Carbon dioxide adsorption material, carbon dioxide adsorption device, method for producing same, and carbon dioxide adsorption method

Abstract

Provided is a carbon dioxide adsorbent which is capable of suppressing the occurrence of deterioration over year and which exhibits high durability even when used repeatedly in a carbon dioxide adsorption treatment. The carbon dioxide adsorbent comprises an amine compound including: a first amino group comprising a primary amino group; a second amino group comprising a primary amino group, a secondary amino group, or a tertiary amino group; and a linear alkylene group having 2-6 carbon atoms, which connects the first amino group and the second amino group, and which is substituted by a linear alkyl group having 1-3 carbon atoms or a branched alkyl group having 3-4 carbon atoms.

Description

Technical Field

[0001] The present invention relates to a carbon dioxide adsorption material for adsorbing carbon dioxide in a gas, and particularly to a carbon dioxide adsorption material with improved durability by suppressing deterioration over the years. Background Art

[0002] In recent years, there has been a high demand for air purification in many aspects. For example, there is a need to remove carbon dioxide to maintain clean air in living spaces. Also, there is a high demand for materials that can adsorb carbon dioxide in combustion exhaust gases discharged into the atmosphere for air purification.

[0003] On the other hand, the growth of plants requires the supply of carbon dioxide. Especially in plastic greenhouses, etc., except when ventilating to avoid temperature rise during the day, it is usually in a closed state. Therefore, the carbon dioxide required for the growth of cultivated plants such as strawberries or tomatoes cultivated in plastic greenhouses, etc., is often insufficient.

[0004] Moreover, the cultivated plants cultivated in plastic greenhouses, etc., absorb carbon dioxide through photosynthesis during the day, resulting in the carbon dioxide concentration around the leaves being lower than the carbon dioxide concentration in the atmosphere (about 400 ppm).

[0005] In this case, the photosynthesis of the cultivated plants is inhibited, leading to a decrease in the yield or sugar content of the cultivated plants, etc. Therefore, treatments such as forcibly supplying carbon dioxide from the outside to increase the yield of the cultivated plants are carried out. Specifically, as a method for supplying carbon dioxide, a method of burning kerosene, etc., or a supply based on a liquefied carbon dioxide gas cylinder is carried out.

[0006] However, such existing methods for supplying carbon dioxide are methods for increasing carbon dioxide in the environment and are in a direction opposite to the carbon dioxide reduction policy such as carbon neutrality. Therefore, a cleaner method for supplying carbon dioxide is required.

[0007] In order to meet such social needs, the applicant has been developing a carbon dioxide supply device using a honeycomb rotor for the purpose of supplying clean gas that is environmentally friendly and does not require processes such as replacement.

[0008] For example, as an existing carbon dioxide supply device developed by the applicant to date, there is the following carbon dioxide absorption type removal / concentration device: It has a carbon dioxide removal rotor that holds a carbon dioxide adsorbent material having a carbon dioxide absorption function, etc. The carbon dioxide removal rotor is at least divided into an adsorption zone and a desorption zone. By ventilating the air to be treated to the adsorption zone, the carbon dioxide contained in the air to be treated is absorbed by the absorbent held by the carbon dioxide removal rotor part, separated and removed, and supplied to the supply destination. In the desorption zone, by ventilating the regeneration air that uses a total heat exchanger to recover the latent heat and sensible heat of the regeneration exhaust gas from the desorption zone, the carbon dioxide absorbed by the absorbent in the adsorption zone is desorbed, thereby regenerating the absorbent (refer to Patent Document 1).

[0009] In such a carbon dioxide absorption type removal / concentration device, organic absorbents such as triethanolamine and monoethanolamine, or amine-based weakly basic anion exchange resins, amine-supported solid absorbents such as activated carbon, silica gel, or mesoporous silica supported with amine (hereinafter, referred to as "amine compounds") are used as carbon dioxide adsorbent materials by utilizing their property of being able to absorb carbon dioxide.

[0010] In order to desorb the carbon dioxide absorbed by the amine compound, the amine compound is usually heated. However, by this heating, the amino group constituting the amine compound is oxidized or detached. That is, the carbon dioxide adsorbent material using the amine compound is liable to deteriorate due to oxidation over time during long-term use, resulting in a decline in the carbon dioxide absorption / desorption characteristics.

[0011] Methods for suppressing the oxidation of amine compounds have also been studied. For example, it is known to suppress the oxidation of amine compounds by forming a nitrogen atmosphere (refer to Non-Patent Document 1). And, for example, it is also known to suppress the oxidation of amine compounds by mixing antioxidants (refer to Non-Patent Document 2).

[0012] However, generally, in a carbon dioxide absorption type removal / concentration device, the absorption / desorption of carbon dioxide is carried out in the atmosphere and under the premise of coexistence of oxygen, so methods such as those changing the usage conditions of amine compounds as described in Non-Patent Document 1 or Non-Patent Document 2 cannot be applied and are not effective enough.

[0013] Therefore, active research and development of new materials of amine compounds that can exhibit excellent characteristics as carbon dioxide adsorbent materials are being carried out.

[0014] As a property of amine compounds, carbon dioxide absorption / desorption is usually carried out under atmospheric pressure through chemical reactions involving amino groups. However, when using amino groups alone, the amount of carbon dioxide absorption is not sufficient. Therefore, in order to more efficiently absorb / desorb carbon dioxide in the atmosphere, among existing carbon dioxide adsorption materials, amine compounds containing multiple primary amino groups or secondary amino groups are mainly used.

[0015] For example, as an existing carbon dioxide adsorption material, a material containing an organosilicon compound containing a cyclic guanidine moiety or a linear guanidine moiety (e.g., 1-[3-(trimethoxysilyl)propyl]-2-imidazoline, 1-[3-(trimethoxysilyl)propyl]-1,4,5,6-tetrahydropyrimidine, 1-[3-(silatranyl (aza-silatrane derivative))propyl]-2-imidazoline, or 1-[3-(silatranyl)propyl]-1,4,5,6-tetrahydropyrimidine) is known (refer to Patent Document 2).

[0016] And, for example, as an existing carbon dioxide adsorption material, a material is known that contains a polymer compound having a chemical structure formed by bonding functional groups containing at least primary amino groups and that is formed into a porous shape, and the ratio d / w of the stress d at 10% deformation in the dry state to the stress w at 10% deformation in the wet state is a value in the range of 1 or more and 10 or less (refer to Patent Document 3).

[0017] And, for example, as an existing carbon dioxide adsorption material, there is also a material that uses a composition containing at least one amine compound selected from the group consisting of amine compounds represented by the following general formula and a carrier (in the following formula, R 1 and R 2 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. n represents 0 or 1. R 9 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aminoalkyl group having 3 to 4 carbon atoms, or a hydroxyalkyl group having 1 to 4 carbon atoms. R 10 and R 11 each independently represent an alkylene group having 1 to 4 carbon atoms.) (refer to Patent Document 4).

[0018] [Chemical Formula 1]

[0019]

[0020] Prior Art Documents

[0021] Patent Documents

[0022] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-89891.

[0023] Patent Document 2: Japanese Patent No. 5498717.

[0024] Patent Document 3: Japanese Unexamined Patent Application Publication No. 2022-122253.

[0025] Patent Document 4: Japanese Unexamined Patent Application Publication No. 2022-154003.

[0026] Non-Patent Documents

[0027] Non-Patent Document 1: "Energy Fuels", (USA), 2019, Vol. 33, p. 3370-3379.

[0028] Non-Patent Document 2: "Industrial & Engineering Chemistry Research", (USA), 2019, Vol. 58, p. 15598-15605. Summary of the Invention

[0029] Problems to be Solved by the Invention

[0030] However, even in the case of amine compounds containing both primary amino groups and secondary amino groups among existing carbon dioxide adsorbents, if they are used in an oxygen-containing atmospheric atmosphere, oxidation or detachment of the amino groups occurs due to the reactivity between the primary amino groups and the secondary amino groups, and as a result, they are liable to decompose.

[0031] For example, as shown in the following general formula described in Claim 2 of the above Patent Document 2, there is a double bond between the amino groups in the amine compound constituting the existing carbon dioxide adsorbent. The electron density of the π bond forming the double bond is relatively high. Therefore, it has a structure that is liable to be cleaved by a radical reaction.

[0032] The general formula described in Claim 2 of the above Patent Document 2 is as follows.

[0033] [Chemical Formula 2]

[0034]

[0035] In the above formula, R 21 is a hydrogen atom or an alkyl group having 1 to 27 carbon atoms, R 22 and R 23 are each independently an alkyl group having 1 to 4 carbon atoms, and R 24 , R 25 and R 26 are each independently an alkyl group having 1 to 30 carbon atoms.

[0036] And, for example, as in the above Patent Document 3 Figure 7As shown in the following Compound 57 described in [reference], the amine compound that constitutes the existing carbon dioxide adsorption material has a C=S double bond between two amino groups. The electron density of the π bond forming this C=S double bond is relatively high. Therefore, it has a structure that is easily cleaved by a radical reaction.

[0037] The [reference document 3] mentioned above Figure 7 Compound 57 is as follows.

[0038] [Chemical formula 3]

[0039]

[0040] In addition, different from the above, there are also compounds that do not have a double bond between amino groups. For example, among the amine compounds that constitute the existing carbon dioxide adsorption material, as in the following Compound 67 described in the above [reference document 3] Figure 8 there are also compounds that do not have a double bond on the alkylene group (methylene group) connecting two amino groups.

[0041] The [reference document 3] mentioned above Figure 8 Compound 67 is as follows.

[0042] [Chemical formula 4]

[0043]

[0044] However, in this case, the alkylene group (e.g., methylene group) connecting two amino groups itself becomes a structure that is easily cleaved by performing the following Hofmann elimination (A).

[0045] [Chemical formula 5]

[0046]

[0047] More specifically, in the existing carbon dioxide adsorption material (e.g., the above Compound 67), since there is no double bond on the alkylene group (e.g., methylene group) connecting two amino groups, during the carbon dioxide adsorption process, an acid amide compound in which the carbonyl group derived from carbon dioxide adds to the terminal amino group exists in a chemical equilibrium state.

[0048] Reacting further with this acid amide compound existing in a chemical equilibrium state, the carbonyl group of the amide detaches from this acid amide compound, and another amine separates (Hofmann elimination). That is, during the process of adsorbing carbon dioxide, due to the occurrence of this Hofmann elimination (A), the existing carbon dioxide adsorption material decomposes. The amino compound in [reference document 4] also has a structure without a double bond between amino groups as described above, but the same phenomenon as in [reference document 3] occurs.

[0049] Further, among existing carbon dioxide adsorption materials, as shown in Patent Documents 2, 3, and 4 above, especially in the case of amino silanes among amine compounds, they are sometimes supported on carriers with a high specific surface area such as silica gel or mesoporous silica and used. However, the adsorption and desorption of carbon dioxide are further accelerated. Therefore, in the above-mentioned amine compounds, the frequency of oxidation / desorption of the amine compounds is also accelerated, resulting in a rapid decline in the carbon dioxide adsorption and desorption performance.

[0050] Thus, existing carbon dioxide adsorption materials have problems with durability such as being prone to aging deterioration through repeated adsorption / desorption of carbon dioxide in the structure of the amine compound.

[0051] Therefore, there is a demand for a carbon dioxide adsorption material composed of an amine compound that is not easily degraded in the presence of oxygen in terms of its carbon dioxide adsorption / desorption characteristics. However, so far, no such excellent carbon dioxide adsorption material has been found.

[0052] The present invention has been completed to solve the above problems, and an object thereof is to provide a carbon dioxide adsorption material that can suppress the occurrence of aging deterioration and exhibit high durability even when repeatedly used for carbon dioxide adsorption treatment.

[0053] Technical means for solving the problems

[0054] As a result of intensive research by the present inventors, the chemical structure of an amine compound that can be a carbon dioxide adsorption material was carefully conceived, and an amine compound that can be a new type of carbon dioxide adsorption material that suppresses the occurrence of aging deterioration was discovered, thereby completing the present invention.

[0055] Thus, the carbon dioxide adsorption material disclosed in the present application is composed of an amine compound, and the amine compound includes: a first amino group composed of a primary amino group; a second amino group composed of a primary amino group, a secondary amino group, or a tertiary amino group; and a linear alkylene group having 2 to 6 carbon atoms that connects the first amino group and the second amino group and is substituted with a linear alkyl group having 1 to 3 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 It is a structural diagram showing a carbon dioxide adsorption material according to a first embodiment of the present invention.

[0057] Figure 2 It is an explanatory diagram showing a manufacturing method of a carbon dioxide adsorption material according to a first embodiment of the present invention.

[0058] Figure 3 It is a flowchart showing a usage method of a carbon dioxide adsorption material according to a first embodiment of the present invention.

[0059] Figure 4It is a structural diagram of the carbon dioxide adsorption material according to the second embodiment of the present invention.

[0060] Figure 5 It is a diagram showing an example of the filter shape of the carbon dioxide adsorption device according to the second embodiment of the present invention.

[0061] Figure 6 It is an explanatory diagram showing the usage method of the carbon dioxide adsorption device according to the second embodiment of the present invention.

[0062] Figure 7 It is a flowchart showing the usage method of the carbon dioxide adsorption device according to the third embodiment of the present invention.

[0063] Figure 8 It is an explanatory diagram showing the usage method of the carbon dioxide adsorption device according to the third embodiment of the present invention.

[0064] Figure 9 It is a structural diagram showing an example of a honeycomb rotor of the carbon dioxide adsorption device according to the third embodiment of the present invention.

[0065] Figure 10 It is an explanatory diagram showing the usage method of the carbon dioxide adsorption device according to the third embodiment of the present invention.

[0066] Figure 11 It shows the durability test results of the carbon dioxide adsorption material of Example 1 of the present invention.

[0067] Figure 12 It shows the dynamic performance test results of the carbon dioxide adsorption material of Example 2 of the present invention. Detailed implementation mode

[0068] (The first embodiment)

[0069] The carbon dioxide adsorption material according to the first embodiment is composed of an amine compound, and the amine compound includes: a first amino group composed of a primary amino group; a second amino group composed of a primary amino group, a secondary amino group or a tertiary amino group; and a linear alkylene group having 2 to 6 carbon atoms, connecting the first amino group and the second amino group, and substituted by a linear alkyl group having 1 to 3 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms.

[0070] Since the first amino group is configured as a primary amino group at the end of the amine compound, the NH bonds participating in the carbon dioxide adsorption reaction are abundant, and carbon dioxide can be sufficiently adsorbed even under low-temperature conditions, and high adsorption performance for carbon dioxide can be exhibited.

[0071] The second amino group may be a primary amino group, a secondary amino group, or a tertiary amino group, and there is no particular limitation. In terms of exhibiting high carbon dioxide adsorption performance, a primary amino group or a secondary amino group having an NH bond participating in the carbon dioxide adsorption reaction is preferred.

[0072] The first amino group and the second amino group are respectively connected to the carbon atoms at both ends of the linear alkylene group through a C—N bond.

[0073] The main skeleton of the linear alkylene group is a linear structure having 2 to 6 carbon atoms. Further, at least one atom constituting the linear structure is substituted with a linear alkyl group having 1 to 3 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms. In addition, if there are many substituted alkyl groups, the specific heat increases and the energy load during carbon dioxide desorption increases. Therefore, the upper limit of the carbon atom number is set to 3 for the linear alkyl group and 4 for the branched alkyl group. And as will be described later for the linear alkylene group, it is considered that by substituting an alkyl group for a part of the linear alkylene group, an optimal steric hindrance that makes it difficult for carbon dioxide molecules to approach is formed between the amino groups of the first amino group and the second amino group, suppressing the elimination of the primary amino group (such as Hofmann elimination) or the reduction of the secondary amino group, and suppressing the oxidation of the primary amino group (such as a radical mechanism). If the linear alkylene group is long, the specific heat increases and the energy load during carbon dioxide desorption increases. Therefore, the upper limit of the carbon atom number is set to 6. On the other hand, when the carbon atom number of the linear alkylene group is 1 (methylene), as described above, Hofmann elimination easily occurs. Therefore, it does not include a linear alkylene group having 1 carbon atom. And if the carbon atom number of the substituted alkyl group or the linear alkylene group increases, the ratio of the NH bond participating in the carbon dioxide adsorption reaction to the molecular weight of the amine compound decreases, and the carbon dioxide adsorption performance deteriorates. Therefore, the upper limit of the carbon atom number is set as described above.

[0074] Examples of the linear structure as the main skeleton of the linear alkylene group include ethylene, n-propylene, n-butylene, n-pentylene, and n-hexylene, and any of them can be used. For example, ethylene can be used.

[0075] Examples of the linear alkyl group as the alkyl group substituting a part of the linear structure of the main skeleton of the linear alkylene group include methyl, ethyl, and propyl, and examples of the branched alkyl group include isopropyl and tert-butyl.

[0076] The alkyl group substituting a part of the linear structure of the main skeleton of the linear alkylene group is a group substituting at least one carbon atom constituting the linear structure, and it may substitute only 1 carbon atom constituting the linear structure, or may substitute 2 or more carbon atoms constituting the linear structure. Further, it may substitute a plurality of hydrogen atoms on the same carbon atom constituting the linear structure.

[0077] Examples of the amine compound having such a structure include, for example, a compound represented by the following general formula (1).

[0078] [Chemical Formula 6]

[0079]

[0080] In the above formula, R 1 and R 1 ’ are functional groups constituting the second amino group, and are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. When both R 1 and R 1 ’ are hydrogen atoms, the second amino group constitutes a primary amino group. When any one of R 1 and R 1 ’ is a hydrogen atom, the second amino group constitutes a secondary amino group. When any one of R 1 and R 1 ’ is an alkyl group, the second amino group constitutes a tertiary amino group.

[0081] R 21m and R 22m are each independently a hydrogen atom or a linear alkyl group having 1 to 3 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms, and at least one of R 21m and R 22m is a linear or branched alkyl group, and m is a natural number from 2 to 6.

[0082] That is, the natural number m represents the carbon chain length of the linear alkylene group connecting the first amino group and the second amino group. Therefore, the linear alkylene group represents a chain length longer than that of ethylene.

[0083] At least one of the carbon atoms constituting the carbon chain is a structure substituted with a linear or branched alkyl group represented by R 21m or R 22m .

[0084] For example, when the natural number m is 2, as R 21m and R 22m , there are 4 alkyl groups, namely R 211 , R 212 , R 221 and R 222 . However, for example, only 1 of them, R 211 , can be a linear or branched alkyl group, and the other R 212 , R 221 and R 222 are hydrogen atoms. And, for example, 2 of them, R 211 and R 212 , can be linear or branched alkyl groups, and the other R 221 and R 222 are hydrogen atoms. And, for example, 3 of them, R 211 , R212 and R 221 is a linear or branched alkyl group, and the other R 222 is a hydrogen atom. And, for example, four of the Rs 211 , R 212 , R 221 and R 222 can all be linear or branched alkyl groups.

[0085] In the carbon dioxide adsorbent material according to this embodiment, since an aminosilane is preferably used particularly during operation in the amine compound, it is more preferably a structure including the following: a silicon atom substituted with an alkoxy group having 1 to 6 carbon atoms; and a linear alkylene group having 1 to 6 carbon atoms connecting the silicon atom and the nitrogen atom in the second amino group.

[0086] The silicon atom may be substituted with one alkoxy group, two alkoxy groups, or three alkoxy groups. In addition, if the number of carbon atoms in the alkoxy group is large, the specific heat increases and the energy load during the desorption of carbon dioxide increases, so the upper limit of the number of carbon atoms is set to 6. And for the same reason, the upper limit of the number of carbon atoms of the linear alkylene group connecting the silicon atom and the nitrogen atom in the second amino group is set to 6.

[0087] Examples of the linear alkylene group having 1 to 6 carbon atoms connecting the nitrogen atom in the second amino group and the silicon atom include a methylene group, an ethylene group, a n-propylene group, a n-butylene group, a n-pentylene group, and a n-hexylene group, and any one of them can be used. For example, an ethylene group or a n-propylene group can be used.

[0088] For example, as the carbon dioxide adsorbent material according to this embodiment, an amine compound represented by the following general formula (2) or its derivative can be cited.

[0089] [Chemical formula 7]

[0090]

[0091] In the above general formula (2), the definitions of R 1 , R 21m , R 22m and m are the same as the definitions in the above general formula (1). R 31 , R 32 and R 33 are each independently a hydrogen atom, an alkoxy group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms. At least one of R 31 , R 32 and R 33 is an alkoxy group, and n is a natural number from 1 to 6. In addition, if the number of carbon atoms in the alkoxy group or the alkyl group is large, the specific heat increases and the energy load during the desorption of carbon dioxide increases, so the upper limit of the number of carbon atoms is set to 6.

[0092] As an example of the above general formula (2), for instance, amine compounds or their derivatives having the following structures (2-1) to (2-3) can be cited. Further, in the following formulas (2-1) to (2-3), R 31 , R 32 and R 33 at least any one of them is a methoxy group, and the others are methyl groups. Further, in the following chemical formulas including the general formula hereafter, for simplicity, an unsubstituted alkylene group (e.g., methylene, ethylene) is represented by a parenthesis indicating the repetition number of the minimum unit, i.e., methylene (e.g., 2 in the case of ethylene, 3 in the case of propylene).

[0093] [Chemical formula 8]

[0094]

[0095] [Chemical formula 9]

[0096]

[0097] [Chemical formula 10]

[0098]

[0099] That is, the carbon dioxide adsorbent material according to the present embodiment can be, for example, a structure in which one methyl group is added to the alkylene group (propylene group) between the first amino group and the second amino group as in the above chemical formulas (2-1) and (2-2), or a structure in which two methyl groups are added to the alkylene group (propylene group) between the first amino group and the second amino group as in the above chemical formula (2-3).

[0100] The amine compound required for the carbon dioxide adsorbent material according to the present embodiment can be synthesized, but it can also be obtained from the market.

[0101] The carbon dioxide adsorbent material according to the present embodiment configured as such adsorbs carbon dioxide at room temperature and can release carbon dioxide below 200°C. Moreover, it is confirmed that the occurrence of aging deterioration can be suppressed, and excellent durability is exhibited for repeated use of the carbon dioxide adsorption treatment (refer to the examples described later).

[0102] The excellent mechanism has not been elucidated in detail, but it is presumed as follows: In this amine compound, a part of the linear alkylene connecting the first amino group and the second amino group is substituted with a linear alkyl group having 1 to 3 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms. During the carbon dioxide adsorption treatment, while maintaining the carbon dioxide adsorption performance, the alkyl group substituting a part of the linear alkylene forms an optimal steric hindrance that is difficult for carbon dioxide molecules to approach between the amino groups of the first amino group and the second amino group, suppressing the detachment of the primary amino group (such as Hofmann elimination) or the reduction of the secondary amino group, and suppressing the oxidation of the primary amino group (such as a radical mechanism).

[0103] The carbon dioxide adsorption material 1 according to the present embodiment configured as such has a wide range of uses, and in particular, its usage method is not limited. For example, as shown in Figure 1 (a), it can be used as a carbon dioxide adsorption device 10. The carbon dioxide adsorption device 10 includes an adsorption part 2 fixed to a specified base material 21, which brings a gas containing carbon dioxide into contact with the amine compound and separates carbon dioxide from the gas containing carbon dioxide.

[0104] The base material 21 is not particularly limited as long as it can fix the carbon dioxide adsorption material 1, but as shown in Figure 1 (b), a porous body having porous holes 21a has a high specific surface area, so it is preferred. As such a base material 21, those selected from the group consisting of silica, vermiculite, activated carbon, alumina, aluminosilicate, diatomaceous earth, porous glass, porous resin, porous fiber, and zeolite can be used.

[0105] As a manufacturing method of such a carbon dioxide adsorption device 10, for example, as shown in Figure 2 (b), for the base material 21 having porous holes 21a as shown in Figure 2 (a), the carbon dioxide adsorption material 1 is supported on the base material 21 by spraying, impregnation, coating, or a silane coupling reaction, impregnation, evaporation to dryness, and other bonding methods (supporting step).

[0106] For example, the carbon dioxide adsorption material 1 can be made into a solution state and sprayed onto the base material 21 by spray injection or impregnated to support it on the base material 21. In addition, for example, the carbon dioxide adsorption material 1 can also be made into a solution state and supported on the base material 21 by impregnation, evaporation to dryness, or coating.

[0107] Moreover, for example, when the amine compound constituting the carbon dioxide adsorption material 1 is an aminosilane represented by the above general formula (2), the carbon dioxide adsorption material 1 can also be supported on the base material 21 by a silane coupling reaction to obtain high adhesiveness with the base material 21.

[0108] Thus, as shown inFigure 2 (As shown in (c), the carbon dioxide adsorbent material 1 penetrates into the porous holes 21a. The adsorption part 2 is formed by supporting the carbon dioxide adsorbent material 1 on the base material 21 through a silane coupling reaction, impregnation, evaporation to dryness, and other bonding methods.)

[0109] As described above, the base material 21 may or may not be a porous body. However, especially when the base material 21 is a porous body, due to its high permeability, the impregnation efficiency is high, and thus a firm support can be obtained.)

[0110] As Figure 3 (As shown, the carbon dioxide adsorption method using the carbon dioxide adsorption device 10 can adsorb carbon dioxide by passing a gas containing carbon dioxide (S1: adsorption step).)

[0111] As the gas containing carbon dioxide to be targeted, as long as it is a gas containing carbon dioxide, there is no particular limitation. For example, since the atmosphere, exhaust gas discharged from factories or automobiles, etc. also contain carbon dioxide, they can be utilized. As a method for passing the gas containing carbon dioxide, a blower that causes forced convection can be used.)

[0112] In this way, by a simple method such as only passing the gas containing carbon dioxide through the carbon dioxide adsorption device 10, carbon dioxide can be easily adsorbed. And as described above, the occurrence of aging deterioration is suppressed, and excellent durability can be exhibited for repeated use of the carbon dioxide adsorption treatment.)

[0113] Therefore, the carbon dioxide adsorption device 10 according to the present embodiment has a wide range of uses. For example, it can adsorb and remove carbon dioxide in the atmosphere and supply air with a low carbon dioxide concentration to a living space. And, for example, it can be used as an air purification material for adsorbing and concentrating carbon dioxide in combustion exhaust gas.)

[0114] (Second Embodiment)

[0115] Similar to the first embodiment, the carbon dioxide adsorption device 10 according to the second embodiment has the following structure: it includes the carbon dioxide adsorbent material 1, the base material 21, and the adsorption part 2. Furthermore, as Figure 4 (shown, it includes a filter part 3 composed of a filter on which the adsorption part 2 is fixed.)

[0116] The shape of the filter part 3 is not particularly limited. For example, it can be set to a honeycomb structure. As this honeycomb structure, as Figure 5As shown in (a) to (d), a structure including regularly arranged hollow regular hexagonal prisms in a honeycomb shape without gaps is a honeycomb structure in a narrow sense, but is not limited to this shape. As a honeycomb structure in a broad sense, it also includes a structure in which arbitrary hollow three-dimensional figures, not limited to hollow regular hexagonal prisms, are arranged without gaps as a honeycomb structure in a broad sense. For example, a structure in which incombustible inorganic fibers are processed into a corrugated cardboard shape and laminated to form a rotor shape is also included as a honeycomb structure.

[0117] With this honeycomb structure, as Figure 6 shown, in the carbon dioxide adsorption device 10, the surface area of the carbon dioxide adsorption material 1, which is the processing part of the carbon dioxide adsorption device 10, is increased. By allowing only the gas X containing carbon dioxide to flow through the filtration part 3, the filtration part 3 can easily and efficiently adsorb carbon dioxide, and then the carbon dioxide-removed gas Xa is discharged.

[0118] (The third embodiment)

[0119] Similar to the first and second embodiments, the carbon dioxide adsorption method using the carbon dioxide adsorption device 10 according to the third embodiment includes the adsorption step (S1). Furthermore, as Figure 7 shown, it includes a regeneration step (S2) of heating or reducing the pressure of the carbon dioxide adsorption material 1 that has adsorbed carbon dioxide through the adsorption step (S1) to discharge carbon dioxide.

[0120] Regarding the heating in this regeneration step (S2), the carbon dioxide adsorption material 1 can be directly heated, or high-temperature gas can be allowed to flow through the carbon dioxide adsorption material 1. And regarding the pressure reduction in this regeneration step (S2), the carbon dioxide adsorption material 1 can be directly depressurized, or low-pressure gas can be allowed to flow through the carbon dioxide adsorption material 1.

[0121] As Figure 8 (a) shown, in the initial state L in which the carbon dioxide adsorption device 10 according to the third embodiment does not contain carbon dioxide in the carbon dioxide adsorption material 1, a gas X containing carbon dioxide such as air is fed into the carbon dioxide adsorption device 10.

[0122] By allowing this gas X containing carbon dioxide to flow through the carbon dioxide adsorption material 1, as Figure 8 (b) shown, the carbon dioxide adsorption material 1 adsorbs carbon dioxide in the gas X containing carbon dioxide, thus becoming an adsorption state M containing carbon dioxide, and the carbon dioxide-removed gas Xa is discharged.

[0123] As Figure 8As shown in (c), an external force P such as heating or depressurization is applied to the carbon dioxide adsorbent material 1 in the adsorption state M, thereby discharging the gas Xb containing carbon dioxide, and the carbon dioxide adsorbent material 1 is regenerated to the original initial state L (S2: regeneration step).

[0124] As described above, since the carbon dioxide adsorbent material 1 suppresses the occurrence of aging deterioration and exhibits excellent durability for repeated use in carbon dioxide adsorption treatment, it can be repeatedly used for a long time.

[0125] Moreover, the carbon dioxide adsorption device 10 according to the third embodiment can also be configured in the shape of a honeycomb rotor.

[0126] As Figure 9 shown, the honeycomb rotor refers to a rotor having a filter section 3 with a honeycomb structure formed in a drum shape with a circular cross-section. The cross-section of the carbon dioxide adsorption device 10 configured as this honeycomb rotor is bisected to form an adsorption zone A and a desorption zone B respectively. More preferably, as Figure 9 shown, for each of the two semi-circular cross-sections obtained by bisecting the circular cross-section of the honeycomb rotor 1 along the diameter of the circle, an adsorption zone A and a desorption zone B are formed.

[0127] Regarding the operation of the carbon dioxide adsorption device 10 as this honeycomb rotor, a gas X containing carbon dioxide such as air is sent into the adsorption zone A of the honeycomb rotor. As Figure 10 (a) shown, carbon dioxide in the gas X containing carbon dioxide is adsorbed by the carbon dioxide adsorbent material 1 located in the adsorption zone A of the honeycomb rotor, and thus the carbon dioxide-removed gas Xa is discharged.

[0128] In this case, in the adsorption zone A of the honeycomb rotor, a state where carbon dioxide is adsorbed on the carbon dioxide adsorbent material 1 is formed. By subsequent rotation of the rotor, as Figure 10 (b) shown, the side that was initially in the adsorption zone A is now in the desorption zone B, forming a state where carbon dioxide is adsorbed in the desorption zone B.

[0129] Next, the desorption zone B rich in this carbon dioxide is heated or depressurized. Thereby, the gas Xb containing carbon dioxide containing a high concentration of carbon dioxide is discharged, and the carbon dioxide adsorption performance of the carbon dioxide adsorbent material 1 is regenerated (S2: regeneration step).

[0130] The resulting carbon dioxide-containing gas Xb has a higher concentration of carbon dioxide than the carbon dioxide-containing gas X used as a raw material, and thus can be widely used in applications that can utilize carbon dioxide. For example, in order to grow plants, it is necessary to supply carbon dioxide. Therefore, for example, by supplying the carbon dioxide-containing gas Xb to a plant greenhouse (plastic greenhouse), the growth of cultivated plants can be promoted. In addition to these plants, the growth of algae can also be promoted by supplying the carbon dioxide-containing gas Xb in the same manner.

[0131] Hereinafter, examples will be described to more specifically illustrate the features of the present embodiment, but the present embodiment is not limited by the following examples.

[0132] (Example 1)

[0133] As the carbon dioxide adsorption material related to Example 1, an amine compound having the following structure (2-4) was obtained from the market.

[0134] [Chemical formula 11]

[0135]

[0136] In the above formula (2-4), R 31 , R 32 and R 33 At least any one of them is a methoxy group, and the others are methyl groups.

[0137] Moreover, as the carbon dioxide adsorption material related to the comparative example, a commercially available product of an amine compound having the following structure (B) was purchased as an existing product.

[0138] [Chemical formula 12]

[0139]

[0140] In the above formula (B), R 31 , R 32 and R 33 At least any one of them is a methoxy group, and the others are methyl groups.

[0141] The amine compound related to Example 1 and the amine compound of the existing product were respectively supported on silica, and the silica was supported on the filter unit 3 having the above honeycomb structure, thereby constructing the carbon dioxide adsorption device 10 related to the above third embodiment.

[0142] Since the adsorption of carbon dioxide is derived from amino groups, it is possible to judge the decline in the carbon dioxide adsorption performance of amino groups by measuring the carbon dioxide adsorption isotherm. Therefore, an accelerated test was carried out using the amine compound involved in Example 1 and the amine compound of the existing product respectively, and the carbon dioxide adsorption isotherm before and after the accelerated test was measured. By leaving each amine compound at a temperature and humidity above the commonly used temperature range, an 80°C / 50% RH durability test was carried out as the accelerated test.

[0143] This durability test was carried out for 7 days, and the measured carbon dioxide adsorption isotherm was taken as the carbon dioxide adsorption performance, and the existing product and Example 1 were compared. Regarding the durability of this carbon dioxide adsorption performance, the experimental results with the horizontal axis being the number of durability days are shown in Figure 11 .

[0144] From the obtained results, it was confirmed that the amine compound involved in Example 1 maintained a high carbon dioxide adsorption amount even after the accelerated test compared with the amine compound of the existing product in the comparative example, showing more than twice the durability. Thus, it can be said that the amine compound involved in Example 1 is different from the existing product, and the detachment of primary amino groups (such as Hofmann elimination) or the reduction of secondary amino groups are suppressed, and deterioration reactions such as the oxidation of primary amino groups (such as free radical mechanisms) are suppressed.

[0145] (Example 2)

[0146] In the same manner as in Example 1 above, the amine compound involved in Example 1 and the amine compound of the existing product were respectively supported on silica, and this silica was supported on the filter unit 3 having the above honeycomb structure, thereby constructing the carbon dioxide adsorption device 10 of the above Embodiment 3. A dynamic performance test was carried out under the following conditions to confirm the dynamic performance of carbon dioxide adsorption using the carbon dioxide adsorption device having this honeycomb structure.

[0147] · Adsorption zone inlet temperature TP1 = 23.5°C, adsorption zone inlet absolute humidity XP1 = 12 g / kg', adsorption zone inlet carbon dioxide concentration 400 ppm

[0148] · Desorption zone inlet temperature TR1 = 45°C, desorption zone inlet absolute humidity XR1 = 18.5 g / kg', desorption zone inlet carbon dioxide concentration 550 ppm

[0149] In the carbon dioxide adsorption device of the above Embodiment 3, the results of measuring and plotting the carbon dioxide concentration of the carbon dioxide-containing gas Xb shown above for each honeycomb rotor speed [rph] at the regeneration outlet CO2 concentration [ppm] are shown in Figure 10 The results of measuring and plotting the carbon dioxide concentration of the carbon dioxide-containing gas Xb shown above for each honeycomb rotor speed [rph] at the regeneration outlet CO2 concentration [ppm] are shown in Figure 12It was confirmed from the obtained results that the amine compound involved in Example 1 above exhibited carbon dioxide adsorption performance equal to or better than that of the amine compound of the existing product in the comparative example.

[0150] (Example 3)

[0151] As the carbon dioxide adsorbent material involved in Example 3, amine compounds having the following structures (ethylenediamine, 2-methyl-1,3-propanediamine, 1,4-diaminobutane from top to bottom) were obtained from the market. These amine compounds differed in terms of the difference in the carbon chain length and the presence or absence of branching in the carbon chain. For each of these amine compounds, they were supported on silica in the same manner as in Example 1 above to produce adsorbent materials.

[0152] [Chemical formula 13]

[0153]

[0154] Since the adsorption of carbon dioxide is derived from amino groups, by measuring the carbon dioxide adsorption isotherm, it is possible to judge the decrease in the carbon dioxide adsorption performance of amino groups. Therefore, an accelerated test using each of the above amine compounds was carried out, and the carbon dioxide adsorption isotherms before and after the accelerated test were measured. By leaving each amine compound at a temperature and humidity above the normally used temperature range, an 80°C / 50% RH durability test was carried out as an accelerated test.

[0155] The accelerated test was carried out for 3 days, and the measured carbon dioxide adsorption isotherm was used as the carbon dioxide adsorption performance, and each adsorbent material was compared.

[0156] It was confirmed from the obtained results that for the chemical structure of ethylenediamine, the carbon dioxide adsorption performance after the accelerated test of 2-methyl-1,3-propanediamine with a long straight-chain alkylene group between amino groups and having a methyl branch and 1,4-diaminobutane with a long straight-chain alkylene group between amino groups was approximately 2 times that of ethylenediamine after the accelerated test, and the durability was improved.

[0157] It was confirmed from the results of the above examples that the amine compound involved in Example 1 above maintained the carbon dioxide adsorption performance and significantly improved the durability compared to the amine compound of the existing product in the comparative example.

[0158] Explanation of reference numerals

[0159] 1 - Carbon dioxide adsorbent material,

[0160] 2 - Adsorption part,

[0161] 21 - Substrate,

[0162] 21a - Porous hole,

[0163] 3 - Filter section,

[0164] 10 - Carbon dioxide adsorption device.

Claims

1. A carbon dioxide adsorption material, characterized in that, Composed of amine compounds, The amine compounds include: A first amino group, composed of a primary amino group; A second amino group, composed of a primary amino group, a secondary amino group or a tertiary amino group; and A linear alkylene group having 2 to 6 carbon atoms, connecting the first amino group and the second amino group, and substituted by a linear alkyl group having 1 to 3 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms.

2. The carbon dioxide adsorbent according to claim 1, wherein The amine compounds include: A silicon atom substituted by an alkoxy group having 1 to 6 carbon atoms; and A linear alkylene group having 1 to 6 carbon atoms, connecting the silicon atom and the nitrogen atom in the second amino group.

3. The carbon dioxide adsorbent according to claim 2, wherein The amine compound is an amine compound represented by the following general formula (1) or its derivative, In the formula, R 1 is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, R 21m and R 22m are each independently a hydrogen atom or a linear alkyl group having 1 to 3 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms, and at least one of R 21m and R 22m is a linear or branched alkyl group, R 31 , R 32 and R 33 are each independently a hydrogen atom or an alkoxy group having 1 to 6 carbon atoms or an alkyl group having 1 to 6 carbon atoms, and at least one of R 31 , R 32 and R 33 is an alkoxy group. m is a natural number from 2 to 6, and n is a natural number from 1 to 6.

4. The carbon dioxide adsorbent according to any one of claims 1 to 3, wherein A gas containing carbon dioxide is brought into contact with the amine compound, and carbon dioxide is separated from the gas containing carbon dioxide.

5. A carbon dioxide adsorption device, characterized in that, Comprises: An adsorption part, which is formed by fixing the carbon dioxide adsorbent according to claim 4 to a substrate selected from the group consisting of silica, vermiculite, activated carbon, alumina, aluminosilicate, diatomaceous earth, porous glass, porous resin, porous fiber and zeolite, A gas containing carbon dioxide is brought into contact with the amine compound, and carbon dioxide is separated from the gas containing carbon dioxide.

6. The carbon dioxide adsorption device according to claim 5, wherein The adsorption part is formed by supporting the carbon dioxide adsorbent on the substrate through a silane coupling reaction, impregnation, evaporation to dryness or other bonding methods.

7. The carbon dioxide adsorption device according to claim 6, characterized in that, Comprises: A filter part, composed of a filter fixed with the adsorption part.

8. A manufacturing method of a carbon dioxide adsorption device for manufacturing the carbon dioxide adsorption device according to claim 5, characterized in that, Includes: A loading process, using spraying, impregnation, coating or a silane coupling reaction, impregnation, evaporation to dryness or other bonding methods to load the carbon dioxide adsorbent on the substrate.

9. A method for carbon dioxide adsorption, characterized in that, Includes: An adsorption process, in the carbon dioxide adsorption device according to claim 5, a gas containing carbon dioxide is passed through, and carbon dioxide is adsorbed.

10. The carbon dioxide adsorption method according to claim 9, wherein, Includes: A regeneration process, heating or reducing the pressure of the carbon dioxide adsorbent that has adsorbed carbon dioxide through the adsorption process, so as to discharge carbon dioxide.

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