JP5738710B2 - Method for producing carbon dioxide separation membrane and carbon dioxide separation module - Google Patents

Description

The present invention relates to a method for manufacturing及Beauty carbon dioxide separation module carbon dioxide separation membrane.

In recent years, development of a technique for selectively separating and removing carbon dioxide in a mixed gas containing carbon dioxide has progressed. For example, as a global warming countermeasure, carbon dioxide in exhaust gas is separated, recovered, concentrated, and steam reformed to convert hydrocarbons to hydrogen and carbon monoxide (CO), and then to convert carbon monoxide and steam. Technology to obtain gas for fuel cells, etc., mainly composed of hydrogen by reacting to generate carbon dioxide and hydrogen, and eliminating and separating and removing carbon dioxide with a membrane that selectively permeates carbon dioxide. Yes.
On the other hand, for the separation of carbon dioxide, an amine absorption method that repeats adsorption and emission by amines is generally used and widely used. However, this method requires a large facility installation area, and it is necessary to repeat the pressure increase, the temperature decrease, the pressure decrease, and the temperature increase at the time of adsorption and dissipation, respectively, and a large amount of energy is required. . In addition, the capacity of the system is determined at the time of design, and it is not easy to expand or contract the capacity of the system once made.
In contrast, the membrane separation method performs natural separation by carbon dioxide partial pressure between two chambers partitioned through a separation membrane, and consumes less energy, and the installation area of the apparatus is an amine absorption method. It has the advantage of being compact compared to. In the case of the membrane separation method, since the capacity of the system can be increased or decreased by increasing or decreasing the filter unit, it is possible to design a system that can flexibly respond to the increase or decrease of the capacity.

Carbon dioxide separation membranes can be broadly divided into so-called facilitated transport membranes that contain carbon dioxide carriers in the membrane and transport carbon dioxide to the opposite side of the membrane, and the dissolution of carbon dioxide and substances to be separated into the membrane. And so-called dissolution diffusion membranes that perform separation utilizing the difference in diffusivity and diffusivity in the membrane. Dissolving and diffusion membranes are separated by the solubility and diffusion rate of carbon dioxide and the substance to be separated in the membrane, so if the material and physical properties of the membrane are determined, the degree of separation is uniquely determined. Therefore, it is generally manufactured as a thin film having a thickness of 1 μm or less by using a layer separation method, an interfacial polymerization method or the like.
On the other hand, the facilitated transport membrane increases the solubility of carbon dioxide by adding carbon dioxide carrier into the membrane and transports it in a high concentration environment. Has a high degree of separation and a high permeation rate of carbon dioxide.

The following are known as the facilitated transport membrane.
For example, after an uncrosslinked vinyl alcohol-acrylate copolymer aqueous solution is applied in a film form on a carbon dioxide permeable support, it is heated, crosslinked, water insolubilized, and carbon insoluble in this water insolubilized product. It has been proposed to produce a carbon dioxide separation gel membrane by absorbing an aqueous solution containing a carrier (a substance having an affinity for carbon dioxide) and gelling (Patent Document 1).

In addition, a gel layer in which an additive made of cesium carbonate, cesium bicarbonate or cesium hydroxide is added to a polyvinyl alcohol-polyacrylic acid copolymer gel film is supported on a hydrophilic porous film to form a CO ₂ facilitated transport film Then, a raw material gas containing at least carbon dioxide and water vapor in a predetermined main component gas is supplied to the raw material side surface of the CO2 facilitated transport film at a supply temperature of 100 ° C. or more, and the carbon dioxide permeated through the carbon dioxide facilitated transport film is permeated. A carbon dioxide separator that is taken out from the side has been proposed (Patent Document 2).

Japanese Patent Publication No. 7-102310 JP 2009-195900 A

In any of the films described in Patent Document 1 or 2, carbon dioxide in the raw material gas supplied to one surface of the film is the following on the surface of the film (hereinafter also referred to as “absorption side surface”). (Hereinafter, this reaction is also referred to as “positive reaction”) and diffuses along the concentration gradient in the form of bicarbonate ions and carbonate ions in the membrane. It is released as carbon dioxide from the surface of the membrane opposite to the surface (hereinafter, also referred to as “dissipation side surface”) according to the reaction formula in the reverse direction of the reaction formula represented by the following formula 1. Also called “reaction”.).
^{_{CO 2 + OH - → HCO 3}} - ··· Formula 1

The molar amount of bicarbonate ions and carbonate ions that can be dissolved in water is much larger than the molar amount that can dissolve carbon dioxide. Therefore, the rate of carbon dioxide permeating the membrane is rarely the rate of diffusion of these bicarbonate ions and carbonate ions in the membrane, and the reaction rate of the reaction formula represented by the above formula 1 The rate of carbon dioxide permeation is limited.
The forward reaction in the above reaction formula is promoted at the basic pH, and the reverse reaction is promoted at the acidic pH. For this reason, simultaneously promoting both reactions within the same membrane is a contradictory event.

  This invention makes it a subject to solve said problem in a carbon dioxide facilitated transport film | membrane. That is, an object of the present invention is to provide a carbon dioxide separation membrane excellent in both selective absorption and diffusion of carbon dioxide, a method for producing the same, and a membrane module using the same.

The present invention for achieving the above object is as follows.
<1> Absorption which has a gel film containing a water-absorbing polymer, a carbon dioxide carrier and water, and a support that supports the gel film, and is a side to which a mixed gas containing carbon dioxide in the gel film is supplied. A method for producing a carbon dioxide separation membrane in which the pH of the side surface is higher than the pH of the dissipating side surface, which is the surface opposite to the absorbing side surface , comprising a water-absorbing polymer, a carbon dioxide carrier on a transfer substrate And a layer in which the gel film transfer material and the support are overlapped so that the gel film of the gel film transfer material faces the support. A method for producing a carbon dioxide separation membrane comprising at least one step of transferring a gel membrane, comprising producing a body and peeling the transfer substrate of the laminate at the interface with the gel membrane .
<2> The method for producing a carbon dioxide separation membrane according to <1>, wherein the gel membrane of the carbon dioxide separation membrane includes at least two layers having different pHs.
<3> The gel membrane of the carbon dioxide separation membrane includes at least three layers stacked, and the pH of the layer having the absorption side surface is different from the pH of the layer having the diffusion side surface <1> or < The manufacturing method of the carbon dioxide separation membrane of 2>.
< 4 > The gel membrane of the carbon dioxide separation membrane has a pH of the absorption side surface of 8.0 or more, a pH of the diffusion side surface of 4.0 or more and less than 8.0, or these The method for producing a carbon dioxide separation membrane according to any one of <1> to <3>, which satisfies both .
<5> The transfer step is included at least twice, and the pH of the gel film in one transfer step is 8.0 or more, and the pH of the gel film in the other transfer step is 4.0 or more and 8.0. The manufacturing method of the carbon dioxide separation membrane as described in any one of <1>-<4> which is less than.
<6> Absorption which has a gel film containing a water-absorbing polymer, a carbon dioxide carrier and water, and a support that supports the gel film, and is a side to which a mixed gas containing carbon dioxide in the gel film is supplied. A method for producing a carbon dioxide separation membrane in which the pH of the side surface is higher than the pH of the dissipating side surface, which is the surface opposite to the absorbing side surface, comprising a water-absorbing polymer, a carbon dioxide carrier and water on a support At least twice, the gel film formed by one of the coating processes has a pH of 8.0 or more, and the pH of the gel film formed by the other coating process is 4. The manufacturing method of the carbon dioxide separation membrane which is 0 or more and less than 8.0.
< 7 > The method for producing a carbon dioxide separation membrane according to any one of <1> to < 6 > , wherein the pH of the carbon dioxide separation membrane decreases from the absorption side surface toward the diffusion side surface.
< 8 > The gel membrane of the carbon dioxide separation membrane includes at least three layers stacked, and the total thickness of the layers excluding the layer having the absorption side surface and the layer having the diffusion side surface is 10 μm to 100 μm. The method for producing a carbon dioxide separation membrane according to any one of <1> to < 7 >.
< 9 > Any one of <1> to < 8 >, wherein the carbon dioxide carrier is at least one compound selected from the group consisting of alkali metal carbonates, alkali metal bicarbonates, and alkali metal hydroxides. A method for producing a carbon dioxide separation membrane according to the above.

<10> a container having a space inside, dividing the space into first chamber and the second chamber, by the method for producing a carbon dioxide separation membrane according to any one of <1> to <9> A carbon dioxide separation module comprising: a produced carbon dioxide separation membrane; and at least a pair of inlets and outlets formed in the container and independently communicating with the first and second chambers.
< 11 > The carbon dioxide separation module according to < 10 >, wherein the carbon dioxide separation membrane has a pleated shape.

  According to the present invention, a carbon dioxide separation membrane having excellent carbon dioxide permeability and carbon dioxide selectivity, a production method thereof, and a carbon dioxide separation module using the same are provided.

It is sectional drawing of the carbon dioxide separation membrane which has a gel membrane comprised by the three layers which concern on this invention. It is explanatory drawing showing the relationship of pH of each layer which concerns on one embodiment of the three layers which comprise the gel membrane of the carbon dioxide separation membrane which concerns on FIG. It is explanatory drawing showing the relationship of pH of each layer which concerns on another embodiment of the three layers which comprise the gel membrane of the carbon dioxide separation membrane which concerns on FIG. It is a partial notch perspective view of the carbon dioxide separation module concerning one embodiment using the carbon dioxide separation membrane concerning the present invention. It is a schematic perspective view of the carbon dioxide separation module which concerns on another embodiment using the carbon dioxide separation membrane which concerns on this invention. It is sectional drawing in the surface which bisects the entrance 566 of FIG.

  The carbon dioxide separation membrane according to the present invention has a gel membrane containing a water-absorbing polymer, a carbon dioxide carrier and water, and a support that supports the gel membrane, and the mixed gas containing carbon dioxide in the gel membrane is The pH of the absorption side surface that is the supply side is higher than the pH of the diffusion side surface that is the surface opposite to the absorption side surface.

-Gel membrane-
The gel film may be composed of one layer or a plurality of layers as long as the pH of one surface is different from the pH of the other surface on the opposite side. . The gel film is preferably composed of at least two layers because it is easy to control the pH of the one surface and the pH of the other surface. In this case, it is preferable to arrange each layer so that the pH decreases from the layer having the absorption side surface toward the layer having the diffusion side surface. The gel membrane is more preferably composed of at least three layers from the viewpoint that a carbon dioxide separation efficiency can be obtained.
In the gel film, the pH of the absorption side surface is preferably 7.0 or more, more preferably 7.5 or more, and more preferably 8.0 or more from the viewpoint that the positive reaction according to the above formula 1 proceeds efficiently. Most preferred. Although there is no restriction | limiting in the upper limit of pH of the absorption side surface, it is 12 or less from a practical viewpoint, More preferably, it is 11.8 or less, Most preferably, it is 11.5 or less.

  In addition, the gel film preferably has a pH of the diffusion side surface of 1.0 to 9.5, more preferably 3.0 to 8.0, from the viewpoint that the reverse reaction according to Formula 1 proceeds efficiently. A range is more preferable, and a range of 4.0 to 8.0 is most preferable.

When the gel film is composed of at least three layers, the pH of the central layer sandwiched between the layer having the absorption side surface and the layer having the diffusion side surface is formed by the positive reaction according to Formula 1 above. As long as the bicarbonate ion (HCO ₃ ⁻ ) is maintained in a dissolved state (that is, it cannot be dissolved in the layer by being converted into carbon dioxide by the reverse reaction) Also good.
The pH of the central layer is preferably higher than the pH of the diffusion side surface, and is appropriately selected from the range of 8.0 to 12.5. The pH of the central layer is more preferably selected from a range lower than the pH of the absorption side surface and higher than the pH of the diffusion side surface.

FIG. 1 is a schematic cross-sectional view showing a carbon dioxide separation membrane having a gel membrane composed of three layers according to the present invention. In FIG. 1, the carbon dioxide separation membrane 1 is provided with a gel membrane 20 composed of three layers of a first layer 21, a second layer 22, and a third layer 23 on one surface of a support 10. It has been. A support (not shown) may be further provided on the surface of the third layer 23.
The gel membrane 20 according to the carbon dioxide separation membrane 1 shown in the cross-sectional view of FIG. 1 has an absorption-side surface S to which a mixed gas containing carbon dioxide is supplied on the surface opposite to the support 10 of the third layer 23. The surface on the support 10 side of the first layer 21 is a radiation-side surface R that releases carbon dioxide. Accordingly, the pH of the third layer 23 is set to be higher than the pH of the first layer 21.

FIG. 2 is an explanatory diagram showing the pH relationship of each layer from the first layer 21 to the third layer 23 according to an embodiment of the gel membrane 20 of the carbon dioxide separation membrane according to FIG. As shown in FIG. 2, in this embodiment, the pH is set to increase stepwise in the order of the first layer 21 to the third layer 23.
FIG. 3 is an explanatory diagram showing the pH relationship of each layer from the first layer 21 to the third layer 23 according to another embodiment of the gel membrane 20 of the carbon dioxide separation membrane according to FIG. As shown in FIG. 3, in this embodiment, the pH of the third layer 23 is set higher than the pH of the first layer 21, and the pH of the second layer 22 is It is set to gradually increase from the layer 21 side toward the third layer 23.

The component constituting the gel film containing the carbon dioxide carrier and water as described above is composed of a water-absorbing polymer for forming a gel film, a carbon dioxide carrier and water, and further promotes carbon dioxide absorption as necessary. Additives such as agents and set agents may be included.
Hereinafter, each of these components will be described.
-Water-absorbing polymer-
The water-absorbing polymer is preferably a functional polymer so that the gel film has a desired pH.
Here, the “functional polymer” means a polymer having at least one functional group selected from a basic group and an acidic group having a function of determining the pH of the polymer in the polymer molecule. The “base” and “acid” in the basic group and acidic group include broad bases and acids. The pH of the polymer is determined by the method described later.

Such functional groups include the following monovalent to tetravalent groups.
For example, carboxyl group, phosphoric acid group, phosphonic acid group, phosphinic acid group, thiol group, amino group, hydroxyl group, cyano group, ether group, thioether group, amine group, imine group, amide group, imide group, carbonamido group , Sulfonamide groups, carbamine groups, sulfamine groups, groups containing quaternary nitrogen atoms, sulfonium groups, and the like.
These groups may be contained alone in the polymer structure, or two or more kinds may be contained in combination.

Specific examples of suitable functional polymers include, for example, polyvinyl alcohol, polyacrylic acid, poly 1-hydroxy-2-propyl acrylate, polyethylene oxide modified phosphate methacrylate, polyallyl sulfonic acid, polyvinyl sulfonic acid, polyacrylamide methylpropane. Examples include sulfonic acid, polyethyleneimine, polyallylamine, chitin, chitosan, gelatin, polylysine, polyglutamic acid, polyarginine, polyglycidyl methacrylate, poly 1-hydroxy-2-propyl acrylate, and polyethylene oxide-modified phosphate methacrylate.
Among these, polyvinyl alcohol, polyacrylic acid, polyethyleneimine, and polyallylamine, from the point of being excellent in at least one of water absorption, water retention, strength as a gel film, and carbon dioxide carrier supportability, These copolymers (for example, polyvinyl alcohol-polyacrylic acid copolymers) are preferably used.
The functional polymer may be further chemically modified as necessary, or other groups other than the functional group may be added. Moreover, you may bridge | crosslink.
The functional polymer can be selected from a wide range of molecular weights as long as the gel film is formed, but generally the weight average molecular weight is in the range of 1,000 to 5,000,000. Selected from things.

These functional polymers may be used alone or in combination of two or more.
The content of the functional polymer in each layer constituting the gel membrane is preferably 0.5 to 50% by mass from the viewpoint of forming a membrane and allowing the carbon dioxide separation membrane to sufficiently retain moisture. Is more preferably 1 to 30% by mass, and particularly preferably 2 to 15% by mass.

-Carbon dioxide carrier-
The carbon dioxide carrier is various water-soluble inorganic substances having affinity with carbon dioxide and showing basicity, and means alkali metal carbonates, alkali metal bicarbonates, and alkali metal hydroxides. .

Examples of the alkali metal carbonate include lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, and cesium carbonate.
Examples of the alkali metal bicarbonate include lithium hydrogen carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, rubidium hydrogen carbonate, and cesium hydrogen carbonate.
Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide and the like.
Among these, a compound containing potassium, rubidium and cesium is preferable from the viewpoint of good affinity with carbon dioxide.

  Although the content of carbon dioxide carrier in each layer constituting the gel membrane depends on the ratio to the amount of the functional polymer, the function as a carbon dioxide carrier is exhibited and stable as a carbon dioxide separation membrane in the use environment. From the point of being excellent in property, it is preferably 0.1 to 30% by mass, more preferably 0.2 to 20% by mass, and particularly preferably 0.3 to 15% by mass.

-Additives-
<Carbon dioxide absorption promoter>
The carbon dioxide absorption promoter is a compound that promotes the reaction between carbon dioxide and a carbon dioxide carrier, and means a nitrogen-containing compound or a sulfur oxide.

Examples of the nitrogen-containing compound include amino acids such as glycine, alanine, serine, proline, histidine, taurine, and diaminopropionic acid, hetero compounds such as pyridine, histidine, piperazine, imidazole, and triazine, monoethanolamine, diethanolamine, Alkanolamines such as triethanolamine, monopropanolamine, dipropanolamine, tripropanolamine, cyclic polyetheramines such as cryptand [2.1] and cryptand [2.2], cryptand [2.2.1] ], Bicyclic polyetheramines such as cryptand [2.2.2], porphyrin, phthalocyanine, ethylenediaminetetraacetic acid and the like can be used.
As the sulfur compound, for example, amino acids such as cystine and cysteine, polythiophene, dodecylthiol and the like can be used.
When a carbon dioxide promoter is added, it is added to at least one of the layers constituting the gel film, and the amount is suitably in the range of 20% by mass to 200% by mass with respect to the added layer.

<Set agent>
The set agent is a film-forming improver that helps the layer constituting the gel film to be in the form of a film, and it is preferable to use a polysaccharide having a property of increasing the viscosity when cooled.
Examples of the set agent include agar, gum arabic, κ-carrageenan, ι-carrageenan, λ-carrageenan, guar gum, locust bean gum, pectin, tragacanth, corn starch, and phosphorylated starch. Examples of animal natural polymers such as dextrin and gelatin include gelatin, casein, sodium chondroitin sulfate and the like. Examples of the cellulose type include ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, nitrocellulose, and cationized cellulose. Examples of the starch system include phosphorylated starch, and examples of the alginic acid system include sodium alginate and propylene glycol alginate, and other classifications include cationized guar gum and sodium hyaluronate.
The set agent is added to at least one of the layers constituting the gel film, and the amount thereof is suitably in the range of 0.5% by mass to 30% by mass with respect to the added layer.

<Crosslinking agent>
The crosslinking agent is added as desired in order to promote the crosslinking when the functional polymer contained in the layer constituting the gel film and the set agent added as necessary are crosslinked. The above crosslinking is generally performed with the help of heating or irradiation with infrared rays, ultraviolet rays, electron beams, radiations, or the like. In particular, in the case of a layer containing a polyvinyl alcohol-polyacrylate copolymer as a functional polymer, a compound having two or more functional groups capable of undergoing a thermal crosslinking reaction with the functional polymer is contained as a crosslinking agent. Is preferred. Specific examples include polyvalent glycidyl ether, polyhydric alcohol, polyvalent isocyanate, polyvalent aziridine, haloepoxy compound, polyvalent aldehyde, and polyvalent amine.

Here, as the polyvalent glycidyl ether, for example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, pentaerythritol poly Examples thereof include glycidyl ether, propylene glycol glycidyl ether, and polypropylene glycol diglycidyl ether.
Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, glycerin, polyglycerin, propylene glycol, diethanolamine, triethanolamine, polyoxypropyl, and oxyethyleneoxypropylene. Examples include block copolymers, pentaerythritol, and sobitol.

Examples of the polyvalent isocyanate include 2,4-toluylene diisocyanate and hexamethylene diisocyanate. Examples of the polyvalent aziridine include 2,2-bishydroxymethylbutanol-tris [3- (1-acylidinyl) propionate], 1,6-hexamethylenediethyleneurea, diphenylmethane-bis-4,4′-. N, N′-diethylene urea and the like can be mentioned.
Examples of the haloepoxy compound include epichlorohydrin and α-methylchlorohydrin.
Examples of the polyvalent aldehyde include glutaraldehyde and glyoxal.
Examples of the polyvalent amine include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and polyethyleneimine.

Of the crosslinking agents, glutaraldehyde is particularly preferable as the thermal crosslinking agent for the polyvinyl alcohol-polyacrylate copolymer.
The content of the crosslinking agent is suitably in the range of 0.1% by mass to 10% by mass with respect to the total mass of the functional polymer and the set agent added as necessary.

The pH of each layer constituting the gel film can be measured using a film surface pH meter (Seven Multi S40 manufactured by METTLER TOLEDO, Inc., pH meter, InLab @ Surface electrode). In an environment of 25 ° C., 30 microliters of ultrapure water (Millipore) is dropped on the membrane surface, and the pH value can be obtained by pressing the membrane surface pH electrode against the dropped ultrapure water and allowing to stand for 1 minute. .
Further, the pH of each layer after the lamination of the gel film composed of at least one layer provided on the support was cut with a microtome so that the angle formed with the surface of the gel film was 2 °, and the cutting surface The surface pH of each layer appearing on the surface can be measured by measuring with a membrane surface pH meter in the same manner as described above.

The pH of each layer constituting the gel film is appropriately selected by selecting the type of functional polymer that is a component constituting the layer, the type of carbon dioxide carrier, and the type of additive contained as necessary. It is adjusted to become.
For example, in the case of a layer constituting the absorption side surface of the gel film, an inorganic polymer having a basic functional group as the functional polymer, for example, polyethyleneimine, or an alkaline substance such as potassium carbonate as the carbon dioxide carrier is selected. By selecting a salt or an alkali metal hydroxide such as cesium hydroxide, or adding a carbon dioxide absorbent such as glycine, or a combination thereof, the pH is 8.0 or more. A layer is obtained.

  In the case of a layer constituting the release side surface of the gel film, an acid functional group having an acid functional group, for example, polyacrylic acid is selected as a functional polymer, and an aqueous solution thereof such as cesium carbonate as a carbon dioxide carrier. By selecting one having a pH of as low as possible, a layer having a pH of less than 8.0 can be obtained.

The thickness of the gel film is suitably in the range of 5 μm to 2 mm, including the case where it is composed of at least two layers. By setting it as such a range, a carbon dioxide can be efficiently removed from the mixed gas containing a carbon dioxide. The total thickness of the gel film is more preferably in the range of 10 μm to 1 mm, and still more preferably in the range of 20 μm to 500 μm.
When the gel film is composed of at least two layers, each layer has a thickness of 1 μm or more and less than 2 mm. The ratio between the plurality of layers constituting the gel film can be selected from a wide range of ratios, but the ratio between two layers arbitrarily selected from the plurality of layers is 1 : It is suitable to be selected from the range of 100 to 50:50.
When the gel film is composed of at least three layers, the total thickness of the central layer excluding the two outer layers of the layer having the absorption side surface and the layer having the diffusion side surface is equal to the outer layer. It is preferable to make it thicker than the thickness of each layer because the performance of removing carbon dioxide is enhanced. The total thickness of the central layer is preferably 1 μm to 2 mm, more preferably 5 μm to 500 μm, and most preferably 10 μm to 100 μm.

-Support-
The support supports the carbon dioxide separation membrane, has carbon dioxide permeability, can stably hold the gel membrane over a long period of time, and can support this membrane. If there is no particular limitation.
Suitable materials for the support include paper, fine paper, coated paper, cast coated paper, synthetic paper, and cellulose, polyester, polyolefin, polyamide, polyimide, polysulfone aramid, polycarbonate, metal, glass, ceramics, etc. it can. More specifically, resin materials such as polypropylene, polyethylene, polystyrene, polyetherimide, polyphenyl sulfide, polyethylene terephthalate, polytetrafluoroethylene (PTFE), and polyvinylidene fluoride can be suitably used. Among these, polyolefins and fluorides thereof can be particularly preferably used from the viewpoint of stability over time that is stably maintained without deterioration over a long period of time.

The support made of the material as described above is porous from the viewpoint of ensuring carbon dioxide permeability. For example, when a resin material is used as a raw material, a woven fabric, a non-woven fabric, or a film having a large number of through holes is used. In the case of a support made of an inorganic material such as metal, glass, or ceramic, a porous material is used.
Of these, a support having a high self-supporting property and a high porosity can be preferably used. Polyphenylsulfide, polysulfone, cellulose membrane filter membranes, polytetrafluoroethylene, polyvinylidene fluoride, high-molecular-weight polyethylene stretched porous membranes, etc. have high porosity and low carbon dioxide diffusion inhibition. From the viewpoints of strength, manufacturability, and the like. Among these, a stretched film of polytetrafluoroethylene is particularly preferable.
These supports may be composed of a single material or may be a composite material integrated with a reinforcing support.

  The shape of the support may be a flat plate or a cylinder. The cylinder includes a tube and a hollow fiber. Further, it is advantageous that the walls constituting the flat plate and the cylinder have a large surface area such as a pleat shape.

In the case of flat membranes and tubes, the thickness of the support is preferably in the range of 30 to 500 μm from the viewpoint of carbon dioxide permeability and gel membrane support. Furthermore, 50-300 micrometers is more preferable, Furthermore, 50-200 micrometers is especially preferable. Here, in the case of a tube, it means the thickness of the wall of the tube.
In the case of a hollow fiber, the wall thickness is preferably in the range of 1 μm to 5 μm.
When the material of the support is hydrophobic, it is preferable to provide a gel film after treating the surface to be hydrophilic.

(Production method of carbon dioxide separation membrane)
The method for producing a carbon dioxide separation membrane of the present invention is not particularly limited as long as a gel membrane can be formed on a support. Specifically, a coating step of coating a composition containing a water-absorbing polymer, a carbon dioxide carrier and water constituting the gel film on a desired substrate, and a part of the water of the composition coated on the substrate A gel film is formed on the base material by a drying step of evaporating and removing. When the composition contains a polysaccharide having a property of increasing the viscosity by cooling, it is preferable to insert a cooling step subsequent to the coating step and then perform the drying step.
As the substrate, a support may be used, or a transfer substrate different from the support may be used. When a gel film transfer material in which a gel film is formed on a transfer substrate is prepared, a laminate is produced in which the gel film side of the gel film transfer material is opposed to the surface of the support, and this laminate is produced. From the above, by separating the transfer substrate at the interface with the gel membrane, the gel membrane of the gel membrane transfer material is transferred onto the support, and a carbon dioxide separation membrane having the gel membrane on the support is produced. .
When the gel film is composed of two or more layers, prepare individual gel film transfer materials in which each layer is formed on a separate transfer substrate in advance, and transfer these individual gel film The material layer is sequentially transferred onto the support, or the individual gel film transfer material layers are temporarily transferred onto a temporary substrate to temporarily form a gel film composed of two or more layers. It is advantageous to employ a method for producing a carbon dioxide separation membrane by forming the gel membrane on the temporary substrate and transferring the gel membrane onto the support after being formed on the substrate.

As a method for applying the composition, a conventionally known method can be employed. Examples include curtain flow coaters, extrusion die coaters, air doctor coaters, blade coaters, rod coaters, knife coaters, squeeze coaters, reverse roll coaters, and bar coaters. In particular, an extrusion die coater is preferable from the viewpoint of film thickness uniformity, coating amount, and the like.
Further, when the gel film is composed of at least two layers, it may be a sequential coating method in which layers are applied one by one or a simultaneous multilayer coating method.

When the gel film is composed of at least two layers, the at least two layers formed on the support may be formed so as to be superimposed on one surface of the support, or both of the supports It may be divided into planes. In the latter case, the voids of the support are filled with at least one layer component constituting the gel film.
The carbon dioxide separation membrane is preferably in a shape in which the gel membrane is sandwiched between two supports because it is less likely to be physically damaged during handling.

(CO2 separation module)
The carbon dioxide separation module according to the present invention includes a container having a space inside thereof, a carbon dioxide separation membrane that divides the space into a first chamber and a second chamber, and each of the first and second chambers. The container has at least a pair of inlets and outlets communicating with each other.
The shape of the carbon dioxide separation membrane used in the carbon dioxide separation module can take a known form such as a spiral type, a pleat type, or a flat membrane. Hereinafter, the module will be described taking the case of a flat membrane and the case of a pleat type as an example.
FIG. 4 is a perspective view showing an embodiment of the carbon dioxide separation module according to the present invention, in which a part of the wall of the container is cut out at a cutout portion A. FIG.
In the carbon dioxide separation module 40 according to FIG. 4, a space 45 inside the cylindrical container 43 is partitioned by a carbon dioxide separation membrane 42 into a first chamber 451 and a second chamber 452. A pair of inlets 461 and outlets 462 that communicate with the first chamber 451 are provided in the container 43, and a pair of inlets 466 and outlets 467 that communicate with the second chamber 452 are provided.
The carbon dioxide separation membrane 42 has, for example, the same cross-sectional structure as the carbon dioxide separation membrane 1 shown in FIG. 1, the absorption side surface S faces the first chamber 451, and the diffusion side surface R is the second. It is installed so as to face the chamber 452. The outer peripheral end face of the carbon dioxide separation membrane 42 is in close contact with and fixed to the inner wall of the container 43, and the gap between the outer peripheral end face and the inner wall is between the first chamber 451 and the second chamber 452. Gas is prevented from passing through and leaking.

A mixed gas containing carbon dioxide is introduced from an inlet 461 leading to the first chamber 451 and taken out from an outlet 462. While the mixed gas passes through the first chamber 451, at least a part of the carbon dioxide contained therein is absorbed by the absorption side surface S of the carbon dioxide separation membrane 42. As a result, the concentration of carbon dioxide in the mixed gas discharged from the outlet 462 is lower than the concentration of carbon dioxide in the mixed gas introduced from the inlet 461.
The carbon dioxide absorbed on the absorption side surface S of the carbon dioxide separation membrane 42 becomes bicarbonate ions according to the positive reaction of the reaction formula represented by the above-described formula 1, and this is expressed by the above-described formula 1 on the radiation-side surface R. It is released as carbon dioxide according to the reverse reaction of the reaction formula. The released carbon dioxide is discharged from the outlet 467 together with a carrier gas such as air introduced from the inlet 466 leading to the second chamber 452.
In the carbon dioxide separation module shown in FIG. 4, a flat plate-shaped carbon dioxide separation membrane is used, but a carbon dioxide separation module using a cylindrical carbon dioxide separation membrane may be used. In this case, a large number of cylindrical carbon dioxide separation membranes are arranged so that the longitudinal directions of the cylinders are parallel, and the first chamber is the inside of the cylinder and the second chamber is the outside of the cylinder, The reverse is good.

FIG. 5 is a schematic perspective view of a carbon dioxide separation module according to another embodiment using a carbon dioxide separation membrane according to the present invention, and FIG. 6 is a cross-sectional view of a plane that bisects the inlet 566 of FIG. It is.
The carbon dioxide separation module 50 shown in FIG. 5 has a hollow pipe 51 extending in a straight line having a diameter smaller than the diameter of the container 53 in the vicinity of the axis LL of the cylindrical container 53. . A partition plate (not shown) is installed near the center of the hollow pipe 51 in the direction of the axis L, and gas passes directly from the opening 511 at one end of the hollow pipe 51 to the opening 512 at the other end. Is preventing. A plurality of vent holes 513 formed at equal intervals around the axis L are formed in the pipe wall near the opening 511 in the hollow pipe 51, and the axis around the axis LL is formed in the pipe wall near the opening 512. A plurality of ventilation holes 514 formed at equal intervals are formed.

In the space between the inner wall of the container 53 and the outer wall of the hollow pipe 51, one end 523 of each pleat is provided so that the carbon dioxide separation membrane 521 folded in a pleat shape surrounds the outer wall of the hollow pipe 51. Close to the hollow pipe 51, the other end 524 is installed at a position close to the inner wall of the container 53. By the carbon dioxide separation membrane 521, the internal space of the container 53 is partitioned into a first chamber 551 and a second chamber 552 (see FIG. 6). As shown in FIG. 6, the carbon dioxide separation membrane 521 has an inner surface 521S as an absorption side surface of the carbon dioxide separation membrane according to the present invention, and an outer surface 521R as the carbon dioxide separation according to the present invention. The surface of the membrane is the diffusion side.
The container 53 has an inlet 566 and an outlet 567 that communicate with the second chamber 552.

Next, a method for separating and removing carbon dioxide from a mixed gas containing carbon dioxide by the carbon dioxide separation module will be described.
The mixed gas containing carbon dioxide is fed from the opening 511 of the hollow pipe 51 and introduced into the first chamber 551 through the vent 513. The mixed gas introduced into the first chamber 551 is included in the first chamber 551 while passing through the flow path as indicated by the arrow 57 shown by the solid line in FIGS. 5 and 6. The absorbed carbon dioxide is absorbed and removed from the absorption-side surface 521S of the carbon dioxide separation membrane 521. The mixed gas from which at least a part of carbon dioxide has been removed in this way is taken out from the opening 512 of the hollow pipe 51 via the vent hole 514.
On the other hand, the carbon dioxide absorbed by the absorption-side surface 521S of the carbon dioxide separation membrane 521 becomes bicarbonate ions in accordance with the positive reaction of the reaction formula represented by the above-described formula 1, and this becomes the above-described formula 1 on the radiation-side surface 521R. The carbon dioxide is released into the second chamber 552 in accordance with the reverse reaction of the reaction formula represented by: The released carbon dioxide, together with a carrier gas such as air introduced from the inlet 566 that leads to the second chamber 552, flows from the outlet 567 in a flow path as indicated by the broken line 59 in FIGS. It is discharged from the outlet 567.

Examples of the present invention will be described below, but the present invention is not limited to these examples.
In addition, pH of each layer which comprises a gel film | membrane was measured as follows using the film | membrane surface pH meter (The METTLER TOLEDO Seven Multi S40: pH meter, InLab @ Surface electrode). That is, in a 25 ° C. environment, 30 microliters of ultrapure water (Millipore) was dropped on the surface of the layer formed on the support, and the membrane surface pH electrode was pressed against the dropped ultrapure water for 1 minute. The pH was measured by allowing to stand.

(Example 1)
Preparation of layer 1: 1.5% by weight polyethyleneimine (weight average molecular weight 300,000), 1.5% by weight polyvinyl alcohol (weight average molecular weight 2,000,000), 0.5% by weight agar, Water containing 4.0% by mass of cesium carbonate was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) having a thickness of 100 μm with an extrusion die coater (clearance 1 mm), cooled and dried to prepare layer 1. The thickness of the layer 1 after drying was 30 μm. Moreover, the pH of the layer 1 measured by the above-mentioned method was 11.5.
Preparation of layer 2: 2.5% by mass of polyvinyl alcohol-polyacrylic acid (the former / the latter copolymerization ratio: 100/200% by mass, (weight average molecular weight 60,000), 0.5% by mass of agar, 4 Water containing 0.0% by mass of cesium carbonate was prepared as a composition, and this composition was applied to a polyethylene terephthalate film (transfer base material) in the same manner as in the case of layer 1, cooled and then dried. The layer 2 after drying had a thickness of 26 μm, and the pH of the layer 2 measured by the above-described method was 9.5.
Preparation of layer 3: 2.0% by weight polyacrylic acid (weight average molecular weight 200,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, 4.0% by weight cesium carbonate Water containing was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) in the same manner as in the case of layer 1, and after cooling, dried, layer 3 was produced. The thickness of the layer 3 after drying was 35 μm. Moreover, the pH of the layer 3 measured by the above-mentioned method was 7.9.
Each layer was peeled off from the transfer substrate, and the layers 1 to 3 were stacked in this order, and a hydrophobic PTFE porous film (T010A047A manufactured by Advantech Co., Ltd.) as a support was attached to the upper and lower surfaces one by one. .

(Example 2)
Preparation of layer 1: 1.5% by weight polyethyleneimine (weight average molecular weight 300,000), 1.5% by weight polyvinyl alcohol (weight average molecular weight 2,000,000), 0.5% by weight agar, Water containing 1.3% by mass of potassium carbonate was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) having a thickness of 100 μm with an extrusion die coater (clearance 1 mm), cooled and dried to prepare layer 1. The thickness of layer 1 after drying was 28 μm. Moreover, the pH of the layer 1 measured by the above-mentioned method was 11.0.
Preparation of layer 2: 2.5% by mass of polyvinyl alcohol-polyacrylic acid (the former / the latter copolymerization ratio: 100/20% by mass, (weight average molecular weight 60,000), 0.5% by mass of agar, 1 Water containing 3% by mass of potassium carbonate was prepared as a composition, and this composition was applied to PET in the same manner as in the case of layer 1, cooled and dried to prepare layer 2. After drying. The thickness of the layer 2 was 24 μm, and the pH of the layer 2 measured by the method described above was 9.0.
Preparation of layer 3: 2.0% by weight polyacrylic acid (weight average molecular weight 200,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, 1.3% by weight potassium carbonate. Water containing was prepared as a composition. This composition was applied to PET in the same manner as in the case of Layer 1, and after cooling, dried, Layer 3 was produced. The thickness of the layer 3 after drying was 32 μm. Moreover, the pH of the layer 3 measured by the above-mentioned method was 7.4.
Each layer was peeled off from the transfer substrate, and the layers 1 to 3 were stacked in this order, and a hydrophobic PTFE porous film (T010A047A manufactured by Advantech Co., Ltd.) as a support was attached to the upper and lower surfaces one by one. .

(Example 3)
Preparation of layer 1: 1.5% by weight polyethyleneimine (weight average molecular weight 300,000), 1.5% by weight polyvinyl alcohol (weight average molecular weight 2,000,000), 0.5% by weight agar, Water containing 4.0% by mass of cesium carbonate was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) having a thickness of 100 μm with an extrusion die coater (clearance 1 mm), cooled and dried to prepare layer 1. The thickness of the layer 1 after drying was 30 μm. Moreover, the pH of the layer 1 measured by the above-mentioned method was 11.5.
Preparation of layer 3: 2.5% by mass of polyvinyl alcohol-polyacrylic acid (the former / the latter copolymerization ratio: 100/200% by mass, (weight average molecular weight 60,000), 0.5% by mass of agar, 4 Water containing 0.0% by mass of cesium carbonate was prepared as a composition, and this composition was applied to a polyethylene terephthalate film (transfer base material) in the same manner as in the case of layer 1, cooled and then dried. The layer 3 after drying had a thickness of 26 μm, and the pH of the layer 3 measured by the above-described method was 9.5.
The respective layers were peeled off from the transfer substrate, overlapped, and a hydrophobic PTFE porous membrane (Advantech T010A047A) as a support was attached to the upper and lower surfaces one by one.

Example 4
Preparation of layer 1: 2.5% by mass of polyvinyl alcohol-polyacrylic acid (the former / the latter copolymerization ratio: 100/200% by mass, (weight average molecular weight 60,000), 0.5% by mass of agar, 4 Water containing 0.0% by mass of cesium carbonate was prepared as a composition, which was applied to a polyethylene terephthalate film (substrate for transfer) with an extrusion die coater (clearance 1 mm), cooled and dried. Thus, layer 1 was produced, and the thickness of layer 1 after drying was 26 μm, and the pH of layer 1 measured by the method described above was 9.5.
Preparation of layer 3: 2.0% by weight polyacrylic acid (weight average molecular weight 200,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, 4.0% by weight cesium carbonate Water containing was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) in the same manner as in the case of layer 1, and after cooling, dried, layer 3 was produced. The thickness of the layer 3 after drying was 35 μm. Moreover, the pH of the layer 3 measured by the above-mentioned method was 7.9.
The respective layers were peeled off from the transfer substrate, overlapped, and a hydrophobic PTFE porous membrane (Advantech T010A047A) as a support was attached to the upper and lower surfaces one by one.

(Example 5)
Preparation of layer 1: 2.5% by mass of polyvinyl alcohol-polyacrylic acid (the former / the latter copolymerization ratio: 100/200% by mass, (weight average molecular weight 60,000), 0.5% by mass of agar, 4 Water containing 0.0% by mass of cesium carbonate was prepared as a composition, which was applied to a polyethylene terephthalate film (substrate for transfer) with an extrusion die coater (clearance 1 mm), cooled and dried. Thus, layer 1 was produced, and the thickness of layer 1 after drying was 26 μm, and the pH of layer 1 measured by the method described above was 9.5.
Preparation of layer 2: 1.5% by weight polyethyleneimine (weight average molecular weight 300,000) and 1.5% by weight polyvinyl alcohol (weight average molecular weight 2,000,000), 0.5% by weight agar, Water containing 4.0% by mass of cesium carbonate was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) in the same manner as in layer 1, and after cooling, dried, layer 2 was produced. The thickness of the layer 2 after drying was 30 μm. Moreover, the pH of the layer 2 measured by the above-mentioned method was 11.5.
Preparation of layer 3: 2.0% by weight polyacrylic acid (weight average molecular weight 200,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, 4.0% by weight cesium carbonate Water containing was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) in the same manner as in the case of layer 1, and after cooling, dried, layer 3 was produced. The thickness of the layer 3 after drying was 35 μm. Moreover, the pH of the layer 3 measured by the above-mentioned method was 7.9.
Each layer was peeled off from the transfer substrate, and the layers 1 to 3 were stacked in this order, and a hydrophobic PTFE porous film (T010A047A manufactured by Advantech Co., Ltd.) as a support was attached to the upper and lower surfaces one by one. .

(Example 6)
Preparation of layer 1: 1.8% by weight polyacrylic acid (weight average molecular weight 200,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, 4.0% by weight cesium carbonate Water containing was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) with an extrusion die coater (clearance 1 mm), cooled and dried to prepare layer 1. The thickness of layer 1 after drying was 35 μm. Moreover, the pH of the layer 1 measured by the above-mentioned method was 8.0.
Preparation of layer 2: 2.8% by weight of polyacrylic acid (weight average molecular weight 200,000), 1.5% by weight of polyvinyl alcohol, 0.5% by weight of agar, 4.0% by weight of cesium carbonate Water containing was prepared as a composition. In the same manner as in the case of Layer 1, this composition was applied to a polyethylene terephthalate film (transfer base material), cooled, and dried to prepare Layer 2. The thickness of the layer 2 after drying was 41 μm. Moreover, the pH of the layer 2 measured by the above-mentioned method was 6.0.
Preparation of layer 3: 2.5% by weight poly-2-acrylamido-2-methylpropanesulfonic acid (weight average molecular weight 800,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, Water containing 4.0% by mass of cesium carbonate was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) in the same manner as in the case of layer 1, and after cooling, dried, layer 3 was produced. The thickness of the layer 3 after drying was 35 μm. Moreover, the pH of the layer 3 measured by the above-mentioned method was 4.0.
Each layer was peeled off from the transfer substrate, and the layers 1 to 3 were stacked in this order, and a hydrophobic PTFE porous film (T010A047A manufactured by Advantech Co., Ltd.) as a support was attached to the upper and lower surfaces one by one. .

(Example 7)
Preparation of layer 1: 2.0% by weight polyacrylic acid (weight average molecular weight 200,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, 4.0% by weight cesium carbonate Water containing was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) with an extrusion die coater (clearance 1 mm), cooled and dried to prepare layer 1. The thickness of layer 1 after drying was 35 μm. Moreover, the pH of the layer 1 measured by the above-mentioned method was 7.9.
Preparation of layer 2: 2.8% by weight of polyacrylic acid (weight average molecular weight 200,000), 1.5% by weight of polyvinyl alcohol, 0.5% by weight of agar, 4.0% by weight of cesium carbonate Water containing was prepared as a composition. In the same manner as in the case of Layer 1, this composition was applied to a polyethylene terephthalate film (transfer base material), cooled, and dried to prepare Layer 2. The thickness of the layer 2 after drying was 41 μm. Moreover, the pH of the layer 2 measured by the above-mentioned method was 6.0.
Preparation of layer 3: 2.5% by weight poly-2-acrylamido-2-methylpropanesulfonic acid (weight average molecular weight 800,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, Water containing 4.0% by mass of cesium carbonate was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) in the same manner as in the case of layer 1, and after cooling, dried, layer 3 was produced. The thickness of the layer 3 after drying was 35 μm. Moreover, the pH of the layer 3 measured by the above-mentioned method was 4.0.
Each layer was peeled off from the transfer substrate, and the layers 1 to 3 were stacked in this order, and a hydrophobic PTFE porous film (T010A047A manufactured by Advantech Co., Ltd.) as a support was attached to the upper and lower surfaces one by one. .

(Example 8)
Preparation of layer 1: 2.3 mass% polyacrylic acid (weight average molecular weight 200,000), 1.5 mass% polyvinyl alcohol, 0.5 mass% agar, 4.0 mass% cesium carbonate Water containing was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) with an extrusion die coater (clearance 1 mm), cooled and dried to prepare layer 1. The thickness of layer 1 after drying was 37 μm. Moreover, the pH of the layer 1 measured by the above-mentioned method was 7.5.
Preparation of layer 2: 2.8% by weight of polyacrylic acid (weight average molecular weight 200,000), 1.5% by weight of polyvinyl alcohol, 0.5% by weight of agar, 4.0% by weight of cesium carbonate Water containing was prepared as a composition. In the same manner as in the case of Layer 1, this composition was applied to a polyethylene terephthalate film (transfer base material), cooled, and dried to prepare Layer 2. The thickness of the layer 2 after drying was 41 μm. Moreover, the pH of the layer 2 measured by the above-mentioned method was 6.0.
Preparation of layer 3: 2.5% by weight poly-2-acrylamido-2-methylpropanesulfonic acid (weight average molecular weight 800,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, Water containing 4.0% by mass of cesium carbonate was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) in the same manner as in the case of layer 1, and after cooling, dried, layer 3 was produced. The thickness of the layer 3 after drying was 35 μm. Moreover, the pH of the layer 3 measured by the above-mentioned method was 4.0.
Each layer was peeled off from the transfer substrate, and the layers 1 to 3 were stacked in this order, and a hydrophobic PTFE porous film (T010A047A manufactured by Advantech Co., Ltd.) as a support was attached to the upper and lower surfaces one by one. .

Example 9
Preparation of layer 1: 2.5% by weight polyacrylic acid (weight average molecular weight 200,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, 4.0% by weight cesium carbonate Water containing was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) with an extrusion die coater (clearance 1 mm), cooled and dried to prepare layer 1. The thickness of layer 1 after drying was 39 μm. Moreover, the pH of the layer 1 measured by the above-mentioned method was 7.0.
Preparation of layer 2: 2.8% by weight of polyacrylic acid (weight average molecular weight 200,000), 1.5% by weight of polyvinyl alcohol, 0.5% by weight of agar, 4.0% by weight of cesium carbonate Water containing was prepared as a composition. In the same manner as in the case of Layer 1, this composition was applied to a polyethylene terephthalate film (transfer base material), cooled, and dried to prepare Layer 2. The thickness of the layer 2 after drying was 41 μm. Moreover, the pH of the layer 2 measured by the above-mentioned method was 6.0.
Preparation of layer 3: 2.5% by weight poly-2-acrylamido-2-methylpropanesulfonic acid (weight average molecular weight 800,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, Water containing 4.0% by mass of cesium carbonate was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) in the same manner as in the case of layer 1, and after cooling, dried, layer 3 was produced. The thickness of the layer 3 after drying was 35 μm. Moreover, the pH of the layer 3 measured by the above-mentioned method was 4.0.
Each layer was peeled off from the transfer substrate, and the layers 1 to 3 were stacked in this order, and a hydrophobic PTFE porous film (T010A047A manufactured by Advantech Co., Ltd.) as a support was attached to the upper and lower surfaces one by one. .

(Example 10)
Preparation of layer 1: 2.6 mass% polyacrylic acid (weight average molecular weight 200,000), 1.5 mass% polyvinyl alcohol, 0.5 mass% agar, 4.0 mass% cesium carbonate Water containing was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) with an extrusion die coater (clearance 1 mm), cooled and dried to prepare layer 1. The thickness of layer 1 after drying was 39 μm. Moreover, the pH of the layer 1 measured by the above-mentioned method was 6.9.
Preparation of layer 2: 2.8% by weight of polyacrylic acid (weight average molecular weight 200,000), 1.5% by weight of polyvinyl alcohol, 0.5% by weight of agar, 4.0% by weight of cesium carbonate Water containing was prepared as a composition. In the same manner as in the case of Layer 1, this composition was applied to a polyethylene terephthalate film (transfer base material), cooled, and dried to prepare Layer 2. The thickness of the layer 2 after drying was 41 μm. Moreover, the pH of the layer 2 measured by the above-mentioned method was 6.0.
Preparation of layer 3: 2.5% by weight poly-2-acrylamido-2-methylpropanesulfonic acid (weight average molecular weight 800,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, Water containing 4.0% by mass of cesium carbonate was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) in the same manner as in the case of layer 1, and after cooling, dried, layer 3 was produced. The thickness of the layer 3 after drying was 35 μm. Moreover, the pH of the layer 3 measured by the above-mentioned method was 4.0.
Each layer was peeled off from the transfer substrate, and the layers 1 to 3 were stacked in this order, and a hydrophobic PTFE porous film (T010A047A manufactured by Advantech Co., Ltd.) as a support was attached to the upper and lower surfaces one by one. .

(Example 11)
Preparation of layer 1: 2.0% by weight polyacrylic acid (weight average molecular weight 200,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, 4.0% by weight cesium carbonate Water containing was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) with an extrusion die coater (clearance 1 mm), cooled and dried to prepare layer 1. The thickness of layer 1 after drying was 35 μm. Moreover, the pH of the layer 1 measured by the above-mentioned method was 7.9.
Preparation of layer 2: 2.5% by weight polyacrylic acid (weight average molecular weight 200,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, 4.0% by weight cesium carbonate Water containing was prepared as a composition. In the same manner as in the case of Layer 1, this composition was applied to a polyethylene terephthalate film (transfer base material), cooled, and dried to prepare Layer 2. The thickness of the layer 2 after drying was 35 μm. Moreover, the pH of the layer 2 measured by the above-mentioned method was 6.0.
Preparation of layer 3: 2.8% by weight poly-2-acrylamido-2-methylpropanesulfonic acid (weight average molecular weight 800,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, Water containing 4.0% by mass of cesium carbonate was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) in the same manner as in the case of layer 1, and after cooling, dried, layer 3 was produced. The thickness of the layer 3 after drying was 35 μm. Moreover, the pH of the layer 3 measured by the above-mentioned method was 3.9.

(Example 12)
Preparation of layer 1: 2.0% by weight polyacrylic acid (weight average molecular weight 200,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, 4.0% by weight cesium carbonate Water containing was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) with an extrusion die coater (clearance 1 mm), cooled and dried to prepare layer 1. The thickness of layer 1 after drying was 35 μm. Moreover, the pH of the layer 1 measured by the above-mentioned method was 7.9.
Preparation of layer 2: 2.5% by weight polyacrylic acid (weight average molecular weight 200,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, 4.0% by weight cesium carbonate Water containing was prepared as a composition. In the same manner as in the case of Layer 1, this composition was applied to a polyethylene terephthalate film (transfer base material), cooled, and dried to prepare Layer 2. The thickness of the layer 2 after drying was 35 μm. Moreover, the pH of the layer 2 measured by the above-mentioned method was 6.0.
Preparation of layer 3: 3.3% by weight poly-2-acrylamido-2-methylpropanesulfonic acid (weight average molecular weight 800,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, Water containing 4.0% by mass of cesium carbonate was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) in the same manner as in the case of layer 1, and after cooling, dried, layer 3 was produced. The thickness of the layer 3 after drying was 37 μm. Moreover, the pH of the layer 3 measured by the above-mentioned method was 2.9.
Each layer was peeled off from the transfer substrate, and the layers 1 to 3 were stacked in this order, and a hydrophobic PTFE porous film (T010A047A manufactured by Advantech Co., Ltd.) as a support was attached to the upper and lower surfaces one by one. .

(Comparative Example 1)
Preparation of layer 1: 2.5% by mass of polyvinyl alcohol-polyacrylic acid (the former / the latter copolymerization ratio: 100/200% by mass, (weight average molecular weight 60,000), 0.5% by mass of agar, 4 Water containing 0.0% by mass of cesium carbonate was prepared as a composition, which was applied to a polyethylene terephthalate film (transfer base material) with an extrusion die coater (clearance 1 mm), cooled and dried. The layer 1 after drying had a thickness of 26 μm, and the pH of the layer 1 measured by the above-mentioned method was 9.5. PTFE porous membrane (T010A047A manufactured by Advantech Co., Ltd.) was attached to the upper and lower surfaces one by one to prepare a sample.

(Comparative Example 2)
2.0% by weight polyacrylic acid (weight average molecular weight 200,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, 1.3% by weight potassium carbonate, 1.2% by weight Water containing glycine was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) in the same manner as in Comparative Example 1, and after cooling, dried, Layer 1 was produced. The thickness of layer 1 after drying was 36 μm. Moreover, the pH of the layer 1 measured by the above-mentioned method was 7.9. Two layers of this layer 1 were peeled off from the transfer substrate, and a hydrophobic PTFE porous membrane (T010A047A manufactured by Advantech) was attached to the upper and lower surfaces one by one to prepare a sample.

(Comparative Example 3)
1.5% by weight polyethyleneimine (weight average molecular weight 300,000), 1.5% by weight polyvinyl alcohol (weight average molecular weight 2,000,000), 0.5% by weight agar, 4.0% by weight Water containing cesium carbonate was prepared as a composition. This composition was applied to a polyethylene terephthalate film (transfer base material) having a thickness of 100 μm with an extrusion die coater (clearance 1 mm), cooled and dried to prepare layer 1. The thickness of the layer 1 after drying was 30 μm. Moreover, the pH of the layer 1 measured by the above-mentioned method was 11.5. Two layers 1 were layered, and a hydrophobic PTFE porous membrane (T010A047A manufactured by Advantech) was attached to the upper and lower surfaces one by one to prepare a sample.

(Comparative Example 4)
A permeation test was performed by exchanging layer 1 and layer 3 of Example 1.

(Example 13)
Preparation of layer 1: 1.5% by weight polyethyleneimine (weight average molecular weight 300,000), 1.5% by weight polyvinyl alcohol (weight average molecular weight 2,000,000), 0.5% by weight agar, Water containing 1.2% by mass of glycine and 4.0% by mass of cesium carbonate was prepared as a composition. This composition was applied to supported PTFE (manufactured by Nakao Filter Co., Ltd., Tetratox 7008, 200 μm thickness) with an extrusion die coater (clearance 1 mm), cooled and dried to prepare layer 1. The thickness of layer 1 after drying was 34 μm. Moreover, the pH of the layer 1 measured by the above-mentioned method was 11.2.
Preparation of layer 2: 2.5% by mass of polyvinyl alcohol-polyacrylic acid (the former / the latter copolymerization ratio: 100/200% by mass, (weight average molecular weight 60,000), 0.5% by mass of agar, 1 Water containing 2% by mass of glycine and 4.0% by mass of cesium carbonate was prepared as a composition, and this composition was applied on the supported PTFE coated with layer 1 and cooled and dried. The layer 2 after drying had a thickness of 30 μm, and the pH of the layer 2 measured by the above method was 9.1.
Preparation of layer 3: 2.0% by weight polyacrylic acid (weight average molecular weight 200,000) and 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, 1.2% by weight glycine, 4 Water containing 0.0 mass% cesium carbonate was prepared as a composition. This composition was applied in layers on the supported PTFE applied up to layer 2, and after cooling, dried, layer 3 was produced. The thickness of the layer 3 after drying was 38 μm. Moreover, the pH of the layer 3 measured by the above-mentioned method was 7.4. Hydrophobic PTFE porous membranes (T010A047A manufactured by Advantech) were attached to the upper and lower surfaces one by one to obtain a permeation test sample.

(Example 14)
Preparation of layer 1: 1.5% by weight polyallylamine (weight average molecular weight 10,000) and 1.5% by weight polyvinyl alcohol (weight average molecular weight 2,000,000), 0.5% by weight agar, Water containing 1.2% by mass of glycine and 1.3% by mass of potassium carbonate was prepared as a composition. This composition was applied to supported PTFE (manufactured by Nakao Filter Co., Ltd., Tetratox 7008, 200 μm thickness) with an extrusion die coater (clearance 1 mm), cooled and dried to prepare layer 1. The thickness of layer 1 after drying was 32 μm. Moreover, the pH of the layer 1 measured by the above-mentioned method was 10.8.
Preparation of layer 2: 2.5% by mass of polyvinyl alcohol-polyacrylic acid (the former / the latter copolymerization ratio: 100/200% by mass, (weight average molecular weight 60,000), 0.5% by mass of agar, 1 Water containing 2% by mass of glycine and 1.3% by mass of potassium carbonate was prepared as a composition, which was applied over the supported PTFE coated with layer 1 and cooled and dried. The layer 2 after drying had a thickness of 30 μm, and the pH of the layer 2 measured by the above method was 8.6.
Preparation of layer 3: 2.0% by weight polyacrylic acid (weight average molecular weight 200,000) and 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, 1.2% by weight glycine, Water containing 3% by mass of potassium carbonate was prepared as a composition. This composition was applied in layers on the supported PTFE applied up to layer 2, and after cooling, dried, layer 3 was produced. The thickness of the layer 3 after drying was 38 μm. Moreover, the pH of the layer 3 measured by the above-mentioned method was 7.1. Hydrophobic PTFE porous membranes (T010A047A manufactured by Advantech) were attached to the upper and lower surfaces one by one to obtain a permeation test sample.

(Example 15 to Example 19)
Preparation of layer 1: 1.5% by weight polyethyleneimine (weight average molecular weight 300,000), 1.5% by weight polyvinyl alcohol (weight average molecular weight 2,000,000), 0.5% by weight agar, Water containing 4.0% by mass of cesium carbonate was prepared as a composition. This composition was applied to supported PTFE (manufactured by Nakao Filter Co., Ltd., Tetratox 7008, 200 μm thickness) with an extrusion die coater (clearance 1 mm), cooled and dried to prepare layer 1. The thickness of layer 1 after drying was 34 μm. Moreover, the pH of the layer 1 measured by the above-mentioned method was 11.5.
Preparation of layer 2: 2.5% by mass of polyvinyl alcohol-polyacrylic acid (the former / the latter copolymerization ratio: 100/200% by mass, (weight average molecular weight 60,000), 0.5% by mass of agar, 4 Water containing 0.0% by mass of cesium carbonate was prepared as a composition, and this composition was applied onto the supported PTFE coated with layer 1 with an extrusion die coater as necessary, cooled and dried. This produced layer 2. The pH of layer 2 measured by the method described above was 9.5.
Preparation of layer 3: 2.0% by weight polyacrylic acid (weight average molecular weight 200,000), 1.5% by weight polyvinyl alcohol, 0.5% by weight agar, 4.0% by weight cesium carbonate Water containing was prepared as a composition. This composition was applied in layers on the supported PTFE applied up to layer 2, and after cooling, dried, layer 3 was produced. The thickness of the layer 3 after drying was 38 μm. Moreover, the pH of the layer 3 measured by the above-mentioned method was 7.9. Hydrophobic PTFE porous membranes (T010A047A manufactured by Advantech) were attached to the upper and lower surfaces one by one to obtain a permeation test sample.

-Gas separation evaluation-
The separation performance of carbon dioxide gas was evaluated as follows using the gel membranes prepared in Examples and Comparative Examples.
Each sample was cut to a diameter of 47 mm together with the support to prepare a transmission test sample. Here, the sample according to the example was installed so that the layer 1 side was the carbon dioxide supply side and the layer 3 side was the carbon dioxide side. The chamber on the absorption side and the chamber on the diffusion side were stainless steel containers and were sealed with screws using an O-ring.
As a test gas, a mixed gas of CO ₂ / H ₂ : 10/90 (volume ratio) was used with each sample (effective area 2.40 cm ² ) at a relative humidity of 70%, a flow rate of 100 ml / min, a temperature of 130 ° C., and a total pressure of 3 atm. ) And Ar gas (flow rate 90 ml / min) was allowed to flow on the permeate side without applying pressure (1 atm). The permeated gas was analyzed with a gas chromatograph, and the carbon dioxide permeation rate [Q (CO ₂ )] and the separation factor [α] were calculated.
Here, the permeation rate of carbon dioxide and the separation factor are defined as follows.
Carbon dioxide permeation rate [Q (CO ₂ )]: 1 × 10 ⁻⁶ cm ³ (STP) / (s · cm ² · cmHg)
Separation coefficient [α]: Q (CO ₂ ) / Q (H ₂ )
The results for the carbon dioxide separation membranes of Examples 1 to 14 and Comparative Examples 1 to 4 are shown in Table 1, and the results for the carbon dioxide separation membranes of Examples 15 to 19 are shown in Table 2.

  From the results of Examples 1 to 12 in Table 1, it can be seen that layers having different pHs can be prepared by using different functional polymers. And as can be seen by comparing Examples 1-12 and Comparative Examples 1-4, the carbon dioxide separation membranes of Examples 1-14, in which the pH of the absorption side surface according to the present invention is higher than the pH of the diffusion side surface, It can be seen that the permeation rate of carbon dioxide is high and the separation factor is high.

Further, as can be seen by comparing Example 1 and Example 13 and Example 2 and Example 14, towards the carbon dioxide separation membrane using a gel membrane containing a carbon dioxide absorption promoter, it It can be seen that the permeation rate of carbon dioxide is much faster and the separation factor is higher than those not included.

  Furthermore, from the results in Table 2, carbon dioxide separation with a higher intermediate layer has a higher carbon dioxide separation coefficient in the range where the thickness of the intermediate layer in the gel membrane composed of three layers is 100 μm or less. It can be seen that a film is obtained.

  The carbon dioxide separation membrane of the present invention and the carbon dioxide separation module using the same have excellent characteristics for separating and removing carbon dioxide from a mixed gas containing carbon dioxide, and thus various types of carbon dioxide that require separation of carbon dioxide. Can be used in the field. For example, it can be widely used for natural gas purification for removing carbon dioxide contained in natural gas, CCS, hydrogen production for fuel cells, carbon dioxide supercritical fluid purification, and the like.

Explanation of sign

1, 42, 521 Carbon dioxide separation membrane 10 Support 20 Gel membrane 40, 50 Carbon dioxide separation module 43, 53 Container 451, 551 First chamber 452, 552 Second chamber

Claims (11)

A gel film containing a water-absorbing polymer, a carbon dioxide carrier and water, and a support that supports the gel film, and the surface of the absorption side that is a side to which a mixed gas containing carbon dioxide in the gel film is supplied. A method for producing a carbon dioxide separation membrane , the pH of which is higher than the pH of the radiation-side surface that is the surface opposite to the absorption-side surface ,
Producing a gel film transfer material having a single gel film containing a water-absorbing polymer, a carbon dioxide carrier and water on a transfer substrate; and the gel film of the gel film transfer material facing the support. A gel film transfer step comprising: producing a laminate in which the gel film transfer material and the support are superimposed; and peeling the transfer substrate of the laminate at the interface with the gel film. A method for producing a carbon dioxide separation membrane comprising at least one time. The method for producing a carbon dioxide separation membrane according to claim 1, wherein the gel membrane of the carbon dioxide separation membrane includes at least two layers having different pHs. Gel film of said carbon dioxide separation membrane, comprising at least three layers are laminated, in claim 1 or claim 2 and the pH of the layer differing with pH and the dissipation surface of the layer having the absorbent surface The manufacturing method of the carbon dioxide separation membrane of description. The gel membrane of the carbon dioxide separation membrane has a pH of the absorption side surface of 8.0 or more, a pH of the emission side surface of 4.0 or more and less than 8.0, or satisfies both of them. The manufacturing method of the carbon dioxide separation membrane as described in any one of Claims 1-3 . The transfer process includes at least twice, and the pH of the gel film in one transfer process is 8.0 or more, and the pH of the gel film in the other transfer process is 4.0 or more and less than 8.0. The manufacturing method of the carbon dioxide separation membrane as described in any one of Claims 1-4.   A gel film containing a water-absorbing polymer, a carbon dioxide carrier and water, and a support that supports the gel film, and the surface of the absorption side that is a side to which a mixed gas containing carbon dioxide in the gel film is supplied. A method for producing a carbon dioxide separation membrane, the pH of which is higher than the pH of the diffusion side surface that is the surface opposite to the absorption side surface,
  Including a step of applying a composition containing a water-absorbing polymer, a carbon dioxide carrier and water on the support at least twice, and the pH of the gel film formed by one of the application steps is 8.0 or more, The manufacturing method of the carbon dioxide separation membrane whose pH of the gel membrane formed by the other application | coating process is 4.0 or more and less than 8.0. The said carbon dioxide separation membrane is a manufacturing method of the carbon dioxide separation membrane as described in any one of Claims 1-6 in which pH falls toward an emission side surface from an absorption side surface. The gel membrane of the carbon dioxide separation membrane includes at least three layers stacked, and a total thickness of layers excluding the layer having the absorption side surface and the layer having the diffusion side surface is 10 μm to 100 μm. method for producing a carbon dioxide separation membrane according to any one of 1 to claim 7. The carbon dioxide carrier, an alkali metal carbonate, according to any one of claims 1 to 8 is at least one compound selected from alkali metal bicarbonates, and the group consisting of alkali metal hydroxides A method for producing a carbon dioxide separation membrane. A container having a space inside, dividing the space into first chamber and second chamber, manufactured by the manufacturing method of the carbon dioxide separation membrane according to any one of claims 1 to 9 A carbon dioxide separation module comprising: a carbon dioxide separation membrane; and at least a pair of an inlet and an outlet formed in the container and independently communicating with the first and second chambers. The carbon dioxide separation module according to claim 10 , wherein the carbon dioxide separation membrane has a pleated shape.

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