Carbon dioxide fixation member, carbon dioxide fixation method, and cation storage body

Abstract

To provide a carbon dioxide fixation member capable of fixing more carbon dioxide. To also provide a method for fixing more carbon dioxide using the carbon dioxide fixation member. To also provide a cation reservoir capable of fixing more carbon dioxide. [Solution] A carbon dioxide fixing member 1a comprising a water-absorbing, swellable gel 11,11' containing carbonic anhydrase or a microorganism capable of producing the carbonic anhydrase, and a cation capable of reacting with carbon dioxide to produce a water-insoluble or water-slightly soluble carbonate, and a fibrous material 12 supporting the gel 11,11'.

Description

[Technical Field]

[0001] The present invention relates to a carbon dioxide fixation member, a carbon dioxide fixation method using the carbon dioxide fixation member, and a cation reservoir that can be used with the carbon dioxide fixation member. [Background technology]

[0002] In recent years, the Sustainable Development Goals (SDGs) have been established, and there is a particular need to reduce carbon dioxide emissions. The concept of carbon neutrality is also effective in reducing carbon dioxide emissions. That is, there is a method of reducing net emissions by absorbing and removing carbon dioxide from the atmosphere and subtracting that amount from the carbon dioxide that is emitted.

[0003] As an example of a method for absorbing and removing carbon dioxide, Non-Patent Document 1 discloses a carbon dioxide fixation reactor that generates calcium carbonate by immersing hydrogels processed into bead shape in water, stirring them, and supplying or aerating carbon dioxide to the mixture. Patent Document 1 also discloses a method for repairing cracks and niches in concrete using carbonic anhydrase embedded in an aqueous matrix. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] U.S. Patent Application Publication No. 2023 / 0192548 [Non-patent literature]

[0005] [Non-Patent Document 1] Process Biochemistry,2012,Vol.47,p.585-590 [Overview of the project] [Problems that the invention aims to solve]

[0006] The carbon dioxide fixation reactor disclosed in Non-Patent Document 1 is capable of fixing carbon dioxide, but it has the problem of being difficult to use as a carbon dioxide absorption material because it is gel-like and has difficulty maintaining a consistent shape. Patent Document 1 does not disclose actively absorbing carbon dioxide into concrete using carbonic anhydrase. Furthermore, from the perspective of SDGs, there is a need to use construction materials that are used in large quantities as carbon dioxide fixation (absorption) materials. However, there are no conventional construction materials that can fix (absorb) a large amount of carbon dioxide.

[0007] This invention has been made in view of the above circumstances and provides a carbon dioxide fixation member capable of fixing a larger amount of carbon dioxide. Furthermore, this invention provides a method for fixing a larger amount of carbon dioxide using the carbon dioxide fixation member. It also aims to provide a cation reservoir capable of fixing a larger amount of carbon dioxide. [Means for solving the problem]

[0008] To achieve the above objective, firstly, the present invention provides a carbon dioxide fixing member comprising a water-absorbing, swellable gel containing carbonic anhydrase or a microorganism capable of producing said carbonic anhydrase, and a cation capable of reacting with carbon dioxide to produce a water-insoluble or sparingly water-soluble carbonate, and a fibrous material supporting the gel (Invention 1).

[0009] In the above invention (Invention 1), it is preferable that at least a portion of the gel is sandwiched between the fibrous material (Invention 2).

[0010] In the above invention (Invention 2), it is preferable that the degree of swelling of the gel upon water absorption is uniform throughout the entire gel (Invention 3).

[0011] In the above invention (Invention 2), it is preferable that the degree of swelling of at least a portion of the gel upon water absorption is different from the degree of swelling of the other portion of the gel (Invention 4).

[0012] In the above invention (Invention 2), it is preferable that the fibrous material has a notch, and that the notch becomes an opening connecting the outside of the carbon dioxide fixing member and the gel when the fibrous material is expanded by the swelling of the gel (Invention 5).

[0013] In the above invention (Invention 1), it is preferable that the gel is impregnated into at least a portion of the fiber material (Invention 6).

[0014] In the above invention (Invention 1), it is preferable that the gel comprises a portion containing the carbonic anhydrase or the microorganism and a portion for storing the cation (Invention 7).

[0015] In the above invention (Invention 1), it is preferable that the carbon dioxide fixing member has a block-like or panel-like shape (Invention 8).

[0016] Secondly, the present invention provides a method for fixing carbon dioxide, which includes arranging the carbon dioxide fixing member (Invention 1) so that its surface is in contact with the atmosphere, installing it in a pipe through which a gas containing carbon dioxide passes, or immersing it in a water tank through which a gas containing carbon dioxide is aerated (Invention 9).

[0017] Thirdly, the present invention provides a cation reservoir comprising a component containing a cation that can react with carbon dioxide to produce a water-insoluble or sparingly water-soluble carbonate, which is encapsulated within an outer membrane (Invention 10). [Effects of the Invention]

[0018] The carbon dioxide fixing member according to the present invention can make the shape of the water-absorbing and swelling gel a stable shape by supporting the water-absorbing and swelling gel on a fibrous material. Further, the carbon dioxide fixing member according to the present invention can enhance gas diffusibility by supporting the water-absorbing and swelling gel on a fibrous material, and can improve the reaction efficiency of carbon dioxide fixation. For these reasons, the carbon dioxide fixing member according to the present invention can fix more carbon dioxide.

Brief Description of the Drawings

[0019] [Figure 1] It is a cross-sectional view of a carbon dioxide fixing member according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view of a carbon dioxide fixing member according to another embodiment of the present invention. [Figure 3] It is a cross-sectional view of a carbon dioxide fixing member according to still another embodiment of the present invention. [Figure 4] It is a cross-sectional view of an example of the gel in the present invention.

Embodiments for Carrying Out the Invention

[0020] Hereinafter, embodiments of the present invention will be described. The carbon dioxide fixing member according to the present embodiment includes a water-absorbing and swelling gel and a fibrous material that supports the gel. The gel contains carbonic anhydrase or a microorganism that can produce the carbonic anhydrase, and a cation that can react with carbon dioxide to form a water-insoluble or poorly water-soluble carbonate.

[0021] The carbon dioxide fixing member according to the present embodiment can generate carbonate inside by being exposed to outside air containing carbon dioxide in a state where water is supplied, using the water and the carbon dioxide as materials.

[0022] The mechanism of carbon dioxide fixation according to the present invention will be described. When water is supplied to the carbon dioxide fixing member according to the present embodiment, the gel contained in the carbon dioxide fixing member is supplied with water, and the gel is in a state of swelling by absorbing water. Then, carbon dioxide in the outside air dissolves in the water contained in the water-absorbed and swollen gel.

[0023] Furthermore, due to the action of carbonic anhydrase contained in the gel or the action of carbonic anhydrase produced by the microorganism, a reaction that generates bicarbonate ions (HCO3 - ) from water and carbon dioxide, that is, H20 + CO2 → H2CO3 → H + + HCO3 - proceeds, and bicarbonate ions (HCO3 - ) are generated.

[0024] Subsequently, carbonate ions (CO3 2- ) generated by the desorption of hydrogen ions from bicarbonate ions react with the above-mentioned cations present in the gel, and a carbonate is formed. For example, when the carbon dioxide fixing member according to the present embodiment has calcium ions (Ca 2+ ) as cations, the following reaction CO3 2- + Ca 2+ [[ID=二十九]]→ CaCO3 proceeds, and water-insoluble calcium carbonate (CaCO3) is generated.

[0025] The carbon dioxide fixing member according to the present embodiment can fix more carbon dioxide. In the present embodiment, in the carbon dioxide fixing member, since it contains a gel containing cations together with carbonic anhydrase, bicarbonate ions (HCO3 - ) are generated from carbon dioxide and water in the outside air, and a water-insoluble or poorly water-soluble carbonate is generated by the reaction of bicarbonate ions and cations, so that more carbon dioxide in the outside air can be fixed to the carbon dioxide fixing member.

[0026] 1. Example of the configuration of the carbon dioxide fixing member The carbon dioxide fixing member according to this embodiment can hold the gel in a stable shape by impregnating or retaining the gel in a fibrous material, thereby increasing the amount of carbon dioxide fixed from the outside air. Furthermore, the carbon dioxide fixing member according to this embodiment can be used as a construction material for building wall structures (including exterior walls, interior walls, and exterior walls of buildings, fences, etc.), landscaping materials, inner walls of pipes, filters that adsorb carbon dioxide, and other construction materials.

[0027] For example, the carbon dioxide fixation member according to this embodiment may be in a form in which at least a portion of the gel is sandwiched between fibrous materials. Alternatively, as another example, the carbon dioxide fixation member according to this embodiment may be in a form in which at least a portion of the gel is impregnated into fibrous materials.

[0028] Furthermore, in the carbon dioxide fixation member according to this embodiment, the fibrous material may have notches that connect the gel to the outside (or a member adjacent to the outside).

[0029] The configuration of the carbon dioxide fixation member according to this embodiment will be described below with reference to Figures 1 to 3. However, the carbon dioxide fixation member according to this embodiment is not limited to the form shown in Figures 1 to 3, and may take other forms.

[0030] (1) First form Figure 1 is a schematic diagram showing a cross-section of the carbon dioxide fixing member 1a according to the first embodiment. Figure 1(a) shows the initial state of the carbon dioxide fixing member 1a (the state in which the gel 11 has not absorbed water and swelled), and Figure 1(b) shows the state in which the gel 11 has absorbed water and swelled, and the carbon dioxide fixing member 1a has fixed carbon dioxide.

[0031] As shown in Figure 1(a), the carbon dioxide fixing member 1a according to the first embodiment has a structure in which a gel 11 is sandwiched between fibrous materials 12, and furthermore, a plurality of units of this structure are sandwiched between a pair of opposing restraining members 13.

[0032] Furthermore, as shown in Figure 1(a), in the carbon dioxide fixation member 1a, the fiber material 12 has the aforementioned notches. In particular, in the carbon dioxide fixation member 1a, there are notches between the gel 11 and one of the restraining members 13, and between the gel 11 and the other restraining member 13.

[0033] As shown in Figure 1(b), these notches become openings connecting the outside of the carbon dioxide fixing member 1a to the gel 11' when the fibrous material 12 is expanded by the swollen gel 11'. As a result, the contact area between the gel 11' and the outside air increases, making it possible to efficiently take in carbon dioxide into the gel 11'. Furthermore, as the gel 11 swells and the surface area of ​​the gel 11' increases, the contact area between the gel 11' and the outside air also increases, enabling efficient carbon dioxide take-up.

[0034] (2) Second form Figure 2 is a schematic diagram showing a cross-section of the carbon dioxide fixing member 1b according to the second embodiment. Figure 2(a) shows the initial state of the carbon dioxide fixing member 1b (the state in which the gel 11 has not absorbed water and swelled), and Figure 2(b) shows the state in which the gel 11 has absorbed water and swelled, and the carbon dioxide fixing member 1b has fixed carbon dioxide.

[0035] As shown in Figure 2(b), the carbon dioxide fixing member 1b according to the second embodiment also has a structure in which the gel 11 is sandwiched between fibrous materials 12, and furthermore, multiple units of this structure are sandwiched between a pair of opposing restraining members 13.

[0036] As shown in Figure 2(a), the carbon dioxide fixation member 1b also has the aforementioned notches in the fiber material 12. However, unlike the carbon dioxide fixation member 1a in the first embodiment, the carbon dioxide fixation member 1b has notches only in the gel 11 and one of the restraining members 13.

[0037] Thus, even if a notch exists on only one side, similar to the carbon dioxide fixing member 1a of the first embodiment, the swollen gel 11' causes the notch to become an opening for carbon dioxide uptake, enabling efficient carbon dioxide uptake.

[0038] Here, as will be described later, the gel 11 may have non-uniformity in terms of the degree of swelling when absorbing water. That is, the degree of swelling when absorbing water in at least a part of the gel 11 may differ from the degree of swelling in other parts of the gel 11. For example, in the carbon dioxide fixing member 1b shown in Figure 2, the swelling rate on the side with the notch is described as being higher than the swelling rate on the side without the notch. As a result, when the gel 11 swells, as shown in Figure 2(b), the side with the notch swells more, the opening opens wider, and the efficiency of carbon dioxide uptake is further improved. Also, in the carbon dioxide fixing member 1b shown in Figure 2, because the notch is present on only one side, the effect of the fibrous material 12 being pushed out by the swelling of the gel 11 is concentrated in the notch area, resulting in a wider opening.

[0039] (3) Third form Figure 3 is a schematic diagram showing a cross-section of the carbon dioxide fixation member 1c according to the third embodiment. As shown in Figure 3, the carbon dioxide fixation member 1c according to the third embodiment has a structure in which the gel 11 is impregnated into at least a portion of the fibrous material 13, and the fibrous material 13 is further sandwiched between a pair of opposing restraining members 13.

[0040] In the third embodiment of the carbon dioxide fixing member 1c, the gel 11 is widely spread within the fibrous material 13, which increases the contact area with carbon dioxide and allows for efficient absorption of carbon dioxide.

[0041] 2. Gel In this embodiment, the gel 11 is not limited in its specific composition or properties, as long as it has water-absorbing swelling properties, contains the carbonic anhydrase or microorganisms mentioned above, and contains the cations mentioned above.

[0042] As described above, in this embodiment, at least a portion of the gel 11 may be sandwiched between the fiber material 12, or at least a portion of the fiber material 12 may be impregnated with it. Alternatively, a portion of the gel 11 may be sandwiched between the fiber material 12, and a portion of the gel 11 may be impregnated with at least a portion of the fiber material 12.

[0043] (1) Gel materials In this embodiment, carbonic anhydrase is used to produce bicarbonate ions (HCO3) from water and carbon dioxide in the gel 11. - A reaction that produces ) that is, H2O + CO2 → H + +HCO3 - It is not particularly limited as long as it is possible to catalyze the reaction.

[0044] Specific examples of carbonic anhydrase in this embodiment may be any carbonic anhydrase extracted from bacteria, fungi, microalgae, protozoa, etc. Among these, it is preferable to use carbonic anhydrase extracted from at least one type of bacteria or fungi, as it is easier to control and maintain the activity state in the gel 11. Carbonic anhydrous enzymes extracted from genera such as Bacillus, Escherichia, Alcaligenes, and Sporosarcina can be used, including Bacillus pumilus, Bacillus megaterium, Bacillus simplex, Bacillus licheniformis, Bacillus toyonensis, Bacillus schlegelii, Bacillus safensis, Bacillus mucilaginosus, Bacillus subtilis, and Escherichia. It is preferable to use carbonic anhydride extracted from coli (Escherichia coli), Alcaligenes faecalis, or Sporosarcina pasteurii.

[0045] The microorganism in this embodiment is not limited as long as it is capable of producing the carbonic anhydrase described above. The microorganism may maintain its activity in the gel 11 and continue to produce carbonic anhydrase when the carbon dioxide fixing member according to this embodiment is used, or it may produce carbonic anhydrase only at a predetermined timing and then lose its activity.

[0046] Furthermore, the microorganisms described above may either secrete the carbonic anhydrase they produce externally or retain it internally.

[0047] The above microorganisms may be bacteria, fungi, microalgae, protozoa, etc., but from the viewpoint of being able to easily control and maintain their activity in the gel 11, it is preferable to use at least one species of bacteria and fungi. Specific examples of microorganisms that can be used include genera such as Bacillus, Escherichia, Alcaligenes, and Sporosarcina. Among these, Bacillus pumilus, Bacillus megaterium, Bacillus simplex, Bacillus licheniformis, Bacillus toyonensis, Bacillus schlegelii, Bacillus safensis, Bacillus mucilaginosus, Bacillus subtilis, and Escherichia. It is preferable to use *Escherichia coli*, *Alcaligenes faecalis*, or *Sporosarcina pasteurii*.

[0048] The aforementioned cations are not particularly limited as long as they can react with carbon dioxide to produce water-insoluble or sparingly water-soluble carbonates. For example, such cations include ions of Group 2 elements (alkaline earth metals) such as calcium ions, magnesium ions, and barium ions.

[0049] In this embodiment, the cation content in the gel 11 is preferably 0.1 to 27% by mass, particularly preferably 0.2 to 10% by mass, and even more preferably 0.4 to 5% by mass. Within this range, the above-mentioned reaction can proceed more efficiently, resulting in more efficient carbon dioxide fixation.

[0050] The main component (matrix) of the gel 11 in this embodiment is not particularly limited as long as it is a gel-like component that enables the water absorption and swelling properties of the gel 11. For example, alginic acid, polyvinyl alcohol, gelatin, agar, superabsorbent polymer, etc. can be used as the main component, and among these, alginic acid is preferred from the viewpoint of easily forming a gel 11 that exhibits the desired properties.

[0051] The gel 11 in this embodiment may contain other components besides those described above. For example, the gel 11 in this embodiment may contain components for maintaining and adjusting the activity state of carbonic anhydrase and the microorganisms, or components for adjusting water absorption and swelling properties.

[0052] The water content in gel 11 is not particularly limited. As mentioned above, water is essential for the carbon dioxide fixation reaction to proceed, but it is sufficient if the water is supplied only when carbon dioxide is being fixed. On the other hand, when using the carbon dioxide fixation member according to this embodiment, it is preferable that the water content be between 20% and 98% from the viewpoint of achieving more efficient carbon dioxide fixation.

[0053] (2) Swelling degree of the gel As described above, the gel 11 in this embodiment has water-absorbing and swelling properties. The degree of swelling of the gel 11 (i.e., the ratio of the gel 11 in use to the state of the carbon dioxide fixing member when not in use) can be set as appropriate, but is preferably 10 to 100, particularly preferably 50 to 250, and even more preferably 250 to 1000. When the degree of swelling is within these ranges, if the fibrous material 12 has notches as shown in Figures 1 and 2, it becomes possible to create a larger opening when absorbing water.

[0054] Furthermore, in the gel 11 of this embodiment, the degree of swelling of the gel 11 when it absorbs water may be uniform throughout the entire gel 11, or the degree of swelling of at least a part of the gel 11 when it absorbs water may differ from the degree of swelling of the other parts of the gel 11. In the latter case, where the degree of swelling of the gel 11 differs locally, it is preferable, from the viewpoint of making it easier to widen the opening, that the degree of swelling is higher in the part proximal to the cut in the fiber material 12 and lower in the distal part, as shown in the carbon dioxide fixing member 1b in Figure 2.

[0055] (3) Cation reservoir In this embodiment, it is also preferable that the gel 11 comprises a portion containing carbonic anhydrase or the above-mentioned microorganism (matrix portion, labeled "112" in Figure 4) and a portion for storing cations (cation reservoir, labeled "111" in Figure 4), as shown in Figure 4.

[0056] In this embodiment, if the gel 11 is equipped with such a cation reservoir 111, the cations will essentially be retained in the cation reservoir 111, thus suppressing the leakage of cations to the outside of the gel 11. On the other hand, the reaction to fix carbon dioxide can proceed sufficiently using the cations supplied from the cation reservoir 111. As a result, carbon dioxide fixation can proceed more efficiently.

[0057] The structure of the cation reservoir 111 is not particularly limited, as long as it is capable of storing cations. For example, it is preferable that the cation reservoir 111 comprises a component containing cations that can react with carbon dioxide to produce water-insoluble or sparingly water-soluble carbonates, encapsulated within an outer membrane. As the outer membrane, the aforementioned gel-like material can be used, and alginic acid is particularly preferred.

[0058] (4) Method for producing gel The gel 11 in this embodiment can be manufactured in the same way as a general gel with water-absorbing and swelling properties. For example, when using alginic acid as the gel component, first prepare an aqueous solution of sodium alginate, add carbonic anhydrase or the above-mentioned microorganism to the aqueous solution, and then add the above-mentioned cation (e.g., calcium ion) and mix to promote gelation and produce gel 11.

[0059] Furthermore, when impregnating the fiber material 12 with gel 11, as shown in the carbon dioxide fixing member 1c in Figure 3, for example, an aqueous solution of sodium alginate to which carbonic anhydrase or the above-mentioned microorganism is added is impregnated at a predetermined position in the fiber material 12, and then a solution containing the above-mentioned cations (e.g., calcium ions) is supplied to further promote the gelation of alginate at that position, thereby forming gel 11.

[0060] The cation reservoir 111 described above can be formed, for example, by dropping a solution containing the above-mentioned cations (e.g., calcium ions) into an aqueous solution of sodium alginate to which carbonic anhydrase or the above-mentioned microorganism has been added, thereby promoting the gelation of alginate around the cation solution, and as a result, a cation reservoir 111 can be formed in which the cation solution is surrounded by gelled alginate.

[0061] 3. Textile materials The fibrous material 12 in this embodiment is not limited as long as it can support the gel 11. The fibrous material 12, at least a portion of which is fibrous, can supply water and carbon dioxide from outside the carbon dioxide fixing member to the gel 11. From the viewpoint of exhibiting such permeability and liquid permeability, it is preferable to use rock wool, glass wool, plastic fibers, plant fibers, animal fibers, etc., as the fibrous material 12, and it is particularly preferable to use a material in which the direction of the fibers is constant.

[0062] Furthermore, as shown in Figures 1 and 2, the carbon dioxide fixing members 1a and 1b may have notches in the fiber material 12 that connect from the gel 11 to the outside (or to the restraining member 13). Multiple such notches may be present.

[0063] 4. Restraining member The restraining member 13 in this embodiment is not particularly limited as long as it can restrain the gel 11 and the fiber material 12 and maintain the desired shape of the carbon dioxide fixing member.

[0064] When the carbon dioxide fixation member according to this embodiment is installed outdoors, it will be exposed to wind, rain, and sunlight for a long period of time. It is preferable that the restraining member 13 has sufficient strength to maintain restraint even in such cases. It is also preferable that the restraining member 13 has a shape that does not obstruct the supply of water and carbon dioxide from the carbon dioxide fixation member to the gel 11. From these viewpoints, the restraining member 13 is preferably made of a mesh, a panel with predetermined holes, a net-like structure, a rod-like structure, or the like. Furthermore, the material of the restraining member 13 is preferably metal, resin, or the like.

[0065] Furthermore, the carbon dioxide fixation member according to this embodiment may also preferably include, as a restraining member 13, wires or rod-shaped members provided to tie together the mesh or panels described above. By including these members, particularly in the carbon dioxide fixation members 1a and 1b shown in Figures 1 and 2, the tightening of the fiber material 12 by these members and the swelling of the gel 11 combine to increase the amount of deformation of the fiber material 12, making it easier to create larger openings.

[0066] Furthermore, the carbon dioxide sequestration member according to this embodiment is preferably block-shaped or panel-shaped from the viewpoint of ease of handling as a construction material, etc. When such a shape is envisioned, it is preferable that the restraining member 13 also has a corresponding shape.

[0067] 5. Method for manufacturing carbon dioxide fixation member The method for manufacturing the carbon dioxide fixation member according to this embodiment is not particularly limited, as long as the gel 11 and the fiber material 12 are arranged in a predetermined state.

[0068] For example, when manufacturing the carbon dioxide fixation members 1a and 1b shown in Figures 1 and 2, the gel 11 manufactured by the method described above can be sandwiched between fibrous material 12 molded into a predetermined shape, and then fixed with a restraining member 13 to obtain the carbon dioxide fixation members 1a and 1b.

[0069] Furthermore, when manufacturing the carbon dioxide fixation member 1c shown in Figure 3, as described above, the material of the gel 11 is impregnated into the fiber material 12 and then gelled. The resulting gel-impregnated fiber material 12 is then fixed with the restraining member 13 to obtain the carbon dioxide fixation member 1c.

[0070] As described above, the carbon dioxide fixing member equipped with a cation reservoir 111 can be obtained by gelling the manufactured cation reservoir 111 with the material of the gel 11, sandwiching the resulting gel 11 containing the cation reservoir 111 between fibrous materials 12, and further fixing it with a restraining member 13.

[0071] 6. How to use carbon dioxide fixation materials The carbon dioxide fixing member according to this embodiment can be used in a method for fixing carbon dioxide. For example, such a method includes arranging the carbon dioxide fixing member such that its surface is in contact with the atmosphere, installing it in a pipe through which a gas containing carbon dioxide passes, or immersing it in a tank in which a gas containing carbon dioxide is aerated.

[0072] Carbon dioxide sequestration materials can be used as construction materials such as exterior walls of buildings, interior walls of pipes, and filters that adsorb carbon dioxide. By using carbon dioxide sequestration materials as construction materials, they can be widely applied to living spaces, both indoors and outdoors, and the number of places where carbon dioxide can be sequestrated can be increased. As a result, the amount of carbon dioxide sequestrated can be increased.

[0073] When a carbon dioxide fixation member is placed with its surface in contact with the atmosphere, for example, it can be installed as a construction material on the exterior wall of a building. Alternatively, the carbon dioxide fixation member can be used as an exterior wall. In this case, moisture from the atmosphere or rain supplies water to the carbon dioxide fixation member, causing the gel to absorb water and swell. Furthermore, the aforementioned reaction occurs due to the action of carbonic anhydrase, and carbon dioxide is fixed.

[0074] When carbon dioxide fixation members are installed in pipes, ducts, or mufflers of automobiles that carry gases containing carbon dioxide, such as in combustion facilities like thermal power plants and waste incineration plants, the carbon dioxide fixation members may be installed as part of the inner wall of the pipe, or as a filter for the pipe. In this case, water may be supplied to the carbon dioxide fixation member by moisture in the gas, or water may be supplied to the carbon dioxide fixation member by a separately provided water supply means.

[0075] When a carbon dioxide fixing member is immersed in a tank of water through which a gas containing carbon dioxide is aerated, the carbon dioxide fixing member may simply be immersed in the tank, or the carbon dioxide fixing member may be placed in the flow path of the aerated gas. In this case, the gel will swell due to water absorption by the water in the tank.

[0076] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit it. Accordingly, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention. [Examples]

[0077] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0078] 1. Gel preparation Deinnococcus proteolyticus was selected as the enzyme-producing microorganism. This microorganism was cultured for 24 hours, and only those with an optical density (OD600) of 1.2 were used.

[0079] 0.6 ml of a 5% by mass sodium alginate aqueous solution was mixed with 0.1 ml of the culture solution of the above microorganism.

[0080] 0.7 ml of the obtained mixture was added dropwise to 30 ml of a 2.5% aqueous calcium chloride solution to gel the mixture into particulate matter. This yielded a gel containing the microorganisms mentioned above.

[0081] 2. Carbon dioxide sequestration To the solution containing the gel obtained as described above, 20 ml of pure water containing approximately 0.44% by mass of carbon dioxide, which had been prepared by pre-aerating with carbon dioxide, was added, the container was sealed, and the mixture was mixed.

[0082] Seven days after mixing, the mass of the precipitate (calcium carbonate) was calculated from the decrease in calcium ions in the solution. The results, including the amount of carbon dioxide fixed in the precipitate (calcium carbonate), are shown in Table 1.

[0083] Furthermore, the gel preparation, precipitate formation, and its recovery and mass measurement were carried out in the same manner as described above, except that the concentration of the sodium alginate aqueous solution used in gel preparation was changed as shown in Table 1. These measurement results are also shown in Table 1.

[0084] Furthermore, the gel preparation, precipitate formation, and subsequent collection and mass measurement were carried out in the same manner as described above, except that no microbial culture medium was added during gel preparation. The results of this measurement are also shown in Table 1.

[0085] [Table 1]

[0086] As is clear from the results in Table 1, little precipitate was produced in gels without microorganisms, while precipitate was produced in gels containing microorganisms, suggesting that carbon dioxide was fixed by microorganisms in the form of calcium carbonate. Furthermore, a tendency was observed for the amount of precipitate to increase with increasing concentration of sodium alginate during gel preparation, but the amount of precipitate produced decreased at 5% by mass, suggesting that there is an optimal amount of gel to use for carbon dioxide fixation.

[0087] Based on these results, it can be inferred that the carbon dioxide fixation member according to this embodiment is also capable of effective carbon dioxide fixation. [Industrial applicability]

[0088] The carbon dioxide fixation member of the present invention can be suitably used as a construction material, etc. [Explanation of Symbols]

[0089] 1a, 1b, 1c... Carbon dioxide fixation components 11,11'...Gel 111...Cation reservoir 112…Matrix section 12…Textile materials 13…Restraining member

Claims

1. A water-absorbing, swellable gel containing carbonic anhydrase or a microorganism capable of producing said carbonic anhydrase, and a cation capable of reacting with carbon dioxide to produce a water-insoluble or sparingly water-soluble carbonate, A fibrous material supporting the gel and A carbon dioxide fixation member equipped with the following features.

2. The carbon dioxide fixing member according to claim 1, wherein at least a portion of the gel is sandwiched between the fibrous material.

3. The carbon dioxide fixing member according to claim 2, wherein the degree of swelling of the gel upon water absorption is uniform throughout the entire gel.

4. The carbon dioxide fixing member according to claim 2, wherein the degree of swelling of at least a portion of the gel upon water absorption is different from the degree of swelling of the other portion of the gel.

5. The aforementioned fibrous material has notches, The aforementioned cut becomes an opening that connects the outside of the carbon dioxide fixing member to the gel when the fibrous material is expanded by the swelling of the gel. The carbon dioxide fixing member according to claim 2.

6. The carbon dioxide fixing member according to claim 1, wherein the gel is impregnated into at least a portion of the fibrous material.

7. The carbon dioxide fixing member according to claim 1, wherein the gel comprises a portion containing the carbonic anhydrous enzyme or the microorganism and a portion for storing the cation.

8. The carbon dioxide fixing member according to claim 1, wherein the carbon dioxide fixing member has a block-like or panel-like shape.

9. A method for fixing carbon dioxide, comprising arranging the carbon dioxide fixing member described in claim 1 such that its surface is in contact with the atmosphere, installing it in a pipe through which a gas containing carbon dioxide passes, or immersing it in a water tank through which a gas containing carbon dioxide is aerated.

10. A cation reservoir comprising a component containing cations that can react with carbon dioxide to produce water-insoluble or sparingly water-soluble carbonates, encapsulated within an outer membrane.

Images