Carbon dioxide capture module, scrubber for carbon dioxide capture, carbon dioxide capture device, and carbon dioxide capture method

Abstract

A carbon dioxide capture module according to one embodiment of the present invention is provided with a carbon dioxide capture material, a solution in contact with the carbon dioxide capture material so as to cover the carbon dioxide capture material, and a supply unit for supplying carbon dioxide to the solution, wherein the carbon dioxide capture material contains iron or an iron compound as a main component.

Description

Technical Field

[0001] The present invention relates to a carbon dioxide capture module, a carbon dioxide capture scrubber, a carbon dioxide capture device, and a carbon dioxide capture method. This application claims priority based on Japanese Patent Application No. 2022-166997 filed in Japan on October 18, 2022, and all the contents described in the above Japanese application are cited. Background Art

[0002] In order to collect carbon dioxide in industrial facilities, living spaces, and the like, the use of materials capable of capturing carbon dioxide (hereinafter also referred to as “carbon dioxide capturing materials”) has been studied (see Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2007-031169

[0006] Patent Document 2: Japanese Patent Application Publication No. 2007-075773 Summary of the invention

[0007] A carbon dioxide capture module according to one embodiment of the present invention includes a carbon dioxide capture material, a solution in contact with the carbon dioxide capture material so as to cover the carbon dioxide capture material, and a supply unit for supplying carbon dioxide to the solution, wherein the carbon dioxide capture material mainly contains iron or an iron compound. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a schematic perspective view of a carbon dioxide capture module according to one embodiment of the present invention and a carbon dioxide capture device including the carbon dioxide capture module.

[0009] Figure 2 yes Figure 1 Schematic II-II line cross-sectional view of the carbon dioxide capture device.

[0010] Figure 3 Yes means Figure 1 Schematic cross-sectional view of a modified example of a support body in a carbon dioxide capture module.

[0011] Figure 4 It is shown Figure 1 The support body of the carbon dioxide capture module Figure 3 Schematic cross-sectional views of different variants.

[0012] Figure 5 This means that Figure 1Schematic perspective views of a carbon dioxide capture module according to different embodiments and a carbon dioxide capture device including the carbon dioxide capture module.

[0013] Figure 6 This means that Figure 1 and Figure 5 Schematic diagram of a carbon dioxide capture module according to different embodiments and a carbon dioxide capture scrubber including the carbon dioxide capture module.

[0014] Figure 7 This is a flow chart showing a carbon dioxide capture method according to one embodiment of the present invention. DETAILED DESCRIPTION

[0015] [Problems to be Solved by the Invention]

[0016] Patent document 1 describes a method for capturing carbonate by applying mechanical impact to a metal body, supplying water and carbon dioxide. Patent document 2 describes a method for capturing carbon dioxide that generates carbonate by contacting metal, water and carbon dioxide with a particle size below a certain value. However, if the technology described in patent documents 1 and 2 is used in common industrial equipment, living spaces, etc., the metal is easily exposed to oxygen in the atmosphere. Therefore, due to oxidation of the metal, the capture efficiency of carbon dioxide may be reduced.

[0017] The present invention has been made based on the above circumstances, and an object of the present invention is to provide a carbon dioxide capture module having excellent carbon dioxide capture efficiency.

[0018] [Effects of the Invention]

[0019] A carbon dioxide capture module according to one embodiment of the present invention is excellent in carbon dioxide capture efficiency.

[0020] [Description of Embodiments of the Invention]

[0021] First, embodiments of the present invention will be described below.

[0022] (1) A carbon dioxide capture module according to one embodiment of the present invention includes: a carbon dioxide capture material; a solution in contact with the carbon dioxide capture material so as to cover the carbon dioxide capture material; and a supply unit for supplying carbon dioxide to the solution, wherein the carbon dioxide capture material contains iron or an iron compound as a main component.

[0023] The carbon dioxide capture module can make the above-mentioned solution dissolved with carbon dioxide fully contact with the carbon dioxide capture agent in a manner covering the above-mentioned carbon dioxide capture material. At this time, a part of the dissolved carbon dioxide changes into carbonate ions or bicarbonate ions (hereinafter, carbonate ions and bicarbonate ions are collectively referred to as "carbonate ions, etc."). Therefore, the above-mentioned carbon dioxide capture material can easily capture carbonate ions dissolved in the above-mentioned solution, etc. By making the above-mentioned solution fully contact with the above-mentioned carbon dioxide capture material, it is easy to suppress the above-mentioned carbon dioxide capture material from being deteriorated due to oxidation, etc. Therefore, the capture efficiency of carbon dioxide of the carbon dioxide capture module is excellent. Through the above-mentioned carbon dioxide capture material with iron or iron compound as the main component, as the ion bonded with carbonate ions, etc., divalent iron ions are dissolved from the above-mentioned carbon dioxide capture material (more specifically, iron or iron compound contained in the carbon dioxide capture material). The above-mentioned carbon dioxide capture material is fully contacted with the above-mentioned solution, so it is easy to suppress the oxidation of divalent iron ions into trivalent iron ions and change into iron oxide. Thus, the above-mentioned carbon dioxide capture material can more easily capture carbonate ions, etc. More specifically, divalent iron ions generate iron carbonate or iron bicarbonate (hereinafter, iron carbonate and iron bicarbonate are also collectively referred to as "iron carbonate, etc.") by bonding with carbonate ions, etc. Iron carbonate, etc. can be attached to the above-mentioned carbon dioxide capture material, or precipitate or float in the above-mentioned solution. "Main component" refers to that the content in the material is more than 50% by mass. The iron ions dissolved from the iron or iron compound contained in the above-mentioned carbon dioxide capture material also constitute the above-mentioned carbon dioxide capture material.

[0024] (2) In the above (1), the pH of the above solution and the potential of the above carbon dioxide capture material can be controlled within the range where divalent iron ions or divalent iron hydroxide are stable in the potential-pH diagram. In this way, by controlling the pH of the above solution and the potential of the above carbon dioxide capture material within the range where divalent iron ions or divalent iron hydroxide are stable in the potential-pH diagram, the chemical equilibrium in the above solution is easily transferred in a manner that increases the ratio of divalent iron ions. Therefore, the capture efficiency of carbon dioxide can be further improved. "Potential-pH diagram" refers to the potential-pH diagram of iron in the above solution at 25°C.

[0025] (3) In the above (1) or (2), the above solution may contain a pH buffer. When the above solution contains a pH buffer, it is easy to maintain a state in which the ratio of divalent iron ions in the above solution is increased. Therefore, it is easy to maintain the capture efficiency of carbon dioxide.

[0026] (4) In any one of (1) to (3) above, a solution adjustment mechanism for supplying at least one of an acidic substance, a reducing agent, a metal ion chelating agent, and a detergent to the solution may be provided. By providing the solution adjustment mechanism, it is easy to maintain a state in which the ratio of divalent iron ions in the solution is increased. Therefore, the capture efficiency of carbon dioxide can be easily maintained.

[0027] (5) In any one of the above (1) to (4), a voltage applying mechanism for applying voltage to the carbon dioxide capture material may be provided. By providing the voltage applying mechanism, it is easy to maintain a state in which the ratio of divalent iron ions in the above solution is increased. Therefore, it is possible to easily maintain the capture efficiency of carbon dioxide.

[0028] (6) In any one of (1) to (5) above, a degassing promotion mechanism for promoting the degassing of dissolved oxygen in the solution may be provided. By providing the degassing promotion mechanism, the oxidation caused by the dissolved oxygen in the solution is reduced, and it is easy to maintain a state in which the ratio of divalent iron ions in the solution is increased. Therefore, the capture efficiency of carbon dioxide can be easily maintained.

[0029] (7) In any one of (1) to (6) above, the solution may contain a carbonation promoter for promoting the carbonation of iron ions dissolved from the carbon dioxide capture material. By making the solution contain a carbonation promoter, the carbon dioxide capture efficiency of the carbon dioxide capture module can be improved.

[0030] (8) In any one of (1) to (7) above, a dissolution promoting mechanism for promoting the dissolution of the carbon dioxide in the solution may be provided. In the solution, for example, under conditions such as pH at which divalent iron ions can stably exist, carbonate ions and the like in the solution tend to decrease. On the other hand, by providing a dissolution promoting mechanism, carbonate ions and the like in the solution can be increased. Therefore, the capture efficiency of carbon dioxide can be further improved.

[0031] (9) In any one of (1) to (8) above, the solution may contain a dissolution promoter that promotes the dissolution of the carbon dioxide in the solution. When the solution contains a dissolution promoter, the amount of carbon dioxide in the solution can be easily increased. Therefore, the capture efficiency of carbon dioxide can be further improved.

[0032] (10) In any one of the above (1) to (9), the dissolution rate of the carbon dioxide in the solution may be lower than the carbonation rate of the carbon dioxide capture material. By making the dissolution rate of the carbon dioxide in the solution lower than the carbonation rate of the carbon dioxide capture material, the carbon dioxide supplied from the supply unit can be more reliably captured by the carbon dioxide capture material.

[0033] (11) In any one of the above (1) to (10), multiple of the above carbon dioxide capture materials may be provided, and the average particle size of the multiple carbon dioxide capture materials is 5 nm or more and 500 μm or less. By making the average particle size of the multiple carbon dioxide capture materials equal to or greater than the above lower limit, the contact area between the carbon dioxide capture materials and the above solution can be increased. By making the average particle size equal to or less than the above upper limit, the dispersion of the carbon dioxide capture materials can be made easier. Therefore, the carbon dioxide capture efficiency can be further improved.

[0034] (12) In the above (11), a dispersion mechanism for dispersing the multiple carbon dioxide capture materials in the above solution may be provided, and the dispersion mechanism maintains the average particle size of the multiple carbon dioxide capture materials at 5 nm or more and 500 μm or less. By providing a dispersion mechanism for dispersing the multiple carbon dioxide capture materials in the above solution, aggregation of the carbon dioxide capture materials can be suppressed, and an appropriate particle size of the carbon dioxide capture materials can be easily maintained.

[0035] (13) In any one of the above (1) to (12), a display mechanism for displaying a decrease in the activity of the carbon dioxide capture material when the activity decreases may be provided. By providing a display mechanism for displaying a decrease in the activity of the carbon dioxide capture material, it is easy to control the environment of the above solution to maintain the carbon dioxide capture efficiency.

[0036] (14) In any one of the above (1) to (13), multiple of the above carbon dioxide capture materials may also be provided, and a dispersion mechanism for dispersing the above solution onto the multiple carbon dioxide capture materials may be provided. By providing a dispersion mechanism for dispersing the above solution onto the multiple carbon dioxide capture materials, the above solution can be brought into uniform contact with the multiple carbon dioxide capture materials. Thereby, it is easy to improve the carbon dioxide capture efficiency.

[0037] (15) In the above (14), a housing portion for housing the multiple carbon dioxide capture materials may be provided. By providing a housing portion for housing the multiple carbon dioxide capture materials, it is easy to supply the above solution in such a manner that it uniformly contacts the multiple carbon dioxide capture materials housed in a predetermined position.

[0038] (16) In any one of the above (1) to (15), a porous support for disposing the carbon dioxide capture material may be provided. By providing a porous support on which the carbon dioxide capture material is disposed, it is easy to stably hold the carbon dioxide capture material.

[0039] (17) In the above (16), the support is a porous particle, and the average particle size of the porous particles in the state where the carbon dioxide capture material is arranged can be 10 mm or less. By making the average particle size of the porous particles below the upper limit, the overall homogenization of the system is achieved, thereby easily improving the capture efficiency of the carbon dioxide capture material for carbonate ions and the like. The lower limit of the average particle size of the porous particles can be 1.0×10 -5 mm.

[0040] (18) In the above (16), the support may be a porous thread or a porous sheet, and a plurality of the carbon dioxide capture materials are arranged on the support. The support is a porous thread or a porous sheet, and a plurality of the carbon dioxide capture materials are arranged on the support, thereby enabling carbonate ions and the like to easily and reliably contact the plurality of carbon dioxide capture materials.

[0041] (19) In any of the above (16) to (18), a plurality of the above-mentioned supports may be provided, and the plurality of the above-mentioned supports may be arranged at intervals from each other. By arranging the plurality of the above-mentioned supports at intervals from each other, the plurality of the above-mentioned carbon dioxide capture materials can be easily and stably maintained in a state where they are easily in contact with carbonate ions, etc.

[0042] (20) A carbon dioxide capture scrubber according to another aspect of the present invention includes the carbon dioxide capture module according to any one of (1) to (19), wherein the solution is spread on the carbon dioxide capture material.

[0043] The scrubber for capturing carbon dioxide includes the carbon dioxide capturing module and therefore has excellent carbon dioxide capturing efficiency.

[0044] (21) A carbon dioxide capture device according to another aspect of the present invention comprises the carbon dioxide capture module according to any one of (1) to (19) above and a storage tank for storing the solution, wherein the carbon dioxide capture material is immersed in the solution.

[0045] The carbon dioxide capture device includes the carbon dioxide capture module, and the carbon dioxide capture material is immersed in the solution, so the carbon dioxide capture efficiency is excellent.

[0046] (22) A carbon dioxide capture method according to another aspect of the present invention comprises a step of bringing carbonate ions or bicarbonate ions into contact with a carbon dioxide capture material covered with a solution, wherein the carbon dioxide capture material contains iron or an iron compound as a main component.

[0047] In the carbon dioxide capture method, the above-mentioned solution is fully in contact with the above-mentioned carbon dioxide capture material in a manner covering the above-mentioned carbon dioxide capture material, so the above-mentioned carbon dioxide capture material can easily capture carbonate ions dissolved in the above-mentioned solution, etc. By making the above-mentioned solution fully contact with the above-mentioned carbon dioxide capture material, it is easy to suppress the above-mentioned carbon dioxide capture material from deteriorating due to oxidation, etc. Therefore, the capture efficiency of carbon dioxide of the carbon dioxide capture method is excellent. The above-mentioned carbon dioxide capture material is mainly composed of iron or iron compounds, so carbonate ions, etc. can be more easily captured.

[0048] In the present invention, "the solution in contact with the carbon dioxide capture material in a manner covering the carbon dioxide capture material" only needs to be in a state where the carbon dioxide capture material is covered by the solution, and is not limited to a structure where the carbon dioxide capture material is always covered by the solution. It only needs to be in a state where the carbon dioxide capture material is partially covered by the solution, and is not limited to a structure where the entire carbon dioxide capture material is covered by the solution. The carbon dioxide capture material may be in contact with a member such as a cloth for transferring the solution, or may be provided in a manner covered by the solution transferred through the member. The form of carbon dioxide supplied by the "supply unit" is not limited to gas, but may also be in a state dissolved in a solution. That is, the supply unit may supply carbon dioxide in the form of, for example, carbonate ions or bicarbonate ions. "Particle size" refers to the particle size in secondary particles. In the case where secondary particles are not formed, it refers to the particle size of primary particles. "Average particle size" refers to the median particle size (D50) at which the volume-based cumulative distribution calculated in accordance with JIS-Z-8819-2:2001 becomes 50%.

[0049] [Details of the embodiments of the present invention]

[0050] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings as appropriate. In the following description, the carbon dioxide capture material is sometimes referred to as the capture material, the carbon dioxide capture module is referred to as the capture module, the carbon dioxide capture scrubber is referred to as the capture scrubber, the carbon dioxide capture device is referred to as the capture device, and the carbon dioxide capture unit is referred to as the capture unit.

[0051] [First embodiment]

[0052] Figure 1 and Figure 2 The carbon dioxide capture module 101 includes a carbon dioxide capture material 10, a solution 20 in contact with the carbon dioxide capture material 10 in a manner covering the carbon dioxide capture material 10, and a supply unit 30 for supplying carbon dioxide to the solution 20. Figure 1 and Figure 2 As shown, the capture module 101 is configured in the carbon dioxide capture device 1 .

[0053] The capture material 10, the solution 20 and the supply unit 30 of the capture module 101 are arranged in a container. In more detail, the capture material 10 and the solution 20 are contained in the container, and the supply unit 30 is configured to be able to supply carbon dioxide into the container. As a container, for example, the storage tank 102 described later can be cited. The carbon dioxide supplied to the solution 20 by the supply unit 30 dissolves in the solution 20. The carbon dioxide dissolved in the solution 20 is captured by the capture material 10.

[0054] The capture module 101 can make the solution 20 in which carbon dioxide is dissolved fully contact with the capture material 10 in a manner that covers the capture material 10. At this time, a part of the dissolved carbon dioxide becomes carbonate ions, etc. Therefore, the capture material 10 can easily capture carbonate ions, etc. dissolved in the solution 20. By fully contacting the solution 20 with the capture material 10, it is easy to suppress the deterioration caused by oxidation of the capture material 10. Therefore, the capture efficiency of carbon dioxide of the capture module 101 is excellent.

[0055] The capture module 101 and the capture device 1 are used, for example, to capture or recover carbon dioxide in production facilities, living spaces, offices, etc. The sizes of the capture module 101 and the capture device 1 are appropriately set according to the place of use and purpose. The capture module 101 and the capture device 1 having the capture module 101 are described in detail below.

[0056] <Carbon dioxide capture module>

[0057] The capture module 101 allows a solution 20 containing dissolved carbon dioxide to fully contact the capture material 10 in a manner that covers the capture material 10, and uses the capture material 10 to capture carbonate ions and the like generated in the solution 20. The capture module (101) comprises: a dissolution promoting mechanism (40) for promoting the dissolution of carbon dioxide into the solution (20); a dispersing mechanism (50) for dispersing a plurality of capture materials (10) in the solution (20); a solution adjusting mechanism (60) for supplying at least one of an acidic substance, a reducing agent, a metal ion chelating agent and a detergent to the solution (20); a display mechanism (90) for displaying the reduction in the activity of the capture material (10); and a porous support (71a) on which the capture material (10) is disposed.

[0058] (Carbon dioxide capture material)

[0059] The capture material 10 is in a granular form, or more specifically, in a powdered form. The capture material 10 is mainly composed of iron or an iron compound. Examples of the capture material 10 having iron as the main component include iron and iron alloys. Iron alloys may also be metals that contain, in addition to iron, elements such as manganese, chromium, molybdenum, aluminum, copper, zinc, and nickel. Examples of iron compounds include iron (II) hydroxide, iron (II) hexacyanoferrate (II), and the like. The capture material 10 is mainly composed of iron or an iron compound, so that carbonate ions and the like in the solution 20 can be more easily captured. In the capture module 101, as the capture material 10, only one of the above-mentioned iron, iron alloy, and iron compound may be included, or two or more may be included.

[0060] If the capturing material 10 is mainly composed of iron or an iron compound, the divalent iron ions are dissolved in the solution 20 and react with the carbonate ions in the solution 20 as shown in the following formula (1) or the following formula (2). When the divalent iron ions dissolved from the capturing material 10 generate iron (II) hydroxide, the ionized divalent iron ions also react with the carbonate ions in the solution 20 as shown in the following formula (1) or the following formula (2). In the following formula (1) and the following formula (2), aq represents a hydrated state.

[0061] Fe 2+ (aq)+CO 3 2- (aq) = FeCO 3 (aq)···(1)

[0062] Fe 2+ (aq)+2HCO 3 - (aq)=Fe(HCO 3 ) 2 (aq)··(2)

[0063] In this embodiment, the capturing material 10 can capture carbonate ions and the like in the solution 20 by generating iron carbonate or iron bicarbonate. The carbon dioxide captured by the capturing material 10 can be recovered by washing the capturing material 10, filtering the solution 20, and the like.

[0064] When the capturing material 10 is an iron alloy, the lower limit of the content of the iron element in the iron alloy can be 50 mass%, 60 mass%, or 70 mass% from the viewpoint of ensuring the amount of iron ions eluted into the solution 20. The upper limit of the content of the iron element in the iron alloy can be, for example, 99.99 mass%. When the capturing material 10 is mainly composed of an iron compound, the lower limit of the content of the iron compound in the capturing material 10 can be 50 mass%, 60 mass%, or 70 mass% from the viewpoint of ensuring the amount of iron ions eluted into the solution 20. The upper limit of the content of the iron compound in the capturing material 10 can be, for example, 99.99 mass%.

[0065] The lower limit of the average particle size of the plurality of capturing materials 10 may be 5 nm, 10 nm, or 15 nm from the viewpoint of increasing the contact area between the capturing material 10 and the solution 20. The upper limit of the average particle size may be 500 μm, 200 μm, or 100 μm from the viewpoint of making it easy to disperse the capturing material 10. The average particle size may be 5 nm or more and 500 μm or less, 10 nm or more and 200 μm or less, or 15 nm or more and 100 μm or less.

[0066] (Supporting body)

[0067] A plurality of capturing materials 10 are disposed on the support 71a. The capturing module 101 can stably hold the capturing material 10 by including the support 71a. According to this configuration, when carbon dioxide adheres to the capturing material 10 as iron carbonate, for example, it can be easily recovered and cleaned.

[0068] exist Figure 1 and Figure 2 In the embodiment, the support body 71a is a porous sheet. Figure 1 and Figure 2 In the embodiment, a plurality of capturing materials 10 are arranged on a porous sheet. Since the support 71a is a porous sheet, carbonate ions and the like can be easily and reliably contacted with the capturing material 10. A plurality of capturing materials 10 are arranged at intervals on a porous sheet. Since the support 71a is a porous sheet, a plurality of capturing materials 10 can be easily arranged at intervals. As a result, it is easy to suppress the aggregation of the capturing material 10, and improve the capturing effect of the capturing material 10 on carbonate ions and the like.

[0069] Examples of the support 71a include cloth, nonwoven fabric sheets, fabric sheets, sponge sheets, cellulose fiber sheets such as Japanese paper, carbon fiber sheets, ceramic fiber sheets such as alumina, and metal fiber sheets such as copper and stainless steel. The support 71a may be subjected to surface treatment such as gold plating or resin coating to prevent deterioration and corrosion caused by the solution 20 described later.

[0070] The capturing material 10 may be disposed on the surface of the support 71a or may be disposed inside the support 71a. The capturing material 10 may be supported on the surface or pores of the support 71a using the support 71a as a carrier.

[0071] The support is not limited to a porous sheet, and may be, for example, porous particles or porous fibers. Figure 3 and Figure 4 , the configuration in which the capturing material 10 is disposed on porous particles or porous fibers is described. Even in the case of being disposed on porous particles or porous fibers, the capturing material 10 may be disposed on the surface of the supporting bodies 71b and 71c, or may be disposed inside the supporting bodies 71b and 71c. The supporting bodies 71b and 71c may also be used as carriers and carried on the surface or pores of the supporting bodies 71b and 71c.

[0072] Figure 3 The support body 71b is a porous particle. Figure 3 In the embodiment, a plurality of capturing materials 10 are arranged on one porous particle. More specifically, a plurality of capturing materials 10 are arranged at intervals on one porous particle. By arranging in this way, it is easy to suppress the aggregation of the capturing material 10, and improve the capturing effect of the capturing material 10 on carbonate ions and the like.

[0073] Examples of porous particles include silica gel, water-absorbing polymers, activated carbon particles, porous glass, and porous metal particles. In order to prevent deterioration and corrosion caused by the solution 20 described later, the porous particles may be subjected to surface treatments such as gold plating and resin coating. From the perspective of easy configuration of the capture material 10, the lower limit of the average particle size of the porous particles may be 2 times, 5 times, or 10 times the average particle size of the capture material 10. The lower limit of the average particle size of the porous particles may be 1.0×10 -5 mm, or 2.5×10 -5 mm, and can also be 5.0×10 -4The upper limit of the average particle size of the porous particles may be 10 mm from the viewpoint of easily improving the capture efficiency of the capture material 10 for carbonate ions and the like by achieving uniformity of the entire system. The upper limit of the average particle size of the porous particles may be 200 times, 100 times, or 50 times the average particle size of the capture material 10. The average particle size of the porous particles may be more than 2 times and less than 200 times the average particle size of the capture material 10, more than 5 times and less than 100 times, or more than 10 times and less than 50 times. The average particle size of the porous particles may be 1.0×10 -5 mm or more and 10 mm or less, or 2.5×10 -5 mm or more and 10 mm or less, and 5.0×10 -4 mm or more and 10 mm or less.

[0074] Figure 4 The support body 71c is a porous wire. Figure 4 In the embodiment, a plurality of capturing materials 10 are arranged on a porous silk. Since the support 71c is a porous silk, carbonate ions and the like can be easily and reliably contacted with the plurality of capturing materials 10. A plurality of capturing materials 10 are arranged at intervals on a porous silk. Since the support 71c is a porous silk, a plurality of capturing materials 10 can be spaced apart from each other and easily arranged. As a result, it is easy to suppress the aggregation of the capturing material 10, and improve the capturing effect of the capturing material 10 on carbonate ions and the like.

[0075] The porous fiber is not particularly limited as long as it has a plurality of holes, and for example, a hollow fiber membrane having a fibrous skeleton can be used.

[0076] The lower limit of the average pore diameter of the supports 71a, 71b, and 71c may be equal to, 3 times, 5 times, or 10 times the average particle diameter of the capture material 10 from the perspective of ensuring air permeability or from the perspective of facilitating the loading of the capture material 10. The upper limit of the average pore diameter of the supports 71a, 71b, and 71c is not particularly limited, and may be, for example, 100 times the average particle diameter of the capture material 10. The "average pore diameter" is calculated from the BET specific surface area and pore volume determined by the gas adsorption method in accordance with JIS-Z-8830-2:2013.

[0077] The number of supports in the capture module 101 is not particularly limited, and may be one or more. When the capture module 101 has a plurality of supports, the supports may be any one of a porous sheet, porous particles, and porous wires, or a combination of two or more of the porous sheets, porous particles, and porous wires.

[0078] When the capture module 101 has a plurality of supports, the plurality of supports may be arranged at intervals from each other. With such a configuration, the plurality of capture materials 10 can be easily and stably held in a state where they can easily come into contact with carbonate ions and the like.

[0079] like Figure 1 and Figure 2 As shown in FIG. 1 , when a plurality of support bodies 71 a are arranged at intervals from each other, these support bodies 71 a may be arranged with spacers 72 interposed therebetween. Figure 1 and Figure 2 In the capture module 101, the plurality of support bodies 71a are alternately arranged with the spacers 72 in the thickness direction thereof. The plurality of support bodies 71a make the one-side surface contact with the spacers 72 and are alternately arranged with the spacers 72. The plurality of support bodies 71a may also be fixed to the spacers 72. In the capture module 101, the plurality of capture materials 10, the plurality of support bodies 71a and the plurality of spacers 72 constitute the capture unit 70 as a whole.

[0080] The spacer 72 is, for example, in the shape of a plate. The spacer 72 is arranged alternately with the support 71a in a state where its plate surface is in contact with the support 71a. The spacer 72 is a porous body. The spacer 72 is a porous body, thereby constituting a passage for carbonate ions and the like to reach the capture material 10. As the spacer 72, for example, a mesh body and a sponge body can be cited. The spacer 72 is not limited to a plate shape, and can also be a rod-shaped member that only contacts a part of the support 71a. By having the spacer 72, the capture module 101 can easily keep a plurality of supports 71a spaced apart from each other and arrange them at a high density.

[0081] (Supply Department)

[0082] The supply unit 30 supplies a gas containing carbon dioxide to the solution 20. The supply unit 30 supplies carbon dioxide to the solution 20 by supplying a gas containing carbon dioxide to a storage tank 102 (described later) storing the solution 20. The supply unit 30 includes, for example, a supply pipe capable of supplying carbon dioxide into the storage tank 102 from a lower portion of the storage tank 102.

[0083] (Solution)

[0084] The solution 20 always covers the plurality of capturing materials 10 . In the capturing module 101 , the plurality of capturing materials 10 are immersed in the solution 20 , and more specifically, the capturing unit 70 is immersed in the solution 20 .

[0085] The pH of the solution 20 and the potential of the capturing material 10 can be controlled within the range in which the divalent iron ions or divalent iron hydroxide are stable in the potential-pH diagram. The pH of the solution 20 and the potential of the capturing material 10 can be controlled so that the content of the divalent iron ions or divalent iron hydroxide in the solution 20 is increased. From the viewpoint that it is easier to generate iron carbonate and the like through formula (1) or formula (2), the pH of the solution 20 and the potential of the capturing material 10 can be controlled within the range in which the divalent iron ions are stable in the potential-pH diagram. As a method for controlling the pH of the solution 20, the pH buffer material described later, the salt showing acidity in the solution 20, etc. can be listed. As a method for controlling the potential of the capturing material 10, applying a voltage to the capturing material 10 can be listed. As a means for measuring the pH in the solution 20, the display mechanism 90 described later can be listed, and as a means for measuring the potential of the capturing material 10, an ORP meter can be listed.

[0086] In the potential-pH diagram, the range in which divalent iron ions are stable refers to the range in which the pH of the solution 20 satisfies not less than -2 and not more than 9.5, and the potential (E (V vs. SHE)) of the capture material 10 satisfies the following equations (3), (4) and (5).

[0087] E<-0·218pH+1.67(4≤pH≤9.5)···(3)

[0088] E<0.8(-2≤pH≤4)···(4)

[0089] E>-0.6(-2≤pH≤9.5)···(5)

[0090] In the potential-pH diagram, the range in which divalent iron hydroxide is stable refers to the range in which the pH of the solution 20 satisfies 9.5 or more and 16 or less, and the potential (E (V vs. SHE)) of the capture material 10 satisfies the following equations (6) and (7).

[0091] E<-0.0615pH+0.285···(6)

[0092] E>-0.0615pH-0.0154···(7)

[0093] The upper limit of the pH of the solution 20 may be 6.0, 5.0, 4.0, 3.0, 2.5, 2.0, or 1.5 from the viewpoint of easily increasing the divalent iron ions in the solution 20. The lower limit of the pH of the solution 20 is not particularly limited, and may be 0.0, for example.

[0094] In order to stop the use of the capture module 101 and recover the compounds dissolved in the solution 20 (for example, carbonate ions, etc.), the potential of the capture material 10 and the pH of the solution 20 can also be temporarily controlled outside the stable range of divalent iron ions or divalent ferric hydroxide in the potential-pH diagram, or the pH of the solution 20 can be temporarily controlled outside the pH range of the solution 20.

[0095] The solution 20 contains water as a solvent. The solution 20 may contain a dissolution promoter that promotes the dissolution of carbon dioxide in the solution 20, may contain a pH buffer material, may contain a salt that exhibits acidity in the solution 20 in order to reduce the pH of the solution 20, and may contain a carbonation promoter 21 for promoting the carbonation of iron ions dissolved from the capture material 10.

[0096] A gas containing carbon dioxide is supplied from the supply unit 30 to the solution 20. In the solution 20, a chemical equilibrium represented by the following equation (8) and the following equation (9) is generated, and carbonate ions (CO 3 2- ) or bicarbonate ion (HCO 3 - ). In the following formula (8) and the following formula (9), aq represents a hydrated state.

[0097] CO 2 (aq) = H + (aq)+HCO 3 - (aq)···(8)

[0098] HCO 3 - (aq) = H + (aq)+CO 3 2- (aq)···(9)

[0099] 〔Dissolution accelerator〕

[0100] As a dissolution promoter, for example, carbonic anhydrase can be mentioned. Carbonic anhydrase promotes the dissolution of bicarbonate ions (HCO 3 - ) is generated. By including the dissolution promoter in the solution 20, it is easy to increase the amount of carbonate ions and the like in the solution 20. Therefore, the capture efficiency of carbon dioxide can be further improved.

[0101] [pH buffer]

[0102] The pH buffer (buffer) easily maintains the pH of the solution 20 at a desired value. As pH buffer materials, sodium tartrate, sodium acetate, sodium borate, sodium citrate, ammonium chloride, sodium phosphate, etc. can be cited. By including the pH buffer in the solution 20, it is easy to maintain a state in which divalent iron ions or divalent iron hydroxide increase in the solution 20. Therefore, the capture efficiency of carbon dioxide can be easily maintained.

[0103] [Salt]

[0104] As salts showing acidity in the solution 20, that is, salts showing acidity by dissolving in the solution 20, sodium hydrogen sulfate, ammonium hydrogen sulfate, sodium dihydrogen phosphate, iron (II) sulfate, iron (II) chloride, etc. can be cited. When the solution 20 contains the above salts, the pH of the solution 20 can be easily reduced. As a result, divalent iron ions are easily eluted from the capture material 10 into the solution 20. That is, the activity of the capture material 10 in capturing carbonate ions and the like is easily maintained.

[0105] [Carbonation accelerator]

[0106] In the present embodiment, the carbonation promoter 21 is in a granular form. The carbonation promoter 21 is mainly composed of iron carbonate or iron bicarbonate. The carbonation promoter 21 can become a seed for carbonating iron ions. By using the carbonation promoter 21 as a seed to grow crystals such as iron carbonate, the capture of carbonate ions and the like by the iron ions dissolved from the capture material 10 is promoted. By becoming a seed, the carbonation promoter 21 can suppress the capture material 10 from being coated with iron carbonate and the like and the associated reduction in the activity of the capture material 10.

[0107] The carbonation promoter 21 may also be configured at a distance from the capture material 10. By configuring the carbonation promoter 21 in this way, it is possible to easily recycle the iron carbonate etc. that is a seed of the carbonation promoter 21. When the capture material 10 is not coated with the iron carbonate etc., it is possible to selectively recycle the iron carbonate etc. that is a seed of the carbonation promoter 21 without reclaiming the capture material 10.

[0108] like Figure 1 As shown, in the present embodiment, the carbonation promoter 21 is arranged with a porous membrane 102a disposed in a storage tank 102 described later, and is arranged at intervals from the capture material 10 and the support 71a. By configuring the carbonation promoter 21 with the porous membrane 102a, it is easy to maintain the interval between the carbonation promoter 21 and the capture material 10. The porous membrane 102a can also be configured to suppress the passage of iron carbonate, etc., so that carbonate ions, etc. pass through. Thus, it is easier to suppress the reduction of the activity of the capture material 10, and promote the supply of carbonate ions, etc. to the capture material 10.

[0109] (Dissolution promoting mechanism)

[0110] The dissolution promoting mechanism 40 promotes the dissolution of carbon dioxide in the solution 20. The capturing module 101 can easily increase the amount of carbon dioxide in the solution 20 by including the dissolution promoting mechanism 40. Therefore, the capturing efficiency of carbon dioxide can be further improved.

[0111] As the dissolution promoting mechanism 40, for example, there can be listed a bubble generating device (bubbling device) capable of generating fine bubbles such as nanobubbles and microbubbles in the solution 20, an ultrasonic generating device capable of generating cavitation bubbles in the solution 20, and a temperature-pressure control device capable of lowering the water temperature of the solution 20 and increasing the partial pressure of carbon dioxide.

[0112] exist Figure 1 and Figure 2 In the embodiment, a bubble generator is provided as the dissolution promoting mechanism 40. The bubble generator is disposed in the flow path of carbon dioxide from the supply unit 30 to the storage tank 102. The bubble generator converts the gas containing carbon dioxide into fine bubbles and supplies the fine bubbles to the solution 20.

[0113] The upper limit of the bubble diameter of the fine bubbles can be 1.0 μm, 0.8 μm, or 0.6 μm from the viewpoint of increasing the contact area between the carbon dioxide and the solution 20 as a whole in the capture module 101. The lower limit of the bubble diameter is not particularly limited, and can be set to 0.005 μm, for example. The bubble diameter can be greater than 0.005 μm and less than 1.0 μm, greater than 0.005 μm and less than 0.8 μm, or greater than 0.005 μm and less than 0.6 μm. "Bubble diameter" refers to the diameter at the moment of ejection from the bubble generating device.

[0114] The lower limit of the partial pressure of carbon dioxide in the gas supplied from the supply unit 30 to the storage tank 102 can be 4.0×10 -5 MPa, or 6.0×10 -5 MPa, and can also be 8.0×10 -5 MPa. The upper limit of the partial pressure is not particularly limited, but can be set to 1.0×10 -1 MPa. The partial pressure can be 4.0×10 -5 MPa or above and 1.0×10 -1 MPa or less, can be 6.0×10 -5 MPa or above and 1.0×10 -1 MPa or less, can be 8.0×10 -5 MPa or above and 1.0×10 -1When the dissolution promoting mechanism 40 is a temperature and pressure control device, the dissolution promoting mechanism 40 can control the partial pressure of carbon dioxide within the above range.

[0115] When the dissolution promoting mechanism 40 is a temperature and pressure control device, the upper limit of the temperature of the solution 20 controlled by the dissolution promoting mechanism 40 may be 99° C. or 95° C. from the viewpoint of facilitating the handling of the solution 20. The lower limit of the temperature may be 25° C., 50° C., 70° C. or 90° C. from the viewpoint of improving the capture efficiency of the capture material 10 for carbonate ions and the like. The temperature may be 25° C. or higher and 99° C. or lower, 50° C. or higher and 99° C. or lower, 70° C. or higher and 99° C. or lower, 90° C. or higher and 99° C. or lower, or 90° C. or higher and 95° C.

[0116] (Decentralized Organization)

[0117] The dispersion mechanism 50 disperses the plurality of capture materials 10 in the solution 20. The dispersion mechanism 50 maintains the average particle size of the plurality of capture materials 10. The lower limit of the average particle size of the plurality of capture materials 10 maintained by the dispersion mechanism 50 may be 5 nm, 10 nm, or 15 nm. The upper limit of the average particle size of the plurality of capture materials 10 maintained by the dispersion mechanism 50 may be 500 μm, 200 μm, or 100 μm. The average particle size may be greater than 5 nm and less than 500 μm, greater than 10 nm and less than 200 μm, or greater than 15 nm and less than 100 μm. By having the dispersion mechanism 50, the capture module 101 can suppress the aggregation of the capture material 10 and can easily maintain the appropriate particle size of the capture material 10.

[0118] The dispersion mechanism 50 functions particularly effectively when a plurality of capture materials 10 are prone to agglomeration. For example, when a plurality of capture materials 10 are not arranged on the support bodies 71a, 71b, and 71c, agglomeration of the capture materials 10 may occur temporarily. In this case, by using the dispersion mechanism 50 to disperse a plurality of capture materials 10 when carbon dioxide is supplied to the solution 20, it is possible to easily maintain an appropriate particle size of the capture material 10. In the case where the capture material 10 is arranged in porous particles, by providing the dispersion mechanism 50, the porous particles can be dispersed in the solution 20 with each other, and it is easy to maintain an appropriate particle size of the porous particles. By providing the capture module 101 with the dispersion mechanism 50, it is possible to achieve homogenization of the entire system including the solution 20, so that the capture material 10 can easily capture carbon dioxide.

[0119] As the dispersion mechanism 50, a mechanism that generates a water flow in the solution 20 can be used, and an ultrasonic generator, a stirring device, etc. can be used. Figure 1 As the dispersion mechanism 50, a device that can induce, divide, and fix (fix at a specific position) the capture material 10 by magnetic force can also be used. As such a device, for example, a magnetic separation device can be cited.

[0120] (Solution adjustment mechanism)

[0121] The solution adjusting mechanism 60 supplies an acidic substance to the solution 20, for example, when the pH of the solution 20 rises. As the acidic substance, the above-mentioned salt and a solution in which the salt is dissolved can be cited. The upper limit of the pH of the solution 20 at which the solution adjusting mechanism 60 starts to supply the acidic substance can be 6.0, 5.0, 4.0, or 3.0. Through the solution adjusting mechanism 60, it is easier to maintain the state in which the divalent iron ions in the solution 20 increase. Therefore, it is easier to maintain the capture efficiency of carbon dioxide. The solution adjusting mechanism 60 can also control the start and end of the supply of the acidic substance based on the display of the display mechanism 90 described later.

[0122] In order to suppress the oxidation of the divalent iron ions in the solution 20, the solution adjustment mechanism 60 can supply at least one of a reducing agent, a metal ion chelating agent and a builder. As the reducing agent, polyphenols such as catechins and chlorogenic acid can be listed. As the metal ion chelating agent, citric acid, gluconic acid, etc. can be listed. The builder can be used as a cleaning aid. As the builder, carbonates, silicates, aluminosilicates, sulfates, carboxymethyl cellulose (CMC), etc. can be listed.

[0123] (Show organization)

[0124] The display unit 90 displays the decrease in activity when the activity of the capturing material 10 decreases. By including the display unit 90, the capturing module 101 can easily control the environment of the solution 20 so as to maintain the capture efficiency of carbon dioxide.

[0125] In the capture module 101, the pH of the solution 20 is related to the activity of the capture material 10. For example, when the pH rises to above 4, the activity of the capture material 10 may decrease due to the decrease in divalent iron ions dissolved from the capture material 10. The display mechanism 90 may include a pH indicator or a pH meter. More specifically, the display mechanism 90 may include a pH indicator supplied to the solution 20 or a pH meter capable of measuring the pH of the solution 20. By displaying the pH of the solution 20 using a pH indicator or a pH meter, a decrease in the activity of the capture material 10 can be displayed.

[0126] [pH indicator]

[0127] As the pH indicator, an indicator capable of indicating a decrease in the activity of the capturing material 10 can be used, and examples thereof include thymol blue, methyl orange, methyl red, bromocresol purple, bromothymol blue (BTB), phenol red, and neutral red.

[0128] In the capture module 101, the dissolution rate of carbon dioxide in the solution 20 can be lower than the carbonation rate of the capture material 10. By configuring in this way, the carbon dioxide supplied from the supply unit 30 can be more reliably captured by the capture material 10. From this point of view, the upper limit of the ratio of the content [ppm] of carbon dioxide in the gas released from the solution 20 (more specifically, the gas discharged from the degassing promotion mechanism 103 described later) to the content [ppm] of carbon dioxide in the gas supplied from the supply unit 30 can be 0.8, 0.6, or 0.4. The lower limit of the above ratio is not particularly limited, for example, it can be set to 0.1. As the above ratio, it can be greater than 0.1 and less than 0.8, it can be greater than 0.1 and less than 0.6, or it can be greater than 0.1 and less than 0.4.

[0129] <Carbon dioxide capture device>

[0130] The capturing device 1 includes a capturing module 101 and a storage tank 102 for storing a solution 20. The capturing device 1 includes a degassing promotion mechanism 103 for exhausting gas released from the solution 20. In the capturing device 1, the capturing material 10 is immersed in the solution 20.

[0131] The capturing device 1 includes a capturing module 101 , and the capturing material 10 is immersed in a solution 20 , so the capturing efficiency of carbon dioxide is excellent.

[0132] (Storage tank)

[0133] The shape of the storage tank 102 is appropriately set according to the shape of the capture module 101. The storage tank 102 is provided so that the capture unit 70 can be immersed in the solution 20 in its entirety in the state of storing the solution 20. In the present embodiment, the storage tank 102 has a porous membrane 102a for arranging the carbonation promoter 21 at a distance from the capture material 10 and the support 71a (capture unit 70).

[0134] 〔Porous membrane〕

[0135] like Figure 1As shown, the porous membrane 102a, for example, separates the carbonation promoter 21 from the capture material 10 and the support 71a up and down in the storage tank 102. Alternatively, the carbonation promoter 21 may be disposed below the porous membrane 102a, and the capture material 10 and the support 71a may be disposed above the porous membrane 102a. By separating the carbonation promoter 21 from the capture material 10 and the support 71a through the porous membrane 102a, iron carbonate or the like with the carbonation promoter 21 as a seed can be easily recovered.

[0136] The porous membrane 102a can also be configured to suppress the passage of iron carbonate, etc., and allow carbonate ions, etc. to pass through. By suppressing the passage of iron carbonate, etc. through the porous membrane 102a, it is possible to suppress the iron carbonate, etc. with the carbonation promoter 21 as the seed from being coated on the capture material 10, thereby further suppressing the reduction of the activity of the capture material 10. By allowing carbonate ions, etc. to pass through the porous membrane 102a, it is easy to promote the supply of carbonate ions, etc. to the capture material 10.

[0137] The lower limit of the average pore size of the porous membrane 102a can be 0.38 nm, 0.50 nm, or 1.00 nm from the viewpoint of allowing carbonate ions to pass through. The upper limit of the average pore size can be 20 nm, 15 nm, or 10 nm from the viewpoint of suppressing the passage of iron carbonate and the like.

[0138] (Degassing promotion mechanism)

[0139] The degassing promotion mechanism 103 is arranged at the upper part of the storage tank 102. The degassing promotion mechanism 103 discharges the gas released from the liquid surface of the solution 20 while rising in the solution 20 to the outside of the capture device 1. The degassing promotion mechanism 103 discharges the above-mentioned gas to the outside of the capture device 1 to reduce the pressure of the gas in contact with the solution 20. By reducing the pressure of the gas in contact with the solution 20, the degassing promotion mechanism 103 reduces the content of dissolved oxygen in the solution 20. As a result, the oxidizing effect of the dissolved oxygen in the solution 20 is reduced, and it is easy to maintain the state in which the ratio of divalent iron ions in the solution 20 is increased.

[0140] The degassing promotion mechanism 103 may blow in a gas other than oxygen so as to reduce the partial pressure of oxygen in the gas instead of reducing the pressure of the gas in contact with the solution 20. Examples of such a gas include nitrogen gas.

[0141] [Second embodiment]

[0142] Figure 5 The carbon dioxide capture module 201 includes a carbon dioxide capture material 210, a solution 20 in contact with the carbon dioxide capture material 210 in a manner covering the carbon dioxide capture material 210, and a supply unit 30 for supplying carbon dioxide to the solution 20. Figure 5 As shown, the capture module 201 is configured in the carbon dioxide capture device 2 .

[0143] The capture module 201 can make the solution 20 in which carbon dioxide is dissolved fully contact with the capture material 210 in a manner that covers the capture material 210. A portion of the dissolved carbon dioxide becomes carbonate ions, etc. The capture material 210 can easily capture carbonate ions, etc. dissolved in the solution 20. By making the solution 20 fully contact with the capture material 210, it is easy to suppress the deterioration of the capture material 210 caused by oxidation, etc. The capture module 201 is equipped with a voltage application mechanism 280 described later, so that the dissolution of ions from the capture material 210 can be promoted, and the potential of the capture material 210 can be easily controlled. Therefore, the capture efficiency of carbon dioxide of the capture module 201 is excellent.

[0144] <Carbon dioxide capture module>

[0145] The capture module 201 allows the solution 20 in which carbon dioxide is dissolved to fully contact the capture material 210 in a manner that covers the capture material 210, and uses the capture material 10 to capture carbonate ions and the like generated in the solution 20. The capture module 201 includes: a dissolution promoting mechanism 40 that promotes the dissolution of carbon dioxide into the solution 20; a solution adjusting mechanism 60 that supplies at least one of an acidic substance, a reducing agent, a metal ion chelating agent, and a detergent to the solution 20; a display mechanism 90 that displays the reduction in the activity of the capture material 10; and a voltage applying mechanism 280 that applies a voltage to the capture material 210. In this embodiment, the solution 20, the supply unit 30, the dissolution promoting mechanism 40, the solution adjusting mechanism 60, and the display mechanism 90 can be the same as those in the first embodiment. The capture device 2 can be the same as the first embodiment except for the capture module 201. The capture material 210 and the voltage applying mechanism 280 are described below.

[0146] (Carbon dioxide capture material)

[0147] The capture material 210 is a plate-shaped member mainly composed of iron or an iron alloy. Since the iron or the iron alloy can be the same as in the first embodiment, the description thereof will be omitted.

[0148] (Voltage application mechanism)

[0149] The voltage applying mechanism 280 has a plate-shaped counter electrode 281 facing the plate surface of the capturing material 210, and a voltage applying part 282 connected to the capturing material 210 and the counter electrode 281. The capturing material 210 and the counter electrode 281 are arranged with a gap. As a material of the counter electrode 281, platinum can be cited, for example. The voltage applying part 282 is connected to the capturing material 210 and the counter electrode 281, for example, by an insulating coated wire. The voltage applying mechanism 280 promotes the dissolution of divalent iron ions from the capturing material 210 into the solution 20, for example, by applying a positive voltage to the capturing material 210.

[0150] The direction and magnitude of the voltage applied by the voltage applying mechanism 280 to the capturing material 210 are appropriately set according to the pH of the solution 20. The direction and magnitude of the voltage may also be controlled so that the potential of the capturing material 210 satisfies equations (3) to (5), or equations (6) and (7).

[0151] The voltage applying mechanism 280 can also control the side where the negative voltage is applied between the capturing material 210 and the electrode 281 to reduce the iron ions contained in the solution 20 (cathodic reduction). In this way, the content of trivalent iron ions in the solution 20 can be reduced and the content of divalent iron ions can be increased.

[0152] [Third Embodiment]

[0153] Figure 6 The carbon dioxide capture module 301 includes a carbon dioxide capture material, a solution 20 in contact with the carbon dioxide capture material so as to cover the carbon dioxide capture material, and a supply unit 330 for supplying carbon dioxide to the solution 20. Figure 6 In the embodiment, the capture module 301 is arranged in the scrubber 3 for capturing carbon dioxide.

[0154] The capture module 301 can make the solution 20 in which carbon dioxide is dissolved fully contact with the capture material in a manner that covers the capture material. A portion of the dissolved carbon dioxide becomes carbonate ions, etc. Therefore, the capture material can easily capture carbonate ions, etc. dissolved in the solution 20. By fully contacting the solution 20 with the capture material, it is easy to suppress the deterioration caused by oxidation of the capture material, etc. Therefore, the capture efficiency of carbon dioxide of the capture module 301 is excellent.

[0155] The sizes of the capture module 301 and the capture scrubber 3 are appropriately set according to the place of use or the purpose. Hereinafter, the capture module 301 and the capture scrubber 3 including the capture module 301 will be described in detail.

[0156] <Carbon dioxide capture module>

[0157] The capture module 301 allows the solution 20 in which carbon dioxide is dissolved to contact the capture material in a manner that covers the capture material, and uses the capture material to capture carbonate ions and the like generated in the solution 20. The capture module 301 includes a plurality of capture materials. The capture module 301 includes a storage unit 340 for storing a plurality of capture materials and a spreading mechanism 350 for spreading the solution 20 to the plurality of capture materials.

[0158] The capture material, solution 20 and supply unit 330 of the capture module 301 are arranged in a container. The capture material is arranged in the container in a state of being accommodated in the container 340, the solution 20 is dispersed in the container by the dispersion mechanism 350, and the supply unit 330 is configured to be able to supply carbon dioxide into the container. As an example of the container, the housing 303 described later can be cited.

[0159] (Carbon dioxide capture material)

[0160] As the capture material in the capture module 301, the same material as the capture material 10 in the first embodiment can be used. In the capture module 301, the capture material can also be arranged on the support bodies 71a, 71b, 71c in the same manner as the capture material 10 in the first embodiment. The capture module 301 can also have a plurality of support bodies 71a, 71b, 71c in the same manner as the first embodiment. The plurality of support bodies 71a, 71b, 71c can also be arranged at intervals from each other, and in this case, spacers can also be arranged between the support bodies 71a, 71b, 71c in the same manner as the first embodiment. In the capture module 301, the plurality of capture materials, the plurality of support bodies, and the above-mentioned spacers constitute a carbon dioxide capture unit as a whole.

[0161] (Solution)

[0162] The solution 20 is spread by the spreading mechanism 350, so as to contact with a plurality of capture materials in a manner of continuously covering a plurality of capture materials. As the solution 20 in the capture module 301, the same solution as the solution 20 in the first embodiment can be used. That is, the solution 20 may include a dissolution promoter that promotes the dissolution of carbon dioxide in the solution 20, may also include a pH buffer, may also include a salt that shows acidity in the solution 20, and may also include a carbonation promoter for promoting the carbonation of iron ions dissolved from the capture material.

[0163] (Accommodation)

[0164] The storage part 340 is a container for accommodating a plurality of capture materials. The storage part 340 accommodates the entire capture unit. The storage part 340 has a plurality of openings for the solution 20 to pass through. The storage part 340 has a plurality of openings, and these plurality of openings serve as a flow path for the solution 20 spread from above by the spreading mechanism 350 to contact with the plurality of capture materials in a manner covering the plurality of capture materials and to flow out from below through the plurality of capture materials. By having the storage part 340, the capture module 301 can easily supply the solution 20 in a manner uniformly contacting with the plurality of capture materials contained in predetermined positions.

[0165] (Distribution Agency)

[0166] The spreading mechanism 350 is arranged at a position above the container 340. The spreading mechanism 350 spreads the solution 20 from above to the container 340. The spreading mechanism 350 is set in a manner that the solution 20 is uniformly spread in the container 340. The capture module 301 makes the solution 20 contact with multiple capture materials uniformly through the spreading mechanism 350, thereby easily improving the capture efficiency of carbon dioxide. The solution 20 spread by the spreading mechanism 350 contacts the carbon dioxide supplied from the supply unit 330 and moved to the degassing promotion mechanism 304 described later in the form of droplets with a large surface area. Therefore, it is easy to further improve the capture efficiency of carbon dioxide. In addition, according to the capture module 301, the solution 20 spread by the spreading mechanism 350 will not be retained in the container 340. Therefore, it is easy to control the solution 20 to an appropriate pH.

[0167] (Supply Department)

[0168] The supply unit 330 supplies the gas containing carbon dioxide to the storage unit 340. Figure 6 In the embodiment, the supply unit 330 is configured to supply the gas containing carbon dioxide from below to the container 340. The capture module 301 has a flow path in which the solution 20 spread by the spreading mechanism 350 falls downward through the container 340. The supply unit 330 supplies the gas containing carbon dioxide into the flow path from below the container 340. The supply unit 330 is configured in such a way that the carbon dioxide supplied into the flow path dissolves in the solution 20 in the container 340. The supply unit 330 may also be configured to fill the flow path with carbon dioxide.

[0169] The supply unit 330 ejects a gas containing carbon dioxide into the flow path. As the lower limit of the partial pressure of carbon dioxide in the gas supplied from the supply unit 330, from the viewpoint of making carbon dioxide uniformly dissolved in the solution 20 dispersed by the dispersion mechanism 350, it can be 0.005 MPa or 0.010 MPa. As the upper limit of the partial pressure, from the viewpoint of the operability of the capture module 301, it can be set to 0.99 MPa, for example. As the partial pressure, it can be 0.005 MPa or more and 0.99 MPa or less, or it can be 0.010 MPa or more and 0.99 MPa or less.

[0170] <Scrubber for carbon dioxide capture>

[0171] The capture scrubber 3 is a wet scrubber. The capture scrubber 3 includes a capture module 301 that spreads the solution 20 on the capture material. The capture scrubber 3 includes: a housing 303 that is provided with the capture module 301; a degassing promotion mechanism 304 that discharges the gas in the housing 303; and a pump 305 that circulates the solution 20 flowing out of the storage unit 340 to the spreading mechanism 350.

[0172] Since the capture scrubber 3 includes the capture module 301 , the capture efficiency of carbon dioxide is excellent.

[0173] (case)

[0174] The housing 303 has a cylindrical portion extending up and down, and a storage portion arranged below the cylindrical portion. The cylindrical portion is, for example, cylindrical. A spreading mechanism 350 is arranged on the upper portion of the cylindrical portion. A receiving portion 340 is arranged at a position below the spreading mechanism 350 of the cylindrical portion. The receiving portion 340 is arranged in a manner that blocks the internal space of the cylindrical portion at a part of the axial direction of the cylindrical portion. A supply portion 330 is connected to the peripheral wall of the cylindrical portion below the receiving portion 340. The area below the spreading mechanism 350 in the internal space of the cylindrical portion constitutes the flow path of the solution 20.

[0175] The storage part is provided continuously with the lower end of the cylindrical part. The storage part stores the solution 20 which is spread by the spreading mechanism 350 and passes through the containing part 340. Carbon dioxide may be dissolved in the solution 20 stored in the storage part.

[0176] The storage part is connected to a water supply mechanism 306 and a drainage mechanism 307. The water supply mechanism 306 and the drainage mechanism 307 can supply the solution 20 to the storage part or discharge the solution 20 stored in the storage part in order to adjust the pH of the solution 20 stored in the storage part. The water supply mechanism 306 can also be set as a solution adjustment mechanism. A display mechanism can also be set in the storage part.

[0177] (Degassing promotion mechanism)

[0178] The degassing mechanism 304 is disposed above the housing 340. The degassing mechanism 304 is disposed, for example, at the top of the cylindrical portion. The function of the degassing mechanism 304 can be the same as that of the degassing mechanism 103 according to the first embodiment, and thus description thereof is omitted.

[0179] (Pump)

[0180] The pump 305 pumps up the solution 20 stored in the storage portion and circulates it in the spreading mechanism 350 .

[0181] [Fourth Embodiment]

[0182] [Carbon dioxide capture method]

[0183] Figure 7 The carbon dioxide capture method includes a step of contacting carbonate ions or bicarbonate ions with a carbon dioxide capture material covered with a solution (hereinafter also referred to as "contact step S2"). The carbon dioxide capture method includes a step of dissolving carbon dioxide in a solution (hereinafter also referred to as "dissolution step S1").

[0184] In the carbon dioxide capture method, the solution is in full contact with the capture material in a manner that covers the capture material, so that the capture material can easily capture carbonate ions dissolved in the solution, etc. By fully contacting the above-mentioned solution with the capture material, it is easy to suppress the deterioration caused by oxidation of the capture material, etc. Therefore, the capture efficiency of carbon dioxide in the carbon dioxide capture method is excellent.

[0185] The carbon dioxide capture method can be performed using the capture module 101, the capture module 201, or the capture module 301. The carbon dioxide capture method will be described in detail below.

[0186] (Dissolution process)

[0187] The dissolving step S1 is performed by supplying a gas containing carbon dioxide from the supply unit 30 of the capture module 101 or 201 to the solution 20. Alternatively, the dissolving step S1 is performed by supplying a gas containing carbon dioxide from the supply unit 330 to the solution 20 dispersed by the dispersion mechanism 350 of the capture module 301.

[0188] In the dissolution step S1, the dissolution promoting mechanism 40 can promote the dissolution of carbon dioxide in the solution 20. In the dissolution step S1, a plurality of capture materials can also be dispersed in the solution 20 by the dispersion mechanism 50. In the dissolution step S1, at least one of an acidic substance, a reducing agent, a metal ion chelating agent and a detergent can be supplied to the solution 20 by the solution adjustment mechanism 60, and the reduction in the activity of the capture material can also be displayed by the display mechanism 90. The solution 20 can contain a carbonation promoter 21. If the capture module 201 described in the second embodiment is used, a positive voltage can also be applied to the capture material 210.

[0189] (Contact process)

[0190] In the contact process S2, the capture material is brought into contact with carbonate ions, etc., so that the capture material captures carbonate ions, etc. More specifically, the carbonate ions, etc. are captured by bonding the divalent iron ions dissolved from the capture material with carbonate ions, etc. In the contact process S2, the carbonate ions, etc. generated in the solution 20 are brought into contact with the capture material 10 immersed in the solution 20. Alternatively, in the contact process S2, the solution 20 containing carbonate ions, etc. is passed through the containing part 340 of the capture module 301, so that the carbonate ions, etc. are brought into contact with a plurality of capture materials 10.

[0191] In the carbon dioxide capture method, as a step of making a capture material capture carbonate ions, etc., a dissolution step S1 and a contact step S2 are performed in sequence. As a whole, the capture modules 101, 201, and 301 can perform the dissolution step S1 and the contact step S2 in parallel. At this time, the dissolution rate of carbon dioxide in the solution 20 can be lower than the carbonation rate of the capture material 10.

[0192] The carbon dioxide capture method may include a step of recovering the capture material that has captured carbonate ions and the like (also referred to as a “recovery step”) after the contact step S2.

[0193] [Other embodiments]

[0194] The embodiments of the present invention should be considered in all respects as illustrative and non-restrictive. The scope of the present invention is not limited to the configurations involved in the above embodiments, but is indicated by the claims, and is intended to include all changes within the meaning and scope equivalent to the claims.

[0195] The capture module may be disposed in a device other than the capture device and the capture scrubber described in the above embodiment.

[0196] The arrangement of the capturing material is not limited to the configuration described in the above embodiment. For example, the capturing material may not be arranged on the support. The capturing material may be arranged on the porous particles and further arranged on another support.

[0197] In the above embodiment, the capturing material is in the form of particles or plates, but the present invention is not limited thereto. The capturing material may be in the form of blocks, for example. In this case, the capturing material may be contained in a 30 cm square for ease of handling.

[0198] The solution may contain an emulsifier (surfactant). When the solution contains an emulsifier, the emulsifier is adsorbed to the capturing material to form micelles, thereby suppressing the aggregation of the capturing material and easily maintaining the appropriate particle size of the capturing material.

[0199] From the viewpoint of sufficiently suppressing the aggregation of the capturing material, the lower limit of the HLB value of the emulsifier may be 4 or 6. The upper limit of the HLB value of the emulsifier is not particularly limited, and may be, for example, 20. The HLB value of the emulsifier may be 4 or more and 20 or 6 or more and 20 or less.

[0200] The lower limit of the absolute value of the Zeta potential of the micelle formed by the emulsifier may be 20 mV or 25 mV from the viewpoint of maintaining the stability of the micelle. The upper limit of the absolute value of the Zeta potential of the micelle is not particularly limited, and may be, for example, 40 mV. The absolute value of the Zeta potential of the micelle may be 20 mV or more and 40 mV or more and 25 mV or less.

[0201] In the above embodiment, water is used as the solvent of the solution, but the present invention is not limited thereto. As the solvent, for example, an organic solvent can be used.

[0202] One or both of the dissolution promoting mechanism and the dispersion mechanism may be omitted when the carbon dioxide can be properly captured by the capture material. The solution may also be a structure that does not contain one or both of the dissolution promoting agent and the pH buffer. The capture module may not have a display mechanism and a solution adjustment mechanism as long as it can prevent the decrease in the activity of the capture material or predict the decrease in activity.

[0203] In the above-mentioned embodiment, a granular carbonation accelerator is used as the carbonation accelerator, but the carbonation accelerator is not limited to the granular state. The carbonation accelerator can be, for example, a sludge or solution containing iron carbonate or the like. The carbonation accelerator can be a granular or porous material having a crystal structure similar to that of iron carbonate or the like.

[0204] In the above-mentioned embodiment, the carbonation promoter is described as being separated from the capture material by a porous membrane, but the carbonation promoter may also be separated from the capture material and arranged on a support. When the capture module has a plurality of supports, it may also have a support that only has the carbonation promoter and a support that only has the capture material.

[0205] Example

[0206] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

[0207] [No.1]

[0208] Follow the steps below to make a device containing a carbon dioxide capture module and inject CO into the device. 2 gas.

[0209] 20 g of powdered carbon dioxide capture material wrapped in non-woven fabric is contained in the space formed by taking out activated carbon from the activated carbon box of the bubbling device (manufactured by Water Making (Co., Ltd.), product name: Water Making Device S). As the carbon dioxide capture material, highly compressible atomized pure iron powder (manufactured by Kobe Steel, Ltd., product number: Atmel (registered trademark) 300M) is used. The average particle size of the carbon dioxide capture material is 80 μm. Then, the bubbling device is arranged in a water tank (width 100 mm, depth 100 mm, height 150 mm). The water tank is arranged in a cubic reaction container.

[0210] The solution was supplied to the water tank in such a way that the bubbling device was completely immersed. The solution was distilled water. An air pump (AS ONE Co., Ltd., product number: SA-1200S) was connected to the bubbling device. CO was placed in the reaction container. 2 The sensor (manufactured by Shin-COSMOS Electric Co., Ltd., product number: XP-3340II) constantly monitors CO 2 Concentration. CO is injected into the reaction vessel 2 Gas, in CO 2 When the concentration reaches 95% by volume, stop CO 2 In other words, 95% by volume of CO is formed in the reaction vessel. 2 The reaction vessel was left in this state for a certain period of time.

[0211] [No.2]

[0212] The device was prepared in the same manner as in No. 1 except that no carbon dioxide capture material was contained in the bubbling device. CO was injected into the bubbling device. 2 gas.

[0213] [No.3]

[0214] The apparatus was prepared in the same manner as in No. 1 except that citric acid was added to distilled water at a content of 0.2 mass %, and CO was injected. 2 gas.

[0215] [No.4]

[0216] The bubbling device was prepared in the same manner as in No. 1 except that no carbon dioxide capturing material was placed in the bubbling device and citric acid was added to distilled water to a content of 0.2 mass %. CO was injected into the bubbling device. 2 gas.

[0217] [No.5]

[0218] The apparatus was prepared in the same manner as in No. 1 except that citric acid was added to distilled water at a content of 2.0 mass %, and CO was injected. 2 gas.

[0219] [No.6]

[0220] The apparatus was prepared in the same manner as in No. 1 except that citric acid was added to distilled water at a content of 10.0 mass %, and CO was injected. 2 gas.

[0221] [No.7]

[0222] The apparatus was prepared in the same manner as in No. 1 except that citric acid was added to distilled water in an amount of 30.0 mass %, and CO was injected. 2 gas.

[0223] [No.8]

[0224] In No.8, the CO 2 The sensor measures the CO in the reaction vessel. 2 In this device, no iron powder remained in the solution, 20 g of the same carbon dioxide capture material (iron powder) as No. 1 was added to the bubbling device, and CO was injected in the same steps as No. 1. 2 gas.

[0225] [No.9]

[0226] In No.9, the CO 2 The sensor measures the CO in the reaction vessel. 2In this device, no iron powder remained in the solution, 20 g of the same carbon dioxide capture material (iron powder) as No. 1 was added to the bubbling device, and CO was injected in the same steps as No. 1. 2 gas.

[0227] [No.10]

[0228] In addition to the formation of 60% by volume of CO in the reaction vessel 2 The apparatus was prepared in the same manner as in No. 5 except that a mixed atmosphere of 40% by volume of air was added and CO 2 gas.

[0229] [No.11]

[0230] In addition to the formation of 15 vol% CO in the reaction vessel 2 The apparatus was prepared in the same manner as in No. 5 except that a mixed atmosphere of 85% by volume of air was added and CO 2 gas.

[0231] [evaluate]

[0232] Calculate the CO in the devices No. 1 to No. 11 2 The ratio of the reduction in CO2 [g] to the mass of the CO2 capture material [kg] is taken as the “CO 2 Table 1 shows the CO capture efficiency of devices No. 1 to No. 11. 2 Table 1 shows the pH and oxygen content of the solution in each device. The pH of the solution in No. 9 refers to the pH at the end of the experiment (i.e., CO 2 The pH values ​​are the values ​​at the time when the concentration reaches 0 volume %), and the other pH values ​​are the values ​​at the start of the experiment. The parts indicated by "-" in Table 1 mean that there is no data. 2 The “-” in the capture efficiency column means that the CO 2 The concentration was already 0% by volume. The potential (V vs. SHE) of the carbon dioxide capture material (iron powder) in the solution of each device was estimated to be 0.0 V to 0.4 V.

[0233] [Table 1]

[0234]

[0235] No.1 CO with carbon dioxide capture material (iron powder) 2 The capture efficiency was equal to that of No. 2 without a carbon dioxide capture material after 200 minutes, but it showed a higher CO2 capture efficiency than No. 2 as time passed. 2 Capture efficiency: No.1 in CO 2The capture efficiency is always higher than that of No. 4 without the carbon dioxide capture material.

[0236] According to the comparison of No.1, No.3, No.5 to No.7, the lower the pH of the solution, the higher the CO 2 It is estimated that the capture efficiency of No.7 with a solution pH of 1.4 is higher than that of No.1 with a solution pH of 3.8-4.1. 2 The capture efficiency is 16.5 times higher.

[0237] Comparison of No. 6, No. 8, and No. 9 suggests that the pH value can be increased by consuming iron powder in the solution, and that CO 2 The capture efficiency can be reduced. However, No.9 still maintains high CO 2 The capture efficiency is about 70% compared to No.6. 2 Capture efficiency.

[0238] As shown in No. 5, No. 10 and No. 11, when the pH of the solution is lower than 3.0, the CO can be maintained even when the oxygen concentration of the gas in contact with the solution is high. 2 Capture efficiency: This is considered to be mainly because when the pH of the solution is low, the divalent iron ions in the solution are easily stabilized.

[0239] As described above, it can be seen that by contacting with the carbon dioxide capture material in a manner covered by the solution, a high CO 2 Capture efficiency; CO can be increased by adjusting the pH of the solution 2 capture efficiency; and the ability to maintain CO in common industrial equipment, living spaces, etc. that are easily exposed to oxygen. 2 Capture efficiency.

[0240] Description of Reference Numerals

[0241] 1, 2: Carbon dioxide capture device;

[0242] 3: Scrubber for carbon dioxide capture;

[0243] 10, 210: Carbon dioxide capture materials;

[0244] 20: solution;

[0245] 21: Carbonation accelerator;

[0246] 30, 330: Supply department;

[0247] 40: dissolution promoting mechanism;

[0248] 50: dispersion mechanism (ultrasonic wave generating device);

[0249] 60: solution adjustment mechanism;

[0250] 70: Carbon dioxide capture unit;

[0251] 71a, 71b, 71c: supporting body;

[0252] 72: spacer;

[0253] 90: display mechanism (pH indicator or pH meter);

[0254] 280: voltage applying mechanism;

[0255] 281: counter electrode;

[0256] 282: voltage applying unit;

[0257] 101, 201, 301: CO2 capture module;

[0258] 102: storage tank;

[0259] 102a: porous membrane;

[0260] 103, 304: degassing promotion mechanism;

[0261] 303: housing;

[0262] 305: Pump;

[0263] 306: Water supply agencies;

[0264] 307: Drainage mechanism;

[0265] 340: Accommodation portion;

[0266] 350: Dispersed organization.

Claims

1. A carbon dioxide capture module, in, The carbon dioxide capture module comprises: Carbon dioxide capture materials; a solution in contact with the carbon dioxide capture material in a manner covering the carbon dioxide capture material; and a supply unit for supplying carbon dioxide to the solution, The carbon dioxide capture material contains iron or an iron compound as a main component.

2. The carbon dioxide capture module according to claim 1, in, The pH of the solution and the potential of the carbon dioxide capture material are controlled in a range where divalent iron ions or divalent iron hydroxide are stable in a potential-pH diagram.

3. The carbon dioxide capture module according to claim 1 or 2, in, The solution comprises a pH buffer.

4. The carbon dioxide capture module according to any one of claims 1 to 3, in, The carbon dioxide capture module includes a solution adjustment mechanism for supplying at least one of an acidic substance, a reducing agent, a metal ion chelating agent, and a builder to the solution.

5. The carbon dioxide capture module according to any one of claims 1 to 4, in, The carbon dioxide capture module includes a voltage applying mechanism for applying a voltage to the carbon dioxide capture material.

6. The carbon dioxide capture module according to any one of claims 1 to 5, in, The carbon dioxide capture module includes a degassing promotion mechanism that promotes degassing of dissolved oxygen in the solution.

7. The carbon dioxide capture module according to any one of claims 1 to 6, in, The solution contains a carbonation promoter for promoting carbonation of iron ions dissolved from the carbon dioxide capture material.

8. The carbon dioxide capture module according to any one of claims 1 to 7, in, The carbon dioxide capture module includes a dissolution promotion mechanism that promotes dissolution of the carbon dioxide into the solution.

9. The carbon dioxide capture module according to any one of claims 1 to 8, in, The solution includes a dissolution promoter that promotes dissolution of the carbon dioxide into the solution.

10. The carbon dioxide capture module according to any one of claims 1 to 9, in, The dissolution rate of the carbon dioxide in the solution is lower than the carbonation rate of the carbon dioxide capture material.

11. A carbon dioxide capture module according to any one of claims 1 to 10, in, The carbon dioxide capture module comprises a plurality of carbon dioxide capture materials. The average particle size of the plurality of carbon dioxide capture materials is 5 nm or more and 500 μm or less.

12. The carbon dioxide capture module according to claim 11, in, The carbon dioxide capture module includes a dispersing mechanism for dispersing the plurality of carbon dioxide capture materials in the solution. The dispersion mechanism maintains an average particle size of the plurality of carbon dioxide capture materials at 5 nm or more and 500 μm or less.

13. A carbon dioxide capture module according to any one of claims 1 to 12, in, The carbon dioxide capture module includes a display unit that displays the decrease in activity when the activity of the carbon dioxide capture material decreases.

14. A carbon dioxide capture module according to any one of claims 1 to 13, in, The carbon dioxide capture module comprises a plurality of carbon dioxide capture materials. The carbon dioxide capture module includes a spreading mechanism that spreads the solution over the plurality of carbon dioxide capture materials.

15. The carbon dioxide capture module according to claim 14, in, The carbon dioxide capture module includes a housing for housing a plurality of the carbon dioxide capture materials.

16. A carbon dioxide capture module according to any one of claims 1 to 15, in, The carbon dioxide capture module includes a porous support on which the carbon dioxide capture material is arranged.

17. The carbon dioxide capture module according to claim 16, in, The support is a porous particle. The average particle size of the porous particles in a state where the carbon dioxide capture material is arranged is 10 mm or less.

18. The carbon dioxide capture module according to claim 16, in, The support is a porous wire or a porous sheet. A plurality of the carbon dioxide capture materials are arranged on the support.

19. A carbon dioxide capture module according to any one of claims 16 to 18, in, The carbon dioxide capture module comprises a plurality of the support bodies. The plurality of supports are arranged at intervals from each other.

20. A scrubber for capturing carbon dioxide, in, The carbon dioxide capture scrubber comprises the carbon dioxide capture module according to any one of claims 1 to 19, The carbon dioxide capture scrubber spreads the solution on the carbon dioxide capture material.

21. A carbon dioxide capture device, in, The carbon dioxide capture device comprises: The carbon dioxide capture module according to any one of claims 1 to 19; and a storage tank for storing the solution, The carbon dioxide capture material is immersed in the solution.

22. A method for capturing carbon dioxide, in, The carbon dioxide capture method includes a step of bringing carbonate ions or bicarbonate ions into contact with a carbon dioxide capture material covered with a solution, wherein the carbon dioxide capture material contains iron or an iron compound as a main component.

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