Co2 adsorbent

Abstract

The present invention provides a CO2 adsorbent having excellent carbon dioxide adsorption performance. A CO2 adsorbent 100 disclosed herein comprises an amine compound 10 and a carrier structure 20 for supporting the amine compound 10. The carrier structure 20 is provided with: a resin matrix 30 having a three-dimensional network structure including pores 32; and porous particles 40 having a plurality of mesopores. The porous particles 40 are arranged in the pores 32 of the resin matrix, and the amine compound 10 is disposed in the plurality of mesopores of the porous particles 40.

Description

CO2 absorbent

[0001] The present invention relates to a CO2 oxidizer comprising an amine compound and a support structure supporting the amine compound. ２ This application claims priority based on Japanese Patent Application No. 2023-203701, filed on December 1, 2023, the entire contents of which are incorporated herein by reference.

[0002] Exhaust gases emitted from thermal power plants, factories, automobiles, etc. contain various harmful components, and there is a need to develop materials and technologies that can selectively separate and capture them. For example, carbon dioxide (CO ２ ) are greenhouse gases, and therefore, a significant reduction in emissions is required. In order to efficiently separate and recover such components, materials are used that include an active substance such as an adsorbent or a catalyst, and a carrier that supports the active substance. Examples of related technologies include Patent Documents 1 and 2.

[0003] Japanese Application Publication No. 2014-506836 Japanese Application Publication No. 2018-187574

[0004] CO ２ Examples of carriers that support an adsorbent material (e.g., an amine compound) include those that use a honeycomb structure or a nonwoven fabric as a substrate. These carriers are arranged only on the surface of the substrate, so the amount of CO per volume is ２ There is a problem in that the amount of adsorbent material carried is small.

[0005] Also, CO ２ Another example of a carrier that supports an adsorbent material is a structure made up of carrier particles. The carrier particles may have a high specific surface area or pore volume in order to increase the amount of support. A structure made up of such carrier particles is formed by firing the carrier particles or densifying them by pressing. Therefore, even if carrier particles with a high specific surface area or pore volume are used, the specific surface area or pore volume decreases during the process of forming the structure. As a result, CO ２ There is a problem in that the amount of adsorbent material carried is reduced.

[0006] The present invention has been made in view of the above circumstances, and its main object is to provide a CO2 adsorption device having excellent carbon dioxide adsorption performance. ２ To provide an adsorbent.

[0007] The CO disclosed herein ２ The adsorbent comprises an amine compound and a carrier structure for supporting the amine compound. The carrier structure comprises a resin matrix having a three-dimensional network structure including pores, and porous particles having a plurality of mesopores. The porous particles are disposed in the pores of the resin matrix, and the amine compound is disposed in the plurality of mesopores of the porous particles.

[0008] According to this configuration, the mesopores of the porous particles are not crushed or filled with the resin, and therefore the amount of the amine compound supported on the support structure can be suitably increased. ２ Excellent CO adsorption performance ２ The CO 2 adsorbent disclosed herein can also be used. ２ The carrier structure of the adsorbent has a three-dimensional network structure, which provides excellent gas diffusion. ２ Since CO can be efficiently contacted with the amine, even if the amount of amine supported is reduced, ２ The adsorption performance can be improved.

[0009] The CO disclosed herein ２ In a preferred embodiment of the adsorbent, the amount of the amine compound supported is 24% by mass or more and 56% by mass or less. ２ CO of adsorbent ２ The adsorption performance can be improved.

[0010] The CO disclosed herein ２ In a preferred embodiment of the adsorbent, the amine compound contains at least polyethyleneimine. ２ CO of adsorbent ２ Adsorption performance can be exerted.

[0011] The CO disclosed herein ２In a preferred embodiment of the adsorbent, the adsorbent has hot water resistance of 120° C. or more and 250° C. or less. With this configuration, the adsorbent has excellent hot water resistance. ２ An adsorbent can be provided.

[0012] The CO disclosed herein ２ In a preferred embodiment of the adsorbent, the resin matrix contains a resin having a glass transition temperature of 70° C. or higher and 250° C. or lower. ２ The heat resistance of the adsorbent can be suitably improved.

[0013] The CO disclosed herein ２ In a preferred embodiment of the adsorbent, the porous particles include at least one selected from the group consisting of silica particles, alumina particles, ceria particles, zirconia particles, and titania particles. This configuration allows the amine compound to be more suitably supported.

[0014] FIG. 1 is a diagram illustrating a CO ２ 2 is a diagram showing a schematic structure of the adsorbent of Example 1. ２ CO of adsorbent ２ Breakthrough curve and N ２ FIG. 1 shows a breakthrough curve.

[0015] Preferred embodiments of the technology disclosed herein are described below. Matters necessary for implementation other than those specifically mentioned in this specification can be understood based on the technical content taught by this specification and the general technical common sense of a person skilled in the art. The technology disclosed herein can be implemented based on the content disclosed in this specification and the general technical common sense of a person skilled in the art. In this specification, the expression "A to B" indicating a range means A or more and B or less.

[0016] <CO ２ Adsorbent> FIG. ２ 1 is a diagram showing a schematic structure of the adsorbent material. ２The adsorbent 100 includes an amine compound 10 and a support structure 20 for supporting the amine compound 10. The support structure 20 includes a resin matrix 30 and porous particles 40. ２ The adsorbent 100 can support a larger amount of the amine compound 10 because the pores 42 of the porous particles 40 are not crushed or filled with resin or the like. ２ The amount of the amine compound 10 supported on the adsorbent 100 (hereinafter, simply referred to as the "amine supported amount") can be increased, and CO ２ CO that can optimally demonstrate adsorption performance ２ The adsorbent 100 can be realized. ２ The adsorbent (hereinafter sometimes simply referred to as "adsorbent") is used to reversibly adsorb and remove carbon dioxide from a gas to be treated that contains carbon dioxide.

[0017] The CO disclosed herein ２ In the adsorbent 100, the amine compound 10 is supported in the pores 42 of a plurality of porous particles 40 included in the carrier structure 20. As shown in FIG. 1 , the carrier structure 20 includes a resin matrix 30 having a three-dimensional network structure including pores 42, and porous particles 40 having a plurality of pores 42. The resin matrix 30 can function as a skeleton in the carrier structure 20. The resin matrix 30 can be formed, for example, by bonding crystalline particles of a resin. The pores 32 may be interconnected pores. A plurality of porous particles 40 are arranged within the pores 32. The porous particles 40 have a plurality of pores 42. It is preferable that the majority of the porous particles 40 are present in the pores 32, separated from the resin matrix 30. ２ The fact that the adsorbent 100 has a carrier structure 20 having a resin matrix 30 and porous particles 40, and that the amine compound 10 is supported on the carrier structure 20, can be inferred, for example, by thermogravimetry (TG) or the like.

[0018] The CO disclosed herein ２The adsorbent 100 can support a larger amount of the amine compound 10 than conventional adsorbents because the porous particles 40 are arranged in the pores 32 of the resin matrix 30. ２ CO of the adsorbent 100 ２ The adsorption performance can be suitably improved. Although there is no intention to limit the technology disclosed herein, the reason why such an effect is obtained is presumed to be as follows. In the carrier structure 20, the porous particles 40 are arranged in the pores 32 of the resin matrix 30, so that the porous particles 40 can exist in a state where the pores 42 of the porous particles 40 are not crushed or filled with resin or the like. As a result, the CO ２ In the adsorbent 100, the amount of the amine compound 10 supported per unit area increases. In addition, the carrier structure 20 has a three-dimensional network structure, and therefore has excellent gas diffusion properties. As a result, the amount of CO ２ can be efficiently brought into contact with the amine compound 10. These actions result in a high CO ２ CO adsorption performance ２ The adsorbent 100 can be realized.

[0019] The CO disclosed herein ２ As described above, the adsorbent 100 has an improved amine loading. ２ The adsorbent 100 is, for example, ２ The amount of amine compound 10 supported on the adsorbent 100 is preferably 24% by mass or more and 56% by mass or less, more preferably 24.2% by mass or more and 56% by mass or less, even more preferably 30% by mass or more and 56% by mass or less, and particularly preferably 43% by mass or more and 56% by mass or less. ２ The adsorbent 100 is a conventional CO ２ The amount of the amine compound supported on the adsorbent is approximately twice the amount supported on the adsorbent. ２ By using the adsorbent 100, it is possible to absorb CO ２ It is possible to ensure a sufficient amount of CO adsorption. ２The adsorbent 100 is not limited to a particular amine loading. ２ The adsorbent 100 has a carrier structure 20 with excellent gas diffusion properties. Therefore, according to the technology disclosed herein, even if the amount of amine supported is small, CO ２ The adsorption performance can be improved.

[0020] Amine compound 10 has at least one primary amino group (NH ２ -) are various compounds having CO ２ The CO ２ The adsorbent 100 ２ Strong interaction with CO ２ The number of primary amino groups contained in amine compound 10 is not particularly limited, and may be singular or plural. Furthermore, amine compound 10 may further contain a secondary amino group and / or a tertiary amino group in addition to the primary amino group. The state of amine compound 10 is not particularly limited, and may be solid or liquid at room temperature. Note that amine compound 10 may contain CO ２ When adsorbed, it becomes a solid and CO ２ Some compounds (e.g., isophoric diamine) become liquid upon desorption. ２ The adsorbent 100 may also use such an amine compound.

[0021] Examples of the amine compound 10 include compounds having primary to tertiary amino groups, such as amines, polyamines, and aminoorganosilanes. Examples of the amines include monoethanolamine, diethanolamine, triethanolamine, and isophorodiamine. Examples of the polyamines include polyethyleneimine, polypropyleneimine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine. Examples of aminoorganosilanes include (3-aminopropyl)trimethoxysilane (APTMS), N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and N-(n-butyl)-3-aminopropyltrimethoxysilane. One type of amine compound may be used alone, or two or more types may be mixed and used. Among these, it is preferable that the amine compound 10 contains a polyalkyleneimine such as polyethyleneimine or polypropyleneimine.

[0022] The carrier structure 20 may be formed into a sheet shape, a rectangular parallelepiped shape, a cube shape, a prism shape, a cylinder shape, a sphere shape, or the like. Although not particularly limited, the carrier structure 20 is preferably a carrier sheet formed into a sheet shape. When the carrier structure 20 is in a sheet shape, it is preferable that the thickness thereof is, for example, 0.3 mm or more and 5 mm or less.

[0023] Although not particularly limited, it is preferable that the carrier structure 20 has high hot water resistance. The hot water resistance of the carrier structure 20 is preferably 120°C or higher, more preferably 140°C or higher, and may be 150°C or higher, or may be 160°C or higher. This allows the CO 2 disclosed herein to be used in an environment exceeding 100°C or in a relatively humid environment. ２The adsorbent 100 can be suitably used. The hot water resistance of the carrier structure 20 is preferably 250°C or less, for example, and may be 200°C or less. The "hot water resistance of the carrier structure" can be evaluated by immersing the carrier structure in hot water in an autoclave, drying it, and measuring its strength using a conventionally known tensile test.

[0024] The resin matrix 30 has a three-dimensional network structure including a plurality of pores 32. The average pore diameter A of the resin matrix 30 is preferably 0.4 μm or more, more preferably 0.5 μm or more, and may be 1 μm or more. This allows the amount of amine supported to be suitably improved. If the average pore diameter A of the resin matrix 30 is too large, the porous particles 40 may be detached from the resin matrix 30. From this perspective, the average pore diameter A of the resin matrix 30 is, for example, preferably 7 μm or less, more preferably 5 μm or less, and even more preferably 3 μm or less. The "average pore diameter of the resin matrix" can be determined, for example, by performing a mercury intrusion method using a commercially available mercury porosimeter.

[0025] The resin matrix 30 contains a resin and can be formed by bonding crystalline particles of the resin. Although not particularly limited, the resin matrix 30 preferably contains a resin having a glass transition temperature (Tg) of 70° C. or higher. This allows the CO ２ The heat resistance of the adsorbent 100 is improved. The glass transition temperature of the resin contained in the resin matrix 30 is preferably 70°C or higher, more preferably 100°C or higher, and even more preferably 120°C or higher. The glass transition temperature of the resin contained in the resin matrix 30 may be, for example, 260°C or lower, or 250°C or lower. The "glass transition temperature of the resin" can be measured according to conventionally known methods such as differential scanning calorimetry (DSC) measurement or dynamic viscoelasticity measurement (DMA).

[0026] Although not particularly limited, it is preferable that the resin matrix 30 contains a resin that is highly resistant to hot water. ２This can improve the hot water resistance of the adsorbent 100. The hot water resistance of the resin contained in the resin matrix 30 is preferably 120°C or higher, more preferably 140°C or higher, and may be 150°C or higher, or may be 160°C or higher. The hot water resistance of the resin contained in the resin matrix 30 is, for example, preferably 300°C or lower, may be 250°C or lower, or may be 200°C or lower. Note that the nominal value (catalog value) from each manufacturer or the like may be used for the "hot water resistance of the resin."

[0027] The resin content is not particularly limited, but is preferably 30% by mass or more and 80% by mass or less, more preferably 35% by mass or more and 70% by mass or less, and even more preferably 40% by mass or more and 60% by mass or less, when the total mass of the carrier structure 20 is taken as 100% by mass. This allows the amount of amine supported to be suitably increased, and CO ２ CO of the adsorbent 100 ２ The adsorption performance can be improved.

[0028] Although not particularly limited, examples of resin components contained in the resin matrix 30 include acrylic resins, cellulose resins, and resins classified as super engineering plastics. The resin matrix 30 may contain any one of the above resins alone or a combination of two or more of them.

[0029] Acrylic resins encompass polymers containing alkyl (meth)acrylate as a constituent monomer component and their derivatives. In this specification, the term "(meth)acrylate" is used to refer collectively to acrylate and / or methacrylate. Examples of acrylic resins include polymers containing alkyl (meth)acrylate as the main monomer (a component accounting for 50% by mass or more of the total monomers) and copolymers containing such a main monomer and a secondary monomer copolymerizable with the main monomer. Specific examples include poly(meth)acrylic acid, poly(meth)acrylamide, and polymethyl methacrylate (PMMA). Among these, the resin matrix 30 preferably contains methacrylic acid or PMMA.

[0030] The cellulose-based resin encompasses all compounds derived from cellulose (cellulose derivatives). Specific examples include ethyl cellulose (EC), hydroxyethyl cellulose (HEC), ethyl methyl cellulose (EMC), hydroxyethyl methyl cellulose (HEMC), nitrocellulose, and diacetyl cellulose. Among these, it is preferable that the resin matrix 30 contains ethyl cellulose.

[0031] Super engineering plastics are thermoplastic resins with extremely high heat resistance and mechanical strength. Specific examples of super engineering plastics include fluororesins such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluorovinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), chlorotrifluoroethylene homopolymer (PCTFE), tetrafluoroethylene-ethylene copolymer (ETFE), chlorotrifluoroethylene-ethylene copolymer (ECTFE), and vinylidene fluoride homopolymer (PVDF); thermoplastic polyimides such as polybenzimidazole (PBI), polyimide (PI), polyetherimide (PEI), and polyamideimide (PAI); polyethersulfone (PES), polyetheretherketone (PEEK), polyethersulfide, and polyphenylene sulfide. Among these, the resin matrix 30 preferably contains PEI, PES, or PVDF.

[0032] The porous particles 40 may be any inorganic porous material capable of supporting the amine compound 10. For example, a porous material with a relatively large specific surface area is preferred. For example, oxides of semimetallic elements and metallic elements or solid solutions thereof can be preferably used as the porous particles 40. Specific examples include silica particles, alumina particles, ceria particles, zirconia particles, and titania particles. One or more of these can be used without any particular limitation. Of these, it is preferable that the porous particles 40 include silica particles.

[0033] The porous particle 40 has a plurality of pores 42. The porous particle 40 may be, for example, a mesoporous material having mesopores. "Mesopores" refers to pores having a pore diameter in the range of 2 nm or more and less than 50 nm, based on the IUPAC classification. The amine compound 10 is disposed in the plurality of pores 42 of the porous particle 40. It is preferable that the amine compound 10 is disposed in the mesopores of the porous particle 40, for example.

[0034] The average pore diameter B of the porous particles 40 is, for example, preferably 2 nm or more, and more preferably 10 nm or more. This allows the amine compound 10 to be suitably introduced into the pores 42 when it is supported. The average pore diameter B of the porous particles 40 is, for example, preferably 100 nm or less, more preferably 70 nm or less, even more preferably less than 50 nm, and particularly preferably 30 nm or less. This allows the specific surface area of ​​the porous particles 40 to be suitably increased, and the amount of amine supported can be further improved. The "average pore diameter of the porous particles" can be measured, for example, by measuring the pore size distribution of the support structure by a gas adsorption method based on the BJH method using a commercially available pore size distribution measurement device.

[0035] The average particle size of the porous particles 40 is not particularly limited. If the average particle size of the porous particles 40 is too small, they tend to be difficult to disperse in the support structure 20. From this perspective, the average particle size of the porous particles 40 may be, for example, 100 nm or more, 1 μm or more, 3 μm or more, or 5 μm or more. On the other hand, as described above, the porous particles 40 contain many voids (pores 42). Therefore, if the average particle size is too large, the porous particles 40 may be easily broken due to collisions between the porous particles. From this perspective, the average particle size of the porous particles 40 may be, for example, 100 μm or less, 50 μm or less, or 15 μm or less. In this specification, the "average particle size of the porous particles" refers to the arithmetic mean value of the circle-equivalent diameter measured based on optical microscope observation. Here, the circle-equivalent diameter refers to the diameter of a circle having the same area as the area of ​​an ellipse formed by the major axis, which is the longest diameter of a porous particle observed in a microscope image, and the minor axis, which is the longest diameter of a line intersecting the major axis at a right angle. In this specification, the average particle size of porous particles refers to the arithmetic mean value of the circle-equivalent diameters of 200 randomly selected porous particles.

[0036] Although not particularly limited, CO ２ In the adsorbent 100, the amine compound 10 and CO ２ From the viewpoint of increasing the contact area with the porous particles 40, it is preferable that the porous particles 40 have a large specific surface area. The specific surface area of ​​the porous particles 40 measured by the BET method (BET specific surface area) is, for example, 130 m ２ / g or more 650m ２ / g or less, and ２ / g or more 550m ２ / g or less is more preferable, and 200m ２ / g or more 450m ２ In this specification, the "BET specific surface area of ​​the porous particles" can be measured by a nitrogen adsorption method using a commercially available specific surface area measuring device.

[0037] Furthermore, although not particularly limited, from the viewpoint of increasing the amount of amine supported, porous particles 40 having a high oil absorption are preferred. The oil absorption of porous particles 40 is, for example, preferably 100 ml / 100 g or more and 400 ml / 100 g or less, more preferably 150 ml / 100 g or more and 380 ml / 100 g or less, and even more preferably 240 ml / 100 g or more and 330 ml / 100 g or less. Note that for the "oil absorption of porous particles," the catalog value provided by each manufacturer may be used.

[0038] The content of the porous particles 40 is not particularly limited, but is preferably 20% by mass or more and 70% by mass or less, more preferably 30% by mass or more and 65% by mass or less, and even more preferably 40% by mass or more and 60% by mass or less, when the total mass of the support structure 20 is taken as 100% by mass. ２ CO of the adsorbent 100 ２ The adsorption performance can be suitably improved.

[0039] Although not particularly limited, the mass ratio of the porous particles 40 to the resin constituting the resin matrix 30 in the carrier structure 20 is preferably, for example, 20:80 to 70:30, more preferably 30:70 to 65:35, and even more preferably 40:60 to 65:35. This allows the balance between the pores 32 derived from the resin matrix 30 and the pores 42 derived from the porous particles 40 to be suitably adjusted, thereby enabling the amount of amine supported to be improved.

[0040] <CO ２ Next, the CO ２ An example of a method for manufacturing the adsorbent 100 will now be described. ２ The adsorbent 100 may include a preparation step of preparing a carrier structure forming slurry, a forming step of producing a molded body from the carrier structure forming slurry, an immersion step of immersing the molded body in an aqueous solvent, a first drying step of drying the molded body after the immersion step, a supporting step of supporting the amine compound 10 on the carrier structure 20 after the first drying step, and a second drying step of drying the carrier structure 20 on which the amine compound 10 is supported.２ The adsorbent 100 is not limited to those manufactured by the following manufacturing method.

[0041] In the preparation step, a slurry-like composition (slurry for forming a carrier structure) containing at least porous particles 40, a resin, and an organic solvent is prepared. In this specification, the term "paste" is used to encompass forms called "slurry" and "ink." As an example, in the preparation step, the porous particles 40 are introduced into an organic solvent and stirred. This causes the porous particles 40 to be dispersed in the organic solvent. Next, a resin is introduced into the organic solvent in which the porous particles 40 have been dispersed and stirred. This causes the resin to dissolve in the organic solvent. Although not particularly limited, in the preparation step, the porous particles 40 and the resin may be introduced into an organic solvent and stirred while heated to 40°C to 60°C.

[0042] The resin is preferably one that dissolves in an organic solvent and precipitates in a network structure during the immersion step described below, and among these, it is preferable to use PEI, PES, or PVDF.

[0043] The mass ratio of the porous particles 40 to the resin is preferably, for example, 20:80 to 70:30, more preferably 30:70 to 65:35, and even more preferably 55:45 to 65:35.

[0044] The organic solvent is not particularly limited as long as it can dissolve the resin. Examples of organic solvents include amides such as diethylformamide, dimethylacetamide, dimethylformamide, N-methylpyrrolidone, and dimethylimidazolidinone; alkyl ketones such as dimethyl sulfoxide, acetone, and methyl ethyl ketone; ethers such as tetrahydrofuran, dioxane, and diglyme; and glycol ethers such as ethylene glycol and diethylene glycol. These may be used alone or in combination of two or more. The mass ratio of the organic solvent contained in the support structure-forming slurry is not particularly limited. The content of the organic solvent in the support structure-forming slurry is preferably, for example, 30% by mass to 80% by mass. This allows for the production of a molded body in the molding process.

[0045] In addition, conventionally known additives may be added to the support structure forming slurry as long as they do not significantly impair the effects of the technology disclosed herein. Examples of such additives include dispersants, plasticizers, antifoaming agents, thickeners, etc. For example, hydrophilic polymers such as polyethylene glycol (PEG) can be preferably used as additives. The content of the additive in the support structure forming slurry is preferably, for example, 30% by mass or less, and may be 20% by mass or less, or may be 10% by mass or less.

[0046] In the molding step, a molded body is molded using the above-prepared slurry for forming the carrier structure. For example, a sheet-like molded body can be produced by supplying the slurry for forming the carrier structure to a predetermined thickness on a glass substrate using a doctor blade. Alternatively, a molded body of a desired shape can be produced by extruding the slurry for forming the carrier structure into a predetermined shape, printing it on a metal plate or metal mesh, or dip-coating it onto a core material.

[0047] In the immersion step, the molded body prepared in the molding step is immersed in an aqueous solvent (e.g., water). As a result, the organic solvent contained in the molded body is replaced with the aqueous solvent, and the resin precipitates. The areas where the organic solvent contained in the molded body has been replaced with the aqueous solvent become pores 32, and when the resin precipitates, the resin matrix 30 as described above is suitably formed. Because the porous particles 40 are dispersed in the organic solvent, the resin matrix 30 is formed to envelop the porous particles 40, and the porous particles 40 are arranged in the pores 32 of the resin matrix 30.

[0048] The aqueous solvent used in the immersion step is not particularly limited. The aqueous solvent may be, for example, water, a mixed solution of water and alcohol, or water to which a surfactant may be added. Preferred aqueous solvents include ion-exchanged water (deionized water), pure water, ultrapure water, and distilled water.

[0049] In the first drying step, the compact after the immersion step is dried to remove the aqueous solvent from the compact. This allows the carrier structure 20 having the structure described above to be suitably produced. The drying means used in the first drying step are not particularly limited, and for example, a hot air dryer, a low-humidity air dryer, a vacuum dryer, various infrared dryers, an electromagnetic induction dryer, a microwave dryer, dry air, etc., or drying promotion means such as air blowing, reduced pressure, and heating can be used alone or in combination. The drying temperature (such as the set temperature of the dryer) in the first drying step can be appropriately selected depending on the type and amount of solvent in the mixture, and can be set, for example, to 60°C to 150°C, preferably 80°C to 120°C. The drying time can also be appropriately selected depending on the type and amount of aqueous solvent, and is not particularly limited.

[0050] Because the carrier structure 20 has the structure described above, it has a high water absorption rate. Although not particularly limited, the water absorption rate of the carrier structure 20 based on the Archimedes method is preferably 140% or more, more preferably 145% or more, even more preferably 147% or more, and may be 190% or more, or even 200% or more. The high water absorption rate of the carrier structure 20 can increase the amount of amine compound 10 supported per volume, allowing a larger amount of amine compound 10 to be supported in the supporting step described below than in the past. From this perspective, a higher water absorption rate is preferable, and the upper limit is not particularly limited. For example, the water absorption rate of the carrier structure 20 based on the Archimedes method may be 400% or less, 370% or less, or 350% or less. The "water absorption rate of the carrier structure" can be calculated based on the Archimedes method. More specifically, the dry weight W of the carrier structure after the first drying step is Ａｉｒ , underwater weight W Ａｑ , water content W ａ＋ｗ The water absorption rate (Aw) can be calculated based on the following formula (1): Aw (%) = (W ａ＋ｗ -W Ａｉｒ ) / W Ａｉｒ ×100 (1)

[0051] Furthermore, since the support structure 20 has the structure described above, it has a high porosity. Although not particularly limited, the porosity of the support structure 20 based on the Archimedes method is preferably 65% ​​or more, more preferably 70% or more, and even more preferably 75% or more. This allows the amine compound 10 and CO ２ The porosity of the support structure 20 based on Archimedes' method is preferably 90% or less, and may be 86% or less. The "porosity of the support structure" can be calculated based on Archimedes' method. More specifically, the dry weight W of the support structure after the first drying step is Ａｉｒ , underwater weight W Ａｑ , water content W ａ＋ｗThe porosity (P) can be calculated based on the following formula (2): P (%) = (W ａ＋ｗ -W Ａｉｒ ) / (W ａ＋ｗ -W Ａｑ ) x 100 (2)

[0052] In the supporting step, amine compound 10 is supported on the support structure 20 prepared as above. The method for introducing amine compound 10 into the support structure 20 may follow a conventionally known method. For example, a solution in which the amine compound 10 is dissolved in a predetermined organic solvent (for example, a lower alcohol such as ethanol) is prepared, and the support structure 20 is immersed in such a solution, thereby making the amine compound 10 supported on the support structure 20. Alternatively, in the supporting step, the amine compound 10 may be supported on the support structure 20 by exposing the support structure 20 to an atmosphere in which the amine compound 10 is in a gas phase.

[0053] As mentioned above, the CO ２ The adsorbent 100 has a predetermined structure, which improves the amount of amine supported on the support structure 20. The concentration of the amine compound in the supporting step is not particularly limited. For example, ２ The concentration of the amine compound is preferably adjusted so that the amount of the amine compound 10 relative to the adsorbent 100 (amine support amount) is 24% by mass or more and 56% by mass or less (more preferably 25% by mass or more and 56% by mass or less, even more preferably 30% by mass or more and 56% by mass or less, and particularly preferably 43% by mass or more and 56% by mass or less). ２ Excellent CO adsorption performance ２ An adsorbent 100 can be provided.

[0054] In the second drying step, the support structure 20 after the supporting step is dried to remove the organic solvent from the support structure 20. As a result, the CO ２The adsorbent 100 can be suitably produced. The drying means in the second drying step is not particularly limited and may be the same as that in the first drying step, for example. The drying temperature in the second drying step (such as the set temperature of the drying device) can be selected appropriately depending on the type and amount of solvent in the mixture, and can be set to, for example, 60°C to 150°C, preferably 80°C to 120°C. The drying time can also be selected appropriately depending on the type and amount of organic solvent, and is not particularly limited.

[0055] As described above, the CO ２ The adsorbent 100 can be suitably produced. ２ As described above, the adsorbent 100 has a large amount of amine supported, and therefore, ２ The adsorption performance is good. ２ The adsorbent 100 can efficiently adsorb and remove carbon dioxide from exhaust gas containing carbon dioxide.

[0056] <Test Examples> Test examples relating to the technology disclosed herein will be described below, but it is not intended that the technology disclosed herein be limited to such test examples.

[0057] <CO ２ Preparation of Adsorbent> (Example 1) First, porous silica particles (SiO ２ 135 g of cellulose acylate (cellulose acetate, average particle diameter: 9 μm), 80 g of polyetherimide (PEI) as a resin, 500 g of dimethyl sulfoxide (DMSO) as an organic solvent, and 28 g of polyethylene glycol (PEG) as an additive were prepared. Thus, a slurry for forming a carrier structure of Example 1 was prepared. Next, the slurry for forming a carrier structure of Example 1 was applied to a glass substrate using a doctor blade to a thickness of 2 mm, thereby obtaining a sheet-like molded product. The sheet-like molded product was immersed in water for 24 hours. The molded product after immersion in water was then dried at 80°C for 5 hours, thereby obtaining a sheet-like carrier structure (carrier sheet) of Example 1.

[0058] Next, ethanol and polyethyleneimine (Epomin, PEI012, manufactured by Nippon Shokubai Co., Ltd.) were mixed in a mass ratio of 1:1, and the mixture was stirred for 24 hours by rotating the rotor of a stirrer at 150 rpm. The carrier sheet of Example 1 obtained above was cut into a piece with a diameter of 6 mm, a thickness of 1 mm, and a weight of 1 g. This carrier sheet piece was placed in 15 g of the stirred solution and shaken for 24 hours. The carrier sheet piece was recovered from the solution, and the surface of the carrier sheet piece was washed with ethanol. Then, it was dried at 80°C for 5 hours. This produced a CO2 extract of Example 1 in which an amine compound was supported on a carrier structure. ２ The adsorbent was obtained.

[0059] (Example 2) In Example 2, porous particles having an average particle diameter of 6 μm SiO ２ Then, each material was mixed in a mass ratio of SiO ２ The components were mixed in a ratio of 18:11:67:4 to prepare a slurry for forming a carrier structure of Example 2. The slurry was then molded into a sheet in the same manner as in Example 1, and the sheet was immersed in a solution in which water and ethanol were mixed in a ratio of 5:95 for 24 hours. Except for these, the carrier structure of Example 2 formed into a sheet was obtained in the same manner as in Example 1. Next, an amine compound was supported on the carrier structure in the same manner as in Example 1, and the CO ２ The adsorbent was obtained.

[0060] In Example 3, N-methylpyrrolidone (NMP) was used as the solvent. Each material was mixed in a mass ratio of SiO ２ The components were mixed in a ratio of 18:11:67:4 to prepare a slurry for forming a carrier structure of Example 3. Except for this, the carrier structure of Example 3 formed in a sheet shape was obtained in the same manner as in Example 1. Then, an amine compound was supported on the carrier structure in the same manner as in Example 1, and the CO2 of Example 3 was obtained. ２ The adsorbent was obtained.

[0061] (Example 4) In Example 4, porous particles having an average particle diameter of 6 μm SiO ２ Then, each material was mixed in a mass ratio of SiO ２The components were mixed in a ratio of 14:8:51:27 to prepare a slurry for forming a carrier structure of Example 4. Except for this, the carrier structure of Example 4 formed in a sheet shape was obtained in the same manner as in Example 1. Next, an amine compound was supported on the carrier structure in the same manner as in Example 1, and the CO ２ The adsorbent was obtained.

[0062] (Example 5) In Example 5, porous particles having an average particle diameter of 6 μm SiO ２ Polyethersulfone (PES) was used as the resin. Each material was mixed in a mass ratio of SiO ２ The components were mixed in a ratio of 18:11:67:4 to prepare a slurry for forming a support structure of Example 5. Except for this, the same procedure as in Example 1 was repeated to obtain a support structure of Example 5 formed in a sheet shape. Then, an amine was supported on the support structure in the same manner as in Example 1, and the CO ２ The adsorbent was obtained.

[0063] (Example 6) In Example 6, NMP was used as a solvent. Each material was mixed in a mass ratio of SiO ２ The components were mixed in a ratio of 16:20:60:4 to prepare a slurry for forming a carrier structure of Example 6. Except for this, the carrier structure of Example 6 formed in a sheet shape was obtained in the same manner as in Example 1. Next, an amine was supported on the carrier structure in the same manner as in Example 1, and the CO ２ The adsorbent was obtained.

[0064] In Example 7, PES was used as the resin. N-methylpyrrolidone (NMP) was used as the solvent. Each material was mixed in a mass ratio of SiO ２ The components were mixed in a ratio of 24:13.5:56:6.5 to prepare a slurry for forming a support structure of Example 7. Except for this, the same procedure as in Example 1 was repeated to obtain a support structure of Example 7 formed in a sheet shape. Then, an amine was supported on the support structure in the same manner as in Example 1, and the CO ２ The adsorbent was obtained.

[0065] Example 8 In Example 8, PEI and polymethyl methacrylate (PMMA) were used as resins. N-methylpyrrolidone (NMP) was used as a solvent. SiO ２ The components were mixed in a ratio of 16:10:10:60:4 to prepare a slurry for forming a carrier structure of Example 8. Except for this, the carrier structure of Example 8 formed in a sheet shape was obtained in the same manner as in Example 1. Next, an amine was supported on the carrier structure in the same manner as in Example 1, and the CO ２ The adsorbent was obtained.

[0066] Example 9 In Example 9, PEI and ethyl cellulose (EC) were used as the resin. N-methylpyrrolidone (NMP) was used as the solvent. SiO ２ The components were mixed in a ratio of 16:10:10:60:4 to prepare a slurry for forming a carrier structure of Example 9. Except for this, the carrier structure of Example 9 formed in a sheet shape was obtained in the same manner as in Example 1. Next, an amine was supported on the carrier structure in the same manner as in Example 1, and the CO ２ The adsorbent was obtained.

[0067] (Example 10) In Example 10, a sheet-like carrier structure was prepared by the procedure of Example 3. Next, in Example 10, an amine compound was supported by the same procedure as in Examples 1 to 9, except that the mass ratio of ethanol to polyethyleneimine was changed from 1:1 to 8:2. As a result, a CO 2 carrier having a small amount of amine supported on the same carrier structure as in Example 3 was prepared. ２ An adsorbent (Example 10) was obtained.

[0068] Comparative Example 1 In Comparative Example 1, porous silica particles (SiO ２ 10 g of porous silica particles (average particle diameter: 6 μm) were prepared. Using a mold and a press, the porous silica particles were press-molded to a diameter of 15 mm and a thickness of 2 mm to obtain a molded body. The molded body was dried at 800° C. for 2 hours to obtain a support structure of Comparative Example 1. Next, 1 g of the support structure was cut out. An amine was supported on the support structure in the same manner as in Example 1, and the CO２ The adsorbent was obtained.

[0069] <Measurement of the average pore diameter of the resin matrix before amine loading> The average pore diameter of the resin matrix in the support structure of each example before amine loading was measured using mercury intrusion porosimetry. Specifically, first, the support structure of each example before amine loading was cut into a size of approximately 5 mm x 5 mm and pretreated by heating to 120 ° C. for 3 hours. Next, mercury was introduced into the support structure in a range of 0.10 to 60,000 psia using a mercury porosimeter (Micromeritics, Auto Pore IV 9500) to obtain the pore distribution of each example. From the peak position of the obtained pore distribution, the average pore diameter A (μm) of the resin matrix in the support structure of each example before amine loading was calculated. The results are shown in Table 1. Note that Comparative Example 1 did not contain a resin, but the pore diameter calculated using the same method as above was taken as the average pore diameter A, and the results are shown in Table 1.

[0070] <Measurement of the average pore diameter of porous particles before amine loading> The average pore diameter of the porous particles in the support structure of each example before amine loading was measured using a nitrogen gas adsorption method. Specifically, first, the support structure of each example before amine loading was cut into a size of about 5 mm x 5 mm, and pretreated by holding it under vacuum at 120°C for 3 hours. Next, using a pore size distribution measuring device (Microtrac-Bell, BELSORP MINI), the adsorption isotherm of each example was determined by introducing nitrogen gas at 77 K. The obtained adsorption isotherm was converted into a pore distribution by the BJH method, and the pore volume V (cm ３ / g) and specific surface area S (m ２ The average pore diameter B (nm) of the porous particles in the support structure of each example before the amine was supported was calculated using the following formula: average pore diameter B (nm) = 4V / S. The results are shown in Table 1.

[0071] <Measurement of amine loading amount> ２ The amount of the amine compound supported on the adsorbent (amine supported amount) was determined as follows: ２ The mass (g) of the adsorbent (carrier structure) is A0, and the CO ２The mass (g) of the adsorbent (carrier structure + amine compound) was designated as A1. The amount of amine supported (mass%) for each example was calculated using the following formula: Amount of amine supported (mass%) = {(A1 - A0) / A1} × 100. The results are shown in Table 1.

[0072] <CO ２ Measurement of adsorption amount> CO ２ CO of adsorbent ２ The adsorption amount was determined as follows: First, the CO ２ After the adsorbent was placed in the glass tube, He gas was passed through to separate the water and the adsorbed CO. ２ and N ２ At this time, He gas was passed through the sample for 3 hours under the conditions of a temperature of 100°C and a flow rate of 30 ml / min. ２ 5% CO relative to the adsorbent ２ -N ２ Gas was passed through the chamber. At this time, 5% CO ２ -N ２ The gas was passed through for 150 minutes under the conditions of a temperature of 60°C and a flow rate of 30 ml / min. The CO contained in the gas on the exhaust side was measured using a mass spectrometer (Microtrac-Bell, Belcat, BEL Mass). ２ and N ２ Detecting CO ２ Breakthrough curve and N ２ A breakthrough curve was obtained. ２ Breakthrough curve and N ２ The breakthrough curves are shown in Figure 2. ２ The adsorption amount was calculated as follows: ２ The time of the lowest intensity just before the detected intensity began to increase rapidly is t1, CO ２ The time when the detected intensity reached its maximum immediately before it began to decrease rapidly was defined as t2. ２ The signal intensity was set to P2, and the area S1 was calculated from the formula: S1 = (t2 - t1) x P2. The calculated area S1 was used as the CO ２ The CO ２ The area S2 was determined by integrating the breakthrough curve. Then, the area S3 was calculated from (S1-S2), and the area S3 was used as the CO ２By converting it into the adsorption amount (mmol / g), the CO ２ The amount of adsorption was calculated, and the results are shown in Table 1.

[0073]

[0074] As shown in Table 1, in Examples 1 to 9, CO ２ The adsorption amount is 1.45 mmol / g or more, and CO ２ This is because in Examples 1 to 9, the CO 2 adsorption performance is good, which has a structure in which porous particles are arranged in the pores of a resin matrix having a three-dimensional network structure, and an amine compound is arranged in the pores of the porous particles. ２ This is presumably because the amount of the amine compound supported increased by using the adsorbent. On the other hand, in Comparative Example 1, which was composed of porous particles without a resin, the amount of the amine supported was significantly reduced, even though the amine was supported in the same manner as in Examples 1 to 9. This is the reason why the CO ２ This is presumably one of the reasons for the low adsorption performance.

[0075] In Example 10, the amine loading conditions were changed so that the amount of amine loaded was smaller than that in Comparative Example 1. However, even in Example 10, the CO ２ This confirmed the CO adsorption performance of the technology disclosed herein. ２ The improvement in adsorption performance is presumed to be due to the increase in the amount of amine carried as described above, as well as the following phenomenon. First, the support structure used in Example 10 has a three-dimensional network structure. This network-structured support structure has an extremely large number of pores, and therefore has excellent gas diffusion properties. This allows the target gas (CO ２ As a result, in Example 10, although the amount of amine supported was smaller than that in Comparative Example 1, a suitable CO ２ It is expected that the adsorption performance can be demonstrated.

[0076] While specific examples of the technology disclosed herein have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and alterations of the specific examples exemplified above.

[0077] The technology disclosed herein includes the following items 1 to 6. The following items 1 to 6 are not limited to the above-described embodiment.

[0078] Item 1 is CO ２ Regarding the adsorbent: CO in item 1 ２ The adsorbent comprises: an amine compound; and a support structure for supporting the amine compound. ２ The adsorbent comprises a carrier structure including a resin matrix having a three-dimensional network structure including pores, and porous particles having a plurality of mesopores, the porous particles being disposed in the pores of the resin matrix, and the amine compound being disposed in the plurality of mesopores of the porous particles.

[0079] Item 2 is the CO ２ The adsorbent has a supported amount of the amine compound of 24% by mass or more and 56% by mass or less.

[0080] Item 3 is the CO described in Item 1 or Item 2 ２ The adsorbent comprises: the amine compound containing at least polyethyleneimine.

[0081] Item 4 is a CO according to any one of items 1 to 3. ２ The adsorbent has hot water resistance of 120°C or higher and 250°C or lower.

[0082] Item 5 is a CO according to any one of items 1 to 4. ２ The adsorbent comprises a resin matrix having a glass transition temperature of 70°C or higher and 250°C or lower.

[0083] Item 6 is a CO according to any one of items 1 to 5. ２The adsorbent comprises porous particles containing at least one selected from the group consisting of silica particles, alumina particles, ceria particles, zirconia particles, and titania particles.

[0084] 10 Amine compound 20 Support structure 30 Resin matrix 32 Pore 40 Porous particle 42 Pore 100 CO ２ Adsorbent

Claims

1. A CO catalyst comprising: an amine compound; and a support structure for supporting the amine compound. ２ A CO adsorbent, the carrier structure comprising: a resin matrix having a three-dimensional network structure including pores; and porous particles having a plurality of mesopores, the porous particles being disposed in the pores of the resin matrix, and the amine compound being disposed in the plurality of mesopores of the porous particles. ２ Adsorbent.

2. The CO catalyst according to claim 1, wherein the amount of the amine compound supported is 24% by mass or more and 56% by mass or less. ２ Adsorbent.

3. The CO according to claim 1 or 2, wherein the amine compound contains at least polyethyleneimine. ２ Adsorbent.

4. The CO according to claim 1 or 2, which has hot water resistance of 120°C or more and 250°C or less. ２ Adsorbent.

5. The CO according to claim 1 or 2, wherein the resin matrix contains a resin having a glass transition temperature of 70° C. or higher and 250° C. or lower. ２ Adsorbent.

6. The CO according to claim 1 or 2, wherein the porous particles include at least one selected from the group consisting of silica particles, alumina particles, ceria particles, zirconia particles, and titania particles. ２ Adsorbent.

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