unit 153 may be a current control unit that controls a current flowing between the cathode electrode 135 and the anode electrode 134. The electrical control unit 153 may include a mode that functions as a cell voltage control unit and a mode that functions as a current control unit.

  The cathode electrode 135 is, for example, a cathode (cathode) and is installed between the non-aqueous phase 132 and the extraction aqueous phase 133b and functions as a porous membrane. The anode electrode 134 is, for example, an anode (anode), and is disposed between the supply aqueous phase 133a and the non-aqueous phase 132 and functions as a porous film. Further, the cathode electrode 135 and the anode electrode 134 also serve as a support substrate for the non-aqueous phase 132. The cathode electrode 135 and the anode electrode 134 have three internal spaces in the third cell body C3, that is, a chamber for the supply aqueous phase 133a, a chamber for the non-aqueous phase 132, and a chamber for the extraction aqueous phase 133b. It is divided into and. The cathode electrode 135 and the anode electrode 134 shown in FIG. 1 are installed between the supply aqueous phase 133a and the non-aqueous phase 132 and between the non-aqueous phase 132 and the extraction aqueous phase 133b, respectively. The electrode 135 and the anode electrode 134 can be installed at any other location in the non-aqueous phase 132. The cathode electrode 135 and the anode electrode 134 in the third block can be installed in the non-aqueous phase 132 with the same configuration as the cathode electrode 125 and the anode electrode 124 in the second block.

  The third block 130 includes a reference electrode 136 in addition to the cathode electrode 135 and the anode electrode 134. Since the design of the reference electrode 136 in the third block 130 such as the position where the reference electrode 136 is installed can be the same as the design of the reference electrode 116 in the first block 110, the details are omitted.

  In the case of a two-electrode system, the cell voltage control unit (electric control unit 153) controls the voltage applied to the electrodes. On the other hand, for example, in the case of a three-electrode system, the cell voltage control unit controls the potential applied to the electrodes.

  A pseudo reference electrode may be used instead of the reference electrode. Since the design of the pseudo reference electrode such as the position where the pseudo reference electrode is installed can be the same as the design of the reference electrode, the details are omitted.

  When the extraction liquid containing the second reaction product 25 is introduced from the extraction aqueous phase 123b of the second block 120 into the supply aqueous phase 133a of the third block 130, the ionic liquid contained in the non-aqueous phase 132 causes the second As the reaction product 25 is selectively absorbed, the second reaction product 25 is supplied to the non-aqueous phase 132. The second reaction product 25 is reduced to the third reaction product 35 by the catalytic action of the enzyme 32 of the enzyme body 31. The cathode electrode 135 donates electrons to the enzyme 32 and reduces the oxidized enzyme of the enzyme 32 to the reduced enzyme of the enzyme 32.

  Next, the generated third reaction product 35 is extracted by the extract in the extracted aqueous phase 133b. Thereafter, the third reaction product 35 is recovered as a final product. For example, the third reaction product 35 as a final product can be recovered from the extraction liquid outlet 56.

  Further, as shown in the drawing, the extract derived from the extracted aqueous phase 133 b of the third block 130 can be reintroduced into the aqueous phase 113 of the first block 110 through the external flow path 54. At this time, the third reaction product 35 may be concentrated and recovered by providing, for example, a device (not shown) for concentrating the third reaction product 35 in the external channel 54. In addition, the pH of the extract can be adjusted appropriately by connecting a pH adjustment line (not shown) to the external channel 54 through which the extract flows.

  Similar to the first block 110 and the second block 120, the flow rate of the extraction liquid in the supply water phase 133 a and the extraction water phase 133 b of the third block 130 is supplied to the liquid flow control valve 57 and the extraction liquid inlet 55. It can be controlled by a pump (not shown) installed in the connected external flow path 54.

  In the carbon dioxide immobilization apparatus 100 shown in FIG. 1, each of the first block 110, the second block 120, and the third block 130 is an electric control unit (151, 152, 153) that controls the operation of the electrodes. However, it is also possible to use one electrical control unit that performs overall control of electrode operations for all of the first block 110, the second block 120, and the third block 130.

  In FIG. 2, the schematic of the carbon dioxide fixing apparatus of another example which concerns on the 1st aspect of embodiment is shown.

  A carbon dioxide immobilization apparatus 200 shown in FIG. 2 includes a first block 210, a second block 220, and a third block 230, similarly to the carbon dioxide immobilization apparatus 100 of FIG. As in the case of FIG. 1, the first block 210 of the carbon dioxide immobilization apparatus 200 includes a gas phase 211, a non-aqueous phase 212, and an aqueous phase 213. On the other hand, the second block 220 includes a non-aqueous phase 222 and an aqueous phase 223, and the third block 230 includes a non-aqueous phase 232 and an aqueous phase 233.

  Moreover, as shown in FIG. 2, the 1st block 210, the 2nd block 220, and the 3rd block 230 are accommodated in the single cell main body C10.

  Here, the non-aqueous phase 212 of the first block 210, the non-aqueous phase 222 of the second block 220, and the non-aqueous phase 232 of the third block 230 are respectively the first non-aqueous phase and the second non-aqueous phase. It can be regarded as an aqueous phase and a third non-aqueous phase. In addition, the water phase 213 of the first block 210, the water phase 223 of the second block 220, and the water phase 233 of the third block 230 are respectively connected to the first water phase, the second water phase, and the third water phase 233. It can be regarded as an aqueous phase.

  In the case of the carbon dioxide fixing device 200, the aqueous phase 213 of the first block 210 is adjacent to the non-aqueous phase 222 of the second block 220 as shown in FIG. After the extract contained in the aqueous phase 213 of the first block 210 extracts the first reaction product 15 generated in the first block, the extraction liquid continuously enters the non-aqueous phase 222 of the second block 220. The first reaction product 15 is directly supplied and becomes a substrate for the enzyme reaction in the second block 220. Similarly, the aqueous phase 223 of the second block 220 is adjacent to the non-aqueous phase 232 of the third block 230. After the extract contained in the aqueous phase 223 of the second block 220 extracts the second reaction product 25 generated in the second block, the non-aqueous phase 232 of the third block 230 is subsequently extracted. The second reaction product 25 is directly supplied and becomes a substrate for the enzyme reaction in the third block 230.

  The configuration of the carbon dioxide immobilization apparatus 200 of FIG. 2 can produce the third reaction product 35, which is the final product of the multistage enzyme reaction, with high production efficiency with a more compact design.

  2, the method for controlling the flow rate of the gas phase 211, the method for recovering the final product (third reaction product) from the aqueous phase 233 of the third block 230, and the method for adjusting the pH are the same as those in FIG. is there. The flow rate of the extract is controlled by a liquid flow control valve 57 installed at the extract introduction port 55.

  Further, a cathode electrode 215 and an anode electrode 214 are provided so as to be in contact with the non-aqueous phase 212. Similarly, a cathode electrode 225 and an anode electrode 224 are disposed so as to be in contact with the non-aqueous phase 222. Further, a cathode electrode 235 and an anode electrode 234 are provided so as to be in contact with the non-aqueous phase 232. Each of the cathode electrodes (215, 225, 235) serving as the cathode and the anode electrodes (224, 234) serving as the anode, excluding the anode electrode 214 in the non-aqueous phase 212, is shown in FIG. In the block 210, the second block 220, and the third block 230), the non-aqueous phase and the aqueous phase are separated. The anode electrode 214 that is an anode is disposed between the non-aqueous phase 212 and the gas phase 211.

  The installation method of the cathode electrode (215, 225, 235) in each non-aqueous phase (212, 222, 232) shown in FIG. 2 is the same as that in FIG. In the case of the carbon dioxide immobilization apparatus 200 of FIG. 2, the operation of the cathode electrode and the anode electrode is the same for all the blocks (the first block 210, the second block 220, and the third block 230) as shown. The two electrical control units 250 can perform overall control. Or you may control operation | movement of an electrode separately by the electrical control part installed in each of each block like FIG.

  The first block 210 includes a reference electrode 216. The second block 220 includes a reference electrode 226. The third block 230 includes a reference electrode 236. The position where the reference electrode (216, 226, 236) is installed in each block (210, 220, 230) in the carbon dioxide fixing device 200 is the position in each block (110, 120, 130) in the carbon dioxide fixing device 100. Since the same design as the reference electrodes (116, 126, 136) can be adopted, the details are omitted. Further, a pseudo reference electrode may be used instead of the reference electrode. Since the design of the pseudo reference electrode such as the position where the pseudo reference electrode is installed can be the same as the design of the reference electrode, the details are omitted.

  In FIG. 3, the schematic of the carbon dioxide fixing device of an example which concerns on the 2nd aspect of embodiment is shown.

  As shown in FIG. 3, the carbon dioxide immobilization apparatus 300 of an example of the second aspect according to the embodiment includes a gas phase 311, a first non-aqueous phase 312, a second non-aqueous phase 322, 3 non-aqueous phases 332 and a single cell body C10 containing the aqueous phase 333 are included. The first non-aqueous phase 312 and the second non-aqueous phase 322 are partitioned by an electrode 315 that also serves as a porous film. The second non-aqueous phase 322 and the third non-aqueous phase 332 are partitioned by an electrode 325 that also serves as a porous film.

  The electrode 315 carries the enzyme body 11. The enzyme body 11 includes an enzyme 12. The electrode 325 carries the enzyme body 21. The enzyme body 21 includes an enzyme 22. The electrode 335 carries the enzyme body 31. The enzyme body 31 includes an enzyme 32. The form of carrying the enzyme body on each electrode is schematically shown.

  The volume (quantity) of each non-aqueous phase depends on the activity and catalytic efficiency of the enzyme (12, 22, 32) in order to efficiently advance the production of intermediate products and final products of each stage in the multistage enzyme reaction. Alternatively, the amount of the enzyme bodies (11, 21, 31) carried on the electrodes (315, 325, 335) can be adjusted as appropriate.

  In the carbon dioxide fixing device 300, when the electrode 315 operates as a cathode, the electrode 304 functions as an anode. For electrode 325 operating as a cathode, electrode 315 becomes the anode. Further, the electrode 325 is an anode with respect to the electrode 335 operating as a cathode.

  Application of a potential (voltage) to the electrode pair can be sequentially performed from left to right. In other words, first, a potential (voltage) for a certain period of time is applied between the electrode 315 that operates as a cathode and the electrode 304 that functions as an anode, so that carbon dioxide is reduced. After that, a potential for a certain time is applied between the electrode 325 serving as the cathode and the electrode 315 serving as the anode. Next, a potential for a predetermined time is applied between the electrode 335 serving as a cathode and the electrode 325 serving as an anode.

  As described above, the potential (or voltage) can be intermittently and sequentially applied to the pair of electrodes (304, 315, 325, 335) a plurality of times. In this case, an electrode that acts as a cathode electrode when applying a potential (or voltage) at one time can act as an anode electrode when applying a potential (or voltage) at another time. In the above example, the example in which the application of the potential (or voltage) is sequentially shifted from the left side to the right side has been described. However, the order in which the potential (or voltage) is applied to the electrode pair is not limited to this order. For example, the order of application may be controlled according to the progress of the enzyme reaction at each stage.

  As described above, when a potential (voltage) is applied to each electrode pair, a time difference is provided, and the potential enzyme is repeatedly and sequentially applied to regenerate the oxidized enzyme in each enzyme body to the reduced enzyme. The enzyme reaction can be maintained.

  As shown in FIG. 3, for example, the application of the potential (voltage) to each electrode pair can be switched by switching the circuit by turning on and off the switch. In addition, each electrode of each electrode pair may be electrically connected to a cell voltage control unit (electrical control unit) via an independent electric line (not shown). In this case, a potential (voltage) can be applied to each electrode pair with a predetermined time difference by automatic control using the cell voltage control unit.

  When the current control unit is used, for example, the current can flow between each electrode pair or the current can be turned off by switching the circuit by turning the switch on and off. In addition, each electrode of each electrode pair may be electrically connected to the current control unit via an independent electric line. In this case, the current can be caused to flow with a predetermined time difference between the electrode pairs by automatic control using the current control unit.

  Further, there may be a pair of electrodes, that is, a total of two electrodes. As a specific example, in the case of the carbon dioxide immobilization apparatus 300, installation of two electrodes among the electrodes (304, 315, 325, 335) shown in FIG. 3 can be omitted. For example, the electrodes 315 and 325 are omitted, and only the electrodes 304 and 335 are installed. Alternatively, the electrode 304 and the electrode 325 are omitted and only the electrode 315 and the electrode 335 are installed. There may be a pair of electrodes, that is, two or more electrodes, and the number of electrodes installed in the apparatus is not particularly limited.

  When changing the position of the electrode installed at the interface of each non-aqueous phase, different non-aqueous phases may be in direct contact with each other. For example, the electrode can be placed at any position in the non-aqueous phase. Furthermore, when changing the position of the electrode that also serves as the porous membrane, for example, a separator may be provided between different non-aqueous phases. Alternatively, the installation of a porous film such as a separator may be omitted in order to promote diffusion of molecules such as reaction products and ions.

  When a gas containing carbon dioxide is introduced into the gas phase 311, carbon dioxide is selectively supplied to the first non-aqueous phase 312 by the action of the ionic liquid contained in the first non-aqueous phase 312. Carbon dioxide is reduced to the first reaction product 15 by the catalytic action of the enzyme 12 of the enzyme body 11.

  The generated first reaction product 15 is further diffused into the second non-aqueous phase 322 and is reduced to the second reaction product 25 by the enzyme 22 of the enzyme body 21. The generated second reaction product 25 is further diffused into the third non-aqueous phase 332 and is reduced to the third reaction product 35 by the enzyme 32 of the enzyme body 31.

  Next, the generated third reaction product 35 is extracted by the extract in the aqueous phase 333. Thereafter, the third reaction product 35 is recovered as a final product. For example, the third reaction product 35 as a final product can be recovered from the extraction liquid outlet 56.

  Further, as shown in the drawing, after extracting the extract containing the third reaction product from the aqueous phase 333, it can be introduced again from the inlet of the aqueous phase 333 through the external channel 54. At that time, for example, by providing a device (not shown) for concentrating the third reaction product 35 in the external channel 54, the third reaction product can be concentrated and recovered. In addition, the pH of the extract can be adjusted appropriately by connecting a pH adjustment line (not shown) to the external channel 54 through which the extract flows.

In the carbon dioxide immobilization apparatus 300, as in the example of the first aspect of the embodiment (FIGS. 1 and 2), the flow rate of the gas phase is changed between the gas inlet (CO ₂ inlet) 51 and the gas outlet (CO ₍₂ outlets) 52 can be controlled by an airflow control valve 53 installed in the gas outlet 52 and a pump (not shown) installed in a gas introduction path connected to the gas introduction port 51. Further, similarly to the carbon dioxide immobilization apparatus 100 shown in FIG. 1, the gas phase 311 may not be accommodated in the cell body C10, and the first non-aqueous phase 312 may be exposed to the atmosphere, for example.

  The flow rate of the extraction liquid in the aqueous phase 333 is also connected to the liquid flow control valve 57 installed at the extraction liquid inlet 55 and the extraction liquid outlet 56 and the extraction liquid inlet 55 as in the first embodiment. It can be controlled by a pump (not shown) installed in the external flow path 54.

  In FIG. 4, the schematic of the carbon dioxide fixing apparatus of another example which concerns on the 2nd aspect of embodiment is shown. 5 and 6 show schematic diagrams of modifications of the carbon dioxide immobilization apparatus shown in FIG.

  The basic configuration of the carbon dioxide fixing device 400 shown in FIG. 4 is the same as that of the carbon dioxide fixing device 300 of FIG. 3, but in the case of FIG. 4, the first non-aqueous phase 412 and the second non-aqueous phase In addition to the aqueous phase 422 and the third non-aqueous phase 432, a fourth non-aqueous phase 402 is further included. Although omitted from the drawings for the sake of simplicity of explanation, each of the electrodes 415, 425, and 435 carries one or more kinds of enzyme bodies. The electrode 414 in contact with the fourth non-aqueous phase 402 does not carry an enzyme body. In addition, although omitted from the drawings for the sake of simplicity of explanation, the electrodes 415, 425, 435, and 414 illustrated by the electrical control unit (cell voltage control unit and / or current control unit) are respectively illustrated. Electrically connected.

  The fourth non-aqueous phase 402 provided in the previous stage of the first non-aqueous phase 412 can contain an ionic liquid that functions to absorb and concentrate carbon dioxide from the gas phase 411. By providing such a fourth non-aqueous phase 402, carbon dioxide can be stably supplied to the first non-aqueous phase 412.

  The fourth non-aqueous phase 402 may be made into a gel-like non-aqueous phase by gelling the ionic liquid in the fourth non-aqueous phase 402, and may be supported on the surface of the electrode 414, for example. By doing so, the contact area between the gas phase 411 and the fourth non-aqueous phase can be increased, and the carbon dioxide absorption efficiency by the fourth non-aqueous phase 402 can be improved. On the other hand, when the ionic liquid contained in the fourth non-aqueous phase 402 is not gelled and is made into a liquid non-aqueous phase, for example, a porous material is formed between the gas phase 411 and the fourth non-aqueous phase 402. By providing the film, the gas phase 411 and the fourth non-aqueous phase 402 can be partitioned. Or it can also be set as the form which does not accommodate the gaseous phase 411 in the cell main body C10.

  Further, as illustrated, a separator 441 may be provided adjacent to the electrode 414 provided between the first non-aqueous phase 412 and the fourth non-aqueous phase 402. As the separator 441, it is desirable to use a separator that can selectively transmit carbon dioxide.

  The electrode 414 and the separator 441 may not be adjacent to each other. For example, as shown in FIG. 5, the separator 441 is installed between the first non-aqueous phase 412 and the fourth non-aqueous phase 402, and the electrode 414 is connected between the gas phase 411 and the fourth non-aqueous phase 402. Can be installed between.

  In addition, the electrode 414 can be provided at any place in the fourth non-aqueous phase 402. For example, as shown in FIG. 6, the electrode 414 can be installed in the fourth non-aqueous phase 402 along the exterior member of the cell body C <b> 10. Note that, depending on the form in which the electrode 414 is installed, for example, a lead wire 419 as illustrated can be used in order to ensure electrical connection with the electrode 414. The electrode 414 may be provided at any place in the first non-aqueous phase 412.

  Further, as shown in FIGS. 4, 5, and 6, a separator 442 may be provided between the third non-aqueous phase 432 and the aqueous phase 433. As the separator 442, it is desirable to use a separator that can selectively permeate the final product (third reaction product) of the multistage reduction reaction of carbon dioxide. Moreover, when the proton source which supplies a proton is contained in the water phase 433, it is desirable that the separator 442 can transmit protons.

  Also, the carbon dioxide immobilization apparatus 400 shown in FIGS. 4, 5, and 6 is similar to the carbon dioxide immobilization apparatus 300 of FIG. 3 in the configuration of a plurality of non-aqueous phases and the arrangement of electrodes. As the method of applying a potential (voltage) to each cathode and anode, the same conditions and procedures as in FIG. 3 can be used.

  In FIG. 7, the schematic of the carbon dioxide fixing apparatus of another example which concerns on the 2nd aspect of embodiment is shown.

  The carbon dioxide immobilization apparatus 500 shown in FIG. 7 is similar to the carbon dioxide immobilization apparatus 300 shown in FIG. 3. The gas phase 511, the first non-aqueous phase 512, the second non-aqueous phase 522, 3 non-aqueous phases 532 and an aqueous phase 533.

  As shown in the drawing, the gas phase 511 flows through a gas flow path constituted by an outer cylinder 551 and an intermediate cylinder 552. Each of the first non-aqueous phase 512, the second non-aqueous phase 522, and the third non-aqueous phase 532 has a cylindrical shape. These cylindrical non-aqueous phases are stored so as to be arranged in a direction perpendicular to the central axis (not shown) of the cylinder, that is, in the radial direction of the cylinder. Specifically, the first non-aqueous phase 512 is installed on the outermost side of the cylindrical shape. The third non-aqueous phase 532 is installed on the innermost side of the cylindrical shape. The second non-aqueous phase 522 is installed between the first non-aqueous phase 512 and the third non-aqueous phase 532. The aqueous phase 533 flows through the inner cylinder 553 as a liquid flow path.

  The outer cylinder 551 itself may be permeable to a gas containing carbon dioxide, or may not be permeable to gas. When the outer cylinder 551 does not have gas permeability, it is desirable to provide a gas inlet or the like for introducing a gas containing carbon dioxide between the outer cylinder 551 and the intermediate cylinder 552.

  As the intermediate cylinder 552 and the inner cylinder 553, for example, a cylinder obtained using a porous film material such as a separator can be used.

  As the intermediate tube 552, it is desirable to use a material having permeability to carbon dioxide. Further, as the inner cylinder 553, it is desirable to use a material having permeability to the reduction product of carbon dioxide. For example, a permeation-separation membrane can be used.

  In FIG. 7, the first non-aqueous phase 512 and the gas phase 511 are in contact via the intermediate cylinder 552, but the intermediate cylinder 552 may be omitted. Similarly, in FIG. 7, the third non-aqueous phase 532 and the aqueous phase 533 are in contact via the inner cylinder 553, but the inner cylinder 553 may be omitted.

  A pair of or more electrodes (514, 515, 525, 535) are installed in the carbon dioxide immobilization apparatus 500 of FIG. As in the method shown in FIG. 3, an insulating separator can be provided between the electrodes (not shown) so that the electrodes do not electrically short-circuit each other. If the non-aqueous phase is thick and there is no possibility of an electrical short circuit due to contact between the electrodes, the separator need not be provided. Each of the electrode 515, the electrode 525, and the electrode 535 carries one or more kinds of enzyme bodies, but the enzyme bodies are omitted from the drawing in order to simplify the explanation as in FIG.

  The potential (voltage) application method to the cathode electrode can follow the application method shown in FIG. 3 (not shown).

  Further, although omitted from the drawings for the sake of simplicity of explanation, an electrical control unit (cell voltage control unit and / or current control unit) is electrically connected to each of the illustrated electrodes.

  In the carbon dioxide fixing device 500, in a gas flow path composed of an outer cylinder 551 and an intermediate cylinder 552, a gas phase 511 (gas containing carbon dioxide) is formed along the central axis (not shown) of the outer cylinder 551 and the intermediate cylinder 552. ) Is distributed. Further, in the inner cylinder 553 as a liquid channel, the aqueous phase 533 (extracted liquid) is circulated along the central axis (not shown) of the inner cylinder 553.

  FIG. 7 shows a form in which the flow path outside the non-aqueous phase is a gas phase and the flow path inside the non-aqueous phase is a water phase. For example, the flow path inside the non-aqueous phase is The gas phase can be used, and the flow path outside the non-aqueous phase can be the aqueous phase.

  As described above, the carbon dioxide immobilization apparatus 500 includes the flow path (inner cylinder 553) through which the aqueous phase 533 flows, and the non-aqueous phase and the aqueous phase 533 are perpendicular to the flow direction of the aqueous phase 533. Next to each other. The carbon dioxide immobilization apparatus 500 includes a flow path (outer cylinder 551 and intermediate cylinder 552) through which the gas phase 511 flows, and the non-aqueous phase is in the direction perpendicular to the flow direction of the gas phase 511. Next to 511.

  Since the interface between the water phase 533 and the electrode 535 can be provided along the length of the flow path through which the water phase 533 flows, the contact area between the water phase 533 and the electrode 535 can be increased. Therefore, the efficiency of supplying the final product from the electrode 535 which is a conductive carrier carrying the enzyme body to the aqueous phase 533 can be improved, and the recovery rate can be increased.

  Further, since the interface between the gas phase 511 and the non-aqueous phase can be provided along the length of the flow path through which the gas phase 511 flows, the contact area between the gas phase 511 and the non-aqueous phase can be increased. . Therefore, the efficiency of supplying carbon dioxide to the non-aqueous phase can be improved.

Using a carbon dioxide immobilization apparatus provided with a cylindrical water phase 533, a non-aqueous phase (512, 522, 532), an electrode (514, 515, 525, 535) and a gas phase 511 as shown in FIG. For example, methanol (CH ₃ OH) can be generated from carbon dioxide (CO ₂ ) by a multistage enzyme reaction represented by the following formula.

  In each of the three stages of the enzymatic reaction for producing methanol from the left side to the right side in the above formula, the electrode 515 provided on the outermost side among the electrodes carrying the enzyme body shown in FIG. The electrode body 525 and the enzyme body contained in each of the electrodes 535 disposed on the innermost side among the electrodes are sequentially performed.

  In order to efficiently promote the production of fuel by the multistage enzyme reaction, the volume (amount) of each non-aqueous phase and the amount of the enzyme supported on the electrode can be appropriately adjusted according to the activity and catalytic efficiency of the enzyme. it can.

The first reaction product (formic acid; HCOOH) generated in the first enzyme reaction (first reduction reaction) catalyzed by the enzyme body supported by the electrode 515 using carbon dioxide as a substrate is second non-concentrated by concentration diffusion. It diffuses into the aqueous phase 522 and becomes a substrate for the second enzyme reaction (second reduction reaction). Similarly, the second reaction product (formaldehyde; HCHO) produced by the second enzyme reaction catalyzed by the enzyme body supported by the electrode 525 using the first reaction product as a substrate is one of the cylinders by concentration diffusion. It diffuses into the third non-aqueous phase 532 on the inner side and becomes a substrate for the third enzyme reaction (third reduction reaction). The third reaction product (methanol; CH ₃ OH) produced by the third enzyme reaction catalyzed by the enzyme supported by the electrode 535 using the second reaction product as a substrate, that is, the final product is an inner cylinder. It is extracted and recovered by the extraction liquid (aqueous phase 533) flowing in 553.

  FIG. 8 shows a schematic diagram of another example of the carbon dioxide immobilization apparatus according to the second aspect of the embodiment. FIG. 9 is a schematic view showing a state in the middle of manufacture of an example of a member included in the carbon dioxide immobilization apparatus shown in FIG. Specifically, FIG. 9A, FIG. 9B, and FIG. 9C show an example of a non-aqueous phase production state that can be provided in the apparatus.

  A carbon dioxide immobilization apparatus 600 shown in FIG. 8 includes a gas phase 611, an enzyme membrane electrode assembly (EMEA) 601, and an aqueous phase 633.

  The gas phase 611 flows in a gas flow path defined by the outer cylinder 651 and the intermediate cylinder 652. Alternatively, the intermediate cylinder 652 may be omitted, and in this case, the gas flow path is defined by the outer cylinder 651 and the enzyme membrane electrode assembly 601.

  The enzyme membrane electrode assembly 601 includes a first non-aqueous phase 612, a second non-aqueous phase 622, a third non-aqueous phase 632, an electrode 614, and an electrode 615. One or both of the electrode 614 and the electrode 615 is a conductive carrier that carries one or more enzyme bodies. The enzyme membrane electrode assembly 601 has a shape in which a plurality of layered portions are wound a plurality of times so as to be aligned in the radial direction, and the first nonaqueous phase 612, the second nonaqueous phase 622, 3 non-aqueous phases 632 are respectively arranged in the plurality of layered portions. The electrode 614 and the electrode 615 also function as a porous film. That is, in the enzyme membrane electrode assembly 601, the electrode 614 and the electrode 615 are wound porous membranes. Note that the inside of the intermediate tube 652 can be filled with a nonaqueous solvent such as an ionic liquid, for example.

  Further, the central portion of the enzyme membrane electrode assembly 601, that is, the space around the winding axis can be used as the flow path. The aqueous phase 633 flows in the flow path constituted by the enzyme membrane electrode assembly 601 having the winding structure as described above. Or you may provide the inner cylinder 653 as a flow path of the water phase 633 so that it may illustrate.

  As can be seen from the state in the middle of production of the enzyme membrane electrode assembly 601 shown in FIGS. 9A to 9C, specifically, the state before winding, the enzyme membrane electrode assembly 601 includes each non-aqueous solution. In addition to the phase and each electrode, a separator 641 and a separator 642 are included. The separator 641 is provided between the electrode 615 and the electrode 614. In the enzyme membrane electrode assembly 601 configured as shown in FIGS. 9A and 9C, the separator 641 is in contact with the surface of the electrode 614 facing the electrode 615. In the example shown in FIG. 9B, the separator 641 is in contact with both the electrode 614 and the electrode 615. The position where the separator 641 is provided is not limited to the illustrated position as long as it is between the electrode 615 and the electrode 614. For example, the separator 641 may be in contact with the surface of the electrode 615 (the surface facing the electrode 614). Note that both the electrode 615 and the electrode 614 are porous electrodes.

  Furthermore, the enzyme membrane electrode assembly 601 includes another separator 642 so that the electrode 615 and the electrode 614 do not contact after winding. That is, in the enzyme membrane electrode assembly 601 after winding, the members excluding each non-aqueous phase, that is, the electrode 614, the separator 641, the electrode 615, and the separator 642 are arranged in this order. In the enzyme membrane electrode assembly 601 after winding, the separators 641 and the separators 642 need only be alternately disposed between the electrodes 614 and 615, and the positions where the separators 642 are provided are not limited to the illustrated positions. . For example, in FIGS. 9A to 9C, the separator 642 is provided so as to be in contact with the electrode 615. By providing the separator 642 on the right side of the electrode 614 (the right side of each figure), the separator The electrode 614 may be positioned between the separator 642 and the separator 642. In FIG. 8, the separator 641 and the separator 642 are not shown.

  As shown in FIGS. 9A to 9C, the widths of the electrodes 615 and 614 (the length of the spiral shape after winding) may be the same.

  As shown in FIGS. 9A to 9C, the first non-aqueous phase 612, the second non-aqueous phase 622, and the third non-aqueous phase 632 are the enzyme membrane electrodes in a state before winding. In the joined body 601, the enzyme membrane electrode assembly 601 is disposed in order in the winding direction. Each of these non-aqueous phases is, for example, a porous membrane laminate in which an electrode 614 and a separator 641 are laminated when an enzyme membrane electrode assembly 601 having the configuration shown in FIG. Further, each non-aqueous phase material (ionic liquid) can be provided by a method such as a spray method (spraying method), a coating method, a reduced pressure method, a casting method, or an impregnation method. By sequentially laminating the electrode 615 and the separator 642 on each non-aqueous phase provided on the electrode 614, the enzyme membrane electrode assembly 601 configured as shown in FIG. 9A can be obtained. In addition, each non-aqueous phase can be gelatinized or hardened by the method mentioned later as needed, for example.

  Alternatively, for example, in the case of producing the enzyme membrane electrode assembly 601 having the configuration shown in FIG. 9B, a porous membrane laminate in which an electrode 614, a separator 641, an electrode 615, and a separator 642 are laminated. Each non-aqueous phase material can be provided on the substrate by the method described above.

  Alternatively, the first non-aqueous phase 612, the second non-aqueous phase 622, and the third non-aqueous phase 632 are stacked in the stacking thickness direction in which the electrode 614, the separator 641, the electrode 615, and the separator 642 are stacked. It may be impregnated throughout. In the case of such a configuration, for example, each non-aqueous phase material can be provided on each of the electrode 614, the separator 641, the separator 642, and the electrode 615 before lamination. Alternatively, as shown in FIGS. 9 (a) to 9 (c), after each non-aqueous phase is provided on the porous film laminate or between the layers, the winding pressure is reduced when the laminate is wound. By appropriate control, the non-aqueous phase can penetrate the separator 641, the separator 642, and the electrode 615.

  In addition, a part of each of the first non-aqueous phase 612, the second non-aqueous phase 622, and the third non-aqueous phase 632 is a porous film (electrode 614, separator 641, electrode 615, and separator 642). And a part of which is provided on the surface of the porous membrane. That is, in the enzyme membrane electrode assembly 601, a part of each non-aqueous phase is on the surface of the porous membrane or between the porous membranes as shown in FIGS. 9 (a) to 9 (c). While present, other parts may be impregnated into the porous membrane. For example, in the case of the configuration of FIG. 9C, the first non-aqueous phase 612, the second non-aqueous phase 622, and the third non-aqueous phase 632 are each interposed between the separator 641 and the electrode 615. There may be portions present, portions present on the face of the separator 642, and portions impregnated in the electrodes (614, 615) and the separator (641, 642).

  As described above, when the non-aqueous phase is gelled or cured, for example, an ionic liquid as a non-aqueous phase material, in addition to the enzyme body, a gelling agent or a polymer material, a binder, a crosslinking agent, A carrier (an immobilizing carrier such as a support or a conductive carrier) can be mixed. Thus, the electrode 614, the separator 641, the electrode 615, and the separator 642 were laminated by mixing a gelling agent or a polymer material, a crosslinking agent, a binder, etc., and a porous film laminate was obtained. Later, the non-aqueous phase can be gelled or cured. Further, after winding, the non-aqueous phase can be gelled or cured.

  When the electrodes (614, 615) are impregnated with the non-aqueous phase, for example, the enzyme body can be supported on the electrode by allowing the ionic liquid containing the enzyme body to permeate the electrode. In addition, for example, the enzyme body can be supported on the electrode by allowing the ionic liquid containing the enzyme body to permeate the electrode, or applying the ionic liquid to the electrode surface, followed by gelling or curing. Alternatively, the enzyme body or the enzyme body / conductive carrier may be preliminarily dispersed and supported on the electrode before providing the non-aqueous phase.

  For example, as shown in FIG. 9C, each non-aqueous phase (612, 622, 632) exists as a layer between the electrode 614 and the electrode 615, and the layer has a sufficient thickness. Since there is no possibility that the electrode 614 and the electrode 615 come into contact without providing the separator (641, 642) on the electrode surface, the separator (641, 642) can be omitted.

  The electrodes (614, 615) include enzyme bodies containing different enzymes in respective portions where the first non-aqueous phase 612, the second non-aqueous phase 622, and the third non-aqueous phase 632 are provided. obtain. Or the enzyme body containing the same 1 or more types of enzyme between each part may be included. When each part in the electrode (614, 615) contains a different enzyme body, that is, when the enzyme reaction in each part is different, it is desirable to take the following treatment.

  For example, in order to reliably perform the first enzyme reaction (first reduction reaction), after the portion including the first enzyme body surrounds the layer including the second enzyme body in the porous membrane laminate. However, it is desirable to set the width of the portion supporting the first enzyme body so as to cover a part of the portion including the first enzyme body. That is, it is desirable that the layer containing the first enzyme body partially overlap.

  Similarly, in order to ensure that the second enzyme reaction (second reduction reaction) is performed, the portion containing the second enzyme body in the porous membrane laminate surrounded the layer containing the third enzyme body. After that, it is desirable to set the width of the portion supporting the second enzyme body so as to cover a part of the portion including the second enzyme body. That is, it is desirable that the layer containing the second enzyme body partially overlap.

  In this way, the multi-stage enzyme reaction is performed by taking a treatment such that different enzyme bodies included in each layered portion are supported so as to be aligned in the radial direction of the wound shape of the enzyme membrane electrode assembly 601. These reaction steps can be carried out reliably and sequentially.

  In addition, when performing a multistage enzyme reaction, the volume (quantity) of each non-aqueous phase and the electrode (conductivity) depending on the activity and catalytic efficiency of the enzyme in order to efficiently produce the final product by the multistage enzyme reaction. The amount of the enzyme in the carrier) can be adjusted as appropriate.

  In the carbon dioxide immobilization apparatus 600 shown in FIG. 8, as in FIG. 7, carbon dioxide is passed through the enzyme membrane electrode assembly 601 by flowing the gas phase 611 through the gas flow channel located on the outer periphery of the enzyme membrane electrode assembly 601. Can supply. Carbon dioxide is reduced by the enzyme reaction in the enzyme membrane electrode assembly 601 to generate a reaction product. In addition, the reaction product can be recovered from the enzyme membrane electrode assembly 601 by flowing the aqueous phase 633 through the liquid flow path which is the center of the enzyme membrane electrode assembly 601.

  The carbon dioxide immobilization apparatus shown in FIG. 8 can generate a reaction product such as fuel from carbon dioxide by a multistage enzyme reaction. For example, as in FIG. 7, methanol can be produced from carbon dioxide by a multistage enzyme reaction.

  In FIG. 10, the schematic of the carbon dioxide fixing apparatus of another example which concerns on the 1st aspect of embodiment is shown.

  A carbon dioxide fixing apparatus 700 shown in FIG. 10 is an example of a batch type apparatus, unlike the flow type apparatus shown in FIGS. 1-8. The carbon dioxide immobilization apparatus 700 includes a gas phase 711, a non-aqueous phase 712, and an aqueous phase 713. Each of these phases is accommodated in the cell body C10.

  The gas phase 711 contains a gas containing carbon dioxide. In FIG. 10, a chamber that accommodates the gas phase 711 is provided in the cell main body C10. The chamber for accommodating the gas phase 711 may not be provided in the cell main body C10. For example, the non-aqueous phase 712 may be exposed to a gas containing carbon dioxide such as the atmosphere, and the gas may be used as the gas phase 711. In addition, when providing the chamber which accommodates the gas phase 711 in the cell main body C10, for example, the gas main body C10 is provided with a gas introduction port and a vent which communicate with this chamber, and the gas containing carbon dioxide is supplied to the gas phase 711. It is desirable to be able to introduce it.

  The non-aqueous phase 712 includes, for example, an ionic liquid, similar to the first block 110 in the apparatus shown in FIG. Further, a cathode electrode 715 and an anode electrode 714 are provided in the non-aqueous phase 712. The cathode electrode 715 carries the enzyme body 11. The carrying form of the enzyme body 11 is schematically shown. The enzyme body 11 includes an enzyme 12.

  Carbon dioxide immobilization device 700 further includes a current control unit. The electrical control unit may be a cell voltage control unit that controls a voltage (or potential) applied to the cathode electrode 715 and the anode electrode 714. Alternatively, the electrical control unit may be a current control unit that controls a current flowing between the cathode electrode 715 and the anode electrode 714. The electrical control unit may include a mode that functions as a cell voltage control unit and a mode that functions as a current control unit.

  Note that the cathode electrode 715 and the anode electrode 714 are not limited to the arrangement shown in FIG. 10 as long as the cathode electrode 715 and the anode electrode 714 are in contact with each other and are not electrically short-circuited but in contact with the non-aqueous phase 712. For example, the position where these electrodes are installed may be the interface between the gas phase 711 and the non-aqueous phase 712 or the interface between the non-aqueous phase 712 and the aqueous phase 713. In the case where the cathode electrode 715 and / or the anode electrode 714 are installed at the interface between different phases, it is desirable to use a porous electrode material for the cathode electrode 715 and / or the anode electrode 714.

  In addition, since the non-aqueous phase 712 as the ionic liquid has a higher specific gravity than the aqueous phase, when using the ionic liquid as it is, a porous support film or a porous substrate is provided between the non-aqueous phase 712 and the aqueous phase 713. May be provided. Further, as shown in the figure, the separator 741 may be installed together with these or alone.

  The aqueous phase 713 includes an extract that extracts the first reaction product 15 from the non-aqueous phase 712. Moreover, it is preferable to provide a mechanism (not shown) for mechanically stirring the extract.

  In the carbon dioxide immobilization apparatus 700 of FIG. 10, the carbon dioxide supplied from the gas phase 711 to the non-aqueous phase 712 is the action of the enzyme 12 as in the first block 110 included in the carbon dioxide immobilization apparatus 100 of FIG. To produce the first reaction product 15. The first reaction product 15 is supplied to the aqueous phase 713.

  After the concentration of the first reaction product 15 reaches a certain value, the aqueous phase 713 can be recovered, for example, from the outlet provided in the lower part of the cell body C10.

  The enzyme reaction for reducing carbon dioxide in the non-aqueous phase 712 may be a single stage or a multistage enzyme reaction.

  In the case of a single-stage reaction, formic acid is produced as the first reaction product 15 by using formate dehydrogenase as the enzyme 12, for example.

  In the case of a multistage reaction, a plurality of different enzyme bodies are supported on the cathode electrode 715. For example, in the case of producing methanol by reducing carbon dioxide by a three-stage reaction, a first enzyme body containing formate dehydrogenase, a second enzyme body containing formaldehyde dehydrogenase, and a third enzyme body containing alcohol dehydrogenase are used as the cathode electrode. 715 is carried.

  In this example, carbon dioxide supplied to the non-aqueous phase 712 is reduced by the first enzyme body to produce formic acid. Formic acid quickly moves to the second enzyme and is reduced to formaldehyde. Similarly, formaldehyde quickly moves to the third enzyme body and is reduced to methanol as the final product.

  When using a multistage reaction using a plurality of different enzyme bodies, it is preferable to adjust so that the extract in the aqueous phase 713 can selectively extract the final product. For example, in the above example, it is preferable to adjust the extract so that methanol is selectively supplied to the aqueous phase 713.

  In addition, the first block 110, the second block 120, and the third block 130 included in the carbon dioxide immobilization apparatus 100 illustrated in FIG. 1 can be replaced with the carbon dioxide immobilization apparatus 700 illustrated in FIG. In this case, an enzyme body to be included in the non-aqueous phase 712 is appropriately selected according to the enzyme reaction performed in each block.

  In FIG. 11, the schematic of the single cell which comprises the stack type carbon dioxide fixation apparatus of an example which concerns on embodiment is shown.

  FIG. 11A is a schematic plan sectional view of the single cell type carbon dioxide immobilization apparatus 800 as viewed from below. FIG. 11B is a schematic cross-sectional view of the single cell type carbon dioxide immobilization apparatus 800 as viewed from the side.

  In the single cell type carbon dioxide immobilization apparatus 800 shown in FIGS. 11A and 11B, a gas phase 811, an electrode 814 (anode electrode), a non-aqueous phase 812, an electrode 815 (cathode electrode), The water phase 813 is arranged in order from the bottom. In the illustrated example, each phase and each electrode have a planar shape.

  The electrode 814 is a porous electrode, and for example, carbon paper can be used as the electrode 814. The electrode 814 is connected to an electrode plate 861 that serves as a flow path / lead wire for the gas phase 811. In the illustrated example, a large number of spacers 816 that define the flow path of the gas phase 811 are provided between the electrode 814 and the electrode plate 861. The spacer 816 can be omitted. For example, the spacer 816 may play a role of preventing deformation of the electrode 814 due to stress such as pressure, but the spacer 816 can be omitted if the electrode 814 has sufficient strength.

  As shown in FIG. 11A, when a gas containing carbon dioxide is introduced from the gas introduction port 51 into the flow path of the gas phase 811, the gas passes through the gap between the electrode plate 861 and the electrode 814 and is planar. It flows along the direction and is discharged from the gas discharge port 52. When carbon dioxide passes through the gap between the electrode plate 861 and the electrode 814, at least a part of the carbon dioxide further passes through the electrode 814 and is supplied to the non-aqueous phase 812, and becomes a substrate for the enzyme reaction in the non-aqueous phase 812.

  As the medium of the non-aqueous phase 812, it is preferable to use an ionic liquid that can selectively absorb carbon dioxide. In this case, gas that has not been absorbed by the non-aqueous phase 812, for example, gas other than carbon dioxide, is discharged from the gas outlet 52.

  The electrode 815 is a porous electrode, and for example, carbon paper can be used as the electrode 815. According to another example, the electrode 815 is a sheet-like electrode provided with a large number of slits, or a porous electrode. Although omitted from the drawing for simplification, the electrode 815 carries an enzyme. The electrode 815 is connected to an electrode plate 862 serving as a flow path / lead wire for the water phase 813.

  Similar to the flow of the gas containing carbon dioxide shown in FIG. 11 (a), when the extract is introduced into the flow path of the aqueous phase 813 from the liquid inlet (not shown), the extract is It passes through the gap between 862 and the electrode 815, flows along the plane direction, and is led out from the liquid outlet.

  Carbon dioxide supplied from the gas phase 811 to the non-aqueous phase 812 is reduced by an enzymatic reaction to generate a reaction product. The reaction product is supplied to the aqueous phase 813 and recovered.

  Furthermore, a temperature sensor may be installed in the single cell (carbon dioxide fixing device 800), or a heat insulating material 870 may be provided outside the single cell. The temperature of the single cell is measured by the temperature sensor, and based on the measurement result, the temperature can be controlled by, for example, a temperature control mechanism so that the conditions are appropriate for the enzyme reaction. Further, by providing the heat insulating material 870, the enzyme reaction can be performed under a more stable temperature condition.

  In FIG. 11, the example which provided the heat insulating material 870 was shown. The shape of the heat insulating material 870 is not particularly limited. For example, the heat insulating material 870 may have a slab-shaped form. The heat insulating material 870 may be omitted.

  Each phase and each electrode are combined by the jig J1, and an integral cell is constructed. In order to prevent an electrical short circuit, for example, the jig J1 can be made of a material having electrical insulation. Alternatively, in view of properties such as strength, for example, when a conductive material such as a metal or an alloy is used as the jig J1, an insulating film is provided on the surface of the jig J1, for example. It is desirable to prevent short circuit.

  The spacer 816 can be formed from, for example, a conductive material. In this case, the electrode 814 and the electrode plate 861 can be electrically connected via the spacer 816. Alternatively, as the electrode plate 861, for example, a projection in which a projection is formed by molding may be used, and this projection may be used in place of the spacer 816. In this case, the electrode 814 and the electrode plate 861 are directly electrically connected by the protrusion.

  On the other hand, instead of electrically connecting the electrode 814 and the electrode plate 861 via the spacer 816, a conducting wire or the like for electrical connection may be separately provided. In this case, it is desirable to use an insulating material as the material of the spacer 816. In addition, it is desirable to select a material for the spacer 816 as appropriate in accordance with the component and temperature of the gas supplied to the gas phase 811.

  Examples of a material that can be used for the spacer 816 include highly conductive materials such as stainless steel, nickel, copper, aluminum, tungsten, a conductive polymer, and graphite. Examples of other materials include non-conductive materials such as plastic, ceramics, and glass.

  By defining the flow path in the gas phase 811 with the spacer 816, the time for the flowing gas to flow along the surface of the electrode 814 can be made sufficiently long. For example, the spacer 816 is installed like a partition so that the flow path from the gas inlet 51 to the gas outlet 52 becomes longer. By doing so, the amount of carbon dioxide supplied from the flowing gas to the non-aqueous phase 812 through the electrode 814 can be increased. The shape and arrangement of the spacer 816 are not limited to those shown in the drawing as long as a flow path capable of supplying carbon dioxide to the non-aqueous phase 812 can be secured. For example, the spacer 816 may have a dot shape instead of a slit shape. It is desirable to appropriately design the shape and arrangement of the spacers 816 according to the conditions of the supply source of the gas introduced into the gas introduction port 51 and the conditions such as the flow rate, temperature, and pressure of the introduced gas.

  Similarly, in the water phase 813, a large number of spacers 817 that define the flow path of the extract can be provided between the electrode 815 and the electrode plate 862. The spacer 817 can be formed from a conductive material, for example. In this case, the electrode 815 and the electrode plate 862 can be electrically connected via the spacer 817. Alternatively, as the electrode plate 862, for example, a projection on which a projection is formed by molding may be used, and this projection may be used in place of the spacer 817. In this case, the electrode 815 and the electrode plate 862 are directly electrically connected by the protrusion.

  On the other hand, instead of electrically connecting the electrode 815 and the electrode plate 862 via the spacer 817, a conducting wire or the like for electrical connection may be separately provided. In this case, it is desirable to use an insulating material as the material of the spacer 817. In addition, it is desirable to appropriately select the material of the spacer 817 according to the components of the extract.

  Examples of a material that can be used for the spacer 817 include highly conductive materials such as stainless steel, nickel, copper, aluminum, tungsten, a conductive polymer, and graphite. Examples of other materials include non-conductive materials such as plastic, ceramics, and glass.

  By defining the flow path in the aqueous phase 813 by the spacer 817, the time for the flowing extract to flow along the surface of the electrode 815 can be sufficiently increased. For example, the spacer 817 is installed like a partition so that the flow path from the liquid inlet to the liquid outlet is longer. By doing so, the amount of the reaction product extracted from the non-aqueous phase 812 by the extract can be increased. The shape and arrangement of the spacer 817 are not limited as long as a flow path capable of extracting the reaction product from the non-aqueous phase 812 can be secured. For example, the spacer 817 may have a slit shape or a dot shape. It is desirable to appropriately design the shape and arrangement of the spacers 817 according to conditions such as the flow rate, temperature, and pressure of the extract introduced into the liquid inlet.

  Note that the spacer 817 may also play a role of preventing deformation of the electrode 815 due to stress such as pressure. If the electrode 815 has sufficient strength, the spacer 817 may be omitted. On the other hand, when the spacer 817 is omitted, it is difficult to control the flow of the extract because there is no flow path for the extract. Therefore, it is preferable to provide a spacer 817 to define the flow path of the extract in the aqueous phase 813.

  Further, for example, a gasket made of a material such as a resin may be provided at the ends of the electrode plate 861 and the electrode plate 862. The gasket can prevent leakage of carbon dioxide and the extract in the single cell.

  FIG. 12 shows a schematic diagram of an example of a stack type carbon dioxide immobilization apparatus according to the embodiment.

  When the single cell type carbon dioxide immobilization apparatus 800 shown in FIG. 11 is stacked, a stacked type carbon dioxide immobilization apparatus 900 shown in FIG. 12 is obtained. In addition, in FIG. 12, the carbon dioxide fixing apparatus 800 shown in FIG. 11 is simplified and drawn. In FIG. 12, reference numeral 871 indicates a gasket.

  A stacked carbon dioxide fixing device 900 shown in FIG. 12 includes a plurality of single cells (carbon dioxide fixing device 800). These single cells are stacked in the thickness direction to form a stack structure, and are integrated by jigs J2 and J3. Between adjacent unit cells, an electrical insulating sheet (not shown) is provided to prevent electrical contact between the electrode plate 861 of one unit cell and the electrode plate 862 of the other unit cell.

  The plurality of single cells are installed along the stacking direction, for example, with the jig J2 disposed at both ends of the stack type structure in the stacking direction and the single cells stacked therebetween. The jig J3 is integrated by connecting the jigs J2 at both ends. The jig J2 can be, for example, a planar member. The jig J3 can be, for example, a columnar member. In order to prevent an electrical short circuit, for example, the jigs J2 and J3 can be made of a material having electrical insulation. Alternatively, in view of properties such as strength, for example, when a conductive material such as a metal or an alloy is used as the jigs J2 and J3, an insulating coating is provided on the surfaces of the jigs J2 and J3. Therefore, it is desirable to prevent an electrical short circuit.

  The gas inlet 51 and the gas outlet 52 of each single cell are connected to a common gas inlet path and a common gas outlet path (both not shown), respectively. Alternatively, the gas discharge port 52 of one single cell may be connected to the gas introduction port 51 of another single cell to configure a gas flow path connected in series. Thus, by changing the connection method of the gas flow paths, the gas phase can be made to flow simultaneously to all the single cells, or the gas phase can be made to flow sequentially to each single cell.

  Further, the liquid inlet and the liquid outlet of each single cell are connected to a common liquid inlet and a common liquid outlet (both not shown), respectively. Alternatively, the liquid outlet of one single cell may be connected to the liquid inlet of another single cell to configure a liquid channel connected in series. In this way, by changing the connection method of the liquid flow path, it is possible to simultaneously flow the extract (water phase) to all the single cells, or to sequentially flow the extract (water phase) to each single cell. it can.

  Further, in the stack composed of these single cells, electrode plates 861 in each single cell are electrically connected to each other by electrode lead wires 961. Similarly, electrode plates 862 in a plurality of single cells are electrically connected by electrode lead wires 962. When the electrode lead 961 and the electrode lead 962 are electrically connected to the cell voltage controller, respectively, and a voltage is applied between the electrode leads 961 and 962 by the cell voltage controller, the electrode plates 861 and 862 of each single cell. A voltage is applied between them.

  Instead of connecting the electrode lead wire 961 and the electrode lead wire 962 to the cell voltage control unit, they may be electrically connected to the current control unit. For example, the current control unit can control the current flowing between the electrode plates 861 and 862 of each single cell. Or you may use the electrical control part which can serve as a cell voltage control part and a current control part.

  In FIG. 12, the electrode plates 861 in each single cell are electrically connected in parallel, but the electrode plates 861 may be electrically connected in series. Similarly, in FIG. 12, the electrode plates 862 are electrically connected in parallel, but the electrode plates 862 may be electrically connected in series.

  According to the apparatus having this configuration, carbon dioxide can be immobilized with high efficiency.

  The carbon dioxide immobilization apparatus according to the first embodiment includes a non-aqueous phase containing an ionic liquid, a conductive carrier installed in contact with the non-aqueous phase, and an enzyme body carried on the conductive carrier. And an aqueous phase containing an extract containing water. The enzyme body catalyzes the reduction reaction of carbon dioxide or its reduction product supplied to the non-aqueous phase. The reaction product of the reduction reaction is supplied to the aqueous phase. According to the apparatus having this configuration, carbon dioxide can be immobilized with high efficiency.

(Second Embodiment)
According to the second embodiment, a fuel production system including a carbon dioxide supply unit, a fuel generation unit, and an extract recovery unit is provided.

  FIG. 13 is a scheme showing an example fuel production system according to the second embodiment.

  By installing the carbon dioxide immobilization device according to the first embodiment in the fuel generation unit of the system shown in FIG. 13, the production of fuel from carbon dioxide can be automatically controlled.

  Dotted lines (external electrical lines E1-E6) in FIG. 13 indicate electrical system circuits. On the other hand, the solid line (L1-L5) in FIG. 13 indicates a gas phase or liquid phase piping system.

  Each wiring (E1-E6) in the electric system circuit functions as an external electric line for supplying power, and also functions as an external signal line for transmitting a signal for controlling each member such as an electric signal.

  In order to apply a voltage from the outside to the carbon dioxide fixing device installed in the fuel generation unit 82, a control unit 91 and an electrical control unit 95 are connected via external electric lines E2 and E3. In addition, a controller 91 and a temperature controller 94 are connected to the fuel generator 82 via external electric lines E2 and E4.

  The control unit 91 in the electric system 90 is supplied to the electric control unit 95 according to the temperature condition information from the sensor installed in the carbon dioxide fixing device, the carbon dioxide supply information of the carbon dioxide supply unit 81, and the like. A voltage condition applied to the carbon fixing device or a current condition in the carbon dioxide fixing device is indicated. Further, the control unit 91 in the electrical system 90 instructs the extraction liquid supply unit 83 on the condition for the supply flow rate of the extraction liquid in accordance with the carbon dioxide supply information of the carbon dioxide supply unit 81 and the like. The control unit 91 instructs the temperature control unit 94 to control the temperature of the fuel generation unit 82.

  The electrical control unit 95 may be a cell voltage control unit that controls a voltage applied to the carbon dioxide fixing device. Alternatively, the electrical control unit 95 may be a current control unit that controls a current in the carbon dioxide fixing device. The electrical control unit 95 may include a mode that functions as a cell voltage control unit and a mode that functions as a current control unit. The electric control unit 95 can switch the operation mode between the mode as the cell voltage control unit and the mode as the current control unit based on an instruction from the control unit 91.

  The carbon dioxide supply unit 81 may have a function of controlling the pressure of a gas containing carbon dioxide. For example, the control unit 91 detects the gas pressure in the carbon dioxide supply unit 81 and instructs pressure control via the external electric line E5 (external signal line) as necessary.

  In the extract recovery unit 84, fuel is recovered from the extract, and the pH of the extract is adjusted. Thereafter, the extract is supplied to the extract supply unit 83 and reused.

  The extract supply unit 83 serves to temporarily store the extract supplied from the extract recovery unit 84, and supplies the extract to the fuel generation unit 82 at a predetermined flow rate in accordance with a command from the control unit 91. .

  Furthermore, by using the extract supply tank 85, the condition of the extract in the extract supply unit 83 can be changed and adjusted.

  The fuel production system according to the second embodiment includes a fuel generation unit including the carbon dioxide fixing device according to the first embodiment. Therefore, this system can immobilize carbon dioxide with high efficiency.

[Example]
Hereinafter, an example will be described as an example of a specific design of the carbon dioxide immobilization apparatus according to the embodiment.

(Example 1)
The carbon dioxide immobilization apparatus of Example 1 is a carbon dioxide immobilization apparatus including a first block, a second block, and a third block, like the carbon dioxide immobilization apparatus 100 shown in FIG. Moreover, in the carbon dioxide fixing device of Example 1, methanol as a fuel is produced from carbon dioxide as an example of a reaction for fixing carbon dioxide.

  In Example 1, methanol is produced by the following three-stage enzymatic reaction.

The first enzymatic reaction, Formate Dehydrogenase; using (F _ate DH FDH) as an enzyme, is from carbon dioxide, a substrate reaction that produces formic acid (formic acid or formate).

The second enzymatic reaction produces formaldehyde in the presence of the enzyme Formaldehyde dehydrogenase ( _Fald DH), using formic acid or formate as a substrate.

  In the third enzyme reaction, formaldehyde is used as a substrate to produce methanol in the presence of the enzyme Alcohol dehydrogenase (ADH).

  Enzymes related to the three enzyme reactions are modified to a cathode electrode as a conductive carrier arranged in each reaction block.

  The enzyme is modified to a conductive carrier (cathode electrode) by the physical method described below.

Formate dehydrogenase (F _ate DH) is dissolved in a pH 6 buffer (0.02 M, phosphate buffer). The obtained aqueous solution of F _ate DH is added in an appropriate amount to a 0.1 M octane solution of sodium 1,2-bis (2-ethylhexylcarbonyl) -1-ethanesulfonate (Aerosol OT; AOT). The above solution is sufficiently stirred to prepare an enzyme / AOT / octane reverse micelle solution.

  Next, graphite is put into an enzyme / AOT / octane reverse micelle solution to prepare an organic ink solution containing the enzyme / reverse micelle and graphite.

A carbon paper electrode (composite electrode) having a dense layer (Micro Porous Layer) on one main surface is separately prepared. The organic ink liquid containing the reverse micelle and graphite prepared previously is put in a low-pressure spray gun, and sprayed uniformly on one side of the carbon paper electrode (the main surface without the dense layer). After spraying the organic ink liquid, the carbon paper electrode is left in the draft chamber to volatilize the octane solution. Thus, _Fate DH is modified as the first enzyme to the first conductive carrier.

Using F _ald DH instead of F _ate DH as the second enzyme, the second conductive carrier is modified in the same manner. In addition, ADH is used as the third enzyme instead of _Fate DH, and the third conductive carrier is modified in the same manner.

  An ionic liquid composed of 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) amide (abbreviation: EMIMTFSI) is used for each non-aqueous phase of the three blocks. PH 6 and a concentration of 50 mM phosphate buffer are used for the extract of each aqueous phase of the three blocks.

  The first conductive carrier, the second conductive carrier, and the third conductive carrier modified with the enzyme are used as cathode electrodes of the first block, the second block, and the third block, respectively. Between the non-aqueous phase and the aqueous phase.

  Carbon paper that is not enzyme-modified is disposed as an anode electrode in the non-aqueous phase of each block. Furthermore, a reference electrode can be arrange | positioned in the appropriate position in the water phase of each block.

  By using the produced carbon dioxide fixing device, methanol can be obtained from carbon dioxide with high fuel conversion efficiency.

(Example 2)
Carbon dioxide fixation device in embodiment 2 is an apparatus for producing methanol carbon dioxide immobilization apparatus as well as F _ate DH of Example 1, F _ald DH, and the three-step enzymatic reaction using ADH. For the non-aqueous phase and the aqueous phase in Example 2, the same ionic liquid and extract as in Example 1 are used.

  A cathode electrode in which an enzyme that catalyzes each enzyme reaction is modified, that is, a conductive carrier carrying the enzyme, is obtained by modifying the enzyme to an electrode by the following method.

First, an appropriate amount of _Fate DH is dissolved in a pH 6 buffer (0.02 M, phosphate buffer) to prepare an enzyme solution. Next, while stirring the enzyme solution, polyvinyl alcohol (PVA) having a polymerization degree of 1500 is gradually added and dissolved to prepare an enzyme / PVA mixture.

Separately, set the carbon cloth on the filter holder for vacuum filtration (Buchner funnel), and set the Buchner funnel on the filter bell. After pouring the enzyme / PVA mixture from the top of the carbon cloth, the enzyme / PVA mixture is infiltrated into the carbon cloth by reducing the pressure with the water pump of the aspirator connected to the filtration bell. The electrode carrying _Fate DH as the first enzyme by the above method is used as the cathode electrode installed in the first block.

Using F _ald DH instead of F _ate DH as the second enzyme, a cathode electrode to be installed in the second block is prepared in the same manner. In addition, using ADH as the third enzyme instead of _Fate DH, a cathode electrode to be installed in the third block is prepared in the same manner.

  A carbon dioxide fixing device is produced in the same manner as in Example 1 except that these cathode electrodes are used.

  In addition, when an enzyme is modified to an electrode by the above method, an electrode covered with an enzyme film having a certain water content (enzyme-modified electrode) can be produced by controlling the drying or vacuum drying time. .

  In addition, after drying the carbon cloth impregnated with the enzyme / PVA mixture under reduced pressure, the carbon cloth containing the enzyme was immersed in a pH 6 buffer solution (0.02M, phosphate buffer solution) for a certain period of time. Water (buffer solution) can be infiltrated into the inside.

  In addition to the above-described vacuum filtration, the enzyme / PVA mixed solution can be penetrated into the electrode network structure by a method such as impregnation or reduced pressure.

  By using the produced carbon dioxide fixing device, methanol can be obtained from carbon dioxide with high fuel conversion efficiency.

(Example 3)
Carbon dioxide fixation device in embodiment 3 is an apparatus for producing methanol carbon dioxide immobilization apparatus as well as F _ate DH of Example 1, F _ald DH, and the three-step enzymatic reaction using ADH. For the non-aqueous phase and the aqueous phase in Example 3, the same ionic liquid and extract as in Example 1 are used.

  A cathode electrode in which an enzyme that catalyzes each enzyme reaction is modified, that is, a conductive carrier carrying the enzyme, is obtained by modifying the enzyme to an electrode by the following method.

  An appropriate amount of PVA (degree of polymerization: 1500) is added to a dispersion of Nafion (5 wt.% In water) in which the enzyme is dissolved, and the mixture is stirred to prepare a mixture of enzyme / Nafion / PVA. Carbon felt (carbon felt) is put into this mixed solution, the mixed solution of enzyme / Nafion / PVA is infiltrated into the inside of the network structure, and then the carbon felt is pulled up. Thereafter, the carbon felt containing the enzyme / Nafion / PVA mixture is appropriately dried and used as a cathode electrode.

Using F _ald DH instead of F _ate DH as the second enzyme, a cathode electrode to be installed in the second block is prepared in the same manner. In addition, using ADH as the third enzyme instead of _Fate DH, a cathode electrode to be installed in the third block is prepared in the same manner.

  A carbon dioxide fixing device is produced in the same manner as in Example 1 except that these cathode electrodes are used.

  By using the produced carbon dioxide fixing device, methanol can be obtained from carbon dioxide with high fuel conversion efficiency.

Example 4
The carbon dioxide immobilization apparatus of Example 4 is a batch type carbon dioxide immobilization apparatus like the carbon dioxide immobilization apparatus 700 shown in FIG. 10, and is an apparatus which produces methanol which is a fuel from carbon dioxide.

In Example 4, likewise F _ate DH Example 1, F _ald DH, and the production of methanol by a three-step enzymatic reaction using ADH. For the non-aqueous phase in Example 4, an ionic liquid made of EMIMTFSI is used. A pH 6 and 50 mM phosphate buffer is used for the aqueous phase extract.

Except for using all three types instead of using each enzyme alone, an electrode modified with the three types of enzymes as conductive carriers is prepared in the same manner as in the preparation of each conductive carrier in Example 1. _{Specifically, F ate DH, F ald DH} , and ADH of three types of enzymes in place to qualify different carbon paper electrode singly, to qualify all these three types of enzymes to the same carbon paper electrodes.

  The obtained cathode electrode is placed in the non-aqueous phase. In addition, carbon paper that is not enzyme-modified as an anode electrode is placed in the non-aqueous phase.

  By using the produced carbon dioxide fixing device, methanol can be obtained from carbon dioxide with high fuel conversion efficiency.

(Example 5)
Carbon dioxide fixation device in embodiment 5, the carbon dioxide fixing apparatus as well as F _ate DH of Example 4, F _ald DH, and a batch type apparatus for producing methanol by an enzymatic reaction of the three steps using ADH is there. For the non-aqueous phase and the aqueous phase in Example 5, the same ionic liquid and extract as in Example 4 are used.

  According to the following method, a cathode electrode in which all the enzymes catalyzing each enzyme reaction are modified, that is, a conductive carrier carrying the enzyme, is obtained.

Electrodes modified with the three types of enzymes as conductive carriers are prepared in the same manner as the preparation of the conductive carriers in Example 2, except that all three types are used instead of using each enzyme alone. _{Specifically, F ate DH, F ald DH} , and ADH of three types of enzymes in place of each modified individually to different carbon cloth, to qualify all these three types of enzymes in the same carbon cloth.

  The obtained cathode electrode is placed in the non-aqueous phase. In addition, a carbon cloth that is not enzyme-modified is placed in the non-aqueous phase as an anode electrode.

  By using the produced carbon dioxide fixing device, methanol can be obtained from carbon dioxide with high fuel conversion efficiency.

(Example 6)
Carbon dioxide fixation device in embodiment 6, the carbon dioxide fixing apparatus as well as F _ate DH of Example 4, F _ald DH, and a batch type apparatus for producing methanol by an enzymatic reaction of the three steps using ADH is there. For the non-aqueous phase and the aqueous phase in Example 6, the same ionic liquid and extract as in Example 4 are used.

  According to the following method, a cathode electrode in which all the enzymes catalyzing each enzyme reaction are modified, that is, a conductive carrier carrying the enzyme, is obtained.

Electrodes modified with the three types of enzymes as conductive carriers are prepared in the same manner as the preparation of the conductive carriers in Example 3, except that all three types are used instead of using each enzyme alone. _{Specifically, F ate DH, F ald DH} , and ADH of three types of enzymes in place to qualify different carbon felt singly, to qualify all these three types of enzymes in the same carbon felt.

  The obtained cathode electrode is placed in the non-aqueous phase. Also, carbon felt that is not enzyme-modified is placed in the non-aqueous phase as an anode electrode.

(Example 7)
The carbon dioxide immobilization apparatus of Example 7 is a carbon dioxide immobilization apparatus including a single cell, and is an apparatus that produces methanol as a fuel from carbon dioxide.

In Example 7, similarly F _ate DH Example 1, F _ald DH, and the production of methanol by a three-step enzymatic reaction using ADH. For the aqueous phase in Example 7, the same extract as in Example 1 is used.

  First, an enzyme membrane electrode assembly (EMEA) for producing fuel (methanol) is produced as follows.

6 wt% Tetra-PEG-NH ₂ is dissolved in an ionic liquid mixture of aprotic [C ₂ mIm ⁺ ] [TFSA ⁻ ] containing 6 mM protic [C ₂ ImH ⁺ ] [TFSA ⁻ ], and Tetra-PEG = NH ₂ Adjust the / [C ₂ ImH ⁺ ] [TFSA ⁻ ] / [C ₂ mIm ⁺ ] [TFSA ⁻ ] solution. ^{_{Further, 6mM protic [C 2 ImH +}} ] [TFSA -] aprotic [C 2 mIm +] containing [TFSA ^-] and dissolved Tetra-PEG-NHS prepolymer ionic liquid mixture of (prepolymers), Tetra-PEG -NHS / [C ₂ ImH ⁺ ] [TFSA ⁻ ] / [C ₂ mIm ⁺ ] [TFSA ⁻ ] solution is prepared.

Then Tetra-PEG = NH ₂ / [C ₂ ImH ⁺ ] [TFSA ⁻ ] / [C ₂ mIm ⁺ ] [TFSA ⁻ ] solution and Tetra-PEG-NHS / [C ₂ ImH ⁺ ] [TFSA ⁻ ] / [ C ₂ mIm +] [TFSA ⁻ ] solution is mixed for about 30 minutes to prepare a ionic liquid casting solution mixed together.

  As an anode electrode, carbon paper having a dense layer on one main surface is separately prepared. The carbon paper is set on an instrument with a spacer. The height of the spacer is appropriately adjusted according to the desired thickness of the non-aqueous phase. At this time, the carbon paper is set in the instrument so that the dense layer side faces the instrument and the non-dense layer side (base carbon paper side) faces outward from the instrument.

Next, the previously prepared casting solution is cast to the height of the spacer on the non-dense layer side of the carbon paper. After pressing with a plate from the upper surface, the ionic liquid gel electrolyte membrane is produced by leaving still for 24 hours. The gelation time of the ionic liquid gel can be adjusted as necessary by appropriately increasing or decreasing the amount of [C ₂ ImH ⁺ ] [TFSA ⁻ ] added.

A cathode electrode for the first block, that is, a first conductive carrier carrying _Fate DH as the first enzyme is prepared by the same method as in Example 1. The produced cathode electrode and reference electrode are arranged at predetermined positions on the ionic liquid gel electrolyte membrane. Thereafter, an enzyme membrane electrode assembly (EMEA) for the first enzyme reaction is produced by placing and pressing a plate on the cathode electrode and the reference electrode.

  When the enzyme is modified only on one side of the electrode (carbon paper or the like) as described above, the enzyme-modified cathode electrode is placed on the ionic liquid gel electrolyte membrane so that the electrode surface modified with the enzyme is in contact with the ionic liquid gel electrolyte membrane. Place on top.

  The location where the reference electrode is installed can be arbitrarily selected. Moreover, a reference electrode can be installed in one or more places, and the number of installation can be increased / decreased appropriately as needed. Moreover, when installing a reference electrode in an aqueous phase, installation to an ionic liquid gel electrolyte membrane (non-aqueous phase) can be omitted. A pseudo reference electrode may be used instead of the reference electrode.

  When installing a reference electrode in a non-aqueous phase, for example, a platinum simulated reference electrode is installed. When installing a reference electrode in the aqueous phase, for example, a silver / silver chloride electrode is installed in the aqueous phase as a reference electrode.

An enzyme for the second enzyme reaction is produced in the same manner as in Example 1 except that a cathode electrode for the second block prepared by the same method as in Example 1, that is, a cathode electrode carrying _Fald DH as the second enzyme is used. A membrane electrode assembly (EMEA) is prepared. In addition, a third enzyme reaction enzyme is produced by the same method except that a third block cathode electrode produced by the same method as in Example 1, that is, a cathode electrode carrying ADH as the third enzyme is used. A membrane electrode assembly (EMEA) is prepared.

  Each of the produced enzyme membrane electrode assemblies (EMEA) is taken out from the instrument, and each is sandwiched by gaskets from both sides of the anode electrode side and the cathode electrode side. Thereafter, each membrane electrode assembly is individually set in a single cell device while being sandwiched between gaskets.

  Each single cell is provided with an electrode plate as a flow path and electrical conductor on the anode electrode side and the cathode electrode side, respectively.

  By adjusting the clamping pressure of the single cell, expansion due to adsorption of carbon dioxide can be mitigated.

  A single cell including the enzyme membrane electrode assembly for the first enzyme reaction is set in the first block. At this time, the single cell is set so that the cathode electrode side faces the aqueous phase.

  A single cell including the enzyme membrane electrode assembly of the second enzyme reaction is set in the second block. At this time, the single cell is set so that the anode phase faces the water phase on the first block side and the cathode electrode faces the water phase on the third block side.

  A single cell including the enzyme membrane electrode assembly of the third enzyme reaction is set in the third block. At this time, the single cell is set so that the anode electrode side faces the aqueous phase on the second block side.

  Further, single cells can be stacked and used. For example, a configuration similar to that of the stacked carbon dioxide immobilization apparatus 900 as shown in FIG.

  By introducing carbon dioxide into the first block and appropriately controlling the cell voltage or current to reduce the enzyme oxidized by the reduction reaction, methanol as a fuel can be produced from the carbon dioxide.

(Example 8)
Carbon dioxide fixation device in embodiment 8, the carbon dioxide fixing apparatus as well as F _ate DH of Example 7, F _ald DH, and the production of methanol by an enzymatic reaction of the three steps using ADH, including single cells Device. In the aqueous phase in Example 8, pH 7, pH 50 mM phosphate buffer is used as the extract.

  Each of the membrane electrode assemblies (EMEA) for fuel production is produced as follows.

[emim] [(CF ₃ SO ₂ ) ₂ N]: Poly (vinylidene fluoride) (PVdF): 1-methyl-2-pyrrolidone (NMP) = 1: 1: 3 .

  A spacer having a certain thickness is provided around a carbon paper electrode having a dense layer on one main surface. The mixed solution is heated to 80 ° C., cast on the surface of the carbon paper electrode on the non-dense layer side, and further pressed with a plate from above until the cast film reaches room temperature. Remove the plate and leave it at room temperature under 25% humidity for more than 2 days. A cathode electrode for the first block is prepared separately by the same method as in the first embodiment. The cathode electrode and the reference electrode are placed at predetermined positions on the cast film and pressed with a plate. Then, the plate is removed and the enzyme membrane electrode assembly for the first enzyme reaction is prepared by allowing the plate to stand for 1 day at room temperature under a humidity of 25% or less.

  An enzyme membrane electrode assembly for the second enzyme reaction is prepared by the same method except that the second block cathode electrode prepared by the same method as in Example 1 is used. Further, an enzyme membrane electrode assembly for the third enzyme reaction is prepared by the same method except that the third block cathode electrode prepared by the same method as in Example 1 is used.

  A carbon dioxide immobilization apparatus is produced in the same manner as in Example 7 except that the thus obtained enzyme membrane electrode assemblies for the first to third enzyme reactions are used.

  By using the produced carbon dioxide fixing device, methanol can be obtained from carbon dioxide with high fuel conversion efficiency.

  The carbon dioxide immobilization apparatus according to at least one embodiment and example described above includes a non-aqueous phase, a conductive carrier, an enzyme body, and an aqueous phase. The non-aqueous phase contains an ionic liquid. Carbon dioxide is supplied to the non-aqueous phase. The conductive carrier is placed in contact with the non-aqueous phase. The enzyme body is supported on a conductive carrier and catalyzes a reduction reaction of carbon dioxide or a reduction product thereof. The aqueous phase contains an extract containing water. The reaction product of the reduction reaction is supplied to the aqueous phase. With such a configuration, it is possible to provide a carbon dioxide fixing device and a fuel production system that fix carbon dioxide with high efficiency.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 11 ... Enzyme body, 12 ... Enzyme, 15 ... First reaction product, 21 ... Enzyme body, 22 ... Enzyme, 25 ... Second reaction product, 31 ... Enzyme body, 32 ... Enzyme, 35 ... Third Reaction product 51 ... Gas inlet, 52 ... Gas outlet, 53 ... Airflow control valve, 54 ... External flow path, 55 ... Extract liquid inlet, 56 ... Extract liquid outlet, 57 ... Liquid flow control valve, 81 DESCRIPTION OF SYMBOLS ... Carbon dioxide supply part, 82 ... Fuel production | generation part, 83 ... Extract liquid supply part, 84 ... Extract liquid recovery part, 85 ... Extract liquid supply tank, 90 ... Electric system, 91 ... Control part, 92 ... Detection process part, 93 ... Database, 94 ... Temperature controller, 95 ... Electrical controller, 100 ... Carbon dioxide immobilization device, 110 ... First block, 111 ... Gas phase, 112 ... Non-aqueous phase, 113 ... Water phase, 114 ... Anode electrode, 115 ... cathode electrode, 116 ... reference electrode, 120 Second block 122 ... non-aqueous phase 123a ... feed water phase 123b ... extraction water phase 124 ... anode electrode 125 ... cathode electrode 126 ... reference electrode 130 ... third block 132 ... non-aqueous phase DESCRIPTION OF SYMBOLS 133a ... Supply water phase, 133b ... Extraction water phase, 134 ... Anode electrode, 135 ... Cathode electrode, 136 ... Reference electrode, 151, 152, 153 ... Electrical control part, 200 ... Carbon dioxide fixing device, 210 ... No. 1 block, 211 ... gas phase, 212 ... non-aqueous phase, 213 ... aqueous phase, 214 ... anode electrode, 215 ... cathode electrode, 216 ... reference electrode, 220 ... second block, 222 ... non-aqueous phase, 223 ... Water phase, 224 ... Anode electrode, 225 ... Cathode electrode, 226 ... Reference electrode, 230 ... Third block, 232 ... Non-aqueous phase, 233 ... Water phase, 234 ... Anode electrode 235 ... cathode electrode, 236 ... reference electrode, 250 ... electrical control unit, 300 ... carbon dioxide fixing device, 304 ... electrode, 306 ... reference electrode, 311 ... gas phase, 312 ... first non-aqueous phase, 315 ... Electrode, 322 ... second non-aqueous phase, 325 ... electrode, 332 ... third non-aqueous phase, 333 ... aqueous phase, 335 ... electrode, 400 ... carbon dioxide fixing device, 411 ... gas phase, 402 ... fourth Non-aqueous phase, 412 ... First non-aqueous phase, 414, 415 ... Electrode, 419 ... Lead wire, 422 ... Second non-aqueous phase, 425 ... Electrode, 432 ... Third non-aqueous phase, 433 ... Water Phase, 435 ... Electrode, 441, 442 ... Separator, 500 ... Carbon dioxide fixing device, 511 ... Gas phase, 512 ... First non-aqueous phase, 514 ... Electrode, 515 ... Electrode, 522 ... Second non-aqueous phase 525 ... Electrode, 532 ... Third non-aqueous phase, 533 ... Water Phase, 535 ... Electrode, 551 ... Outer cylinder, 552 ... Intermediate cylinder, 553 ... Inner cylinder, 600 ... Carbon dioxide immobilization device, 601 ... Enzyme membrane electrode assembly, 611 ... Gas phase, 612 ... First non-aqueous phase , 614 ... 615 ... electrode, 622 ... second non-aqueous phase, 632 ... third non-aqueous phase, 633 ... aqueous phase, 651 ... outer cylinder, 652 ... intermediate cylinder, 653 ... inner cylinder, 700 ... carbon dioxide fixation 711 ... gas phase, 712 ... non-aqueous phase, 713 ... aqueous phase, 714 ... anode electrode, 715 ... cathode electrode, 741 ... separator, 800 ... carbon dioxide fixing device, 811 ... gas phase, 812 ... non-aqueous Phase, 813 ... Water phase, 814, 815 ... Electrode, 816, 817 ... Spacer, 861, 862 ... Electrode plate, 870 ... Insulating material, 871 ... Gasket, 961, 962 ... Electrode lead wire, C1 ... First cell body , C2 ... second Reel body, C3 ... third cell body, C10 ... cell body, J1, J2, J3 ... jig.

Claims (20)

A non-aqueous phase containing an ionic liquid and fed with carbon dioxide;
A conductive support placed in contact with the non-aqueous phase;
An enzyme that is supported on the conductive carrier and catalyzes a reduction reaction of carbon dioxide or a reduction product thereof supplied to the non-aqueous phase;
A carbon dioxide immobilization apparatus comprising an extract containing water and an aqueous phase to which a reaction product of the reduction reaction is supplied.   The carbon dioxide immobilization apparatus according to claim 1, wherein carbon dioxide is supplied to the non-aqueous phase from the atmosphere.   The carbon dioxide immobilization apparatus according to claim 1 or 2, further comprising a separator provided between the non-aqueous phase and the aqueous phase and including a permeation-separation membrane.   The carbon dioxide immobilization apparatus according to any one of claims 1 to 3, wherein the aqueous phase further includes a proton source that supplies protons to the non-aqueous phase.   At least one of the enzyme bodies is an enzyme, a first complex containing a molecular assembly composed of an enzyme and a dispersant, a microcapsule comprising a core part containing the enzyme and a shell part covering the core part, 5. The carbon dioxide according to claim 1, which is selected from the group consisting of a cell containing an enzyme, a microorganism containing the enzyme, and a second complex containing the enzyme and a support on which the enzyme is immobilized. Carbon immobilization equipment.   The carbon dioxide immobilization apparatus according to any one of claims 1 to 5, further comprising an external channel through which the aqueous phase flows.   7. The structure according to claim 1, wherein each of the plurality of single cells includes the non-aqueous phase and the aqueous phase, and the plurality of single cells are stacked to form a stacked structure. Carbon dioxide immobilization equipment. The enzyme body is
A first enzyme that catalyzes a first reduction reaction that reduces carbon dioxide to produce a first reaction product;
A second enzyme that catalyzes a second reduction reaction that reduces the first reaction product to produce a second reaction product;
A third enzyme body that catalyzes a third reduction reaction that reduces the second reaction product to produce a third reaction product,
The non-aqueous phase is
A first non-aqueous phase supplied with carbon dioxide;
A second non-aqueous phase fed with the first reaction product;
A third non-aqueous phase fed with the second reaction product,
The conductive carrier is
A first conductive carrier installed in contact with the first non-aqueous phase and carrying the first enzyme body;
A second conductive carrier that is placed in contact with the second non-aqueous phase and carries the second enzyme body;
A third conductive carrier that is placed in contact with the third non-aqueous phase and carries the third enzyme body,
The aqueous phase is
A first aqueous phase supplied with the first reaction product from the first non-aqueous phase and supplying the first reaction product to the second non-aqueous phase;
A second aqueous phase supplied with the second reaction product from the second non-aqueous phase and supplying the second reaction product to the third non-aqueous phase;
The carbon dioxide immobilization apparatus according to any one of claims 1 to 7, further comprising a third aqueous phase to which the third reaction product is supplied from the third non-aqueous phase. The enzyme body is
A first enzyme that catalyzes a first reduction reaction that reduces carbon dioxide to produce a first reaction product;
A second enzyme that catalyzes a second reduction reaction that reduces the first reaction product to produce a second reaction product;
A third enzyme body that catalyzes a third reduction reaction that reduces the second reaction product to produce a third reaction product,
The non-aqueous phase is
A first non-aqueous phase supplied with carbon dioxide;
A second non-aqueous phase fed with the first reaction product;
A third non-aqueous phase fed with the second reaction product,
The conductive carrier is
A first conductive carrier installed in contact with the first non-aqueous phase and carrying the first enzyme body;
A second conductive carrier that is placed in contact with the second non-aqueous phase and carries the second enzyme body;
A third conductive carrier that is placed in contact with the third non-aqueous phase and carries the third enzyme body,
The carbon dioxide immobilization apparatus according to any one of claims 1 to 7, wherein the third reaction product is supplied to the aqueous phase.   The carbon dioxide fixing device according to claim 8 or 9, wherein carbon dioxide is supplied to the first non-aqueous phase from the atmosphere.   The carbon dioxide fixing device according to any one of claims 1 to 7, wherein the conductive carrier includes a wound porous membrane. The wound porous membrane is wound a plurality of times so that a plurality of layered portions are arranged in the radial direction,
The enzyme body is a plurality of enzyme bodies,
The carbon dioxide immobilization apparatus according to claim 11, wherein the plurality of enzyme bodies are supported by the conductive carrier so that different enzyme bodies are arranged in the radial direction in the wound porous membrane.   The carbon dioxide immobilization apparatus according to any one of claims 1 to 12, further comprising a cathode electrode and an anode electrode installed so as to be in contact with the non-aqueous phase, wherein the conductive carrier includes the cathode electrode.   The carbon dioxide immobilization apparatus according to claim 13, further comprising a reference electrode provided in the aqueous phase.   The carbon dioxide immobilization apparatus according to any one of claims 1 to 14, wherein the non-aqueous phase includes a solid polymer electrolyte. A fuel generator including the carbon dioxide fixing device according to any one of claims 1 to 15,
A carbon dioxide supply unit for supplying carbon dioxide to the fuel generation unit;
A fuel production system comprising: an extract collection unit that collects the reaction product from the fuel generation unit. A fuel generator including the carbon dioxide fixing device according to claim 13 or 14,
A carbon dioxide supply unit for supplying carbon dioxide to the fuel generation unit;
An extract recovery unit for recovering the reaction product from the fuel generation unit;
A fuel production system comprising a cell voltage control unit that controls a voltage applied to the cathode electrode and the anode electrode. A fuel generator including the carbon dioxide fixing device according to claim 13 or 14,
A carbon dioxide supply unit for supplying carbon dioxide to the fuel generation unit;
An extract recovery unit for recovering the reaction product from the fuel generation unit;
A fuel production system comprising: a current control unit that controls a current flowing between the cathode electrode and the anode electrode.   The fuel production system according to any one of claims 16 to 18, further comprising a temperature control unit that controls a temperature in the fuel generation unit.   The fuel production system according to any one of claims 16 to 19, wherein the carbon dioxide supply unit has a function of controlling a pressure of a gas containing carbon dioxide supplied to the fuel generation unit.