Acidic gas adsorbent, structure comprising acidic gas adsorbent, acidic gas adsorption device, and method for producing acidic gas adsorbent

Abstract

The present invention provides an acidic gas adsorbent having improved durability against regeneration treatment by means of steam. This acidic gas adsorbent according to the present invention comprises a polymer P and a carrier that carries the polymer P. The polymer P has a constitutional unit derived from an epoxy compound and a constitutional unit derived from an amine compound. The molecular weight of the amine compound is 300 or more. The residual ratio of the polymer when the acidic gas adsorbent is immersed in water at 25 °C for 15 hours is, for example, 50% or more.

Description

Acidic gas adsorbent, structure equipped with acidic gas adsorbent, acidic gas adsorption device, and method for manufacturing acidic gas adsorbent

[0001] The present invention relates to an acidic gas adsorbent, a structure provided with the acidic gas adsorbent, an acidic gas adsorption device, and a method for producing the acidic gas adsorbent.

[0002] In recent years, carbon capture and storage (CCS) and carbon capture and utilization (CCU) have been considered as a way to reduce the amount of carbon dioxide in the atmosphere. In CCS and CCU, carbon dioxide is sometimes captured by separating it from the atmosphere.

[0003] As a method for separating acidic gases such as carbon dioxide from the atmosphere, an adsorption method has been developed in which the acidic gas is adsorbed onto an adsorbent to separate the gas. The adsorbent used in the adsorption method can adsorb the acidic gas, for example, by contacting the adsorbent with the atmosphere. As the adsorbent, a porous material having pores filled with an amine compound is sometimes used (for example, Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2015-9185

[0005] Adsorbents that have adsorbed acidic gases must be regenerated to desorb the acidic gases. The regeneration can be performed, for example, by contacting the adsorbent with high-temperature steam. However, conventional adsorbents have room for improvement in terms of durability against the regeneration treatment using steam.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an acid gas adsorbent having improved durability against regeneration treatment with steam.

[0007] The present invention provides an acidic gas adsorbent comprising: a polymer; and a support that supports the polymer; the polymer has a structural unit derived from an epoxy compound and a structural unit derived from an amine compound; and the molecular weight of the amine compound is 300 or more.

[0008] The present invention further provides an acidic gas adsorbent comprising a polymer and a support that supports the polymer, wherein the polymer has a structural unit derived from an epoxy compound and a structural unit derived from an amine compound, and when the acidic gas adsorbent is immersed in water at 25°C for 15 hours, a residual rate of the polymer is 50% or more.

[0009] The present invention further provides a structure comprising the above-described acid gas adsorbent and a ventilation path.

[0010] The present invention further provides an acidic gas adsorption device comprising an adsorption section having a gas inlet and a gas outlet, the adsorption section containing the above-mentioned acidic gas adsorbent.

[0011] The present invention further provides a method for producing an acidic gas adsorbent, which comprises contacting a group of compounds including an epoxy compound and an amine compound with a support and reacting the group of compounds to form a polymer supported on the support, wherein the molecular weight of the amine compound is 300 or more.

[0012] According to the present invention, an acid gas adsorbent having improved durability against regeneration treatment with water vapor can be provided.

[0013] The present invention relates to a method for measuring the amount of carbon dioxide adsorbed by an acidic gas adsorbent, ...

[0014] An acidic gas adsorbent according to a first aspect of the present invention comprises a polymer and a support that supports the polymer, wherein the polymer has a structural unit derived from an epoxy compound and a structural unit derived from an amine compound, and the molecular weight of the amine compound is 300 or more.

[0015] An acidic gas adsorbent according to a second aspect of the present invention is an acidic gas adsorbent comprising a polymer and a support that supports the polymer, wherein the polymer has a structural unit derived from an epoxy compound and a structural unit derived from an amine compound, and when the acidic gas adsorbent is immersed in water at 25°C for 15 hours, the residual rate of the polymer is 50% or more.

[0016] In a third aspect of the present invention, for example, in the acidic gas adsorbent according to the first or second aspect, the support has a particle shape.

[0017] In a fourth aspect of the present invention, for example, in the acidic gas adsorbent according to any one of the first to third aspects, the support has a porous structure.

[0018] In a fifth aspect of the present invention, for example, in the acidic gas adsorbent according to the fourth aspect, the average pore size of the support is 50 nm or less.

[0019] In a sixth aspect of the present invention, for example, in the acidic gas adsorbent according to any one of the first to fifth aspects, the support contains silica.

[0020] In a seventh aspect of the present invention, for example, in the acidic gas adsorbent according to any one of the first to sixth aspects, the epoxy compound has two or more epoxy groups.

[0021] In an eighth aspect of the present invention, for example, in the acidic gas adsorbent according to any one of the first to seventh aspects, the amine compound has a tertiary amino group and at least one selected from the group consisting of a primary amino group and a secondary amino group.

[0022] In a ninth aspect of the present invention, for example, in the acidic gas adsorbent according to any one of the first to eighth aspects, the amine compound includes polyethyleneimine.

[0023] In a tenth aspect of the present invention, for example, in the acidic gas adsorbent according to any one of the first to ninth aspects, the glass transition temperature of the polymer is 40° C. or lower.

[0024] In an eleventh aspect of the present invention, for example, in the acidic gas adsorbent according to any one of the first to tenth aspects, the content of the polymer is 25 wt % or more.

[0025] A structure according to a twelfth aspect of the present invention comprises: an acidic gas adsorbent according to any one of the first to eleventh aspects; and a ventilation path.

[0026] An acidic gas adsorption device according to a thirteenth aspect of the present invention comprises an adsorption section having a gas inlet and a gas outlet, and the adsorption section accommodates the acidic gas adsorbent according to any one of the first to eleventh aspects.

[0027] A method for producing an acidic gas adsorbent according to a fourteenth aspect of the present invention includes contacting a compound group including an epoxy compound and an amine compound with a support and reacting the compound group to form a polymer supported on the support, wherein the molecular weight of the amine compound is 300 or more.

[0028] The present invention will be described in detail below, but the following description is not intended to limit the present invention to a specific embodiment.

[0029] <Embodiment of Acidic Gas Adsorbent> The acidic gas adsorbent of this embodiment includes a polymer P and a support that supports the polymer P. The polymer P has a structural unit U1 derived from an epoxy compound and a structural unit U2 derived from an amine compound. The molecular weight of the amine compound is 300 or more. When the amine compound is a polymer (prepolymer), the molecular weight of the amine compound specifically refers to the weight average molecular weight.

[0030] According to the studies of the present inventors, the acidic gas adsorbent of this embodiment has a tendency that the polymer P is less likely to fall off from the support when it comes into contact with water. Therefore, when the acidic gas adsorbent is brought into contact with water vapor for regeneration treatment, even if the water vapor condenses to produce condensed water, the polymer P is less likely to fall off from the support. Thus, the acidic gas adsorbent of this embodiment has improved durability against regeneration treatment by water vapor.

[0031] (Polymer) Polymer P has an amino group and has the function of adsorbing acidic gases due to the amino group. Polymer P preferably contains at least one amino group selected from the group consisting of a primary amino group, a secondary amino group, and a tertiary amino group. From the viewpoint of adsorption performance for acidic gases, polymer P preferably contains at least one selected from the group consisting of a primary amino group and a secondary amino group, and preferably contains both a primary amino group and a secondary amino group. In polymer P, the larger the substance amount of primary amino groups and secondary amino groups (particularly primary amino groups), the higher the density of nitrogen elements in the acidic gas adsorbent and the higher the amount of acidic gas adsorption tends to be. Note that polymer P preferably further contains a tertiary amino group in addition to the primary amino group and the secondary amino group.

[0032] In this embodiment, in the near-infrared absorption spectrum (spectral data) obtained by performing near-infrared spectroscopy (NIR) on the polymer P, -1 The peak intensity I of the absorption peak present in the vicinity B The wave number is 4930 cm -1 The peak intensity I of the absorption peak present in the vicinity A Ratio I A / I B Generally, when the polymer P contains a primary amino group and a secondary amino group, the wavelength of the polymer P is preferably 6500 cm -1 Absorption peaks due to primary and secondary amino groups were observed around the wavenumber of 4930 cm -1 An absorption peak due to the primary amino group is observed around the A / I B can be used as an index relating to the ratio of the amount of primary amino groups to the amount of secondary amino groups in polymer P. NIR can be performed using a transparent test piece obtained by press-molding polymer P. This test piece is less prone to light scattering, which can affect the NIR results.

[0033] Ratio I A / I Bis more preferably 0.90 or more, and may be 0.95 or more, 1.00 or more, 1.05 or more, 1.10 or more, 1.15 or more, or even 1.20 or more. A / I B The higher the ratio I, the greater the amount of acid gas adsorption. A / I B The upper limit of is not particularly limited, and is, for example, 1.50 or less.

[0034] The weight ratio of nitrogen elements in polymer P is, for example, 5 wt% or more, preferably 10 wt% or more. The higher this weight ratio, the more the acidic gas adsorption performance of the acidic gas adsorbent tends to improve. The upper limit of the weight ratio of nitrogen elements in polymer P is not particularly limited, and is, for example, 30 wt% or less. Note that when all of the nitrogen elements contained in polymer P are derived from amino groups, the weight ratio of nitrogen elements described above can be regarded as the weight ratio of amino groups in polymer P.

[0035] The density of nitrogen elements in polymer P is, for example, greater than 12.0 mmol / g, preferably 12.2 mmol / g or greater, and may be 12.5 mmol / g or greater, 13.0 mmol / g or greater, 13.5 mmol / g or greater, 14.0 mmol / g or greater, 14.5 mmol / g or greater, 15.0 mmol / g or greater, 15.5 mmol / g or greater, 16.0 mmol / g or greater, 16.5 mmol / g or greater, 17.0 mmol / g or greater, or even 17.5 mmol / g or greater. The upper limit of the nitrogen element density is not particularly limited and may be, for example, 30 mmol / g or less, or 20 mmol / g or less. In this specification, the density of nitrogen elements in polymer P refers to the amount of nitrogen elements contained in 1 g of polymer P. Note that when all of the nitrogen elements contained in polymer P are derived from amino groups, the density of nitrogen elements can be considered to be the density of amino groups in polymer P.

[0036] The density of nitrogen elements in polymer P can be measured by the following method. First, the weight ratio w (wt%) of nitrogen elements contained in polymer P is measured using a commercially available CHN elemental analyzer. Based on the obtained results, the density d of nitrogen elements can be calculated using the following formula: Density d (mmol / g) = (weight ratio w (wt%) × 1000) / (atomic weight of nitrogen × 100)

[0037] The polymer P may contain a functional group other than an amino group. Examples of the functional group include a hydroxyl group, an ether group, an ester group, and an amide group. The polymer P preferably contains an ether group as the functional group.

[0038] As described above, the polymer P has a structural unit U1 derived from an epoxy compound and a structural unit U2 derived from an amine compound. The polymer P is typically a reaction product of a group of compounds including an epoxy compound and an amine compound. The polymer P is preferably a polymer in which an amine compound is crosslinked with an epoxy compound (crosslinked product). The crosslinked product of an amine compound with an epoxy compound not only tends to have a high density of nitrogen elements, but also tends to have high heat resistance and moist heat resistance.

[0039] The amine compound is a compound containing at least one amino group, and preferably contains at least one primary amino group or secondary amino group. The number of primary amino groups or secondary amino groups contained in the amine compound is preferably 2 or more, and may be 3 or more, or 4 or more. The upper limit of the number of primary amino groups is not particularly limited, and may be, for example, 100 or less, or may be 10 or less.

[0040] It is particularly preferred that the amine compound has at least one selected from the group consisting of a primary amino group and a secondary amino group, and a tertiary amino group. In the amine compound, the ratio of the number of primary amino groups to the number of all amino groups is not particularly limited, and is, for example, 10% or more, preferably 20% or more, more preferably 30% or more, and may be 40% or more. The higher this ratio, the more crosslinking points in the amine compound increase, and the denser the crosslinked structure in the polymer P, which tends to improve heat resistance and moist heat resistance. The upper limit of this ratio is not particularly limited, and may be, for example, 80% or less, or 60% or less.

[0041] As described above, the molecular weight of the amine compound is 300 or more. Polymer P formed using an amine compound with such a large molecular weight tends to be less likely to fall off from the support even when contacted with water. The molecular weight of the amine compound is preferably 400 or more, and may be 500 or more, 600 or more, 700 or more, 800 or more, 900 or more, 1000 or more, 1200 or more, or even 1500 or more. The larger the molecular weight of the amine compound, the easier it is to adjust the density of the nitrogen element in the polymer P. Furthermore, amine compounds with a large molecular weight tend to be safer to handle. The upper limit of the molecular weight of the amine compound is, for example, 5000 or less, or may be 2000 or less. The amine equivalent of the amine compound is, for example, 10 g / eq. or more, preferably 20 g / eq. or more, and more preferably 30 g / eq. or more. The larger the amine equivalent of the amine compound, the easier it is to adjust the density of the nitrogen element in the polymer P. The upper limit of the amine equivalent of the amine compound is not particularly limited, and may be, for example, 200 g / eq. It may be 150 g / eq. or less, 100 g / eq. or less, or even 50 g / eq. or less. In this specification, the amine equivalent means the mass of the amine compound relative to 1 equivalent of active hydrogen of a primary amino group contained in the amine compound. When the amine compound contains repeating units (structural units), the number of structural units contained in the amine compound (degree of polymerization) is not particularly limited and is, for example, 5 to 100.

[0042] Examples of the amine compound include aliphatic polyamines such as polyethyleneimine, polypropyleneimine, polyalkylenepolyamine, polyallylamine, etc. The amine compound preferably includes polyethyleneimine (PEI).

[0043] In addition, aliphatic polyamines, particularly PEI, tend to be highly safe to handle. For example, amine compounds such as aliphatic polyamines are preferably not classified as hazardous materials under the Fire Service Act and are preferably not subject to the Poisonous and Deleterious Substances Control Act. The amine compounds preferably have negative results in mutagenicity tests (Ames tests). The amine compounds preferably have mild or moderate irritation results in skin irritation tests (primary skin irritation tests using rabbits).

[0044] The epoxy compound is a compound containing at least one epoxy group. The number of epoxy groups contained in the epoxy compound is preferably 2 or more, and may be 3 or more, or 4 or more. The greater the number of epoxy groups, the greater the number of crosslinking points in the epoxy compound, and the denser the crosslinked structure in the polymer P, which tends to improve heat resistance and moist heat resistance. The upper limit of the number of epoxy groups contained in the epoxy compound is not particularly limited, and is, for example, 10 or less.

[0045] The molecular weight of the epoxy compound is not particularly limited and is, for example, less than 1,000, preferably 500 or less. The epoxy equivalent of the epoxy compound is not particularly limited and is, for example, 150 g / eq. or less, preferably 100 g / eq. or less. The smaller the epoxy equivalent of the epoxy compound, the higher the density of the nitrogen element in the polymer P tends to be. The lower limit of the epoxy equivalent of the epoxy compound is not particularly limited and is, for example, 50 g / eq. or more. The epoxy equivalent means the mass of the epoxy compound per equivalent of the epoxy group contained in the epoxy compound.

[0046] Examples of the epoxy compound include monofunctional epoxy compounds such as n-butyl glycidyl ether, higher alcohol glycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, p-sec-butylphenyl glycidyl ether, and t-butylphenyl glycidyl ether; diepoxy alkanes such as 1,5-hexadiene diepoxide, 1,7-octadiene diepoxide, and 1,9-decadiene diepoxide; (poly)ethylene glycol diglycidyl ether, (poly)propylene glycol diglycidyl ether, and (poly)propylene glycol diglycidyl ether. Examples of polyfunctional epoxy compounds having an ether group include polyfunctional epoxy compounds having an ether group, such as ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane polyglycidyl ether, pentaerythritol polyglycidyl ether, and sorbitol polyglycidyl ether; and polyfunctional epoxy compounds having an amino group, such as N,N,N',N'-tetraglycidylmetaxylenediamine and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane.

[0047] The epoxy compound may be an aromatic epoxy resin, a non-aromatic epoxy resin, or the like, depending on the circumstances. Examples of aromatic epoxy resins include polyphenyl-based epoxy resins, epoxy resins containing a fluorene ring, epoxy resins containing triglycidyl isocyanurate, and epoxy resins containing a heteroaromatic ring (e.g., a triazine ring). Examples of polyphenyl-based epoxy resins include bisphenol A-type epoxy resins, brominated bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol AD-type epoxy resins, stilbene-type epoxy resins, biphenyl-type epoxy resins, bisphenol A novolac-type epoxy resins, cresol novolac-type epoxy resins, diaminodiphenylmethane-type epoxy resins, and tetrakis(hydroxyphenyl)ethane-based epoxy resins. Examples of non-aromatic epoxy resins include aliphatic glycidyl ether-type epoxy resins, aliphatic glycidyl ester-type epoxy resins, alicyclic glycidyl ether-type epoxy resins, alicyclic glycidyl amine-type epoxy resins, and alicyclic glycidyl ester-type epoxy resins.

[0048] The epoxy compounds can be used alone or in combination of two or more. When a monofunctional epoxy compound is used, it is preferably used in combination with another epoxy compound containing two or more epoxy groups. The monofunctional epoxy compound can also be used as a reactive diluent to adjust the viscosity of the compounds used to form the polymer P.

[0049] The epoxy compound preferably includes a polyfunctional epoxy compound having an ether group, such as ethylene glycol diglycidyl ether (EDE) or pentaerythritol tetraglycidyl ether (PETG). EDE and PETG have a small epoxy equivalent and can easily lower the glass transition temperature Tg of the polymer P. These epoxy compounds also tend to be low in cost.

[0050] In the polymer P, the content of the structural unit U1 derived from an epoxy compound is, for example, 20 wt % to 70 wt %. In the polymer P, the content of the structural unit U2 derived from an amine compound is, for example, 30 wt % or more, and preferably 50 wt % or more. There is no particular upper limit to the content of the structural unit U2, and it is, for example, 80 wt % or less.

[0051] The polymer P is preferably a liquid. In this specification, the term "liquid" refers to a substance that is in a liquid state at atmospheric pressure (101.325 kPa) and 20°C.

[0052] The glass transition temperature Tg of the polymer P is not particularly limited, and may be, for example, 40 ° C. or lower, 30 ° C. or lower, 20 ° C. or lower, 15 ° C. or lower, 10 ° C. or lower, 5 ° C. or lower, 0 ° C. or lower, -1 ° C. or lower, less than -1 ° C., -2 ° C. or lower, -3 ° C. or lower, -4 ° C. or lower, -5 ° C. or lower, -6 ° C. or lower, -7 ° C. or lower, -8 ° C. or lower, -9 ° C. or lower, -10 ° C. or lower, -11 ° C. or lower, -12 ° C. or lower, -13 ° C. or lower, -14 ° C. or lower, or even -15 ° C. or lower. The lower the glass transition temperature Tg of the polymer P, the higher the rate at which the acidic gas adsorbent adsorbs the acidic gas. The lower limit of the glass transition temperature Tg of the polymer P may be, for example, -100 ° C. or higher, -50 ° C. or higher, -30 ° C. or higher, or even -20 ° C. or higher, from the viewpoint of sufficiently ensuring the adsorption performance of the acidic gas adsorbent, heat resistance, and ease of preparation of the acidic gas adsorbent. In this specification, the glass transition temperature Tg is the midpoint glass transition temperature (T mg ) The polymer P generally corresponds to a thermosetting resin.

[0053] The weight average molecular weight of the polymer P is not particularly limited and is, for example, 500 or more, preferably 1000 or more, more preferably 10000 or more, and even more preferably 100000 or more. The upper limit of the weight average molecular weight of the polymer P is, for example, 10,000,000 or less.

[0054] The polymer P content R1 in the acidic gas adsorbent is, for example, 5 wt% or more, and may be 10 wt% or more, 15 wt% or more, 20 wt% or more, 25 wt% or more, 30 wt% or more, or even 35 wt% or more. The higher the polymer P content R1, the more the acidic gas adsorbent tends to improve its acid gas adsorption performance. The upper limit of the polymer P content R1 is, for example, 80 wt% or less, and may be 60 wt% or less.

[0055] The polymer P content R1 can be measured, for example, by the following method. First, the acidic gas adsorbent is placed in a simultaneous thermal analysis DSC / TGA apparatus. The temperature is set to 30°C. Next, using this apparatus, the temperature is increased from 30°C to 100°C at a heating rate of 10°C / min under a nitrogen atmosphere and maintained at that temperature for 40 minutes (operation 1). According to operation 1, water contained in the acidic gas adsorbent can be removed. Next, the temperature is increased from 100°C to 800°C at a heating rate of 10°C / min and maintained at that temperature for 5 minutes (operation 2). According to operation 2, the polymer P can be removed from the acidic gas adsorbent. The ratio (100 × (W1 - W2) / W1) of the weight W1 (g) of the acidic gas adsorbent immediately after the end of operation 1 to the difference between the weight W1 (g) and the weight W2 (g) of the acidic gas adsorbent immediately after the end of operation 2 can be regarded as the polymer P content R1 in the acidic gas adsorbent.

[0056] (Support) As described above, the support is a member that supports the polymer P. The polymer P is preferably in direct contact with the surface of the support. The support is preferably a porous body having a porous structure. When the support has a porous structure, the polymer P is preferably supported on the surface of the pores of the support. Note that the surface of the pores of the support means the surface facing the internal pores of the support. In this specification, the surface that defines the outer shape of the support may be referred to as the outer surface of the support to distinguish it from the surface of the pores.

[0057] As an example, the acidic gas adsorbent may have a coating layer that coats the surfaces of the pores of the support, and this coating layer may contain polymer P. The coating layer may coat the entire surfaces of the pores, or may coat the surfaces of the pores partially. The coating layer may coat not only the surfaces of the pores but also the outer surface of the support. The coating layer may contain polymer P as a main component, or may be composed essentially of polymer P. In this specification, "consisting essentially of" means excluding other components that would change the essential characteristics of the referenced material, and means, for example, that 95 wt % or more, or even 99 wt % or more is composed of the component in question.

[0058] In a support having a porous structure, the shape of the pores is not particularly limited. The support may have continuous pores formed continuously in a three-dimensional shape, or may have closed pores. The support may have through-holes that penetrate the support.

[0059] The pore volume of the support having a porous structure is, for example, 0.5 cm 3 / g or more, and further 1.0 cm 3 / g or more. A support having a large pore volume can support a sufficient amount of polymer P on the surface of the pores of the support. The upper limit of the pore volume of the support is not particularly limited, and may be, for example, 5.0 cm 3 / g or less, and 3 / g or less, and even 3.0 cm 3 / g or less. The pore volume of the support can be determined by the following method. First, the support is subjected to a gas adsorption method using nitrogen gas. The adsorption isotherm data obtained by the gas adsorption method is converted by the BJH (Barrett-Joyner-Halenda) method. The pore volume of the support can be determined based on the obtained pore size distribution.

[0060] The average pore diameter of the support having a porous structure is, for example, 1 μm or less, and may be 500 nm or less, 100 nm or less, 80 nm or less, 50 nm or less, or even 30 nm or less. The smaller the average pore diameter of the support, the less likely water tends to penetrate into the pores of the support. With this support, the polymer P supported on the surface of the pores is less likely to come into contact with water, so even if the acidic gas adsorbent comes into contact with water, the polymer P tends to be less likely to fall off from the support. The lower limit of the average pore diameter of the support is, for example, 1 nm or more, and may be 5 nm or more, 10 nm or more, or even 20 nm or more. The average pore diameter of the support means the average value of the diameters of multiple pores calculated from the pore size distribution. The pore size distribution can be obtained by the method described above for the pore volume of the support.

[0061] The specific surface area of ​​the support is not particularly limited, and is, for example, 50 m 2 / g or more, and 2 / g or more, 100m 2 / g or more, 200m 2 / g or more, 250m 2 / g or more, 300m 2 / g or more, 400m 2 / g or more, 500m 2 / g or more, 600m 2 / g or more, and even 700m 2 The upper limit of the specific surface area of ​​the support is not particularly limited, and may be, for example, 1000 m 2 / g or less. In some cases, the specific surface area of ​​the support is 300 m 2 The specific surface area of ​​the support means the BET (Brunauer-Emmett-Teller) specific surface area determined by nitrogen gas adsorption.

[0062] The pore volume, average pore diameter, and specific surface area of ​​the support are measured, for example, on the support before polymer P is supported on the pore surfaces. However, this measurement may also be performed on a support obtained by removing polymer P from an acidic gas adsorbent. The polymer P can be removed, for example, by heat treating the acidic gas adsorbent at a temperature of 800°C or higher.

[0063] The support preferably has a particulate shape. In this specification, the particle shape includes spherical, ellipsoidal, scaly, fibrous, etc. The average particle size of the particulate support is, for example, 1 μm or more, and may be 10 μm or more, 20 μm or more, or even 30 μm or more. The average particle size of the support may be, for example, 200 μm or less, 100 μm or less, or even less than 75 μm. In this specification, the average particle size of the support means the particle size (d50) corresponding to 50% cumulative volume in the particle size distribution measured by a laser diffraction particle sizer or the like. The support may be a fibrous structure such as glass paper, but is preferably not a fibrous structure.

[0064] Examples of the support material include inorganic materials and organic materials. The support preferably contains an inorganic material. Examples of inorganic materials include metal oxides such as silica, alumina, silica alumina, magnesia, and zirconia; metals; minerals such as clay minerals and natural minerals; zeolites; and carbon materials such as activated carbon. Examples of organic materials include (meth)acrylate polymers such as polymethyl methacrylate. The support preferably contains silica as an inorganic material, and porous silica is particularly preferred.

[0065] Examples of porous silica include gel-type silica and precipitated silica, with gel-type silica being preferred. Gel-type silica is porous silica that can be synthesized, for example, by carrying out a neutralization reaction between sodium silicate and an inorganic acid under acidic conditions. Precipitated silica is porous silica that can be synthesized, for example, by carrying out the above-mentioned neutralization reaction under basic conditions. Gel-type silica has a smaller average pore size than precipitated silica, and most of the pores are mesopores (pores with a pore size of 2 to 50 nm). Therefore, when the support is gel-type silica, water tends to be less likely to penetrate into the pores of the support.

[0066] The content of the carrier in the acidic gas adsorbent is not particularly limited, and is, for example, 20 wt % to 95 wt %.

[0067] (Other Components) The acidic gas adsorbent may be substantially composed of only the polymer P and the support, or may further contain other components other than these. Examples of other components include a reaction accelerator, a plasticizer, a pigment, a dye, an antioxidant, a conductive material, an antistatic agent, an ultraviolet absorber, a flame retardant, and an antioxidant.

[0068] (Method for producing acidic gas adsorbent) The method for producing an acidic gas adsorbent of this embodiment includes contacting a group of compounds including an epoxy compound and an amine compound with a support and reacting the group of compounds to form a polymer P supported on the support.

[0069] The contact of the compound group with the support can be carried out, for example, by the following method. First, a dispersion containing the support is prepared. Examples of the solvent for the dispersion include water and alcohol (particularly lower alcohols). Next, the compound group is added to this dispersion and mixed, thereby bringing the compound group into contact with the support. When the support has a porous structure, it is preferable that the compound group penetrates into the pores of the support and contacts the surface of the pores. In addition, in order to promote the penetration of the compound group into the pores of the support, the dispersion containing the compound group and the support may be treated under a reduced pressure atmosphere or a vacuum atmosphere.

[0070] The dispersion may further contain components other than the compounds, such as the above-mentioned reaction accelerators.

[0071] The solids concentration in the dispersion is not particularly limited and may be, for example, 50 wt % or less, 30 wt % or less, or even 20 wt % or less. The lower the solids concentration in the dispersion, the easier it tends to be for the compounds to come into contact with the surfaces of the pores of the support. The lower limit of the solids concentration in the dispersion is not particularly limited and is, for example, 5 wt %.

[0072] In the dispersion, the ratio E / A of the equivalent E of the epoxy group in the compound group to the equivalent A of the active hydrogen of the primary amino group in the compound group is preferably 1.00 or less. In particular, it is preferable that the blending ratio of the amine compound and the epoxy compound is adjusted so that the ratio E / A is 1.00 or less. In the compound group, the ratio E / A is preferably 0.90 or less, 0.50 or less, less than 0.50, 0.45 or less, 0.40 or less, 0.35 or less, or even 0.30 or less. The smaller the ratio E / A, the higher the ratio of primary amino groups in the polymer P and the higher the density of nitrogen elements in the acidic gas adsorbent tends to be. From the viewpoint of ease of preparation of the acidic gas adsorbent, the lower limit of the ratio E / A may be, for example, 0.10 or more, 0.15 or more, or even 0.20 or more.

[0073] The reaction of the compounds is typically a crosslinking reaction of the amine compound with the epoxy compound. The reaction of the compounds can be carried out by applying energy to the compounds. The energy applied to the compounds is preferably thermal energy. However, the energy applied to the compounds may also be light energy.

[0074] As an example, thermal energy can be applied to the compound group by heating the dispersion. For example, the compound group can be reacted by heating the dispersion at a temperature of 40°C to 100°C. The dispersion may be heated under a reduced pressure or a vacuum atmosphere. As an example, the dispersion may be heated under a reduced pressure or a vacuum atmosphere using a rotary evaporator. By heating the dispersion, the compound group can be reacted and the solvent contained in the dispersion may be distilled off. After distilling off the solvent contained in the dispersion, the support may be further subjected to a drying treatment. The conditions for the drying treatment of the support are not particularly limited. As an example, the support can be dried by heating the support at a temperature of 50°C to 100°C under a reduced pressure or a vacuum atmosphere.

[0075] In the manufacturing method of this embodiment, the reaction of the compound group is allowed to proceed while the compound group is in contact with the support, thereby forming a polymer P supported on the surface of the support.

[0076] (Characteristics of Acidic Gas Adsorbent) As described above, in the acidic gas adsorbent of this embodiment, the polymer P tends not to fall off from the support when it comes into contact with water. For example, when the acidic gas adsorbent is immersed in water at 25°C for 15 hours, it is preferable that the residual rate of the polymer P is 50% or more.

[0077] In another aspect, the present invention provides an acidic gas adsorbent comprising a polymer P and a support that supports the polymer P, wherein the polymer P has a structural unit U1 derived from an epoxy compound and a structural unit U2 derived from an amine compound, and when the acidic gas adsorbent is immersed in water at 25°C for 15 hours, the residual rate of the polymer P is 50% or more.

[0078] Specifically, the residual rate of polymer P can be determined by the following method. First, the acidic gas adsorbent is immersed in distilled water at 25°C in a dry room with a dew point of approximately -60°C. The acidic gas adsorbent is left to stand in this state for 15 hours. Next, the acidic gas adsorbent is filtered and dried in a dryer at 80°C for 2 hours. The polymer P content R2 in the dried acidic gas adsorbent is measured using the method described above for the content R1. The ratio (100 x R2 / R1) of the polymer P content R2 (wt%) in the acidic gas adsorbent after immersion in water to the polymer P content R1 (wt%) in the acidic gas adsorbent before immersion in water can be considered to be the residual rate of polymer P.

[0079] As described above, the residual rate of polymer P is preferably 50% or more, and may be 60% or more, 70% or more, 80% or more, 90% or more, 95% or more, or even 99% or more.

[0080] Furthermore, the acidic gas adsorbent of this embodiment tends to have high adsorption properties for acidic gases such as carbon dioxide. As an example, when the following adsorption test is performed for 15 hours, the acidic gas adsorbent preferably has an adsorption amount of carbon dioxide of 0.1 mmol / g or more. Adsorption test: A mixed gas G composed of carbon dioxide, nitrogen, and water vapor is continuously fed into a container containing the acidic gas adsorbent. Here, the carbon dioxide concentration in the mixed gas G is 400 vol ppm, and the mixed gas G is at a temperature of 20°C and a humidity of 50% RH.

[0081] The adsorption test will be described in detail below. The adsorption test can be performed using a measurement device 20 shown in FIG. 1. The measurement device 20 includes a first tank 30 and a second tank 31. As an example, the first tank 30 stores dry nitrogen, and the second tank 31 stores a mixed gas of dry nitrogen and dry carbon dioxide. The concentration of carbon dioxide in the mixed gas in the second tank 31 is, for example, 5 vol %.

[0082] The measuring device 20 further includes a first container 40 containing water 70, and a first path 60 for sending nitrogen from the first tank 30 to the first container 40. The first path 60 has one end connected to the gas outlet of the first tank 30 and the other end located in the water 70 of the first container 40. The nitrogen sent from the first tank 30 to the first container 40 is humidified by contact with the water 70. A mass flow controller 35 is arranged in the first path 60 to adjust the flow rate of nitrogen sent from the first tank 30 to the first container 40.

[0083] The measuring device 20 further includes a second container 41, a second path 62, and a bypass path 61. The second path 62 connects the first container 40 and the second container 41. The humidified nitrogen sent to the first container 40 is sent to the second container 41 through the second path 62. The bypass path 61 branches off from the first path 60 at a position between the first tank 30 and the mass flow controller 35 and connects to the second path 62. A portion of the nitrogen sent from the first tank 30 flows into the bypass path 61 and is sent to the second container 41 through the second path 62. A mass flow controller 36 is disposed in the bypass path 61 to adjust the flow rate of nitrogen sent from the first tank 30 to the bypass path 61.

[0084] The measuring device 20 further includes a third path 63 for sending the mixed gas from the second tank 31 to the second path 62. The third path 63 has one end connected to the gas outlet of the second tank 31 and the other end connected to the second path 62. A mass flow controller 37 is disposed in the third path 63 for adjusting the flow rate of the mixed gas sent from the second tank 31 to the second path 62. The mixed gas sent to the second path 62 is sent to the second container 41 through the second path 62.

[0085] The measurement device 20 further includes a third container 42 and a fourth path 64. The third container 42 contains water 71 and an adsorption unit 21 disposed in the water 71. In the third container 42, the temperature of the water 71 is maintained at 20°C. The adsorption unit 21 has a gas inlet 22 and a gas outlet 23. The adsorption unit 21 functions as a container that contains an acidic gas adsorbent therein. The adsorption unit 21 is configured to prevent the water 71 from penetrating into the interior. The adsorption unit 21 is typically a tube made of a hydrophobic resin, for example, a fluororesin such as tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA). As an example, the tube serving as the adsorption unit 21 has an inner diameter of 4 mm and an outer diameter of 6 mm. The adsorption unit 21 is configured to be detachable from the measurement device 20.

[0086] The measuring device 20 can also be used as an acidic gas adsorption device equipped with an adsorption unit 21. In another aspect, the present invention provides an acidic gas adsorption device 20 equipped with an adsorption unit 21 having a gas inlet 22 and a gas outlet 23, the adsorption unit 21 accommodating an acidic gas adsorbent.

[0087] The fourth path 64 connects the second container 41 and the third container 42. Specifically, the fourth path 64 is connected to the gas inlet 22 of the adsorption unit 21 in the third container 42. A first concentration meter 50 is disposed in the fourth path 64 to measure the concentration of carbon dioxide in the gas supplied to the adsorption unit 21. A CO2 / H2O gas analyzer LI-850-3 manufactured by LI-COR Corporation can be used as the first concentration meter 50.

[0088] The measurement device 20 further includes a fifth path 65 connected to the gas outlet 23 of the adsorption unit 21 for discharging gas from the adsorption unit 21 to the outside of the measurement device 20. A back pressure valve 55 and a second concentration meter 51 are disposed in the fifth path 65. The back pressure valve 55 allows the pressure inside the adsorption unit 21 to be adjusted to a constant value. The second concentration meter 51 can measure the concentration of carbon dioxide in the gas discharged from the adsorption unit 21. A CO2 / H2O gas analyzer LI-850-3 manufactured by LI-COR Corporation can be used as the second concentration meter 51.

[0089] Each path of the measuring device 20 is preferably made of metal or resin piping.

[0090] [Pretreatment] First, an acidic gas adsorbent is prepared and dried. The drying is preferably performed by treating the acidic gas adsorbent for at least two hours under conditions of 60°C in a vacuum atmosphere. Next, the dried acidic gas adsorbent is packed into the adsorption unit 21 in a dry room with a dew point of approximately -60°C. The weight of the acidic gas adsorbent packed into the adsorption unit 21 is, for example, 50 mg. Next, the fourth path 64 and the fifth path 65 are connected to both ends of the adsorption unit 21, and the adsorption unit 21 is immersed in water 71 in the third container 42.

[0091] Next, nitrogen from the first tank 30 and the mixed gas from the second tank 31 are supplied to the second container 41 via the first path 60, the second path 62, the bypass path 61, and the third path 63 of the measurement device 20. These gases are mixed in the second container 41 to obtain a mixed gas G composed of carbon dioxide, nitrogen, and water vapor. In the second container 41, the carbon dioxide concentration in the mixed gas G is adjusted to 400 vol ppm. The mixed gas G has a temperature of 20°C and a humidity of 50% RH. The mixed gas G is supplied to the adsorption unit 21 via the fourth path 64 at a flow rate sufficient for the weight of the acidic gas adsorbent, for example, a flow rate of 300 mL / min for 50 mg of acidic gas adsorbent. In the adsorption unit 21, the pressure of the mixed gas G is adjusted to, for example, 107 kPa by the back pressure valve 55.

[0092] Next, while the mixed gas G is being supplied to the adsorption unit 21, the adsorption unit 21 is removed from the third container 42 and immersed in a water bath (not shown) at 80°C for two hours or more. The adsorption unit 21 is immersed in the water bath until the carbon dioxide concentration measured by the first concentration meter 50 and the carbon dioxide concentration measured by the second concentration meter 51 become substantially the same value. This completes the pretreatment of the acidic gas adsorbent in the adsorption unit 21.

[0093] [Adsorption Test] Next, while the mixed gas G is being supplied to the adsorption unit 21, the adsorption unit 21 is removed from the hot water bath and immersed in the water 71 in the third container 42. This starts a carbon dioxide adsorption test for the acidic gas adsorbent in the adsorption unit 21. The adsorption test is carried out for 15 hours after the start. Specifically, the mixed gas G is continuously supplied to the adsorption unit 21 for 15 hours. When the adsorption test is carried out for 15 hours, it can usually be considered that the adsorption of carbon dioxide by the acidic gas adsorbent has reached equilibrium.

[0094] In the adsorption test, the amount of carbon dioxide adsorbed by the acid gas adsorbent from the start to 15 hours is measured as M1. The amount of carbon dioxide adsorbed by the acid gas adsorbent can be calculated from the results of measuring the difference over time between the carbon dioxide concentration measured by the first concentration meter 50 and the carbon dioxide concentration measured by the second concentration meter 51. The amount of carbon dioxide adsorbed by 1 g of the acid gas adsorbent in 15 hours is calculated based on the amount of carbon dioxide M1, and the calculated value is specified as the adsorption amount of carbon dioxide.

[0095] In the acidic gas adsorbent of this embodiment, the amount of carbon dioxide adsorbed when an adsorption test is carried out for 15 hours is preferably 0.2 mmol / g or more, and may be 0.3 mmol / g or more, 0.4 mmol / g or more, 0.5 mmol / g or more, or even 0.6 mmol / g or more. The upper limit of the amount of carbon dioxide adsorption is not particularly limited, and is, for example, 10 mmol / g or less.

[0096] (Uses of Acidic Gas Adsorbent) The acidic gas adsorbent of the present embodiment can adsorb acidic gases. Examples of acidic gases include carbon dioxide, hydrogen sulfide, carbonyl sulfide, sulfur oxides (SOx), hydrogen cyanide, and nitrogen oxides (NOx), and carbon dioxide is preferred.

[0097] The acidic gas adsorbent can be used by the following method. First, a mixed gas containing an acidic gas is contacted with the acidic gas adsorbent. The mixed gas preferably contains other gases in addition to the acidic gas. Examples of other gases include non-polar gases such as hydrogen and nitrogen, and inert gases such as helium, with nitrogen being preferred. The mixed gas is typically atmospheric air. The mixed gas may also be off-gas from a chemical plant or thermal power plant.

[0098] The temperature of the mixed gas is, for example, room temperature (20°C). The concentration of the acidic gas in the mixed gas is not particularly limited and, under standard conditions (0°C, 101 kPa), is, for example, 0.01 vol% (100 volppm) or more, preferably 0.04 vol% (400 volppm) or more, and may be 1.0 vol% or more. The upper limit of the carbon dioxide concentration in the mixed gas is not particularly limited and, under standard conditions, is, for example, 10 vol% or less. The pressure of the mixed gas is typically equal to atmospheric pressure in the environment in which the acidic gas adsorbent is used. However, the mixed gas to be contacted with the acidic gas adsorbent may be pressurized.

[0099] The acidic gas adsorbent that has come into contact with the mixed gas adsorbs the acidic gas contained in the mixed gas. The operation of bringing the mixed gas into contact with the acidic gas adsorbent is preferably carried out until the adsorption of the acidic gas by the acidic gas adsorbent reaches equilibrium.

[0100] Next, the acidic gas adsorbent that has adsorbed the acidic gas is regenerated. As an example, the regeneration can be performed by contacting the acidic gas adsorbent with water vapor. The temperature of the water vapor may be, for example, greater than 35°C, 50°C or higher, 60°C or higher, 70°C or higher, or even 80°C or higher. The upper limit of the water vapor temperature is, for example, 150°C or lower, or even 100°C or lower. By contacting the water vapor with the acidic gas adsorbent, the acidic gas is desorbed from the acidic gas adsorbent. This regenerates the acidic gas adsorbent, allowing it to be reused. The acidic gases, particularly carbon dioxide, desorbed from the acidic gas adsorbent can be used as raw materials for chemical synthesis or as dry ice. The adsorption of acidic gases by the acidic gas adsorbent and the regeneration of the acidic gas adsorbent can be performed using the measuring device 20 (acidic gas adsorption device) described above.

[0101] 2A , the structure 15 of this embodiment includes the above-described acidic gas adsorbent (specifically, the sheet 10 including the acidic gas adsorbent) and ventilation paths 14. The structure 15 is typically a honeycomb structure having a plurality of ventilation paths 14 extending in the same direction. The sheet 10 is, for example, a sheet-like support on which the acidic gas adsorbent is attached. The sheet-like support may be a fibrous structure such as glass paper.

[0102] The structure 15 preferably includes an adsorbent unit U in which a corrugated sheet 10A and a flat sheet 10B are stacked. In the sheet 10A, a plurality of peaks 12 and a plurality of valleys 13 are alternately arranged. An air passage 14 is formed between the peaks 12 or valleys 13 of the sheet 10A and the sheet 10B. In this embodiment, the direction x is the direction in which the plurality of peaks 12 and the plurality of valleys 13 of the sheet 10A are alternately arranged (wave direction). The direction y is the stacking direction of the sheets 10A and 10B in the adsorbent unit U. The direction z is perpendicular to the directions x and y, and is the direction in which the air passage 14 extends.

[0103] The structure 15 preferably includes a plurality of adsorbent units U. The number of adsorbent units U in the structure 15 is not particularly limited and may be, for example, 2 to 100. In the structure 15, the plurality of adsorbent units U are stacked in the direction y such that the plurality of sheets 10A and the plurality of sheets 10B are arranged alternately. By stacking the plurality of adsorbent units U, the structure 15 has a block shape.

[0104] The ventilation paths 14 are through-holes that penetrate the structure 15 in the direction z. The ventilation paths 14 are surrounded by the sheets 10A and 10B. In the structure 15, acidic gases move in the direction z through the ventilation paths 14 and are efficiently adsorbed by the sheets 10A and 10B.

[0105] In the structure 15, the smaller the thickness of the sheets 10A and 10B, the larger the cross-sectional area of ​​the ventilation path 14 can be adjusted. A structure 15 with a large cross-sectional area of ​​the ventilation path 14 is suitable for reducing pressure loss that occurs when the structure 15 comes into contact with acidic gases. A structure 15 with reduced pressure loss can reduce the power of a fan used to move acidic gases. Note that if the amount of amino group substance per unit volume of the sheet 10 is large, the sheet 10 tends to be able to sufficiently adsorb acidic gases even when the thickness of the sheet 10 is small.

[0106] <Modified Structure> The shape of structure 15 including sheet 10 is not limited to that shown in Fig. 2A. Structure 16 shown in Fig. 2B has a shape in which one adsorbent unit U is wound around central tube 80. Except for this, the configuration of structure 16 is the same as the configuration of structure 15.

[0107] The structure 16 has a cylindrical shape. In the structure 16, the plurality of peaks 12 and the plurality of valleys 13 of the sheet 10A are alternately arranged in the circumferential direction of the structure 16. The ventilation paths 14 formed between the peaks 12 or valleys 13 of the sheet 10A and the sheet 10B penetrate the structure 16 in the extension direction of the central tube 80. In the structure 16, acidic gases move through the ventilation paths 14 in the extension direction of the central tube 80 and are efficiently adsorbed by the sheets 10A and 10B.

[0108] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited thereto.

[0109] Example 1 First, 3.00 g of gel-type silica (CARiACT Q30 manufactured by Fuji Silysia Chemical Ltd.) was prepared as a support. This support was a particulate porous body with an average pore diameter of 30 nm and a pore volume of 1.28 cm 3 / g, and the specific surface area is 99 m 2 / g. Next, this support was immersed overnight in 90 g of methanol (special grade, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) to prepare a dispersion. Next, 0.75 g of polyethyleneimine (Epomin SP-012, molecular weight 1200, manufactured by Nippon Shokubai Co., Ltd.) as an amine compound and 0.56 g of ethylene glycol diglycidyl ether (EDE, EX-810, manufactured by Nagase ChemteX Corporation) as an epoxy compound were added to the above dispersion. As a result, the compounds penetrated into the pores of the support and came into contact with the surfaces of the pores of the support. Next, using a rotary evaporator, the dispersion was heated at a temperature of 60°C under a reduced pressure atmosphere. As a result, the reaction of the compounds progressed and the solvent contained in the dispersion was distilled off.

[0110] Next, the support was dried by heating it at a temperature of 80° C. under a vacuum atmosphere, thereby obtaining an acidic gas adsorbent of Example 1 comprising the polymer P and the support carrying the polymer P.

[0111] (Example 2) An acidic gas adsorbent of Example 2 was obtained in the same manner as in Example 1, except that precipitated silica (SIPERNAT 50S manufactured by Evonik) was used as the support and 1.72 g of polyethyleneimine and 1.28 g of ethylene glycol diglycidyl ether were added to the dispersion. The support of Example 2 was a particulate porous body having a specific surface area of ​​309 m. 2 / g.

[0112] (Example 3) An acidic gas adsorbent of Example 3 was obtained in the same manner as in Example 1, except that gel-type silica (CARPLEX BS-303 manufactured by Evonik Corporation) was used as the support. The support of Example 3 was a particulate porous body having a specific surface area of ​​565 m 2 / g.

[0113] Comparative Example 1 An acidic gas adsorbent of Comparative Example 1 was obtained in the same manner as in Example 1, except that no epoxy compound was added to the dispersion.

[0114] (Comparative Example 2) An acidic gas adsorbent of Comparative Example 2 was obtained in the same manner as in Example 1, except that 1.43 g of triethylenetetramine (TETA, manufactured by Sigma-Aldrich, molecular weight 146) as the amine compound and 1.07 g of ethylene glycol diglycidyl ether as the epoxy compound were added to the dispersion.

[0115] [Evaluation] (Polymer Content) The polymer content R1 of the prepared acidic gas adsorbent was measured by the method described above. Note that the simultaneous thermal analysis DSC / TGA device used was SDT6500 manufactured by TA Instruments.

[0116] (Polymer Residual Rate) The polymer residual rate of the prepared acidic gas adsorbent was measured by the following method. First, in a dry room with a dew point of approximately -60°C, approximately 0.2 g of the acidic gas adsorbent was placed in a 100 mL sealed plastic bottle. Approximately 19.8 g of distilled water at 25°C was added to the plastic bottle, and the acidic gas adsorbent was left to stand for 15 hours while immersed in water. Next, the acidic gas adsorbent was filtered using pleated filter paper and dried in a dryer at 80°C for 2 hours. The polymer content R2 in the dried acidic gas adsorbent was measured using the method described above for the content R1. The ratio (100 × R2 / R1) of the content R2 (wt%) to the content R1 (wt%) was considered to be the polymer residual rate.

[0117] (Amount of Carbon Dioxide Adsorbed) The amount of carbon dioxide adsorbed by the prepared acidic gas adsorbent was measured after an adsorption test was carried out for 15 hours by the method described above.

[0118]

[0119] The abbreviations in Table 1 are as follows: CARiACT Q30: Gel-type silica (CARiACT Q30 manufactured by Fuji Silysia Chemical Ltd.) SIPERNAT 50S: Precipitated silica (SIPERNAT 50S manufactured by Evonik Corporation) CARPLEX BS-303: Gel-type silica (CARPLEX BS-303 manufactured by Evonik Corporation) PEI: Polyethyleneimine (Epomin SP-012 manufactured by Nippon Shokubai Co., Ltd., molecular weight 1200, with tertiary amino group) TETA: Triethylenetetramine (TETA, manufactured by Sigma-Aldrich Co., molecular weight 146) EDE: Ethylene glycol diglycidyl ether (EDE, manufactured by Nagase ChemteX Corporation, EX-810)

[0120] As can be seen from Table 1, the acidic gas adsorbents of the Examples, in which a polymer having a structural unit derived from an epoxy compound and a structural unit derived from an amine compound having a molecular weight of 300 or more was supported on a support, had a higher polymer residual rate when immersed in water at 25° C. for 15 hours than the Comparative Examples. From this result, it can be inferred that the acidic gas adsorbents of the Examples have high durability against regeneration treatment using water vapor.

[0121] The acidic gas adsorbent of this embodiment can adsorb carbon dioxide in the atmosphere.

Claims

1. An acidic gas adsorbent comprising a polymer and a support that supports the polymer, wherein the polymer has structural units derived from an epoxy compound and structural units derived from an amine compound, and the molecular weight of the amine compound is 300 or more.

2. An acidic gas adsorbent comprising a polymer and a support that supports the polymer, wherein the polymer has a structural unit derived from an epoxy compound and a structural unit derived from an amine compound, and when the acidic gas adsorbent is immersed in water at 25°C for 15 hours, the residual rate of the polymer is 50% or more.

3. The acid gas adsorbent according to claim 1 or 2, wherein the support has a particulate shape.

4. The acidic gas adsorbent according to claim 1 or 2, wherein the support has a porous structure.

5. The acidic gas adsorbent according to claim 4, wherein the average pore size of the support is 50 nm or less.

6. The acid gas adsorbent according to claim 1 or 2, wherein the support comprises silica.

7. The acidic gas adsorbent according to claim 1 or 2, wherein the epoxy compound has two or more epoxy groups.

8. The acidic gas adsorbent according to claim 1 or 2, wherein the amine compound has at least one selected from the group consisting of a primary amino group and a secondary amino group, and a tertiary amino group.

9. The acid gas adsorbent according to claim 1 or 2, wherein the amine compound comprises polyethyleneimine.

10. The acidic gas adsorbent according to claim 1 or 2, wherein the glass transition temperature of the polymer is 40°C or lower.

11. The acidic gas adsorbent according to claim 1 or 2, wherein the polymer content is 25 wt % or more.

12. A structure comprising the acid gas adsorbent according to claim 1 or 2 and a ventilation path.

13. An acid gas adsorption device comprising an adsorption section having a gas inlet and a gas outlet, the adsorption section containing the acid gas adsorbent according to claim 1 or 2.

14. A method for producing an acidic gas adsorbent, comprising contacting a group of compounds including an epoxy compound and an amine compound with a support and reacting the group of compounds to form a polymer supported on the support, wherein the molecular weight of the amine compound is 300 or more.

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