JP2018001131A - Carbon dioxide separation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carbon dioxide separation apparatus which can easily separate carbon dioxide from gas containing the carbon dioxide.SOLUTION: A carbon dioxide separation apparatus 10 is provided with an electrolyte layer 13, a pair of electrodes 11, 12 arranged on the electrolyte layer 13 with the electrolyte layer 13 interposed therebetween, and a voltage applying part 14 which applies a voltage between the pair of electrodes 11, 12. The pair of electrodes 11, 12 can respectively permeate gas, and the electrolyte layer 13 contains an electrolyte which can dissolve carbon dioxide, and a redox compound having an N-oxyradical group in a molecule.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a carbon dioxide separator.

  Carbon dioxide is not only a widely existing material that occupies about 0.04% of the atmosphere, but is widely used in industry.

  Examples of the method of using carbon dioxide include carbonated beverages, foaming gases such as bathing agents and fire extinguishing agents, dry ice used for cooling, and air for emergency replenishment of bicycles. Carbon dioxide can also be used as an extraction solvent for caffeine and the like by setting it to a supercritical state. Carbon dioxide is also used in carbon dioxide lasers used in lasers used for processing in the industrial field, medical laser scalpels, and the like. Furthermore, carbon dioxide may be used as a refrigerant for the compressor instead of the chlorofluorocarbon refrigerant. Carbon dioxide is also used in the agricultural field for carbon dioxide fertilization for accelerating the growth of plants such as forcing cultivation of strawberries and aquatic plants in ornamental aquariums. Carbon dioxide is also used for CA (Controlled Atomophore) storage of fresh produce.

  As described above, carbon dioxide is used in various fields, and a method for obtaining carbon dioxide by separating carbon dioxide from air or the like is required. Carbon dioxide is said to cause global warming. For this reason as well, it is required to use carbon dioxide by separating it from a gas containing carbon dioxide.

  Various methods have been proposed for separating carbon dioxide from a mixed gas containing oxygen and carbon dioxide, such as air. As this separation method, for example, carbon dioxide in the air is adsorbed using a carbon dioxide adsorbent, and then carbon dioxide adsorbed by the adsorbent is desorbed to separate carbon dioxide from the air. And the like. Examples of the adsorbent that adsorbs carbon dioxide include activated carbon, an amine solvent, and an aqueous potassium carbonate solution. Further, as a carbon dioxide separation method using an adsorbent, more specifically, PSA in which carbon dioxide is adsorbed on the adsorbent under high pressure and then depressurized to desorb carbon dioxide from the adsorbent. (Pressure Swing Adsorption) method and the like. Moreover, as an adsorbent used when carbon dioxide is separated by this PSA method, the adsorbent described in Patent Document 1 can be mentioned.

  Patent Document 1 describes a carbon dioxide adsorbent comprising a composition in which 2 to 80 equivalent% of sodium ions of sodium-containing aluminosilicate are ion-exchanged with barium ions.

  Moreover, as an apparatus which adsorb | sucks and isolate | separates a carbon dioxide, the acidic gas adsorption / desorption device of patent document 2 is mentioned, for example.

  Patent Document 2 discloses a compound capable of adsorbing and desorbing an acidic gas such as carbon dioxide by oxidation and reduction, an acidic gas adsorption / desorption layer including a substrate, and the acidic gas adsorption / desorption. An acid gas adsorption / desorption device having a pair of electrodes sandwiching a layer is described.

JP 7-39552 A JP-A-2015-36128

  According to Patent Document 1, it is an adsorbent having a high carbon dioxide selection ratio and a large absorption capacity even under conditions with a lot of moisture, and this adsorbent is suitably used for separating and concentrating carbon dioxide by the PSA method. It is disclosed that it can be done.

  Further, as described above, the method for separating carbon dioxide by such a PSA method requires pressurization and decompression. In addition, as long as it is a carbon dioxide separation method using an adsorbent, an operation for desorbing carbon dioxide adsorbed on the adsorbent, for example, heat treatment, is required even in a method other than the PSA method. For this reason, the carbon dioxide separation method using an adsorbent may require a relatively large amount of energy or a relatively large apparatus.

  Therefore, as a carbon dioxide separation method, it is required that carbon dioxide can be separated by a simple method without using much energy for carbon dioxide separation and without using a relatively large apparatus.

  Patent Document 2 discloses that acid gas can be adsorbed and desorbed in a solid state. Specifically, in the method described in Patent Document 2, first, a voltage is applied between the electrodes, and the acidic gas is adsorbed on the acidic gas adsorption / desorption layer. Thereafter, the voltage applied between the electrodes is reversed so that the current flowing in the acid gas adsorption / desorption layer disposed between the electrodes is in the direction opposite to that during adsorption, and the acid gas is desorbed from the acid gas adsorption / desorption layer. Is removed. As described above, in the method described in Patent Document 2, when the acidic gas is adsorbed to the acidic gas adsorption / desorption layer and when the adsorbed acidic gas is desorbed from the acidic gas adsorption / desorption layer, the electrode is separated. The voltage applied to is inverted. Focusing on carbon dioxide as the acid gas, even if it was attempted to separate carbon dioxide with this apparatus, it was necessary to reverse the voltage applied between the electrodes as described above. Therefore, in the method described in Patent Document 2, as in the case of using the adsorbent described in Patent Document 1, a relatively large amount of energy or a relatively large apparatus may be required. there were.

  This invention is made | formed in view of this situation, Comprising: It aims at providing the carbon dioxide separator which can isolate | separate a carbon dioxide easily from the gas containing a carbon dioxide.

  As a result of various studies, the present inventor has found that the above object is achieved by the present invention described below.

  A carbon dioxide separator according to one embodiment of the present invention includes an electrolyte layer, a pair of electrodes provided on the electrolyte layer with the electrolyte layer interposed therebetween, and a voltage application that applies a voltage between the pair of electrodes. Each of the pair of electrodes is a gas permeable electrode, the electrolyte layer is an electrolyte solution capable of dissolving carbon dioxide, and a redox compound having an N-oxy radical group in the molecule. A carbon dioxide separator containing

  According to such a configuration, it is possible to provide a carbon dioxide separator that can easily separate carbon dioxide from a gas containing carbon dioxide.

  This is considered to be due to the following.

  Since the voltage application unit applies a voltage between the pair of electrodes, a potential difference is generated between one electrode and the other electrode of the pair of electrodes. Hereinafter, a case where a voltage is applied so that the potential of the one electrode is lower than the potential of the other electrode will be described.

  The pair of electrodes can transmit gas existing around the electrodes. Therefore, the gas which permeate | transmitted the said electrode contacts the said electrolyte layer. Then, carbon dioxide contained in the gas on the one electrode side is dissolved in the electrolyte solution contained in the electrolyte layer.

  At this time, the potential of the one electrode is lower than the potential of the other electrode. In the redox compound contained in the electrolyte layer, an N-oxy radical group is reduced to a N-oxyanion group on the side close to the one electrode having a low potential. Since carbon dioxide dissolved in the electrolytic solution is combined with the N-oxyanion group, dissolution of carbon dioxide in the electrolytic solution is promoted. For this reason, carbon dioxide is taken into the one electrode.

  On the other hand, the potential of the other electrode is higher than the potential of the one electrode. On the side close to the other electrode having the higher potential, the redox compound contained in the electrolyte layer is oxidized in the N-oxyanion group even if the N-oxyradical group is an N-oxyanion group. It becomes an N-oxy radical group. For this reason, when the redox compound to which carbon dioxide is bonded flows to the other electrode side in the electrolyte layer, the carbon dioxide bonded to the N-oxyanion group of the redox compound is desorbed. Carbon dioxide desorbed from the redox compound passes through the other electrode. For this reason, carbon dioxide is released from the other electrode side.

  As described above, the carbon dioxide separator is configured such that, by applying a voltage between the electrodes so that the potential of the one electrode is lower than the potential of the other electrode, the carbon dioxide separation is performed on the one electrode side. It is considered that carbon can be taken in and carbon dioxide can be released on the other electrode side.

  Further, by applying a voltage so that the potential of the one electrode is higher than the potential of the other electrode, carbon dioxide is taken in on the other electrode side, and carbon dioxide is captured on the one electrode side. Can be released.

  From the above, the carbon dioxide separator can separate carbon dioxide by only applying a voltage between a pair of electrodes without inverting the voltage applied between the electrodes. Therefore, the carbon dioxide separator can easily separate carbon dioxide from a gas containing carbon dioxide.

  In the carbon dioxide separator, the pair of electrodes includes a first electrode on the side for taking in carbon dioxide from a gas containing carbon dioxide, and a second electrode on the side for releasing carbon dioxide from the electrolyte layer, The voltage application unit preferably applies the potential of the first electrode so that the potential of the first electrode is always lower than the potential of the second electrode.

  According to such a configuration, carbon dioxide is taken in on the first electrode side simply by applying the voltage application unit so that the potential of the first electrode is always lower than the potential of the second electrode. Carbon dioxide can be released on the second electrode side. Therefore, carbon dioxide can be more easily separated from the gas containing carbon dioxide.

  In the carbon dioxide separator, the redox compound is preferably a compound in which two quaternary carbons are bonded to the N-oxy radical group.

  According to such a configuration, carbon dioxide can be more suitably separated from a gas containing carbon dioxide. This is considered to be due to the fact that carbon dioxide can be taken up and released suitably by the redox compound.

  In the carbon dioxide separator, the redox compound has a compound represented by the following formula (1) or a group in which one hydrogen atom is eliminated from the compound represented by the following formula (1). A compound is preferred.

In formula (1), _{Z, -CR 5 R 6 CR 7 R} 8 -, - CR 9 R 10 CR 11 R 12 CR 13 R 14 -, - (CR 15 R 16) O -, - (CR 17 R _{18) NR 27 -, - (} CR 19 R 20) O (CR 21 R 22) -, _{or, - (CR 23 R 24)} NR 28 (CR 25 R 26) - _indicates, R 1 _{to R 28} are, Each independently represents a hydrogen atom or a substituent.

  According to such a configuration, carbon dioxide can be more suitably separated from a gas containing carbon dioxide. This is considered to be due to the fact that carbon dioxide can be taken up and released suitably by the redox compound.

  Moreover, it is preferable that the said electrode is an electrode containing at least 1 sort (s) chosen from the group which consists of a graphite, a carbon nanotube, and carbon fiber.

  According to such a configuration, carbon dioxide can be more suitably separated from a gas containing carbon dioxide. This is considered to be because gas can be suitably transmitted and voltage can be suitably applied between the electrodes by the voltage application unit.

  According to the present invention, it is possible to provide a carbon dioxide separator that can easily separate carbon dioxide from a gas containing carbon dioxide.

FIG. 1 is a schematic cross-sectional view showing the configuration of a carbon dioxide separator according to an embodiment of the present invention.

  Hereinafter, although the embodiment concerning the present invention is described, the present invention is not limited to these.

  As shown in FIG. 1, the carbon dioxide separator 10 according to the embodiment of the present invention includes a pair of electrodes 11 and 12 provided on the electrolyte layer 13 with the electrolyte layer 13 sandwiched between the electrolyte layer 13 and the electrolyte layer 13. And a voltage applying unit 14 for applying a voltage between the pair of electrodes 11 and 12. Each of the pair of electrodes 11 and 12 is an electrode that can transmit gas. The electrolyte layer 13 includes an electrolytic solution capable of dissolving carbon dioxide and a redox compound having an N-oxy radical group in the molecule. FIG. 1 is a schematic cross-sectional view showing the configuration of the carbon dioxide separator 10 according to the embodiment of the present invention.

The carbon dioxide separator 10 according to the present embodiment may be applied by the voltage application unit 14 so as to increase the potential of either electrode between the pair of electrodes 11 and 12. Can also separate carbon dioxide. Here, the case where the voltage application unit 14 applies the voltage between the pair of electrodes 11 and 12 so that the potential of the one electrode 11 of the pair of electrodes is lower than the potential of the other electrode 12 will be described. In this case, the one electrode 11 becomes an electrode (first electrode: cathode electrode) 11 on the side of taking in carbon dioxide (CO ₂ ) from a gas containing carbon dioxide, and the other electrode 12 is formed from the electrolyte layer 13. It becomes an electrode (second electrode: anode electrode) 12 on the side from which carbon dioxide is released.

  The carbon dioxide separator 10 includes a first flow path 15 through which gas flows while being in contact with the first electrode 11, and a second flow path 16 through which gas flows while being in contact with the second electrode 12. May be provided.

  The carbon dioxide separator 10 according to the present embodiment can easily separate carbon dioxide from a gas containing carbon dioxide. Specifically, the carbon dioxide separator 10 is configured so that the voltage applying unit 14 causes the potential of the first electrode 11 to be lower than the potential of the second electrode 12. When applied, carbon dioxide is separated from the gas containing carbon dioxide as follows. When the carbon dioxide separator 10 circulates a gas containing carbon dioxide, such as air, through the first flow path 15 to bring carbon dioxide into contact with the first electrode 11, carbon dioxide is converted into the electrolyte layer. 13 is preferentially transmitted and emitted from the second electrode 12 side. Thus, since carbon dioxide is preferentially permeated through the electrolyte layer 13, a gas having a high carbon dioxide concentration is circulated in the second flow path 16. Thus, the carbon dioxide separator 10 can preferentially permeate carbon dioxide simply by applying a voltage between the first electrode 11 and the second electrode 12. Therefore, when the carbon dioxide separator 10 is used, carbon dioxide is separated from the gas containing carbon dioxide. Note that a gas having a lower carbon dioxide concentration than the supplied gas is discharged from the first flow path 15. When air is supplied to the first flow path 15, the gas having an increased nitrogen concentration is discharged.

  The above is considered to be due to the following.

  The permeated carbon dioxide in contact with the first electrode 11 is in contact with the electrolyte layer 13 and is dissolved in the electrolytic solution contained in the electrolyte layer 13. At this time, the redox compound contained in the electrolyte layer 13 is reduced in the N-oxy radical group on the side close to the first electrode 11 by the voltage applied by the voltage application unit 14, and the N-oxyanion group is reduced. It has become. Since this N-oxyanion group is easily combined with carbon dioxide dissolved in the electrolytic solution, dissolution of carbon dioxide in the electrolytic solution is promoted. Therefore, the uptake of carbon dioxide to the first electrode 11 side is promoted. On the other hand, the redox compound contained in the electrolyte layer 13 is changed from the N-oxy radical group to the N-oxyanion group on the side close to the second electrode 12 by the voltage applied by the voltage application unit 14. The N-oxyanion group is oxidized to an N-oxy radical group. Even if carbon dioxide is bonded to the N-oxyanion group, carbon dioxide is desorbed from the redox compound when the N-oxyanion group becomes an N-oxy radical group. Accordingly, carbon dioxide is bonded to the redox compound on the side close to the first electrode 11, and then the redox compound combined with carbon dioxide flows in the electrolyte layer 13 to the side close to the second electrode 12. Then, carbon dioxide is desorbed from the redox compound on the side close to the second electrode 12. By such binding and desorption of carbon dioxide to the redox compound, the carbon dioxide separator 10 takes in carbon dioxide on the first electrode 11 side and releases carbon dioxide on the second electrode side. I think it can be done.

When a voltage is applied so that the potential of the one electrode 11 is higher than the potential of the other electrode 12, the electrode 11 on the side from which the one electrode 11 releases carbon dioxide from the electrolyte layer 13 ( The second electrode 12 becomes the electrode (first electrode) 11 on the side of taking in carbon dioxide (CO ₂ ) from the gas containing carbon dioxide. Therefore, carbon dioxide can be taken in on the other electrode 12 side, and carbon dioxide can be released on the one electrode 11 side.

  From the above, the carbon dioxide separator 10 simply applies a voltage between the pair of electrodes 11 and 12 and does not invert the voltage applied between the electrodes (without switching the potential level of each electrode). ), Carbon dioxide can be separated. Therefore, the carbon dioxide separator 10 can easily separate carbon dioxide from a gas containing carbon dioxide.

  Each of the electrodes 11 and 12 is not particularly limited as long as it is an electrode that can transmit gas. That is, each of the electrodes 11 and 12 is a conductive member that can transmit a gas such as carbon dioxide and can pass a current through the electrolyte layer 13 sandwiched between the pair of electrodes 11 and 12. Good. Further, each of the electrodes 11 and 12 is preferably a porous body having a conductivity that does not hinder the movement of electrons and excellent in air permeability. Specifically, the electrodes 11 and 12 are made of a porous conductive material. The electrode etc. which are made are mentioned. More specifically, examples of the electrodes 11 and 12 include a porous body containing carbon as a main component, a porous body made of carbon, and a porous metal layer.

  Specific examples of carbon contained in the porous body include carbonaceous materials such as graphite, carbon nanotubes, activated carbon, activated carbon fibers, and carbon fibers. The carbon is preferably activated carbon or activated carbon fiber from the viewpoint of corrosion resistance and specific surface area. Moreover, as this carbon, various carbonaceous materials may be used independently and may be used in combination of 2 or more type. As the porous body containing carbon, a material obtained by forming the carbonaceous material into a cloth shape or a felt shape is preferable. Thus, specific examples of the porous electrode include carbon sheets, carbon cloth, and carbon paper. Examples of the porous electrode include a carbon-based electrode using activated carbon or carbon fiber, and a high porosity electrode using a needle-like conductive material. The electrode is preferably an electrode including at least one selected from the group consisting of graphite, carbon nanotubes, and carbon fibers among the electrodes. If it is such an electrode, it will be thought that gas can be permeate | transmitted suitably and a voltage can be suitably applied between the said electrodes by the said voltage application part. For this reason, by using this electrode, a carbon dioxide separator capable of more suitably separating carbon dioxide from a gas containing carbon dioxide is obtained.

  The porous metal layer is a metal layer in which a large number of pores are formed. Moreover, it is preferable that the said metal layer is formed over the whole metal layer at the point which the said hole is excellent in air permeability. Further, the method for obtaining the porous metal layer is not particularly limited as long as it is a method (a method for making a porous structure) in which a metal layer in which a large number of holes are not formed is subjected to a treatment for forming a large number of holes. Examples of this method include physical methods such as cutting, polishing, and sand blasting, and chemical methods such as electrolytic etching and electroless etching using an etching solution such as acid and base. Moreover, as a method of making it porous, each said method may be performed independently and may be performed in combination of 2 or more type. Further, as a method for making the pores, a chemical method is preferable from the viewpoint of increasing the surface area, in order to form pores (pores) to be formed more densely. Moreover, it does not specifically limit as a material of the said metal layer, For example, aluminum, copper, iron, titanium, tungsten, nickel, these alloys, etc. are mentioned. Among these, the material of the metal layer is preferably aluminum from the viewpoint of cost and workability. The metal layer is preferably a so-called aluminum foil.

Further, the BET specific surface area of each of the electrodes 11 and 12 is not particularly limited, but is preferably, for example, 1 m ² / g or more, more preferably 100 m ² / g or more, and 500 m ² / g or more. It is more preferable that The BET specific surface area of each of the electrodes 11 and 12 is preferably larger from the viewpoint of gas permeability (breathability), but is preferably 3000 m ² / g or less from the viewpoint of the strength of each electrode 11 and 12. . Therefore, BET specific surface area of the respective electrodes 11 and 12 is preferably 1~3000m ² / g, more preferably 100~2500m ² / g, more to be 500~2000m ² / g preferable. When the BET specific surface area of each electrode is too small, gas permeability (breathability) is lowered and carbon dioxide permeation tends to be inhibited. If the BET specific surface area of each electrode is too large, the strength of the electrode tends to be insufficient. From these things, if the BET specific surface area of each said electrode is in the said range, isolation | separation of a carbon dioxide can be implement | achieved over a long period of time. The BET specific surface area is a specific surface area measured by the BET method and can be measured by a known method. Examples of the method for measuring the BET specific surface area include a method of performing nitrogen adsorption isotherm measurement and calculating from the obtained adsorption isotherm.

  Further, as described above, each of the electrodes 11 and 12 is a conductive member that can pass a current through the electrolyte layer 13 sandwiched between the pair of electrodes 11 and 12, and has a small surface resistance value. For example, it is preferably 1 kΩ / sq or less, and more preferably 200 Ω / sq or less. Further, the surface resistance value of each electrode is preferably as small as possible, but in practice, the limit is 1 Ω / sq. Therefore, the surface resistance value of each electrode is preferably 1 Ω / sq to 1 kΩ / sq, and more preferably 10 to 200 Ω / sq. If it is an electrode of such a surface resistance value, an electric current can be suitably sent through the said electrolyte layer 13, and a carbon dioxide can be isolate | separated suitably.

  Further, the thickness of each of the electrodes 11 and 12 is not particularly limited, but is preferably a thickness that can adsorb carbon dioxide and can appropriately prevent leakage of the electrolytic solution. The thickness of each of the electrodes 11 and 12 is preferably, for example, 20 μm or more and 10 mm or less, and more preferably 50 μm or more and 5 mm. If each electrode is too thin, the strength of the electrode tends to be insufficient. Moreover, when each said electrode is too thick, there exists a tendency for the permeability | transmittance (breathability) of gas to fall and to permeate | transmit carbon dioxide. From these things, if the thickness of each said electrode is in the said range, a carbon dioxide separation is realizable over a long period of time.

  The electrolyte layer 13 is not particularly limited as long as it includes an electrolytic solution capable of dissolving carbon dioxide and a redox compound having an N-oxy radical group in the molecule. Further, as described above, the electrolyte layer 13 is a carbon dioxide separator that contributes to the separation of carbon dioxide. Moreover, the thickness of the electrolyte layer 13 is not particularly limited, but is preferably 0.1 μm to 2 mm, and more preferably 1 μm to 1 mm, for example. If the electrolyte layer 13 is too thin, there is a tendency that minute holes, that is, pinholes, are formed in the electrolyte layer. If pinholes are formed, carbon dioxide cannot be separated properly. On the other hand, if the electrolyte layer 13 is too thick, the carbon dioxide permeation rate, that is, the carbon dioxide absorption rate and the release rate tend to be too low.

  The electrolyte solution is not particularly limited as long as it is an electrolyte solution capable of dissolving carbon dioxide, and may be an electrolyte solution containing an electrolyte and a solvent, or may be an electrolyte solution containing an ionic liquid. In addition, the electrolytic solution capable of dissolving carbon dioxide may be any electrolyte solution that does not dissolve carbon dioxide, that is, any electrolytic solution that dissolves even a small amount of carbon dioxide, and does not require high solubility. . This is considered to be due to the following. As described above, the carbon dioxide separator according to this embodiment captures carbon dioxide in the electrolyte layer on one electrode side and binds to and releases the carbon dioxide from the redox compound. It is thought that the separation of carbon dioxide proceeds by a mechanism in which carbon dioxide is released in the electrolyte layer. For this reason, it is considered that separation of carbon dioxide proceeds if carbon dioxide dissolves even slightly in the electrolyte solution contained in the electrolyte layer.

  The solvent is preferably an electrochemically stable compound with a wide potential window, and may be an aqueous solvent or an organic solvent. Examples of the solvent include water, carbonate compounds, ester compounds, ether compounds, heterocyclic compounds, nitrile compounds, and aprotic polar compounds. Examples of the carbonate compound include dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, and propylene carbonate. Examples of the ester compound include methyl acetate, methyl propionate, and γ-butyrolactone. Examples of the ether compound include diethyl ether, 1,2-dimethoxyethane, 1,3-dioxosilane, tetrahydrofuran, and 2-methyl-tetrahydrofuran. Examples of the heterocyclic compound include 3-methyl-2-oxazozirinone and 2-methylpyrrolidone. Examples of the nitrile compound include acetonitrile, methoxyacetonitrile, propionitrile, 3-methoxypropionitrile, valeric acid nitrile, and the like. Examples of the aprotic polar compound include sulfolane, dimethyl sulfoxide, dimethylformamide, and the like. As the solvent, each of the exemplified solvents may be used alone, or two or more kinds may be used in combination. In addition, among the above-exemplified solvents, the solvent includes carbonate compounds such as ethylene carbonate and propylene carbonate, ester compounds such as γ-butyrolactone, and complex compounds such as 3-methyl-2-oxazodilinone and 2-methylpyrrolidone. Nitrile compounds such as ring compounds, acetonitrile, methoxyacetonitrile, propionitrile, 3-methoxypropionitrile and valeric nitrile are preferred. Moreover, when using in combination of 2 or more types as said solvent, it is preferable to use water from a viewpoint of melt | dissolution of a carbon dioxide.

  The electrolyte is not particularly limited, and examples thereof include quaternary ammonium salts, inorganic salts, and hydroxides. Examples of the quaternary ammonium salt include tetramethylammonium tetrafluoroborate, tetra-n-ethylammonium tetrafluoroborate, tetra-n-propylammonium tetrafluoroborate, tetra-n-butylammonium tetrafluoroborate, and n-hexa. Decyltrimethylammonium tetrafluoroborate, tetra-n-hexadecylammonium tetrafluoroborate, tetra-n-octylammonium tetrafluoroborate, tetra-n-ethylammonium perchlorate, tetra-n-butylammonium perchlorate, and tetraoctadecylammonium Park Loreto etc. are mentioned. Examples of the inorganic salt include lithium perchlorate, sodium perchlorate, potassium perchlorate, sodium acetate, potassium acetate, sodium nitrate, and potassium nitrate. Examples of the hydroxide include sodium hydroxide and potassium hydroxide. Among the electrolytes exemplified above, the electrolyte includes tetramethylammonium tetrafluoroborate, tetra-n-ethylammonium tetrafluoroborate, tetra-n-propylammonium tetrafluoroborate, tetra-n-butylammonium tetrafluoroborate, n -Hexadecyltrimethylammonium tetrafluoroborate, tetra-n-hexadecylammonium tetrafluoroborate, tetra-n-octylammonium tetrafluoroborate, tetra-n-ethylammonium perchlorate, tetra-n-butylammonium perchlorate, tetraoctadecyl Ammonium perchlorate, lithium perchlorate, sodium perchlorate, sodium acetate, and potassium acetate are preferred. . Among the electrolytes, tetra-n-ethylammonium tetrafluoroborate, tetra-n-propylammonium tetrafluoroborate, tetra-n-butylammonium tetrafluoroborate, lithium perchlorate, and sodium perchlorate are more preferable. Tetra-n-butylammonium tetrafluoroborate and lithium perchlorate are more preferable. Further, the electrolyte may have a pH buffering ability by stabilizing carbonate ions or hydrogen carbonate ions as a supporting salt. Specific examples of the electrolyte in this case include sodium hydrogen carbonate, sodium carbonate, acetic acid, and sodium acetate. As the electrolyte, the electrolytes exemplified above may be used alone, or two or more kinds may be used in combination.

  As described above, the electrolytic solution may be an electrolytic solution containing an ionic liquid (ionic liquid). When an ionic liquid is used as the electrolytic solution, the ionic liquid can have both functions without including an electrolyte and a solvent as described above. In addition, the electrolyte solution only needs to contain an ionic liquid, and the ionic liquid may contain a liquid containing an electrolyte, the ionic liquid may contain a solvent, or the ionic liquid may contain an electrolyte and an electrolyte. A liquid containing a solvent may be used, or an ionic liquid may be used. Moreover, it is preferable to use an ionic liquid as the electrolytic solution because the ionic liquid is less likely to volatilize and has high flame retardancy. The ionic liquid is not particularly limited as long as it is a known ionic liquid. For example, imidazolium ionic liquid, pyridine ionic liquid, alicyclic amine ionic liquid, and azonium amine ionic liquid are used. Can be mentioned. Examples of the ionic liquid include 1-methyl-3-octylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium chloride, 1-butyl-3. -Methylimidazolium tetrafluoroborate, 1-decyl-3-methylimidazolium tetrafluoroborate, 1,3-dimethoxyimidazolium tetrafluoroborate, 1,3-diethoxyimidazolium tetrafluoroborate, 1-methyl-3- Octylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-decyl-3-methylimidazolium Kisa hexafluorophosphate, 1,3-dimethoxy-imidazolium hexafluorophosphate, and 1,3-diethoxy hexafluorophosphate, and the like. Examples of the ionic liquid include 1-methyl-3-octylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, and 1-butyl-3-methylimidazole among the exemplified ionic liquids. Lithium tetrafluoroborate, 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonylimide), 1,3-dimethoxyimidazolium tetrafluoroborate, 1-methyl-3-octylimidazolium hexafluorophosphate, and 1- Ethyl-3-methylimidazolium hexafluorophosphate is preferred. Examples of the ionic liquid include 1-methyl-3-octylimidazolium tetrafluoroborate, 1,3-dimethoxyimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonylimide), 1-butyl-3-methylimidazolium chloride and 1-methyl-3-octylimidazolium hexafluorophosphate are more preferable, and 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonylimide), 1-butyl- 3-methylimidazolium chloride and 1-methyl-3-octylimidazolium tetrafluoroborate are more preferred.

  Moreover, the electrolyte solution may be gelled in the electrolyte layer. Specifically, a gelling agent for gelation may be added to the electrolytic solution, or a gelled electrolyte or a polymer electrolyte may be used. Examples of the gelling agent include a gelling agent using a technique such as a polymer, a polymer crosslinking reaction, a polymerizable polyfunctional monomer, and an oil gelling agent. The gelled electrolyte and the polymer electrolyte are not particularly limited as long as they can be used as a gelled electrolyte or a polymer electrolyte. For example, vinylidene fluoride polymers such as polyvinylidene fluoride, polyacrylic acid And acrylic acid polymers such as polyacrylonitrile, acrylonitrile polymers such as polyacrylonitrile, polyether polymers such as polyethylene oxide, and compounds having an amide structure in the structure.

  The redox compound is not particularly limited as long as it is a redox compound having an N-oxy radical group in the molecule. In this redox compound, when the N-oxy radical group is reduced by applying a voltage between the electrodes by the voltage application unit, the N-oxy radical group becomes an N-oxy anion group. . Further, when the N-oxyanion group is oxidized by applying a voltage between the electrodes, the N-oxyanion group returns to the N-oxy radical. The redox compound is thus a compound in which the N-oxy radical group is changed by oxidation and reduction.

  As the redox compound, specifically, a compound represented by the following formula (1) or a compound having a group in which one hydrogen atom is eliminated from the compound represented by the following formula (1) Etc. The compound having a group in which one hydrogen atom is eliminated from the compound represented by the following formula (1) may be any compound having such a group, and is a compound bonded to another low molecular weight compound. It may be a polymer compound.

In formula (1), _{Z, -CR 5 R 6 CR 7 R} 8 -, - CR 9 R 10 CR 11 R 12 CR 13 R 14 -, - (CR 15 R 16) O -, - (CR 17 R _{18) NR 27 -, - (} CR 19 R 20) O (CR 21 R 22) -, _{or, - (CR 23 R 24)} NR 28 (CR 25 R 26) - _indicates, R 1 _{to R 28} are, Each independently represents a hydrogen atom or a substituent.

At least one of R _{1 to} R ₄ is preferably a substituent, more preferably two or more are substituents, and still more preferably all four are substituents. That is, the compound represented by the formula (1) is preferably a compound in which two quaternary carbons are bonded to the N-oxy radical group. The redox compound is preferably a compound in which two quaternary carbons are bonded to the N-oxy radical group, or a compound having a group in which one hydrogen atom is eliminated from the compound. Such a compound is likely to be oxidized / reduced by the N-oxy radical group, and it is considered that carbon dioxide can be taken in and released more favorably by the redox compound. For this reason, by including such a compound in the electrolyte layer, it is possible to obtain a carbon dioxide separator that can more suitably separate carbon dioxide from a gas containing carbon dioxide.

As the Z in the compound represented by the formula _{(1), -CR 5 R 6} CR 7 R 8 -, - CR 9 R 10 CR 11 R 12 CR 13 R 14 -, - (CR 19 R 20) O (CR ₂₁ R ₂₂ ) — and — (CR ₂₃ R ₂₄ ) NR ₂₈ (CR ₂₅ R ₂₆ ) — are preferable.

Examples of the substituent in R _{1 to} R ₂₈ include a hydrocarbyl group having 1 to 30 carbon atoms, a hydrocarbyloxy group having 1 to 10 carbon atoms, a hydroxy group (hydroxyl group), and an optionally substituted amino group ( An unsubstituted or substituted amino group), a carboxyl group, a thiol group, and an optionally substituted silyl group (unsubstituted or substituted silyl group). Further, as the substituent in R ₁ to R _26, among this, hydrocarbyl group having 1 to 30 carbon atoms, hydroxy group and unsubstituted or substituted amino group, are preferable. Moreover, as a substituent in said R <_27> , R < ₂₈ >, a C1-C30 hydrocarbyl group is preferable.

  In addition, the term “optionally substituted” means that the hydrogen atom constituting the compound or group described immediately after that is unsubstituted and the case where part or all of the hydrogen atoms are substituted with a substituent. Includes both.

  The hydrocarbyl group is not particularly limited, and may be linear, branched, or cyclic. Examples of the hydrocarbyl group include a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, a 1-butyl group, a 2-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a hexyl group, and an octyl group. Decyl group, dodecyl group, 2-ethylhexyl group, 3,7-dimethyloctyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, norbornyl group, ammonium ethyl group, benzyl group, α, α-dimethylbenzyl group, 1-phenethyl group, 2-phenethyl group, vinyl group, propenyl group, butenyl group, oleyl group, eicosapentaenyl group, docosahexaenyl group, 2,2-diphenylvinyl group, 1 , 2,2-triphenylvinyl group, 2-phenyl-2-propenyl group, phenyl group, 2-tolyl group, 4-tolyl group, 4-trifluoromethylphenyl group, 4-methoxyphenyl group, 4-cyanophenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, terphenylyl group, 3, 5-diphenylphenyl group, 3,4-diphenylphenyl group, pentaphenylphenyl group, 4- (2,2-diphenylvinyl) phenyl group, 4- (1,2,2-triphenylvinyl) phenyl group, fluorenyl group 1-naphthyl group, 2-naphthyl group, 9-anthryl group, 2-anthryl group, 9-phenanthryl group, 1-pyrenyl group, chrysenyl group, naphthacenyl group, and coronyl group. Among these, methyl group, ethyl group, 1-propyl group, 2-propyl group, 1-butyl group, 2-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group, decyl group, dodecyl group, 2 -Ethylhexyl group, 3,7-dimethyloctyl group, benzyl group, α, α-dimethylbenzyl group, 1-phenethyl group, 2-phenethyl group, vinyl group, propenyl group, butenyl group, oleyl group, eicosapentaenyl group , Docosahexaenyl group, 2,2-diphenylvinyl group, 1,2,2-triphenylvinyl group, 2-phenyl-2-propenyl group, phenyl group, 2-tolyl group, 4-tolyl group, 4-tril group Fluoromethylphenyl group, 4-methoxyphenyl group, 4-cyanophenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, ter Phenylyl group, 3,5-diphenylphenyl group, 3,4-diphenylphenyl group, pentaphenylphenyl group, 4- (2,2-diphenylvinyl) phenyl group, 4- (1,2,2-triphenylvinyl) A phenyl group, a fluorenyl group, a 1-naphthyl group, a 2-naphthyl group, a 9-anthryl group, a 2-anthryl group, and a 9-phenanthryl group are preferable. Furthermore, among these, methyl group, ethyl group, 1-propyl group, 2-propyl group, 1-butyl group, 2-butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, octyl group, 2- An ethylhexyl group, a 3,7-dimethyloctyl group, a benzyl group, and a phenyl group, and more preferably a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, a 1-butyl group, a 2-butyl group, and an isobutyl group. A group, a tert-butyl group, a pentyl group, and a hexyl group are more preferable.

  The hydrocarbyloxy group is not particularly limited, and may be linear, branched, or cyclic. Examples of the hydrocarbyloxy group include methoxy group, ethoxy group, 1-propyloxy group, 2-propyloxy group, 1-butoxy group, 2-butoxy group, isobutoxy group, tert-butoxy group, pentyloxy group, and hexyl. Oxy group, octyloxy group, decyloxy group, dodecyloxy group, 2-ethylhexyloxy group, 3,7-dimethyloctyloxy group, cyclopropanoxy group, cyclopentyloxy group, cyclohexyloxy group, 1-adamantyloxy group, 2 -Adamantyloxy group, norbornyloxy group, ammonium ethoxy group, trifluoromethoxy group, benzyloxy group, α, α-dimethylbenzyloxy group, 2-phenethyloxy group, 1-phenethyloxy group, phenoxy group, alkoxyphenoxy Group, alkyl Examples include phenoxy group, 1-naphthyloxy group, 2-naphthyloxy group, and pentafluorophenyloxy group. Among these, methoxy group, ethoxy group, 1-propyloxy group, 2-propyloxy group, 1-butoxy group, 2-butoxy group, tert-butoxy group, pentyloxy group, hexyloxy group, octyloxy group, decyloxy group , Dodecyloxy group, 2-ethylhexyloxy group, and 3,7-dimethyloctyloxy group are preferable. Furthermore, among these, methoxy group, ethoxy group, 1-propyloxy group, 2-propyloxy group, 1-butoxy group, 2-butoxy group, isobutoxy group, tert-butoxy group, pentyloxy group, and hexyloxy group are included. More preferred.

  The amino group is not particularly limited, and may be linear, branched, or cyclic. Examples of the amino group include methylamino group, ethylamino group, 1-propylamino group, 2-propylamino group, 1-butylamino group, 2-butylamino group, isobutylamino group, tert-butylamino group, Pentylamino group, hexylamino group, octylamino group, decylamino group, dodecylamino group, 2-ethylhexylamino group, 3,7-dimethyloctylamino group, cyclopropylamino group, cyclopentylamino group, cyclohexylamino group, 1-adamantyl Amino group, 2-adamantylamino group, norbornylamino group, ammonium ethylamino group, trifluoromethylamino group, benzylamino group, α, α-dimethylbenzylamino group, 2-phenethylamino group, 1-phenethylamino group , Phenylamino group, alcohol Examples thereof include a xylphenylamino group, an alkylphenylamino group, a 1-naphthylamino group, a 2-naphthylamino group, and a pentafluorophenylamino group. Among these, methylamino group, ethylamino group, 1-propylamino group, 2-propylamino group, 1-butylamino group, 2-butylamino group, tert-butylamino group, pentylamino group, hexylamino group, octyl An amino group, a decylamino group, a dodecylamino group, a 2-ethylhexylamino group, and a 3,7-dimethyloctylamino group are preferred. Furthermore, among these, methylamino group, ethylamino group, 1-propylamino group, 2-propylamino group, 1-butylamino group, 2-butylamino group, isobutylamino group, tert-butylamino group, pentylamino group And hexylamino groups are more preferred.

  The silyl group is not particularly limited. Examples of the silyl group include dimethylsilyl group, diethylsilyl group, diphenylsilyl group, trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, t-butyldiphenylsilyl group, and tristrimethylsilyl group.

  The compound represented by the formula (1) is preferably a compound in which two quaternary carbons are bonded to the N-oxy radical group as described above. In this way, it is considered that radical stericity is enhanced and radical coupling can be suppressed by bonding a group having a large steric hindrance to a site adjacent to the N-oxy radical group. For this reason, it is considered that a carbon dioxide separator capable of more suitably separating carbon dioxide from a gas containing carbon dioxide can be obtained by including such a compound in the electrolyte layer.

  Examples of the compound represented by the formula (1) include N, N-di-tert-butyl nitroxide radical, N, N-diphenyl nitroxide radical, N, N-dinaphthyl nitroxide radical, N, N- Di-2-methylphenyl nitroxide radical, N, N-di-3-methylphenyl nitroxide radical, N, N-di-4-methylphenyl nitroxide radical, N, N-di-2-ethylphenyl nitroxide radical, N, N-di-2-propylphenyl nitroxide radical, N, N-di-2-butylphenyl nitroxide radical, N, N-di-2-pentylphenyl nitroxide radical, N, N-di-2-hexylphenyl nitroxide radical, N, N-di-2-isopropylphenyl nitroxide radical, N, -Di-2-isobutylphenyl nitroxide radical, N, N-di-2-sec-butylphenyl nitroxide radical, N, N-di-2-tert-butylphenyl nitroxide radical, N, N-di-4-tert- Butylphenyl nitroxide radical, N, N-di- (3,5-di-tert-butyl) phenyl nitroxide radical, N, N-di-4-pyridyl nitroxide radical, N, N-di-4-pyridazyl nitroxide Radical, poly (ethylene glycol) -bis-2,2,6,6-tetramethylpiperidinyloxy radical, N-phenyl-N-oxy-tert-butylamine, N-naphthyl-N-oxy-tert-butylamine, N-tert-butyl-N-oxy-2-quinoline, 2,2,6,6-tetramethyl Lupiperidinyloxy radical (TEMPO), 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy radical, 4-amino-2,2,6,6-tetramethylpiperidinyloxy radical, 4 -Carboxy-2,2,6,6-tetramethylpiperidinyloxy radical, 4-methoxy-2,2,6,6-tetramethylpiperidinyloxy radical, 4-oxo-2,2,6,6 -Tetramethylpiperidinyloxy radical, 4-acetamido-2,2,6,6-tetramethylpiperidinyloxy radical, 4-octyloxy-2,2,6,6-tetramethylpiperidinyloxy radical, 2,2,5,5-tetramethylpyrrolidine-oxy radical, 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-oxira Dicar, 3-carboxy-2,2,5,5-tetramethylpyrrolidine-oxy radical, 2,2,6,6-tetramethylmorpholine-N-oxy radical, and 2,2,6,6-tetramethylmorpholine And piperazine-N-oxy radical.

  Further, as described above, the redox compound may be a polymer compound, and examples thereof include a compound obtained by polymerizing the compound represented by the formula (1). Examples of the polymer compound include 4-acryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical, 4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical. 3-acryloyloxy-2,2,6,6-tetramethylpyrrolidinyloxy radical, 3-methacryloyloxy-2,2,6,6-tetramethylpyrrolidinyloxy radical, 4-vinyloyloxy-2,2 , 6,6-tetramethylpiperidinyloxy radical, 4-vinyloyloxy-2,2,5,5-tetramethylpyrrolidinyloxy radical, and the like, and the like. Further, the polymer compound may be a compound obtained by polymerizing the monomer alone, or a compound obtained by polymerizing a combination of two or more of the monomers. The polymer compound may be a compound obtained by polymerizing the compound represented by the formula (1), or a copolymer of ethylene, propylene, butadiene, isoprene, styrene, vinyl acetate, or the like. It may be a copolymer copolymerized with a monomer. Moreover, this copolymer monomer may also be used independently and may be used in combination of 2 or more type.

  The compound represented by the formula (1) may be a compound obtained by synthesis by a predetermined synthesis method, or may be a commercially available product. The synthesis method is not particularly limited as long as the compound represented by the formula (1) is obtained, and examples thereof include a nitroxide method for oxidizing the amino group of the disubstituted amine compound.

  The electrolyte layer 13 may contain components other than the electrolytic solution and the redox compound. Examples of other components contained in the electrolyte layer 13 include polyethylene glycol, polyacrylate, polymethacrylate, and polyvinyl alcohol acetal.

  The electrolyte layer 13 may include a base material. Examples of the electrolyte layer 13 include those obtained by impregnating the base material with the electrolytic solution containing the redox compound. Examples of the substrate include glass fiber filter paper.

  The method for producing the desoldering layer 13 is not particularly limited as long as the electrolyte layer 13 can be produced. When the electrolyte layer 13 includes the base material, for example, a method of dispersing or dissolving the redox compound in the electrolytic solution and impregnating the base material with an electrolytic solution containing the redox compound can be cited. The impregnation is preferably performed while applying ultrasonic vibration to the electrolytic solution or the substrate. By doing so, it is possible to suppress the formation of minute holes, that is, pinholes, in the electrolyte layer.

  The voltage application unit 14 is not particularly limited as long as a voltage can be applied between the pair of electrodes 11 and 12. That is, as described above, the voltage application unit 14 applies a voltage between the pair of electrodes 11 and 12 so as to increase the potential of either electrode between the pair of electrodes 11 and 12. The voltage application unit 14 applies the potential of the first electrode on the side of taking in carbon dioxide from the gas containing carbon dioxide to be always lower than the second electrode on the side of releasing carbon dioxide from the electrolyte layer. It is preferable. By doing so, carbon dioxide is taken in on the first electrode side only by applying the voltage application unit so that the potential of the first electrode is always lower than the potential of the second electrode, and the first electrode Carbon dioxide can be released on the two electrode side. Therefore, carbon dioxide can be more easily separated from the gas containing carbon dioxide. That is, in the carbon dioxide separator according to this embodiment, the voltage application unit simply applies a voltage between the pair of electrodes 11 and 12 without inverting the voltage applied between the electrodes (the potential of each electrode). Carbon dioxide can be separated without switching between high and low. The voltage application unit 14 may be an application unit that cannot reverse the voltage applied between the electrodes. Examples thereof include a secondary battery, an external power source, and a capacitor.

  Moreover, the said 1st flow path 15 and the said 2nd flow path 16 will not be specifically limited if it is a flow path which can distribute | circulate gas.

  Moreover, the manufacturing method of the carbon dioxide separation device 10 is not particularly limited as long as the carbon dioxide separation device 10 can manufacture the above-described structure. Specifically, using the electrodes 11, 12, the electrolyte layer 13, the voltage application unit 14, the first flow path 15, and the second flow path 16, the structure shown in FIG. The method of assembling by a general assembling method is mentioned.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[Example 1]
<Production of carbon dioxide separator>
A carbon dioxide separator having the structure shown in FIG. 1 was produced by the following procedure.

(Electrolyte layer (carbon dioxide separator))
To 14.6 g (0.1 mol) of 1-butyl-3-methylimidazolium chloride (Sigma Aldrich), which is an electrolytic solution (ionic liquid) capable of dissolving carbon dioxide, is 4-octyloxy, which is the redox compound. 28.4 g (0.1 mol) of −2,2,6,6-tetramethylpiperidinyloxy radical and 5 g of polyethylene glycol (molecular weight 10,000) were added, heated to 40 ° C., and mixed with stirring. The liquid thus obtained was impregnated into glass fiber filter paper (GC50 manufactured by ADVANTEC). And the ultrasonic vibration was given to the said liquid in which the said glass fiber filter paper was immersed. By doing so, an electrolyte layer (carbon dioxide separator) was obtained. When the obtained electrolyte layer was visually confirmed, minute holes (pinholes) could not be confirmed.

(electrode)
Carbon paper (GDL35BC manufactured by SGL Carbon Japan Co., Ltd.) was cut into a size of 20 mm long × 20 mm wide × 1 mm thick. A conductive copper foil tape was attached to one surface of the cut out carbon paper. Two of these were prepared and used as each electrode (cathode electrode and anode electrode).

(Flow path)
A resin plate made of polytetrafluoroethylene was cut into a size of 50 mm long × 50 mm wide × 5 mm thick, and two holes were made at appropriate positions. A groove having a depth of 1 mm, a length of 20 mm, and a width of 20 mm connected to the hole was dug in the cut out resin plate. Two of these were prepared and used as each flow path (first flow path and second flow path).

(Carbon dioxide separator)
The electrolyte layer, the electrode, and the flow path were assembled so that the structure shown in FIG. 1 was obtained, and a power source as a voltage application unit was connected to the conductive copper foil tape of the electrode. By doing so, the carbon dioxide separator having the structure shown in FIG. 1 was manufactured.

[Evaluation]
The carbon dioxide separator was evaluated by the following evaluation method.

  First, the carbon dioxide separator was installed in an environment of room temperature (28 ° C.), and a gas bag filled with carbon dioxide was attached to the hole of the channel on the cathode side electrode side. A portable carbon dioxide concentration meter (CGP-31 manufactured by Toa DKK Co., Ltd.) was attached to the hole of the channel on the anode side electrode side. The dioxide concentration measured at the time of wearing was 0.4%. And the voltage (0.5V, 1.5V, 3V) shown in following Table 1 was applied between the said electrodes by adjusting the said power supply. After applying the voltage, the carbon dioxide concentration after 10 minutes was measured.

  As a result, when the applied voltage was 0.5 V, the carbon dioxide concentration was 15.3%. When the applied voltage was 1.5 V, the carbon dioxide concentration was 45%. When the applied voltage was 3V, the carbon dioxide concentration was 90.1%. These results are shown in Table 1.

[Example 2]
As an electrolytic solution (ionic liquid) capable of dissolving carbon dioxide, 42.9 g of 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonylimide) is used instead of 1-butyl-3-methylimidazolium chloride. A carbon dioxide separator was manufactured in the same manner as in Example 1 except that. And evaluation similar to Example 1 was performed using the obtained carbon dioxide separator.

  The results are shown in Table 1.

[Example 3]
As a redox compound, 4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical is used as a monomer instead of 4-octyloxy-2,2,6,6-tetramethylpiperidinyloxy radical Except that 24.0 g of the compound obtained by polymerization as [poly (4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical)] was used and polyethylene glycol was not added In the same manner as in Example 1, a carbon dioxide separator was manufactured. And evaluation similar to Example 1 was performed using the obtained carbon dioxide separator.

  The results are shown in Table 1.

[Comparative Example 1]
A compound obtained by polymerizing redox compound 4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical as a monomer [poly (4-methacryloyloxy-2,2,6,6- 28.4 g of tetramethylpiperidinyloxy radical)] was dissolved in 30.0 g of toluene. This solution was dropped on the entire surface of glass fiber filter paper (GC50 manufactured by ADVANTEC). Thereafter, the glass fiber filter paper onto which the solution was dropped was dried under a nitrogen atmosphere. By doing so, toluene was removed and the solid electrolyte layer was obtained. A carbon dioxide separator was manufactured in the same manner as in Example 1 except that this electrolyte layer was used. And evaluation similar to Example 1 was performed using the obtained carbon dioxide separator.

  The results are shown in Table 1.

[Comparative Example 2]
A carbon dioxide separator was produced in the same manner as in Example 1 except that no redox compound was added. And evaluation similar to Example 1 was performed using the obtained carbon dioxide separator.

  The results are shown in Table 1.

  As can be seen from Table 1, a carbon dioxide separator (Example 1) in which an electrolyte layer containing an electrolyte solution capable of dissolving carbon dioxide and a redox compound having an N-oxy radical group in the molecule is sandwiched between a pair of electrodes. In 3), separation of carbon dioxide from a gas containing carbon dioxide could be confirmed only by applying a voltage between the pair of electrodes with a power source.

  On the other hand, when a solid electrolyte layer made of a redox compound having no N-oxy radical group in the molecule is used (Comparative Example 1), the carbon dioxide is not contained. Carbon dioxide could not be separated from the contained gas. This is considered to be due to the fact that carbon dioxide cannot be taken into the electrolyte layer and that the adsorption and desorption of carbon dioxide by the redox compound could not contribute to the separation of carbon dioxide. In addition, when an electrolyte layer containing an electrolyte solution capable of dissolving carbon dioxide but not containing a redox compound having an N-oxy radical group in the molecule is used (Comparative Example 2), carbon dioxide is removed from a gas containing carbon dioxide. Was slightly separated, but the separability was significantly reduced compared to Examples 1-3. This is presumably because the redox compound does not contain the carbon dioxide separation function of the redox compound.

DESCRIPTION OF SYMBOLS 10 Carbon dioxide separator 11, 12 Electrode 13 Electrolyte layer 14 Voltage application part 15 1st flow path 16 2nd flow path

Claims (5)

An electrolyte layer;
A pair of electrodes provided on the electrolyte layer with the electrolyte layer interposed therebetween,
A voltage application unit for applying a voltage between the pair of electrodes,
Each of the pair of electrodes is an electrode capable of transmitting gas,
The carbon dioxide separator characterized by the said electrolyte layer containing the electrolyte solution which can melt | dissolve a carbon dioxide, and the redox compound which has a N-oxy radical group in a molecule | numerator. The pair of electrodes includes a first electrode on the side for taking in carbon dioxide from a gas containing carbon dioxide, and a second electrode on the side for releasing carbon dioxide from the electrolyte layer,
The carbon dioxide separator according to claim 1, wherein the voltage application unit applies the potential of the first electrode so that the potential of the first electrode is always lower than the potential of the second electrode.   The carbon dioxide separator according to claim 1 or 2, wherein the redox compound is a compound in which two quaternary carbons are bonded to the N-oxy radical group. The redox compound is a compound represented by the following formula (1) or a compound having a group in which one hydrogen atom is eliminated from the compound represented by the following formula (1). The carbon dioxide separator according to any one of claims.

[In formula (1), _{Z, -CR 5 R 6 CR 7 R} 8 -, - CR 9 R 10 CR 11 R 12 CR 13 R 14 -, - (CR 15 R 16) O -, - (CR 17 R < ₁₈ >) NR < ₂₇ >-,-(CR < ₁₉ > R < ₂₀ >) O (CR < ₂₁ > R < ₂₂ >)-, or-(CR < ₂₃ > R < ₂₄ >) NR < ₂₈ > (CR < ₂₅ > R < ₂₆ >)-", wherein R < ₁ > to R < ₂₈ > are And each independently represents a hydrogen atom or a substituent. ]   The carbon dioxide separator according to any one of claims 1 to 3, wherein the electrode is an electrode including at least one selected from the group consisting of graphite, carbon nanotubes, and carbon fibers.

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