Acidic gas adsorbent, structure equipped with the acidic gas adsorbent, acidic gas adsorption device, acidic gas recovery device, method for manufacturing the acidic gas adsorbent, and sheet-like structure

Abstract

The present invention provides a novel acidic gas adsorbent which is suitable for adsorption of an acidic gas. An acidic gas adsorbent 10 according to the present invention is provided with a porous sheet 1 that contains a polymer P. The polymer P has an amino group. The porous sheet 1 has a three-dimensional network skeleton that is configured from the polymer P. A structure 15 according to the present invention is provided with the acidic gas adsorbent 10 and a ventilation path 14. An acidic gas adsorption device 200 according to the present invention is provided with an adsorption unit 221 which has a gas inlet 222 and a gas outlet 223. The acidic gas adsorbent 10 is contained in the adsorption unit 221.

Description

Technical Field

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

Background Art

[0002] In recent years, in order to reduce the amount of carbon dioxide in the atmosphere, carbon dioxide capture and storage (CCS) and carbon dioxide capture and utilization (CCU) have been studied. In CCS and CCU, carbon dioxide may be recovered by separating carbon dioxide 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 for separation. The adsorbent used in the adsorption method can adsorb acidic gases, for example, by contacting the atmosphere.

[0004] For example, Patent Document 1 discloses an adsorbent in which a substrate is coated with an amine compound. Specifically, in Patent Document 1, porous particles of alumina are supported on the substrate, and the pores of the porous particles are filled with an amine compound.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] There is a demand for a new acidic gas adsorbent suitable for the adsorption of acidic gases.

Means for Solving the Problems

[0007] The present invention comprises a porous sheet containing a polymer, wherein the polymer has an amino group, and provides an acidic gas adsorbent in which the porous sheet has a three-dimensional network skeleton composed of the polymer.

[0008] Furthermore, the present invention provides a structure comprising the above acidic gas adsorbent and a ventilation path.

[0009] Furthermore, the present invention provides an acidic gas adsorption device comprising an adsorption part having a gas inlet and a gas outlet, wherein the adsorption part houses the above acidic gas adsorbent.

[0010] Furthermore, the present invention provides an acidic gas recovery device comprising the above acidic gas adsorbent and a medium path, wherein a heat medium for heating the acidic gas adsorbent passes through the medium path during a desorption operation for desorbing the acidic gas adsorbed by the acidic gas adsorbent from the acidic gas adsorbent.

[0011] Furthermore, the present invention provides a method for manufacturing an acidic gas adsorbent comprising a porous sheet, the method comprising: step (I) of curing a liquid mixture containing a group of compounds containing an amine monomer and a porogen to obtain a cured body; and step (II) of removing the porogen from the sheet-like cured body to obtain the porous sheet.

[0012] Furthermore, the present invention provides a structure comprising a porous sheet containing a polymer and a support for supporting the porous sheet. The polymer has an amino group, The porous sheet provides a sheet-like structure having a three-dimensional network skeleton composed of the polymer.

Advantages of the Invention

[0013] According to the present invention, a new acid gas adsorbent suitable for adsorbing acid gases can be provided.

Brief Description of the Drawings

[0014]

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Mode for Carrying Out the Invention

[0015] The acid gas adsorbent according to the first aspect of the present invention includes a porous sheet containing a polymer, the polymer has an amino group, the porous sheet has a three-dimensional network skeleton composed of the polymer.

[0016] In the second aspect of the present invention, for example, in the acid gas adsorbent according to the first aspect, the porous sheet includes continuous pores formed continuously in three dimensions.

[0017] In the third aspect of the present invention, for example, in the acid gas adsorbent according to the first or second aspect, the porous sheet contains the polymer as a main component.

[0018] In the fourth aspect of the present invention, for example, in the acid gas adsorbent according to any one of the first to third aspects, the amino group includes a secondary amino group.

[0019] In the fifth aspect of the present invention, for example, in the acid gas adsorbent according to any one of the first to fourth aspects, the polymer is an epoxy polymer containing a structural unit derived from an amine monomer.

[0020] In the sixth aspect of the present invention, for example, in the acid gas adsorbent according to any one of the first to fifth aspects, the glass transition temperature of the polymer is 40 °C or lower.

[0021] In the seventh aspect of the present invention, for example, in the acid gas adsorbent according to any one of the first to sixth aspects, the specific surface area of the porous sheet is 1.0 m 2 / g or more.

[0022] In the eighth aspect of the present invention, for example, in the acid gas adsorbent according to any one of the first to seventh aspects, the porosity of the porous sheet is 20% or more.

[0023] In the ninth aspect of the present invention, for example, the acid gas adsorbent according to any one of the first to eighth aspects further includes a support for supporting the porous sheet.

[0024] In the tenth aspect of the present invention, for example, the acid gas adsorbent according to any one of the first to ninth aspects has an adsorption amount of carbon dioxide of 0.1 mmol / cm when contacted with a mixed gas composed of carbon dioxide, nitrogen, and water vapor for 15 hours. 3 or more. Here, the concentration of carbon dioxide in the mixed gas is 400 volppm, and the mixed gas has a temperature of 20°C and a humidity of 50%RH.

[0025] In the eleventh aspect of the present invention, for example, the acid gas adsorbent according to any one of the first to tenth aspects has a flat plate shape or a corrugated shape.

[0026] The structure according to the twelfth aspect of the present invention includes an acid gas adsorbent according to any one of the first to eleventh aspects, a ventilation path, and.

[0027] The acid gas adsorption device according to the thirteenth aspect of the present invention includes an adsorption part having a gas inlet and a gas outlet, and the adsorption part houses an acid gas adsorbent according to any one of the first to eleventh aspects.

[0028] The acid gas recovery device according to the fourteenth aspect of the present invention includes an acid gas adsorbent according to any one of the first to eleventh aspects, a medium path, and. During the desorption operation of desorbing the acidic gas adsorbed by the acidic gas adsorbent from the acidic gas adsorbent, a heat medium for heating the acidic gas adsorbent passes through the medium path.

[0029] In the 15th aspect of the present invention, for example, in the acidic gas recovery device according to the 14th aspect, the medium path penetrates the acidic gas adsorbent in the thickness direction of the acidic gas adsorbent.

[0030] In the 16th aspect of the present invention, for example, the acidic gas recovery device according to the 14th aspect includes two of the acidic gas adsorbents, and the medium path is formed between the two acidic gas adsorbents.

[0031] In the 17th aspect of the present invention, for example, in the acidic gas recovery device according to any one of the 14th to 16th aspects, after the desorption operation, a cooling medium for cooling the acidic gas adsorbent passes through the medium path.

[0032] The method for producing an acidic gas adsorbent according to the 18th aspect of the present invention is A method for producing an acidic gas adsorbent provided with a porous sheet, comprising: Step (I) of curing a mixed solution containing a compound group containing an amine monomer and a porogen to obtain a cured body; Step (II) of removing the porogen from the sheet-shaped cured body to obtain the porous sheet; and includes.

[0033] In the 19th aspect of the present invention, for example, in the step (I) in the production method according to the 18th aspect, the mixed solution is applied onto a support, and the obtained coating film is cured to obtain the sheet-shaped cured body.

[0034] The sheet-like structure according to the 20th aspect of the present invention is a porous sheet containing a polymer; a support for supporting the porous sheet; and includes. The polymer has an amino group. The porous sheet has a three-dimensional network skeleton composed of the polymer.

[0035] The acidic gas adsorbent according to the 21st aspect of the present invention comprises a porous resin sheet containing a polymer, and the polymer has an amino group.

[0036] The sheet-like structure according to the 22nd aspect of the present invention comprises a porous resin sheet containing a polymer and a support for supporting the porous resin sheet, and the polymer has an amino group.

[0037] Hereinafter, the details of the present invention will be described, but the following description is not intended to limit the present invention to specific embodiments.

[0038] <Embodiment of Acidic Gas Adsorbent> As shown in FIG. 1, the acidic gas adsorbent 10 of the present embodiment includes a porous sheet 1 containing a polymer P, and further includes, for example, a support 2. The porous sheet 1 is a porous resin sheet containing the polymer P. The polymer P has an amino group and has a function of adsorbing acidic gas due to the amino group.

[0039] The porous sheet 1 has a three-dimensional network skeleton composed of the polymer P. Specifically, the porous sheet 1 has a porous structure, and the porous structure includes pores derived from the three-dimensional network skeleton. The pores derived from the three-dimensional network skeleton have an observable size when observed at a magnification of 5000 times using, for example, a scanning electron microscope (SEM). The diameter (average pore diameter) of these pores is preferably 0.1 μm or more and 5 μm or less, and more preferably 3 μm or less. When the pore diameter is 0.1 μm or more, the gas diffusibility in the porous sheet 1 can be sufficiently ensured. When the pore diameter is 5 μm or less, even with a medium porosity, the three-dimensional network skeleton in the porous sheet 1 does not become too thick, and it is easy to suppress a decrease in the diffusion rate of acidic gas into the polymer P.

[0040] From another aspect of the present invention, a porous sheet 1 having a porous structure including pores derived from a three-dimensional network skeleton is provided, wherein the three-dimensional network skeleton includes a polymer P having an amino group, to provide an acidic gas adsorbent 10.

[0041] The support 2 supports the porous sheet 1 and is in direct contact with the porous sheet 1. The acidic gas adsorbent 10 provided with the support 2 is suitable for use as a component of an acidic gas recovery device described later. The acidic gas adsorbent 10 may or may not further include fixing means for fixing the porous sheet 1 and the support 2. Specific examples of the fixing means include an adhesive, specifically, an adhesive sheet containing an adhesive. In the present specification, the term "adhesive" is used as a term including a pressure-sensitive adhesive.

[0042] Note that the acidic gas adsorbent 10 may not include the support 2 and may be composed of only the porous sheet 1. That is, the acidic gas adsorbent 10 may be a self-supporting film (single-layer film) of the porous sheet 1.

[0043] The acidic gas adsorbent 10 is typically a sheet-like structure. The acidic gas adsorbent 10 as the sheet-like structure has, for example, a flat plate shape or a corrugated shape.

[0044] From another aspect of the present invention, a porous sheet 1 containing a polymer P, a support 2 for supporting the porous sheet 1, are provided, wherein the polymer P has an amino group, and the porous sheet 1 has a three-dimensional network skeleton composed of the polymer P, to provide a sheet-like structure.

[0045] Furthermore, from another aspect of the present invention, a porous sheet 1 having a porous structure including pores derived from a three-dimensional network skeleton, A support 2 that supports the porous sheet 1, is provided, The above three-dimensional network skeleton includes a polymer P having an amino group, and provides a sheet-like structure.

[0046] (porous sheet) In the porous sheet 1, the polymer P contains, for example, at least one selected from the group consisting of a primary amino group, a secondary amino group, and a tertiary amino group as an amino group. From the viewpoint of the adsorbability of acidic gas, the polymer P preferably contains at least one selected from the group consisting of a primary amino group and a secondary amino group, and particularly preferably contains a secondary amino group. In other words, the amino group possessed by the polymer P preferably contains a secondary amino group. According to the polymer P having a secondary amino group, there is also a tendency that the adsorbed acidic gas can be easily desorbed. That is, according to the polymer P having a secondary amino group, the regeneration treatment of the acidic gas adsorbent 10 can be performed under relatively mild conditions. Note that the polymer P may contain a tertiary amino group, or may not contain a tertiary amino group.

[0047] The weight ratio of the nitrogen element in the polymer P is, for example, 5 wt% or more, preferably 10 wt% or more. The higher this weight ratio, the more the adsorbability of the acidic gas in the acidic gas adsorbent 10 tends to improve. The upper limit value of the weight ratio of the nitrogen element in the polymer P is not particularly limited, and is, for example, 30 wt%. When all the nitrogen elements contained in the polymer P are derived from amino groups, the above weight ratio of the nitrogen element can be regarded as the weight ratio of the amino group in the polymer P.

[0048] The density of the amino group in the polymer P is, for example, 1 mmol / g or more, preferably 5 mmol / g or more, and more preferably 10 mmol / g or more. The upper limit value of the density of the amino group is not particularly limited, and is, for example, 30 mmol / g. In this specification, the density of the amino group in the polymer P means the amount of substance of the amino group contained in 1 g of the polymer P.

[0049] Polymer P may contain other functional groups in addition to amino groups. Examples of other functional groups include, for example, hydroxyl groups, ether groups, ester groups, amide groups, and the like.

[0050] Polymer P is, for example, an epoxy polymer containing a structural unit U1 derived from an amine monomer. This epoxy polymer is, for example, at least one selected from the group consisting of a polymer P1 of a monomer group containing an amine monomer and an epoxy monomer, and a reactant P2 of a compound group containing an amine monomer and an epoxy prepolymer, and is preferably polymer P1. A specific example of reactant P2 is a crosslinked product obtained by crosslinking an epoxy prepolymer with an amine monomer (crosslinked product).

[0051] The monomer group for forming polymer P1 contains an amine monomer and an epoxy monomer as described above, and is preferably composed only of these monomers. That is, polymer P1 is preferably a polymer of an amine monomer and an epoxy monomer.

[0052] An amine monomer is a monomer containing at least one amino group, and for example, contains at least one primary amino group. The number of primary amino groups contained in the amine monomer is preferably 2 or more, may be 3 or more, and may be 4 or more. The upper limit value of the number of primary amino groups is not particularly limited, and is, for example, 30, and may be 10. In addition to the primary amino group, the amine monomer may contain a secondary amino group or a tertiary amino group, but may not contain a tertiary amino group. The molecular weight of the amine monomer is not particularly limited, and is, for example, less than 5000, preferably 3000 or less, may be 1000 or less, and may be 500 or less.

[0053] Examples of amine monomers include aliphatic amines such as ethylamine, ethylenediamine, 1,4 - butylenediamine, 1,5 - pentanediamine, 1,6 - hexanediamine, 1,7 - heptanediamine, 1,8 - octanediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, iminobispropylamine, bis(hexamethylene)triamine, 1,3,6 - trisaminomethylhexane, tris(2 - aminoethyl)amine, N,N’ - bis(3 - aminopropyl)ethylenediamine, polymethylenediamine, trimethylhexamethylenediamine, polyether diamine, polyethyleneimine; alicyclic amines such as isophoronediamine, menthanediamine, piperazine, N - aminoethylpiperazine, 3,9 - bis(3 - aminopropyl)2,4,8,10 - tetraoxaspiro(5,5)undecane adduct, bis(4 - amino - 3 - methylcyclohexyl)methane, bis(4 - aminocyclohexyl)methane, and modified products thereof. The amine monomer may, in some cases, be an aliphatic polyamideamine containing polyamines and dimer acid. The amine monomer is preferably an aliphatic amine, particularly triethylenetetramine (TETA). The amine monomer can be used alone or in combination of two or more.

[0054] The epoxy monomer is a monomer containing at least one epoxy group. The number of epoxy groups contained in the epoxy monomer is preferably 2 or more, and may be 3 or more, or 4 or more. The upper limit of the number of epoxy groups contained in the epoxy monomer is not particularly limited, for example, it is 10. The molecular weight of the epoxy monomer is not particularly limited, for example, it is less than 1000, and preferably 500 or less.

[0055] Examples of epoxy monomers 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, t-butylphenyl glycidyl ether; diepoxyalkanes such as 1,5-hexadiene diepoxide, 1,7-octadiene diepoxide, 1,9-decadiene diepoxide; ether group-containing polyfunctional epoxy compounds such as (poly)ethylene glycol diglycidyl ether, (poly)propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane polyglycidyl ether, pentaerythritol polyglycidyl ether; amino group-containing polyfunctional epoxy compounds such as N,N,N’,N’-tetraglycidyl metaxylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane. The epoxy monomer is preferably an ether group-containing polyfunctional epoxy compound such as ethylene glycol diglycidyl ether (EDE), pentaerythritol tetraglycidyl ether (PETG). The epoxy monomer can be used alone or in combination of two or more. When using a monofunctional epoxy compound, it is preferably used in combination with another epoxy monomer containing two or more epoxy groups. The monofunctional epoxy compound can also be used as a reactive diluent for adjusting the viscosity of the monomer group for forming the polymer P1.

[0056] Examples of amine monomers for forming the reactant P2 include those described above for the polymer P1.

[0057] The epoxy prepolymer contains, for example, at least one epoxy group. The number of epoxy groups contained in the epoxy prepolymer is preferably 2 or more, may be 3 or more, and may be 4 or more. The upper limit value of the number of epoxy groups contained in the epoxy prepolymer is not particularly limited, and is, for example, 100. The weight average molecular weight of the epoxy prepolymer is not particularly limited, and is, for example, 1000 to 50000.

[0058] Examples of the epoxy prepolymer include aromatic epoxy resins and non-aromatic epoxy resins. Examples of the aromatic epoxy resin include polyphenyl-based epoxy resins, epoxy resins containing a fluorene ring, epoxy resins containing triglycidyl isocyanurate, epoxy resins containing a heteroaromatic ring (for example, a triazine ring), and the like. Examples of the polyphenyl-based epoxy resin include bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, stilbene type epoxy resin, biphenyl type epoxy resin, bisphenol A novolak type epoxy resin, cresol novolak type epoxy resin, diaminodiphenylmethane type epoxy resin, tetrakis(hydroxyphenyl)ethane-based epoxy resin, and the like. Examples of the non-aromatic epoxy resin include aliphatic glycidyl ether type epoxy resin, aliphatic glycidyl ester type epoxy resin, alicyclic glycidyl ether type epoxy resin, alicyclic glycidyl amine type epoxy resin, alicyclic glycidyl ester type epoxy resin, and the like. The epoxy prepolymer can be used alone or in combination of two or more.

[0059] As described above, the polymer P as an epoxy polymer contains a structural unit U1 derived from an amine monomer. When the polymer P is the polymer P1, the polymer P further contains a structural unit U2 derived from an epoxy monomer. The content rate of the structural unit U1 in the polymer P, particularly the polymer P1, is, for example, 30 wt% or more, preferably 50 wt% or more. The upper limit value of the content rate of the structural unit U1 is not particularly limited and is, for example, 80 wt%. The content rate of the structural unit U2 in the polymer P, particularly the polymer P1, is, for example, 20 wt% to 70 wt%.

[0060] When producing the polymer P, the blending ratio of the amine monomer and the epoxy monomer or epoxy prepolymer is such that the ratio of the equivalent of the epoxy group contained in the epoxy monomer or epoxy prepolymer to the equivalent of the active hydrogen of the primary amino group contained in the amine monomer is, for example, 1 or less, preferably 0.9 or less, more preferably 0.5 or less.

[0061] The glass transition temperature Tg of the polymer P is not particularly limited and is, for example, 40 °C or less, preferably 30 °C or less, more preferably 20 °C or less, and even more preferably 15 °C or less. When the glass transition temperature Tg of the polymer P is this low, the regeneration treatment of the acidic gas adsorbent 10 can be performed under relatively mild conditions, for example, heat treatment at a low temperature. The lower limit value of the glass transition temperature Tg of the polymer P is, from the viewpoints of sufficiently ensuring the adsorbability of the acidic gas in the acidic gas adsorbent 10 and heat resistance, for example, -100 °C, preferably -50 °C, more preferably -10 °C. In this specification, the glass transition temperature Tg means the midpoint glass transition temperature (T mg ) determined in accordance with the provisions of JIS K7121:1987. Incidentally, the polymer P usually corresponds to a thermosetting resin. The polymer P is solid, for example, at 25 °C, preferably in the range of 25 °C to 80 °C.

[0062] The weight-average molecular weight of 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 polymer P is, for example, 10000000.

[0063] The porous sheet 1 contains, for example, polymer P as a main component. In this specification, the "main component" means the component most contained in the porous sheet 1 in terms of weight ratio. The content of polymer P in the porous sheet 1 is, for example, 50 wt% or more, preferably 70 wt% or more, more preferably 90 wt% or more, may be 95 wt% or more, or may be 99 wt% or more. The porous sheet 1 may be substantially composed of only polymer P. The higher the content of polymer P, the more likely the adsorbability of acidic gas in the acidic gas adsorbent 10 will be improved.

[0064] The porous sheet 1 may be substantially composed of only polymer P, but may further contain other materials other than polymer P. Examples of other materials include reaction accelerators, plasticizers, fillers, pigments, dyes, anti-aging agents, conductive materials, antistatic agents, ultraviolet absorbers, flame retardants, antioxidants, and the like. The porous sheet 1 preferably does not contain, for example, porous particles such as alumina and a binder for binding the porous particles to each other as other materials.

[0065] The reaction accelerator is used, for example, when synthesizing polymer P. Examples of the reaction accelerator include tertiary amines such as triethylamine and tributylamine; and imidazoles such as 2-phenol-4-methylimidazole, 2-ethyl-4-methylimidazole, and 2-phenol-4,5-dihydroxyimidazole. These reaction accelerators can, for example, accelerate the reaction for synthesizing polymer P1.

[0066] Examples of the filler include fibers and fibrous structures containing fibers. Examples of the fibers include glass fibers; natural fibers such as wood pulp, cotton, and hemp (e.g., Manila hemp); and chemical fibers (synthetic fibers) such as polyester fibers, rayon, vinylon, acetate fibers, polyvinyl alcohol (PVA) fibers, polyamide fibers, polyolefin fibers, and polyurethane fibers. Examples of the fibrous structure include woven fabrics, non-woven fabrics, and paper. A specific example of the fibrous structure is glass paper. When the porous sheet 1 contains a fibrous structure as a filler, the dimensions of the porous sheet 1 tend to be suppressed from changing, such as when the acidic gas adsorbent 10 is used.

[0067] In addition, when the porous sheet 1 contains a fibrous structure as a filler, in the porous sheet 1, the three-dimensional network skeleton containing the polymer P and the fibrous structure may exist independently of each other. In this case, the porous structure of the porous sheet 1 further has pores derived from the fibrous structure, together with the pores derived from the three-dimensional network skeleton containing the polymer P. In this case, in the porous sheet 1, it can be regarded that the three-dimensional network skeleton containing the polymer P and the fibrous structure are combined.

[0068] From the viewpoint of suppressing changes in the dimensions of the porous sheet 1, the fibrous structure as a filler preferably has a high tensile strength. As an example, the fibrous structure has a tensile strength S TD measured in the following Test 1 of 1 MPa or more. Test 1: Cut out a fibrous structure into a test piece with a width of 10 mm and a length of 100 mm. At this time, align the longitudinal direction of the test piece with the TD direction (transverse direction) of the fibrous structure. Set the test piece on a tensile testing machine and conduct a tensile test under the conditions of a chuck distance of 20 mm and a tensile speed of 100 mm / min. Determine the tensile strength S TD when the test piece has stretched by 3%.

[0069] In the above tensile test, after the start of the test, when the distance between the chucks increases by 0.6 mm, the test force applied to the test piece (the test force when the test piece has a 3% elongation, unit: N / 10 mm) is measured. Based on the obtained value of the test force (N / 10 mm) and the thickness (μm) of the fiber structure, the tensile strength S TD can be calculated by the following formula. The tensile test is carried out in an atmosphere of 25°C. Tensile strength S TD (MPa) = test force (N / 10 mm) / (thickness (μm) / 100)

[0070] The tensile strength S of the fiber structure TD is more preferably 2 MPa or more, and may be 3 MPa or more, 4 MPa or more, 5 MPa or more, 6 MPa or more, 7 MPa or more, and even 8 MPa or more. The upper limit of the tensile strength S TD is not particularly limited, for example, it is 30 MPa.

[0071] Furthermore, except for aligning the longitudinal direction of the test piece with the MD direction (machine direction) of the fiber structure, the tensile strength S MD measured by the same method as the above Test 1 is also preferably 1 MPa or more. The tensile strength S MD is more preferably 2 MPa or more, and may be 5 MPa or more, 8 MPa or more, 10 MPa or more, 11 MPa or more, and even 12 MPa or more. The upper limit of the tensile strength S MD is not particularly limited, for example, it is 30 MPa.

[0072] The density d of nitrogen element in the porous sheet 1 is not particularly limited, for example, it is 1 mmol / g or more, preferably 5 mmol / g or more, and more preferably 10 mmol / g or more. The upper limit of the density d of nitrogen element is not particularly limited, for example, it is 30 mmol / g. When all the nitrogen elements contained in the porous sheet 1 are derived from amino groups, the density d of nitrogen element can be regarded as the density of amino groups in the porous sheet 1.

[0073] The density d of the nitrogen element can be measured by the following method. First, using a commercially available CHN elemental analyzer, measure the weight ratio w (wt%) of the nitrogen element contained in the porous sheet 1. Based on the obtained result, the density d of the nitrogen element can be calculated from the following formula. Density d (mmol / g) = (weight ratio w (wt%) × 1000) / (atomic weight of nitrogen × 100)

[0074] The amount of substance of amino groups per unit volume of the porous sheet 1 is, for example, 4.0 mmol / cm 3 or more, 4.3 mmol / cm 3 or more, 4.5 mmol / cm 3 or more, 5.0 mmol / cm 3 or more, 6.0 mmol / cm 3 or more, 7.0 mmol / cm 3 or more, and further 8.0 mmol / cm 3 or more may be sufficient. The upper limit value of the amount of substance of these amino groups is not particularly limited, and is, for example, 20 mmol / cm 3 for example.

[0075] The weight ratio of the nitrogen element in the porous sheet 1 is, for example, 5 wt% or more, preferably 10 wt% or more. The higher this weight ratio, the more likely the adsorbability of the acidic gas in the acidic gas adsorbent 10 will be improved. The upper limit value of the weight ratio of the nitrogen element in the porous sheet 1 is not particularly limited, and is, for example, 30 wt%. When all the nitrogen elements contained in the porous sheet 1 are derived from amino groups, the above weight ratio of the nitrogen element can be regarded as the weight ratio of the amino groups in the porous sheet 1.

[0076] As described above, the porous sheet 1 has a three-dimensional network skeleton composed of the polymer P. The three-dimensional network skeleton contains, for example, the polymer P as a main component and may substantially contain only the polymer P. The three-dimensional network skeleton may further contain other components other than the polymer P. In the porous sheet 1, for example, the above three-dimensional network skeleton extends continuously. The pores contained in the porous sheet 1 are, for example, continuous pores formed continuously in three dimensions. In other words, the porous sheet 1 contains, for example, continuous pores formed continuously in three dimensions. The porous sheet 1 may have independent pores or may have through holes penetrating the porous sheet 1. Note that the porous sheet 1 preferably does not have fibers containing the polymer P, and preferably is not a nonwoven fabric containing such fibers. That is, in the present embodiment, the porous sheet 1 excludes, for example, nonwoven fabrics having fibers containing the polymer P.

[0077] The thickness of the porous sheet 1 is not particularly limited and is, for example, 1000 μm or less, preferably 500 μm or less, and more preferably 300 μm or less. As will be described later, the smaller the thickness of the porous sheet 1, the larger the cross-sectional area of the ventilation path of, for example, the structure produced using the acidic gas adsorbent 10, particularly the honeycomb structure, can be adjusted. A structure with a large cross-sectional area of the ventilation path is suitable for reducing the pressure loss that occurs when in contact with an acidic gas. Note that in the present embodiment, the porous sheet 1 tends to have a relatively large amount of substance of amino groups per unit volume. According to this porous sheet 1, even when the thickness of the sheet 1 is small, there is a tendency that acidic gas can be sufficiently adsorbed. The lower limit value of the thickness of the porous sheet 1 is not particularly limited and is, for example, 10 μm.

[0078] The specific surface area of the porous sheet 1 is not particularly limited and is, for example, 0.1 m 2 / g or more, preferably 1.0 m 2 / g or more, and more preferably 2.0 m 2 / g or more. The upper limit value of the specific surface area of the porous sheet 1 is not particularly limited and is, for example, 10 m 2 / g. The specific surface area of the porous sheet 1 means the BET (Brunauer - Emmett - Teller) specific surface area by nitrogen gas adsorption. The BET specific surface area can be measured by a method compliant with the provisions of JIS Z8830:2013.

[0079] The porosity of the porous sheet 1 is, for example, 20% or more, preferably 30% or more, more preferably 40% or more. The upper limit value of the porosity of the porous sheet 1 is not particularly limited and may be, for example, 80% or 60%. The porosity of the porous sheet 1 can be calculated by the following formula based on the volume V (cm 3 ) of the porous sheet 1, the weight W (g), and the true density D (g / cm 3 ). Note that the true density D means the specific gravity of the material constituting the porous sheet 1. Porosity (%) = 100×(V - (W / D)) / V

[0080] When the acidic gas adsorbent 10 is used, particularly when the acidic gas adsorbent 10 comes into contact with water, it is preferable that the dimensional change of the porous sheet 1 is suppressed. The porous sheet 1 with suppressed dimensional change tends not to fall off from the support 2, the acidic gas recovery device, etc. when the acidic gas adsorbent 10 is used. Further, this porous sheet 1 is not easily deformed when the acidic gas adsorbent 10 is used, etc., and there is also a tendency that the inhibition of gas passage due to deformation hardly occurs. As described above, the porous sheet 1 containing the fibrous structure as a filler tends to have its dimensional change suppressed when the acidic gas adsorbent 10 is used.

[0081] As an example, it is preferable that the dimensional change rate R TD measured in the following Test 2 of the porous sheet 1 is 5% or less. Test 2: Cut out the porous sheet 1 into a test piece with a length of 30 mm and a width of 20 mm. At this time, align the longitudinal direction of the test piece with the MD direction of the porous sheet 1 (when including the fiber structure, the MD direction of the fiber structure), and align the transverse direction of the test piece with the TD direction of the porous sheet 1 (when including the fiber structure, the TD direction of the fiber structure). Dry the test piece in a vacuum atmosphere at 60 °C for 2 hours. Place the test piece in a dry room with a dew point of about -60 °C. Measure the dimensions of the test piece in the dry room, and regard the obtained value as the dimension of the test piece in the dry state. Next, conduct an immersion test by immersing the test piece in pure water at 22 °C for 2 hours. Measure the dimensions of the test piece after the immersion test, and regard the obtained value as the dimension of the test piece in the water-absorbed state. The length L TD1 (mm) of the transverse direction of the test piece in the dry state, and the length L TD2 (mm) of the transverse direction of the test piece in the water-absorbed state are used to calculate the dimensional change rate R TD (%).

[0082] Note that the dimensional change rate R TD (%) can be calculated by the following formula. The dimensional change rate R TD = 100 × |L TD2 - L TD1 | / L TD1

[0083] The dimensional change rate R TD of the porous sheet 1 is more preferably 4% or less, and may be 3% or less, 2% or less, 1% or less, and even 0.5% or less. The lower limit of the dimensional change rate R TD is not particularly limited, and is, for example, 0.01%.

[0084] Furthermore, it is preferable that the porous sheet 1 also has a dimensional change rate R MD measured in the above Test 2 of 5% or less. The dimensional change rate R MD can be calculated by the following formula based on the length L MD1 (mm) of the longitudinal direction of the test piece in the dry state and the length L MD2 (mm) of the longitudinal direction of the test piece in the water-absorbed state. The dimensional change rate R MD = 100 × |L MD2-L MD1 | / L MD1

[0085] Dimensional change rate R of the porous sheet 1 MD is more preferably 4% or less, and may be 3% or less, 2% or less, or even 1% or less. The dimensional change rate R MD has no particular lower limit, and is, for example, 0.01%.

[0086] (Support) The material of the support 2 is not particularly limited, and examples thereof include ceramics such as cordierite, alumina, cordierite-α alumina, silicon nitride, zircon mullite, wollastonite, alumina-silica magnesia, zircon silicate ester, sillimanite, magnesium silicate, zircon, feldspar, aluminosilicate; metals such as aluminum, titanium, copper, stainless steel, Fe-Cr alloy, Cr-Al-Fe alloy; resins such as silicone resin, polyolefin, polyester, polyurethane, polycarbonate, polyether ether ketone, polyphenylene oxide, polyether sulfone, melamine, polyamide, poly(meth)acrylate, polystyrene, poly(meth)acrylonitrile, polyimide, polyfurfuryl alcohol, phenol furfuryl alcohol, melamine formaldehyde, resorcinol formaldehyde, cresol formaldehyde, phenol formaldehyde, polyvinyl alcohol dialdehyde, polycyanurate, poly(meth)acrylamide, epoxy resin, agar, agarose, cellulose. The material of the support 2 is preferably excellent in thermal conductivity and durability and is less likely to deteriorate due to rust generation or hydrolysis when in contact with water.

[0087] The support 2 may or may not have a porous structure. Examples of the support 2 having a porous structure include paper, non-woven fabric, foam, mesh, etc. Examples of the support 2 not having a porous structure include non-porous sheets, foils, etc. From the viewpoint of easily manufacturing the acidic gas adsorbent 10 having a corrugated shape, the support 2 is preferably an aluminum sheet, paper, non-woven fabric, etc.

[0088] The support 2 may function as a planar heater, and may be a planar thermoelectric heater or a Peltier element.

[0089] The thickness of the support 2 is not particularly limited, and is, for example, 1 μm to 100 μm. The support 2 may be thinner than the porous sheet 1.

[0090] (Method for manufacturing acidic gas adsorbent) The method for manufacturing the acidic gas adsorbent 10 includes, for example, a step (I) of curing a mixed liquid L containing a compound group containing an amine monomer and a porogen to obtain a cured body B, and a step (II) of removing the porogen from the sheet-like cured body B to obtain the porous sheet 1.

[0091] In the step (I), the compound group is typically a monomer group containing an amine monomer and an epoxy monomer. However, the compound group may contain an epoxy prepolymer instead of or together with the epoxy monomer.

[0092] A porogen is a solvent that can dissolve monomers and prepolymers contained in a compound group, for example, and can further cause reaction-induced phase separation after the compound group reacts. Specific examples of the porogen include cellosolves such as methyl cellosolve and ethyl cellosolve, esters such as ethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate, glycols such as polyethylene glycol, polypropylene glycol, and polyoxyalkylene glycol, and ethers such as polyoxyethylene monomethyl ether and polyoxyethylene dimethyl ether. Specific examples of polyoxyalkylene glycol are poly(1,2-butanediol)-6 propylene glycol, polyoxypropylene diglyceryl ether, and the like. The porogen may be a polar solvent such as ethyl acetate, N,N-dimethylformamide (DMF), acetonitrile, ethanol, isopropanol, a nonpolar solvent such as toluene, or a mixed solvent thereof. The porogen can be used alone or in combination of two or more.

[0093] Other components other than the compound group and the porogen may be further added to the mixed solution L. Examples of other components include the reaction accelerators described above.

[0094] In step (I), the polymer P is formed by the reaction of the compound group. As a result, the mixed solution L hardens to obtain a cured body B. The reaction of the compound group is typically a polymerization reaction of an amine monomer and an epoxy monomer. However, the reaction of the compound group may be a crosslinking reaction of an epoxy prepolymer with an amine monomer. In the reaction of the compound group, the amino group of the amine monomer reacts with the epoxy group of the epoxy monomer or the epoxy prepolymer. The reaction of the compound group can be carried out by applying energy to the mixed solution L. The energy applied to the mixed solution L is preferably thermal energy. As an example, the reaction of the compound group can be advanced by heating the mixed solution L at a temperature of 40°C to 100°C. However, the energy applied to the mixed solution L may be light energy.

[0095] The cured body B contains a polymer P and a porogen. In the cured body B, a co-continuous structure is formed by phase separation of the polymer P and the porogen. The shape of the cured body B obtained in step (I) is typically sheet-like. The sheet-like cured body B can be produced, for example, by applying the liquid mixture L onto a support 2 (typically a support 2 having no porous structure) and curing the resulting coating film. The coating method of the liquid mixture L is not particularly limited, and a roll coating method, a spin coating method, a dip coating method, etc. can be used.

[0096] In addition, the sheet-like cured body B can also be produced by bringing the liquid mixture L into contact with another sheet-like base material other than the above-mentioned support 2 and then curing the liquid mixture L. As the base material, for example, a release liner or a fibrous structure can be used. The base material may be a laminate including a release liner and a fibrous structure. When a fibrous structure is used as the base material, the liquid mixture L tends to penetrate into the fibrous structure when the liquid mixture L is brought into contact with the fibrous structure. By curing the liquid mixture L in a state where the liquid mixture L has penetrated into the fibrous structure, a cured body containing the fibrous structure as a filler can be obtained.

[0097] The shape of the cured body B obtained in step (I) does not have to be sheet-like, and may be, for example, block-like, particularly cylindrical or columnar. The block-like cured body B can be produced, for example, by curing the liquid mixture L filled in a mold in step (I). In this case, a sheet-like cured body B used in step (II) can be obtained by cutting the vicinity of the surface of the block-like cured body B to a predetermined thickness. As an example, when the cured body B is cylindrical or columnar, a sheet-like cured body B can be produced by cutting the vicinity of the surface of the cured body B while rotating the cured body B around the cylindrical axis or the columnar axis.

[0098] In step (II), the method for removing the porogen from the sheet-like cured product B is not particularly limited. For example, the porogen may be extracted and removed from the cured product B by immersing the cured product B in a solvent. As the solvent for extracting the porogen, water, aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, aliphatic alcohol solvents, ether solvents, halogen-containing organic solvents, ester solvents, etc. can be used. Examples of aliphatic hydrocarbon solvents include n-hexane, cyclohexane, methylcyclohexane, n-heptane, n-octane, isooctane, petroleum ether, benzene, etc. Examples of aromatic hydrocarbon solvents include toluene, xylene, mesitylene, benzene, etc. Examples of aliphatic alcohol solvents include methanol, ethanol, isopropanol, butanol, cyclohexanol, ethylene glycol, propylene glycol, propylene glycol monomethyl ether, diethylene glycol, etc. Examples of ether solvents include diethyl ether, diisopropyl ether, dibutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, dioxane, anisole, etc. Examples of halogen-containing organic solvents include dichloromethane, chloroform, carbon tetrachloride, dichloroethane, chlorobenzene, etc. Examples of ester solvents include ethyl acetate, etc. These solvents can be used alone or in combination of two or more.

[0099] In step (II), by removing the porogen from the sheet-like cured product B, for example, a porous sheet 1 having a flat plate shape can be obtained. As an example, when the cured product B is produced using a method of applying the mixed liquid L onto the support 2, by removing the porogen from the cured product B, a sheet-like acidic gas adsorbent 10 including the porous sheet 1 and the support 2 is obtained. Note that, a self-supporting film of the porous sheet 1 may be produced by a method using a base material other than the support 2, and the self-supporting film may be used as the acidic gas adsorbent 10. A self-supporting film of the porous sheet 1 may be produced and fixed to the support 2 using fixing means such as an adhesive sheet, and the resulting product may be used as the acidic gas adsorbent 10.

[0100] The acidic gas adsorbent 10 produced by the above method usually has a flat plate shape. The acidic gas adsorbent 10 having a flat plate shape may be further subjected to corrugation processing. Thereby, an acidic gas adsorbent 10 having a corrugated shape can be obtained.

[0101] As an example, the acidic gas adsorbent 10 can be produced using the production apparatus 100 shown in FIG. 2A. FIG. 2A shows a schematic configuration of the production apparatus 100. The production apparatus 100 includes a feeding roll 45 that feeds out the support 2, a winding roll 49 that winds up the produced acidic gas adsorbent 10, and a plurality of guide rolls 46, 47, and 48 positioned between the feeding roll 45 and the winding roll 49. In the production apparatus 100, the support 2 is conveyed from the feeding roll 45 to the winding roll 49. The production apparatus 100 further includes a mixed liquid discharge unit 20, a first heating unit 30, an extraction unit 40, and a second heating unit 35, which are arranged in this order in the conveyance direction of the support 2. Note that, in the production apparatus 100, a base material other than the support 2 may be used instead of the support 2.

[0102] The mixed liquid discharge unit 20 includes a first supply unit 21, a second supply unit 22, a mixing unit 23, and a discharge port 24. The first supply unit 21 can send the first raw material 5 to the mixing unit 23. The second supply unit 22 can send the second raw material 6 to the mixing unit 23. As an example, the first raw material 5 contains an amine monomer, and the second raw material 6 contains an epoxy monomer and / or an epoxy prepolymer. At least one selected from the group consisting of the first raw material 5 and the second raw material 6 contains a porogen. In the mixing unit 23, the first raw material 5 and the second raw material 6 are mixed to prepare a mixed liquid L.

[0103] The mixed liquid L prepared in the mixing unit 23 is discharged to the outside of the mixed liquid discharge unit 20 through the discharge port 24. For example, the mixed liquid discharge unit 20 is located near the guide roll 46, and the mixed liquid L can be applied onto the support 2 conveyed from the feeding roll 45 to the guide roll 46. Thereby, a coating film 7 can be formed on the support 2. The coating film 7, together with the support 2, passes through the guide roll 47 and is sent to the first heating unit 30.

[0104] The first heating unit 30 includes a heater 31 for heating the coating film 7. By moving within the first heating unit 30, the coating film 7 is heated. Thereby, the coating film 7 is cured, and a sheet-like cured body 8 is formed. The cured body 8, together with the support 2, is sent to the extraction unit 40.

[0105] The extraction unit 40 contains a solvent 41 for extracting the porogen from the cured body 8. In the extraction unit 40, the cured body 8 is immersed in the solvent 41. Thereby, the porogen is removed from the cured body 8, and a porous sheet 1 is formed. The porous sheet 1, together with the support 2, is sent to the second heating unit 35.

[0106] The second heating unit 35 includes a heater 36 for drying the porous sheet 1 sent from the extraction unit 40. By moving within the second heating unit 35, the porous sheet 1 is heated. As a result, the porous sheet 1 is dried, and a sheet-shaped acidic gas adsorbent 10 including the porous sheet 1 and the support 2 is obtained. This acidic gas adsorbent 10 passes through the guide roll 48 and is wound around the winding roll 49.

[0107] The manufacturing apparatus 100 for the acidic gas adsorbent 10 is not limited to that shown in Fig. 2A. Fig. 2B shows a schematic configuration of a manufacturing apparatus 110 according to a modification. As shown in Fig. 2B, the manufacturing apparatus 110 does not include the extraction unit 40 and the second heating unit 35. Except for the above, the configuration of the manufacturing apparatus 110 is the same as that of the manufacturing apparatus 100. Therefore, the same reference numerals are given to the elements common to these manufacturing apparatuses 100 and 110, and their descriptions may be omitted. The following descriptions of each embodiment can be mutually applied as long as there is no technical contradiction. Furthermore, as long as there is no technical contradiction, each embodiment may be combined with each other.

[0108] In the manufacturing apparatus 110, the cured body 8 formed in the first heating unit 30, together with the support 2, passes through the guide roll 48 and is wound around the winding roll 49. As a result, a wound body of the cured body 8 and the support 2 is obtained. By immersing this wound body in a solvent and extracting porogen from the cured body 8, a sheet-shaped acidic gas adsorbent 10 can be obtained.

[0109] (Adsorption amount of carbon dioxide by the acidic gas adsorbent) The acidic gas adsorbent 10 of the present embodiment tends to have high adsorbability to acidic gases such as carbon dioxide. As an example, when the acidic gas adsorbent 10 is brought into contact with a mixed gas G composed of carbon dioxide, nitrogen, and water vapor for 15 hours, the adsorption amount a of carbon dioxide is, for example, 0.1 mmol / cm 3 or more, preferably 0.3 mmol / cm 3 or more, more preferably 0.5 mmol / cm 3 or more, and even more preferably 0.7 mmol / cm3 or more, particularly preferably 0.8 mmol / cm 3 or more, particularly preferably 1.0 mmol / cm 3 or more. The upper limit value of the carbon dioxide adsorption amount a is not particularly limited, for example, 10 mmol / cm 3 .

[0110] [Method for Measuring Carbon Dioxide Adsorption Amount] Hereinafter, the method for measuring the carbon dioxide adsorption amount a will be described. The adsorption amount a can be measured, for example, using the measuring device 200 shown in FIG. 3. The measuring device 200 includes a first tank 230 and a second tank 231. As an example, the first tank 230 stores nitrogen in a dry state, and the second tank 231 stores a mixed gas of dry nitrogen and dry carbon dioxide. The concentration of carbon dioxide in the mixed gas in the second tank 231 is, for example, 5 vol%.

[0111] The measuring device 200 further includes a first container 240 containing water 270 and a first path 260 for sending nitrogen from the first tank 230 to the first container 240. The first path 260 has one end connected to the gas outlet of the first tank 230 and the other end disposed in the water 270 of the first container 240. The nitrogen sent from the first tank 230 to the first container 240 is humidified by contacting the water 270. A mass flow controller 235 for adjusting the flow rate of nitrogen sent from the first tank 230 to the first container 240 is disposed in the first path 260.

[0112] The measuring device 200 further includes a second container 241, a second path 262, and a bypass path 261. The second path 262 connects the first container 240 and the second container 241. The nitrogen that is sent to the first container 240 and humidified is sent to the second container 241 through the second path 262. The bypass path 261 branches from the first path 260 at a position between the first tank 230 and the mass flow controller 235 and is connected to the second path 262. A part of the nitrogen sent from the first tank 230 flows into the bypass path 261 and is sent to the second container 241 through the second path 262. A mass flow controller 236 for adjusting the flow rate of the nitrogen sent from the first tank 230 to the bypass path 261 is arranged in the bypass path 261.

[0113] The measuring device 200 further includes a third path 263 for sending the mixed gas from the second tank 231 to the second path 262. The third path 263 has one end connected to the gas outlet of the second tank 231 and the other end connected to the second path 262. A mass flow controller 237 for adjusting the flow rate of the mixed gas sent from the second tank 231 to the second path 262 is arranged in the third path 263. The mixed gas sent to the second path 262 is sent to the second container 241 through the second path 262.

[0114] The measuring device 200 further includes a third container 242 and a fourth path 264. The third container 242 houses water 271 and an adsorption part 221 disposed in the water 271. In the third container 242, the temperature of the water 271 is maintained at 20°C. The adsorption part 221 has a gas inlet 222 and a gas outlet 223. The adsorption part 221 houses the acidic gas adsorbent 10 inside. The adsorption part 221 is configured so that the water 271 does not penetrate inside. The adsorption part 221 is typically a tube made of a hydrophobic resin, such as a fluororesin such as tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA). As an example, the tube as the adsorption part 221 has an inner diameter of 4 mm and an outer diameter of 6 mm. The adsorption part 221 is configured to be detachable from the measuring device 200.

[0115] Note that the measuring device 200 can also be used as an acidic gas adsorption device provided with an adsorption unit 221. From another aspect of the present invention, there is provided an acidic gas adsorption device 200 including an adsorption unit 221 having a gas inlet 222 and a gas outlet 223, and the adsorption unit 221 accommodating an acidic gas adsorbent 10. The adsorption unit 221 of the acidic gas adsorption device 200 may accommodate a structure described later provided with the acidic gas adsorbent 10.

[0116] The fourth path 264 connects the second container 241 and the third container 242. Specifically, the fourth path 264 is connected to the gas inlet 222 of the adsorption unit 221 in the third container 242. A first concentration meter 250 for measuring the concentration of carbon dioxide in the gas supplied to the adsorption unit 221 is arranged in the fourth path 264. As the first concentration meter 250, for example, a CO2 / H2O gas analyzer, LI-850-3 manufactured by LI-COR can be used.

[0117] The measuring device 200 is further provided with a fifth path 265 connected to the gas outlet 223 of the adsorption unit 221 for discharging gas from the adsorption unit 221 to the outside of the measuring device 200. A back pressure valve 255 and a second concentration meter 251 are arranged in the fifth path 265. The pressure inside the adsorption unit 221 can be adjusted to a constant value by the back pressure valve 255. The second concentration meter 251 can measure the concentration of carbon dioxide in the gas discharged from the adsorption unit 221. As the second concentration meter 251, for example, a CO2 / H2O gas analyzer, LI-850-3 manufactured by LI-COR can be used.

[0118] Each path of the measuring device 200 is composed of, for example, a pipe made of metal or resin.

[0119] [Pretreatment] In the method for measuring the adsorption amount a, first, the acid gas adsorbent 10 is subjected to a drying treatment. The drying treatment is performed, for example, by treating the acid gas adsorbent 10 under a vacuum atmosphere at 60°C for 2 hours or more. Next, in a dry room with a dew point of approximately -60°C, the dried acid gas adsorbent 10 is filled into the adsorption part 221. At this time, the acid gas adsorbent 10 is pre-measured to specify the volume of the acid gas adsorbent 10. The weight of the acid gas adsorbent 10 filled into the adsorption part 221 is, for example, 50 mg. Next, the fourth path 264 and the fifth path 265 are connected to both ends of the adsorption part 221, and the adsorption part 221 is immersed in the water 271 of the third container 242.

[0120] Next, nitrogen from the first tank 230 and the mixed gas from the second tank 231 are supplied to the second container 241 through the first path 260, the second path 262, the bypass path 261, and the third path 263 of the measuring device 200. In the second container 241, these gases are mixed to obtain a mixed gas G composed of carbon dioxide, nitrogen, and water vapor. In the second container 241, the concentration of carbon dioxide in the mixed gas G is adjusted to 400 volppm. 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 part 221 through the fourth path 264 at a flow rate sufficient for the weight of the acid gas adsorbent 10, for example, at a flow rate of 300 mL / min with respect to 50 mg of the acid gas adsorbent 10. In the adsorption part 221, the pressure of the mixed gas G is adjusted to 107 kPa by the back pressure valve 255.

[0121] Next, with the mixed gas G being supplied to the adsorption part 221, the adsorption part 221 is taken out from the third container 242 and immersed in a hot water bath (not shown) at 80°C for 2 hours or more. The immersion of the adsorption part 221 in the hot water bath is performed until the concentration of carbon dioxide measured by the first concentration meter 250 and the concentration of carbon dioxide measured by the second concentration meter 251 become substantially the same value. Thereby, the pretreatment of the acid gas adsorbent 10 in the adsorption part 221 is completed.

[0122] [Adsorption test] Next, with the mixed gas G being supplied to the adsorption section 221, the adsorption section 221 is taken out of the hot water bath and immersed in the water 271 of the third container 242. Thereby, an adsorption test is started for the acid gas adsorbent 10 in the adsorption section 221. The adsorption test is carried out until 15 hours have elapsed since the start. When the adsorption test is carried out for 15 hours, the adsorption of carbon dioxide by the acid gas adsorbent 10 can usually be regarded as having reached equilibrium.

[0123] In the adsorption test, the amount of substance M of carbon dioxide adsorbed by the acid gas adsorbent 10 from the start to 15 hours is measured. The amount of substance M of carbon dioxide adsorbed by the acid gas adsorbent 10 can be calculated from the results of measuring the difference in the concentration of carbon dioxide measured by the first concentration meter 250 and the concentration of carbon dioxide measured by the second concentration meter 251 over time. Based on the amount of substance M, the amount of substance of carbon dioxide adsorbed by 1 cm 3 of the acid gas adsorbent 10 in 15 hours is calculated, and the obtained calculated value is specified as the adsorption amount a.

[0124] As described above, in a conventional adsorbent, for example, an amine compound is filled in the pores of porous particles supported on a substrate. In such an adsorbent, since porous particles and a binder for binding the porous particles to each other are required, it is difficult to greatly adjust the amount of substance of amino groups per unit volume of the adsorbent. In a conventional adsorbent, when the filling amount of the amine compound is increased to increase the amount of substance of amino groups per unit volume, the pores of the porous particles may be blocked, and the adsorption performance for acid gas may rather decrease. On the other hand, in the acid gas adsorbent 10 of the present embodiment, by using the porous sheet 1 having a three-dimensional network skeleton composed of the polymer P, the amount of substance of amino groups per unit volume can be easily increased while maintaining the pores of the porous sheet 1. The acid gas adsorbent 10 of the present embodiment tends to have high adsorption performance for acid gas and can be said to be suitable for the adsorption of acid gas.

[0125] (Use of Acid Gas Adsorbent) The acid gas adsorbent 10 of this embodiment can adsorb acid gas. Examples of the acid gas include carbon dioxide, hydrogen sulfide, carbonyl sulfide, sulfur oxides (SOx), hydrogen cyanide, nitrogen oxides (NOx), etc., and carbon dioxide is preferable.

[0126] The acid gas adsorbent 10 can be used, for example, by the following method. First, a mixed gas containing acid gas is brought into contact with the acid gas adsorbent 10. The mixed gas contains, for example, other gases other than the acid gas. Examples of the other gases include non-polar gases such as hydrogen and nitrogen, and inert gases such as helium, and nitrogen is preferable. The mixed gas is typically air. The mixed gas may be off-gas from a chemical plant or a thermal power plant.

[0127] The temperature of the mixed gas is, for example, room temperature (23°C). The concentration of the acid gas in the mixed gas is not particularly limited, and at standard conditions (0°C, 101 kPa), it 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 value of the concentration of carbon dioxide in the mixed gas is not particularly limited, and at standard conditions, it is, for example, 10 vol%. The pressure of the mixed gas is typically equal to the atmospheric pressure in the use environment of the acid gas adsorbent 10. However, the mixed gas brought into contact with the acid gas adsorbent 10 may be pressurized.

[0128] The acid gas adsorbent 10 that has come into contact with the mixed gas adsorbs the acid gas contained in the mixed gas. The operation of bringing the mixed gas into contact with the acid gas adsorbent 10 is performed, for example, until the adsorption of the acid gas by the acid gas adsorbent 10 reaches equilibrium.

[0129] Next, a regeneration process is performed on the acid gas adsorbent 10 that has adsorbed the acid gas. The regeneration process can be carried out, for example, by heating the acid gas adsorbent 10. The heating temperature of the acid gas adsorbent 10 is, for example, 50 to 80°C. The acid gas adsorbent 10 may be heated in a reduced-pressure atmosphere or a vacuum atmosphere. By heating the acid gas adsorbent 10, the acid gas desorbs from the acid gas adsorbent 10. As a result, the acid gas adsorbent 10 is regenerated and can be repeatedly used. The acid gas desorbed from the acid gas adsorbent 10, particularly carbon dioxide, can be utilized as a raw material for chemical synthesis or dry ice. Note that the acid gas adsorption operation by the acid gas adsorbent 10 and the regeneration process of the acid gas adsorbent 10 can be carried out using the above-described measuring device 200 (acid gas adsorption device) and the acid gas recovery device described later.

[0130] <Modification example of acid gas adsorbent> The acid gas adsorbent 10 may include a plurality of porous sheets 1. The acid gas adsorbent 11 shown in FIG. 4 includes two porous sheets 1A and 1B. Except for this, the structure of the acid gas adsorbent 11 is the same as the structure of the acid gas adsorbent 10.

[0131] In the acid gas adsorbent 11, the support 2 is located between the two porous sheets 1A and 1B and is in direct contact with each of the porous sheets 1A and 1B. The composition and structure of the porous sheet 1A may be the same as or different from those of the porous sheet 1B.

[0132] <Embodiment of the structure> As shown in FIG. 5A, the structure 15 of the present embodiment includes the above-described acid gas adsorbent 10 and a ventilation path 14. Note that instead of the acid gas adsorbent 10, the acid gas adsorbent 11 shown in FIG. 4 can also be used. The structure 15 is typically a honeycomb structure having a plurality of ventilation paths 14 extending in the same direction.

[0133] In the structure 15, it is preferable that the acid gas adsorbent 10 includes the support 2 together with the porous sheet 1. In this acid gas adsorbent 10, the porous sheet 1 may contain a fibrous structure as a filler. However, the acid gas adsorbent 10 included in the structure 15 may be a self-supporting film of the porous sheet 1.

[0134] The structure 15 includes, for example, an adsorbent unit U in which an acid gas adsorbent 10A having a corrugated shape and an acid gas adsorbent 10B having a flat plate shape are laminated. In the acid gas adsorbent 10A, a plurality of peak portions 12 and a plurality of valley portions 13 are arranged alternately. A ventilation path 14 is formed between the peak portion 12 or the valley portion 13 of the acid gas adsorbent 10A and the acid gas adsorbent 10B. In the present embodiment, the direction x is the direction (wave direction) in which the plurality of peak portions 12 and the plurality of valley portions 13 of the acid gas adsorbent 10A are arranged alternately. The direction y is the lamination direction of the acid gas adsorbents 10A and 10B in the adsorbent unit U. The direction z is a direction orthogonal to each of the directions x and y and is the direction in which the ventilation path 14 extends.

[0135] The structure 15 includes, for example, a plurality of adsorbent units U. The number of the adsorbent units U in the structure 15 is not particularly limited and is, for example, 2 to 100. In the structure 15, the plurality of adsorbent units U are laminated in the direction y so that the plurality of acid gas adsorbents 10A and the plurality of acid gas adsorbents 10B are arranged alternately. By laminating the plurality of adsorbent units U, the structure 15 has a block shape.

[0136] The ventilation path 14 is a through hole penetrating the structure 15 in the direction z. The ventilation path 14 is surrounded by the acid gas adsorbents 10A and 10B. In the structure 15, the acid gas moves in the direction z through the ventilation path 14 and is efficiently adsorbed by the acid gas adsorbents 10A and 10B.

[0137] In the structure 15, the smaller the thickness of the porous sheet 1 in the acid gas adsorbents 10A and 10B, the larger the cross-sectional area of the ventilation path 14 can be adjusted. The structure 15 with a large cross-sectional area of the ventilation path 14 is suitable for reducing the pressure loss that occurs when contacting with the acid gas. According to the structure 15 with reduced pressure loss, for example, the power of the fan used to move the acid gas can be reduced. Note that since the acid gas adsorbent 10 tends to have a relatively large amount of amino groups per unit volume, even when the thickness of the porous sheet 1 is small, the acid gas can be sufficiently adsorbed.

[0138] <Modification example of the structure> The shape of the structure 15 provided with the acid gas adsorbent 10 is not limited to that shown in Fig. 5A. The structure 16 shown in Fig. 5B has a shape in which one adsorbent unit U is wound around the central tube 50. Except for this, the configuration of the structure 16 is the same as that of the structure 15.

[0139] The structure 16 has a cylindrical shape. In the structure 16, the plurality of peak portions 12 and the plurality of valley portions 13 of the acid gas adsorbent 10A are alternately arranged in the circumferential direction of the structure 16. The ventilation path 14 formed between the peak portion 12 or the valley portion 13 of the acid gas adsorbent 10A and the acid gas adsorbent 10B penetrates the structure 16 in the direction in which the central tube 50 extends. In the structure 16, the acid gas moves in the direction in which the central tube 50 extends through the ventilation path 14 and is efficiently adsorbed by the acid gas adsorbents 10A and 10B.

[0140] <Another modification example of the structure> The structure may not include the corrugated-shaped acid gas adsorbent 10A and may not be a honeycomb structure like the structures 15 and 16. The structure 17 shown in Fig. 5C includes only the acid gas adsorbent 10B having a flat plate shape as the acid gas adsorbent 10. Specifically, the structure 17 includes a plurality of acid gas adsorbents 10B, and the plurality of acid gas adsorbents 10B are arranged with gaps therebetween. The gap between two acid gas adsorbents 10B functions as the ventilation path 14.

[0141] The structure 17 may further include a fixing member 55 for fixing a plurality of acid gas adsorbents 10B to secure the above-mentioned ventilation path 14. The fixing member 55 is, for example, a rod. As an example, in each of the plurality of acid gas adsorbents 10B, a through-hole penetrating the acid gas adsorbent 10B in the thickness direction is formed, and the rod as the fixing member 55 is inserted into the through-holes of the respective acid gas adsorbents 10B, whereby the plurality of acid gas adsorbents 10B are fixed. The rod as the fixing member 55 may be a bolt having a male screw portion formed on its side surface. In this case, at a position between two acid gas adsorbents 10B, by screwing a nut onto the bolt, the ventilation path 14 can be more reliably secured. In this example, the nut functions as a spacer.

[0142] In the example of FIG. 5C, the plurality of acid gas adsorbents 10B each have a rectangular shape in plan view, and through-holes are formed near the four corners thereof. Further, the acid gas adsorbent 10C includes four fixing members 55, and the four fixing members 55 are respectively inserted into the four through-holes formed at the four corners of the acid gas adsorbent 10B. However, the number and positions of the through-holes formed in the acid gas adsorbent 10B and the number of the fixing members 55 are not limited to the example of FIG. 5C.

[0143] In the structure 17, the acid gas moves through the ventilation path 14 between the two acid gas adsorbents 10B and is efficiently adsorbed by the two acid gas adsorbents 10B.

[0144] <Embodiment of Acid Gas Recovery Device> As shown in FIG. 6A, the acid gas recovery device 300 of the present embodiment includes the above-mentioned acid gas adsorbent 10 and a medium path 60. Note that instead of the acid gas adsorbent 10, the acid gas adsorbent 11 shown in FIG. 4 can also be used. In the acid gas recovery device 300, during the desorption operation for desorbing the acid gas adsorbed by the acid gas adsorbent 10 from the acid gas adsorbent 10, a heat medium 61 for heating the acid gas adsorbent 10 passes through the medium path 60.

[0145] In the acid gas recovery device 300, it is preferable that the acid gas adsorbent 10 includes a support 2 together with the porous sheet 1. In this acid gas adsorbent 10, the porous sheet 1 may contain a fibrous structure as a filler. However, the acid gas adsorbent 10 included in the acid gas recovery device 300 may be a self-supporting film of the porous sheet 1.

[0146] The acid gas recovery device 300 includes, for example, a plurality of acid gas adsorbents 10. The plurality of acid gas adsorbents 10 may be arranged with a gap therebetween, and the gap between the two acid gas adsorbents 10 may function as a ventilation path 14. In the acid gas recovery device 300, the configurations of the acid gas adsorbent 10 and the ventilation path 14 may be the same as the configurations described above for the structures 15 to 17.

[0147] In the acid gas recovery device 300, the medium path 60 is composed of, for example, a pipe made of a metal such as copper, specifically a heat transfer pipe. In the acid gas recovery device 300, the medium path 60 penetrates the acid gas adsorbent 10, for example, in the thickness direction of the acid gas adsorbent 10. Specifically, in the acid gas adsorbent 10, through holes are formed that penetrate the acid gas adsorbent 10 in the thickness direction, and the medium path 60 is inserted into the through holes of the acid gas adsorbent 10. The acid gas recovery device 300 typically has the same structure as a fin-tube heat exchanger including heat transfer fins and a heat transfer pipe penetrating the heat transfer fins.

[0148] The medium path 60 has a U shape and may be inserted into two through holes formed in the acid gas adsorbent 10. The number of through holes formed in the acid gas adsorbent 10 and the number of medium paths 60 are not limited to those shown in FIG. 6A. For example, four or more through holes may be formed in the acid gas adsorbent 10, and two or more medium paths 60 having a U shape may be inserted into the through holes of the acid gas adsorbent 10.

[0149] As described above, the medium path 60 functions as a path for the heat medium 61 that heats the acid gas adsorbent 10 during the desorption operation. However, the medium path 60 can also be used as a path for the cooling medium that cools the acid gas adsorbent 10 after the desorption operation. That is, the medium path 60 may serve as both a path for the heat medium 61 and a path for the cooling medium.

[0150] The acid gas recovery device 300 further includes a casing (not shown) that houses the acid gas adsorbent 10 and the medium path 60. The casing has, for example, a mixed gas inlet for sending a mixed gas containing acid gas into the interior of the casing. The casing may further have a desorption gas outlet for discharging the desorption gas desorbed from the acid gas adsorbent 10 to the outside of the casing and a purge gas inlet for sending a purge gas into the interior of the casing during the desorption operation. In the casing, the mixed gas inlet may also serve as the purge gas inlet. Further, the casing may have a medium inlet for sending the heat medium 61 or the cooling medium to the medium path 60 and a medium outlet for discharging the heat medium 61 or the cooling medium from the medium path 60.

[0151] [Operating Method of Acid Gas Recovery Device] The acid gas recovery device 300 repeatedly performs, for example, an adsorption operation in which the acid gas adsorbent 10 adsorbs the acid gas and a desorption operation in which the acid gas adsorbed by the acid gas adsorbent 10 is desorbed from the acid gas adsorbent 10. By performing the adsorption operation and the desorption operation using the acid gas recovery device 300, the acid gas can be recovered.

[0152] (Adsorption Operation) The adsorption operation of the acid gas recovery device 300 is carried out, for example, as follows. First, a mixed gas containing acid gas is sent into the interior of the casing through the above-mentioned mixed gas inlet. Examples of the mixed gas include those described above. The mixed gas contacts the acid gas adsorbent 10 while moving through the ventilation path 14, for example. Thereby, the acid gas adsorbent 10 adsorbs the acid gas contained in the mixed gas. The adsorption operation is carried out, for example, until the adsorption of the acid gas by the acid gas adsorbent 10 reaches equilibrium.

[0153] (Desorption operation) The desorption operation of the acid gas recovery device 300 is carried out, for example, as follows. First, purge gas is sent into the casing through the above purge gas inlet, and the purge gas is discharged from the desorbed gas outlet to the outside of the casing. By this operation, the mixed gas remaining inside the casing can be discharged to the outside of the casing, and the inside of the casing can be filled with the purge gas. As the purge gas, for example, a gas containing a high concentration of acid gas such as water vapor gas or carbon dioxide can be used. In addition, instead of or together with the operation of sending the purge gas into the casing, an operation of reducing the pressure inside the casing may be performed. This pressure reduction operation can be carried out, for example, by a pressure reduction device connected to the desorbed gas outlet of the casing.

[0154] Next, while the purge gas is being supplied into the casing, the heat medium 61 is sent into the medium path 60. As the heat medium 61, hot water, high-temperature gas, etc. can be used. Specific examples of the gas contained in the high-temperature gas are freon, carbon dioxide, air, water vapor, etc. The heat medium 61 can be prepared, for example, by utilizing waste heat, heat pump, self-heat regeneration, etc.

[0155] By sending the heat medium 61 into the medium path 60, heat exchange occurs between the heat medium 61 and the acid gas adsorbent 10 through the medium path 60, and the acid gas adsorbent 10 is heated. The heating temperature of the acid gas adsorbent 10 is, for example, 50 to 80°C. Thereby, the acid gas is desorbed from the acid gas adsorbent 10. The desorbed gas desorbed from the acid gas adsorbent 10 is discharged from the desorbed gas outlet together with the purge gas. Thereby, the acid gas can be recovered. When the purge gas contains water vapor, the purge gas discharged from the desorbed gas outlet can be cooled and the water vapor can be condensed to remove the water vapor. In addition, it is not always necessary to use the heat medium 61 to heat the acid gas adsorbent 10. For example, when the support 2 functions as a planar heater, the acid gas adsorbent 10 may be heated by energizing the support 2.

[0156] The acid gas recovery device 300 is configured such that the heat medium 61 does not come into direct contact with the desorbed gas during the desorption operation. According to this acid gas recovery device 300, acid gas can be efficiently recovered. The recovered acid gas, particularly carbon dioxide, can be used as a raw material for chemical synthesis or dry ice.

[0157] (Preliminary operation) After the desorption operation, the acid gas recovery device 300 may perform a preliminary operation for performing the adsorption operation. The preliminary operation is carried out, for example, as follows. First, the supply of the purge gas into the casing is stopped, and the heat medium 61 is discharged from the medium path 60. Next, a cooling medium is sent to the medium path 60. As the cooling medium, an antifreeze liquid or the like can be used. Heat exchange occurs between the cooling medium and the acid gas adsorbent 10 through the medium path 60, and the acid gas adsorbent 10 is cooled. The acid gas adsorbent 10 is cooled to, for example, room temperature (25 °C). After the cooling of the acid gas adsorbent 10, the cooling medium is discharged from the medium path 60, and the preparation for the adsorption operation is completed.

[0158] <Modification example of the acid gas recovery device> The acid gas recovery device is not limited to the one shown in Fig. 6A. For example, in the acid gas recovery device 310 shown in Fig. 6B, a medium path 60 is formed between two acid gas adsorbents 10. Specifically, in the acid gas recovery device 310, among a plurality of voids formed between a plurality of acid gas adsorbents 10, some voids function as the medium path 60, and the remaining voids function as the ventilation path 14. The medium path 60 and the ventilation path 14 are arranged alternately along the arrangement direction of the plurality of acid gas adsorbents 10. The acid gas recovery device 310 typically has a structure similar to that of a plate heat exchanger in which a plurality of heat transfer plates are stacked.

[0159] In the acid gas recovery device 310, it is preferable that the acid gas adsorbent 10 includes a support 2 together with the porous sheet 1. In the acid gas recovery device 310, for example, the porous sheet 1 included in the acid gas adsorbent 10 faces the ventilation path 14, and the support 2 faces the medium path 60. In the acid gas recovery device 310, a spacer 65 is disposed in the ventilation path 14, and a spacer (not shown) is also disposed in the medium path 60. These spacers are configured to secure the ventilation path 14 and the medium path 60, introduce an appropriate fluid into each path, and further prevent the fluid from leaking into other paths. In FIG. 6B, the ventilation path 14 is connected to the external space of the acid gas recovery device 310 in the depth and the front of the paper surface, and thus, the mixed gas may be configured to be taken into the ventilation path 14 from the external space. Further, during the desorption operation of the acid gas recovery device 310, a member for blocking these connections may be disposed between the ventilation path 14 and the external space.

[0160] The acid gas recovery device 310 further includes a restraint member 70 that restrains a plurality of acid gas adsorbents 10. The restraint member 70 has, for example, a pair of plate members 71a, 71b, a rod 72, and a fixing member 73. The plate members 71a and 71b are arranged in the arrangement direction of the plurality of acid gas adsorbents 10 and sandwich the plurality of acid gas adsorbents 10. According to the plate members 71a and 71b, pressure can be applied to the plurality of acid gas adsorbents 10 in the arrangement direction. The plate members 71a and 71b may be formed with a desorbed gas outlet, a purge gas inlet, a medium inlet, a medium outlet, etc., which are described above for the acid gas recovery device 310.

[0161] Each of the plate members 71a and 71b has a through hole formed therein, and the rod 72 is inserted into the through holes of the plate members 71a and 71b. The rod 72 may be a bolt having a male thread portion formed on its side surface. The fixing member 73 fixes, for example, one of the plate members 71a and 71b and the rod 72 to each other. The fixing member 73 is typically a nut having a female thread portion that can be screwed with the rod 72. The restraining member 70 has a fixing member 73a that fixes the plate member 71a and the rod 72 to each other, and a fixing member 73b that fixes the plate member 71b and the rod 72 to each other.

[0162] In the example of FIG. 6B, each of the two rods 72 is fixed by a fixing member 73. However, the number of rods 72 and the like are not limited to the example of FIG. 6B.

[0163] The acid gas recovery device 310 can implement an operation method similar to the operation method described above for the acid gas recovery device 300. In the acid gas recovery device 310, a medium path 60 is formed between the two acid gas adsorbents 10. According to this configuration, in the desorption operation, the heat medium can uniformly heat the entire acid gas adsorbent 10 by passing through the medium path 60.

[0164] Furthermore, unlike the acid gas recovery device 300, the acid gas recovery device 310 is configured such that the ventilation path 14 does not interfere with the medium path 60. Therefore, in the acid gas recovery device 310, in the adsorption operation, the pressure loss caused by the mixed gas passing through the ventilation path 14 tends to be small.

[0165] The acid gas recovery device 310 makes it easier to remove members such as the acid gas adsorbent 10 compared to the acid gas recovery device 300. By removing the acid gas adsorbent 10 from the acid gas recovery device 310, it is easy to replace the acid gas adsorbent 10. Furthermore, by removing each member of the acid gas recovery device 310, it is easy to perform maintenance such as a cleaning operation on each member.

Example

[0166] 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.

[0167] (Example 1) First, 5.22 g of poly(1,2-butanediol)-6 propylene glycol (manufactured by NOF Corporation, UNION (registered trademark) PB-500) and 5.22 g of polyoxypropylene diglyceryl ether (manufactured by NOF Corporation, UNILUBE (registered trademark) DGP-700) were added to a 50 mL round-bottom screw neck flask (manufactured by AS ONE Corporation). To the resulting mixture, 2.55 g of ethylene glycol diglycidyl ether (manufactured by Nagase ChemteX Corporation, EX-810) and 3.83 g of pentaerythritol tetraglycidyl ether (manufactured by Showa Denko KK, SHOWFREE (registered trademark) PETG) were dissolved to prepare a mixed solution of epoxy monomer and porogen.

[0168] Next, 6.57 g of triethylenetetramine (manufactured by Tosoh Corporation) was added to this mixed solution to prepare a mixed solution of epoxy monomer, amine monomer, and porogen. In this mixed solution, the ratio (E / A) of the equivalent (E) of the epoxy group contained in the epoxy monomer to the equivalent (A) of the active hydrogen of the primary amino group contained in the amine monomer was 0.4.

[0169] Next, a tabletop shaker (Angel Vibrator Digital 60 Hz) was set to intensity 5, and the mixture was shaken for 2 minutes. Next, using an applicator with a gap of 350 μm, this mixture was applied onto an aluminum sheet with a thickness of 20 μm. The obtained coating film was cured by leaving it stationary in a dryer at 120°C for 30 minutes. As a result, a sheet-like cured body containing polymer P having an amino group was obtained. The operation of immersing this cured body in ethyl acetate at 60°C for 30 minutes was repeated twice with liquid replacement. As a result, the porogen was removed from the cured body, and a porous sheet was formed. Next, it was dried in a dryer at 60°C for 30 minutes, and the aluminum sheet was removed to obtain the acid gas adsorbent (self-supporting film of the porous sheet) of Example 1. In Example 1, the porous sheet had a three-dimensional network-like skeleton composed of polymer P.

[0170] In Example 1, the porous sheet had a thickness of 215 μm and a basis weight of 13.03 mg / cm 2 and the porosity calculated from the true density of polymer P and the like was 45%. The density of amino groups in polymer P calculated from the monomer mixing ratio was 13.87 mmol / g. The amount of substance of amino groups per unit volume of the porous sheet was 8.39 mmol / cm 3 .

[0171] (Example 2) First, except that the compounding amounts of the epoxy monomer, amine monomer, and porogen were changed as shown in Table 1, these mixed solutions were prepared in the same manner as in Example 1. Next, a tabletop shaker (Enzel Vibrator Digital 60 Hz) was set to intensity 5, and the mixed solution was shaken for 2 minutes. Next, using an applicator with a gap of 500 μm, this mixed solution was applied onto a glass paper (PHN-50GC, manufactured by Oji Efftex Co., Ltd.) with a thickness of 250 μm. At this time, the mixed solution penetrated into the inside of the glass paper. The glass paper into which the mixed solution had penetrated was left standing in a dryer at 120°C for 30 minutes to cure the mixed solution. Thereby, a sheet-like cured body containing the polymer P having an amino group and the glass paper as a filler was obtained. The operation of immersing this cured body in ethyl acetate at 60°C for 30 minutes was repeated twice with liquid replacement. Thereby, the porogen was removed from the cured body, and a porous sheet was formed. Next, by drying in a dryer at 60°C for 30 minutes, the acidic gas adsorbent (self-supporting film of the porous sheet) of Example 2 containing the glass paper as a filler was obtained. In Example 2, the porous sheet had a three-dimensional network skeleton composed of the polymer P.

[0172] In Example 2, the basis weight of the acidic gas adsorbent (porous sheet) was 15.8 mg / cm 2 . Note that the value obtained by subtracting the basis weight of the glass paper (5.0 mg / cm 2 ) from the basis weight of the acidic gas adsorbent (15.8 mg / cm 2 ) (10.8 mg / cm 2 ) can be regarded as the basis weight of the three-dimensional network skeleton composed of the polymer P. The theoretical thickness of the three-dimensional network skeleton calculated from the true density of the polymer P (1.1 g / cm 3 ) and the porosity of the three-dimensional network skeleton (45%) was 179 μm. The density of amino groups in the polymer P calculated from the monomer compounding ratio was 12.38 mmol / g. The amount of substance of amino groups per unit volume of the three-dimensional network skeleton contained in the porous sheet was 7.49 mmol / cm 3It was. Furthermore, the amount of substance of amino groups per unit volume of the porous sheet was 5.27 mmol / cm 3 It was.

[0173] (Examples 3 to 6) Except for using the fiber structures shown in Table 1 instead of glass paper, acidic gas adsorbents (self-supporting films of porous sheets) of Examples 3 to 6 were obtained by the same method as in Example 2. In each of Examples 3 to 6, the porous sheet had a three-dimensional network skeleton composed of polymer P.

[0174] (Comparative Example 1) First, as a porous body, 3.00 g of porous silica (SUNSPERA H-52 manufactured by AGC Inc.) with a pore volume of 1.5 mL / g, a specific surface area of 700 m 2 / g, a pore diameter of 10 nm, and a true density of 2.2 g / mL was prepared and immersed in 60 g of methanol (special grade manufactured by Fujifilm Wako Pure Chemical Corporation) overnight to prepare a dispersion. Next, 0.447 g of triethylenetetramine (TETA, manufactured by Sigma-Aldrich) was prepared as an amine monomer, and 0.174 g of ethylene glycol diglycidyl ether (EX-810, manufactured by Nagase ChemteX Corporation) and 0.261 g of pentaerythritol tetraglycidyl ether (manufactured by Showa Denko KK, SHOWFREE (registered trademark) PETG) were prepared as epoxy monomers. The ratio (E / A) of the equivalent (E) of epoxy groups contained in the epoxy monomer to the equivalent (A) of active hydrogen of primary amino groups contained in the amine monomer was 0.4.

[0175] Next, these monomers were added to the above dispersion liquid. As a result, the compound group (TETA, EX-810, and PETG) penetrated into the pores of the porous body, and the compound group came into contact with the surface of the pores of the porous body. Next, using a rotary evaporator, the dispersion liquid was heated at a temperature of 60°C in a reduced-pressure atmosphere. As a result, the reaction of the compound group proceeded, and the solvent contained in the dispersion liquid was distilled off. Next, the porous body was dried by heating it at a temperature of 80°C in a vacuum atmosphere. Thereby, an acidic gas adsorbent of Comparative Example 1 in which Polymer P was supported on the porous body was obtained. In the acidic gas adsorbent of Comparative Example 1, the three-dimensional network skeleton described above for the examples did not exist.

[0176] (Comparative Examples 2 to 6) Except that the blending amounts of the epoxy monomer and the amine monomer were changed as shown in Table 1, acidic gas adsorbents of Comparative Examples 2 to 6 were obtained by the same method as in Comparative Example 1. In the acidic gas adsorbents of Comparative Examples 2 to 6, the three-dimensional network skeleton described above for the examples did not exist.

[0177] [Cross-sectional Observation of Porous Sheet] Regarding the porous sheet produced in Example 1, its cross-section was observed using a scanning electron microscope (SEM). The obtained SEM image is shown in FIG. 7. As can be seen from FIG. 7, the porous sheet had a three-dimensional network skeleton composed of Polymer P.

[0178] [BET Specific Surface Area] Regarding the acidic gas adsorbents produced in Examples 1 to 2 and Comparative Examples 1 to 6, the BET specific surface area by nitrogen gas adsorption was measured. The BET specific surface area was measured using a specific surface area measuring device (trade name "BELSORP-mini", manufactured by MicrotracBEL Corporation) by a method conforming to the provisions of JIS Z8830:2013.

[0179] [Glass Transition Temperature Tg] For the polymer P contained in the acid gas adsorbents prepared in the examples and comparative examples, the glass transition temperature Tg was measured by the following method. First, a polymer having the same composition as the polymer P contained in the acid gas adsorbent was synthesized. Approximately 5 mg of this polymer was set in a differential scanning calorimeter (DSC2500 manufactured by TA Instruments). Using this apparatus, the temperature was raised from 30 °C to 200 °C at a heating rate of 10 °C / min under a nitrogen atmosphere and held at that temperature for 1 minute. Next, it was cooled to -50 °C at a cooling rate of 10 °C / min, held at that temperature for 1 minute, and then further heated to 200 °C at a heating rate of 10 °C / min. In the DSC curve during the second heating, the first baseline before the appearance of the specific heat change, the second baseline after the appearance of the specific heat change, and among the bent portions due to the specific heat change, the tangent passing through the point where the slope is maximum were specified. The intermediate temperature between the intersection of the first baseline and the tangent and the intersection of the second baseline and the tangent was specified as the glass transition temperature Tg.

[0180] [True density] For the polymer P contained in the acid gas adsorbents prepared in the examples and comparative examples, the true density was specified by the following method. First, a mixed solution containing an epoxy monomer and an amine monomer was prepared with the same blending amounts as the mixed solutions used in the examples and comparative examples. Next, a tabletop shaker (Enzel vibrator digital 60 Hz) was set to an intensity of 5 and the mixed solution was shaken for 2 minutes. The mixed solution was poured into a PFA petri dish with an inner diameter of 75 mm and cured by allowing it to stand in a dryer at 120 °C for 30 minutes. Thereby, a cured body containing the polymer P having an amino group was obtained. The operation of immersing this cured body in ethyl acetate at 60 °C for 30 minutes was repeated twice with liquid replacement to remove the monomers remaining in the cured body. Next, a cured body composed of the polymer P was obtained by drying in a dryer at 60 °C for 30 minutes. For this cured body, the density was measured by a method compliant with JIS K7112:1999 (Method for measuring the density and specific gravity of non-foamed plastics) using an electronic specific gravity meter (EW-300SG, manufactured by Alpha Mirage), and the obtained measured value was regarded as the true density of the polymer P.

[0181] [Amount of substance of amino groups per unit volume] For the acid gas adsorbents of Comparative Examples 1 to 6, the amount of substance of amino groups per unit volume was specified by the following method. First, the acid gas adsorbent was set in a simultaneous thermal analysis DSC / TGA apparatus (DSC6500, manufactured by TA Instruments). Using this apparatus, the temperature was raised from 30°C to 100°C at a heating rate of 10°C / min under a nitrogen atmosphere and held at that temperature for 40 minutes (Operation 1). Thereby, the water contained in the acid gas adsorbent was removed. Next, the temperature was raised from 100°C to 800°C at a heating rate of 10°C / min and held at that temperature for 5 minutes (Operation 2). Thereby, the polymer P was removed from the acid gas adsorbent.

[0182] Next, the ratio of the weight (g) of the acid gas adsorbent after performing the above Operation 1 to the weight (g) of the acid gas adsorbent before setting in the apparatus (weight retention rate W1 (%)) and the ratio of the weight (g) of the acid gas adsorbent after performing the above Operation 2 to the weight (g) of the acid gas adsorbent before setting in the apparatus (weight retention rate W2 (%)) were specified. Using the weight retention rates W1 and W2, the ratio F of the weight (g) of the polymer P to the weight (g) of the acid gas adsorbent was calculated by the following formula. Ratio F = 1 - (1 / W1) × W2

[0183] Next, the volume A (mL) of the porous body per 1 g, the weight B (g) of the polymer P with respect to 1 g of the porous body, the density C (g / mL) of the composite particles composed of the porous body and the polymer P, and the density D of the amino groups in the composite particles were calculated by the following formulas, respectively. Volume A (mL) = pore volume (mL) of the porous body per 1 g + weight (g) of the porous body / true density (g / mL) of the porous body Weight B (g) = ratio F / (1 - ratio F) × weight (g) of the porous body Density C (g / mL) of the composite particles = (weight (g) of the porous body + weight B (g)) / volume A (mL) Density D (mmol / g) of the amino groups = ratio F × density (mmol / g) of the amino groups in the polymer P

[0184] Furthermore, the amount of substance E of amino groups per unit volume of the acid gas adsorbent was calculated by the following formula. In the following formula, the packing fraction of the composite particles was the value (0.74) assumed when the composite particles were most densely packed in the acid gas adsorbent. Amount of substance E (mmol / cm 3 ) = Density C (g / mL) of composite particles × Packing fraction of composite particles × Density D (mmol / g) of amino groups in composite particles

[0185]

Table 1

[0186]

Table 2

[0187] The abbreviations in Table 1 are as follows. EX-810: Ethylene glycol diglycidyl ether (manufactured by Nagase ChemteX Corporation, EX-810) PETG: Pentaerythritol tetraglycidyl ether (manufactured by Showa Denko K.K., SHOWFREE (registered trademark) PETG) TETA: Triethylenetetramine (manufactured by Tosoh Corporation) PB-500: Poly(1,2-butanediol)-6 propylene glycol (manufactured by NOF Corporation, UNIONOL (registered trademark) PB-500) DGP-700: Polyoxypropylene diglyceryl ether (manufactured by NOF Corporation, UNILUBE (registered trademark) DGP-700) PHN-50GC: Glass paper (pulp-containing nonwoven fabric) (manufactured by Oji Efftex Corporation, PHN-50GC) MP-22: Pulp-containing nonwoven fabric (manufactured by Nippon Paper Papiria Co., Ltd., MP-22) PY120-01: Synthetic fiber nonwoven fabric (manufactured by Awa Paper Co., Ltd., PY120-01) PY120-32: Synthetic fiber nonwoven fabric (manufactured by Awa Paper Co., Ltd., PY120-32) 120H-PB: Pulp-containing nonwoven fabric (manufactured by Nippon Paper Papiria Co., Ltd., 120H-PB base paper)

[0188] [Carbon dioxide adsorption amount] For the acid gas adsorbents of Example 1 and Comparative Examples 1 to 3, the carbon dioxide adsorption amount was measured by the method described above. At this time, in Example 1, a measurement sample obtained by cutting the acid gas adsorbent so that the area of the main surface was 4.72 cm 2 was used. In Comparative Examples 1 to 3, measurement samples whose weights were adjusted to be the same volume as the measurement sample used in Example 1 were used. The weights of the measurement samples in Comparative Examples 1 to 3 were 49 mg, 64 mg, and 76 mg, respectively. For Comparative Examples 1 to 3, the weights of the measurement samples having the same volume as the measurement sample used in Example 1 were calculated by the following formula using the density C (g / mL) of the composite particles composed of the porous body and Polymer P and the packing ratio of the composite particles. In the following formula, the packing ratio of the composite particles adopted a numerical value (0.74) assuming that the composite particles were most densely packed in the acid gas adsorbent. Weight of the measurement sample in the comparative example (mg) = Volume of the measurement sample in Example 1 (cm 3 ) × Density C (g / mL) × Packing ratio of the composite particles

[0189] For Example 1 and Comparative Examples 1 to 3, the measurement results of the carbon dioxide adsorption amount are shown in FIG. 8. FIG. 8 is a graph showing the relationship between the time since the start of the adsorption test and the carbon dioxide adsorption amount by the acid gas adsorbent. From FIG. 8, it was confirmed that the carbon dioxide adsorption amount saturated and stabilized at a predetermined time. As can be seen from FIG. 8, the acid gas adsorbent of Example 1 had a larger carbon dioxide adsorption amount per unit volume than Comparative Examples 1 to 3 and was suitable for the adsorption of acid gas. The carbon dioxide adsorption amount a when the acid gas adsorbent of Example 1 was brought into contact with the above-described mixed gas G for 15 hours was 1.45 mmol / cm 3 .

[0190] Furthermore, for the acid gas adsorbents of Example 2 and Comparative Examples 4 to 6, the carbon dioxide adsorption amount was measured by the method described above. At this time, in Example 2, the area of the main surface was 5.76 cm 2An acid gas adsorbent cut to have a specific size was used as a measurement sample. In Comparative Examples 4 to 6, measurement samples with weights adjusted to have approximately the same volume as the measurement sample used in Example 2 were used. The weights of the measurement samples in Comparative Examples 4 to 6 were 50 mg, 60 mg, and 72 mg, respectively. For Comparative Examples 4 to 6, the weights of the measurement samples having approximately the same volume as the measurement sample used in Example 2 were calculated by the same method as described above for Comparative Examples 1 to 3.

[0191] For Example 2 and Comparative Examples 4 to 6, the measurement results of the carbon dioxide adsorption amount are shown in Fig. 9. Fig. 9 is a graph showing the relationship between the time since the start of the adsorption test and the carbon dioxide adsorption amount by the acid gas adsorbent. From Fig. 9, it was confirmed that the carbon dioxide adsorption amount saturated and stabilized at a predetermined time. As can be seen from Fig. 9, the acid gas adsorbent of Example 2 had a larger carbon dioxide adsorption amount per unit volume than Comparative Examples 4 to 6 and was suitable for the adsorption of acid gas. The carbon dioxide adsorption amount a when the acid gas adsorbent of Example 2 was brought into contact with the above-mentioned mixed gas G for 15 hours was 1.27 mmol / cm 3 It was.

[0192] From the above results, it can be seen that the acid gas adsorbents of Examples 1 and 2 having a porous sheet with a three-dimensional network skeleton containing Polymer P had a larger carbon dioxide adsorption amount than the comparative examples and were suitable for the adsorption of acid gas. The acid gas adsorbents of the other Examples 3 to 6 had the same configuration as Example 2 except for the type of fiber structure used as the filler. Therefore, it is estimated that the acid gas adsorbents of Examples 3 to 6 have the same level of adsorption performance for acid gases such as carbon dioxide as Example 2.

[0193] Since the amount of substance of amino groups per unit volume of the acidic gas adsorbent of the example is relatively large, it is suitable for adjusting the thickness of the porous sheet to be small while maintaining the adsorption performance of the acidic gas. According to the porous sheet with a small thickness, for example, the cross-sectional area of the ventilation path of a structure made using the acidic gas adsorbent, particularly a honeycomb structure, can be adjusted to be large. A structure with a large cross-sectional area of the ventilation path is suitable for reducing the pressure loss that occurs when in contact with the acidic gas. Thus, it can be said that the acidic gas adsorbent of the example is suitable for reducing the pressure loss that occurs in the structure provided with the acidic gas adsorbent.

[0194] (Calculation Example 1) Next, it was assumed that an acidic gas adsorbent was produced using a sheet-like structure formed by aggregation of porous alumina particles. Specifically, it was assumed that the polymer P produced in Example 1 was filled into the pores of the porous particles in the sheet-like structure to produce an acidic gas adsorbent. The amount of substance of amino groups per unit volume of this acidic gas adsorbent was calculated by the following method. In the following calculations, additives such as binders that are usually required for conventional acidic gas adsorbents were not considered.

[0195] First, it was assumed that the porous particles had a pore volume of 1.25 mL / g, a specific surface area of 175 m 2 / g, a pore diameter of 20 nm, and a true density of 3.8 g / mL. The ratio F of the weight of polymer P to the weight of the acidic gas adsorbent (weight of polymer P (g) / (weight of polymer P (g) + weight of porous particles (g))) was assumed to be 0.39.

[0196] The volume A of the porous particles per 1 g was calculated to be 1.51 mL by the following formula. Volume A (mL) = pore volume of porous particles per 1 g (mL) + weight of porous particles (g) / true density of porous particles (g / mL) = 1.25 + 1 / 3.8 = 1.51 (mL)

[0197] In the acid gas adsorbent, the weight B of polymer P with respect to 1 g of the porous particles was calculated to be 0.639 g by the following formula. Weight B (g) = Weight ratio F of polymer P / (1 - Weight ratio F of polymer P) × Weight (g) of porous particles = 0.39 / (1 - 0.39) × 1 = 0.639 (g)

[0198] The density C of the composite particles composed of the porous particles and polymer P was calculated to be 1.08 g / mL by the following formula. Density C (g / mL) of composite particles = (Weight (g) of porous particles + Weight B (g) of polymer P) / Volume A (mL) of porous particles per 1 g = (1 + 0.639) / 1.51 = 1.08 (g / mL)

[0199] The density D of amino groups in the above composite particles was calculated to be 5.4 mmol / g by the following formula. Density D (mmol / g) of amino groups = Ratio F of weight of polymer P × Density (mmol / g) of amino groups in polymer P = 0.39 × 13.87 = 5.4 (mmol / g)

[0200] In Calculation Example 1, the amount of substance E of amino groups per unit volume of the acid gas adsorbent was calculated to be 4.34 mmol / cm 3 as follows. In the following formula, the packing fraction of the composite particles was the value (0.74) assumed when the composite particles were most densely packed in the acid gas adsorbent. Amount of substance E of amino groups (mmol / cm 3 ) = Density C (g / mL) of composite particles × Packing fraction of composite particles × Density D (mmol / g) of amino groups in composite particles = 1.08 × 0.74 × 5.4 = 4.34 (mmol / cm 3 )

[0201] From the amount of substance E of amino groups, the maximum amount of carbon dioxide that the acid gas adsorbent in Calculation Example 1 can adsorb is 0.75 mmol / cm 3It was calculated that it is so. From this result, it can be seen that the acid gas adsorbents of Examples 1 and 2 have higher adsorption performance for acid gases such as carbon dioxide than the acid gas adsorbent of Calculation Example 1.

[0202] [Tensile Strength of Fiber Structure] Regarding the fiber structures used in Examples 2 to 6, the tensile strengths S TD and S MD were measured by the above method. As the tensile testing machine, an autograph device (AGS-50NX, manufactured by Shimadzu Corporation) was used. Table 3 shows the tensile strengths S TD and S MD as well as the test force when the test piece had a 3% elongation.

[0203] [Dimensional Change Rate] Regarding the porous sheets produced in Examples 2 to 6, the dimensional change rates R TD and R MD were measured by the above method.

[0204]

Table 3

[0205] As can be seen from Table 3, the higher the tensile strength of the fiber structure as a filler, the lower the dimensional change rate of the porous sheet tended to be. In particular, in Examples 2 to 5 where the tensile strength S TD of the fiber structure was 2 MPa or more, the dimensional change rate R TD of the porous sheet was a sufficiently low value. From the above results, it is estimated that the porous sheets of Examples 2 to 6, particularly Examples 2 to 5, are less likely to fall off from the support or the acid gas recovery device during use. Furthermore, it is also estimated that these porous sheets are less likely to deform during use and are less likely to cause hindrance to the passage of gas due to deformation.

Industrial Applicability

[0206] The acid gas adsorbent of this embodiment can adsorb, for example, carbon dioxide in the atmosphere.

Claims

1. A porous sheet containing a polymer, wherein the polymer has an amino group, the porous sheet has a three-dimensional network skeleton composed of the polymer, and the glass transition temperature of the polymer is 40°C or lower, an acidic gas adsorbent.

2. A porous sheet containing a polymer, wherein the polymer has an amino group, the porous sheet has a three-dimensional network skeleton composed of the polymer, and the amount of carbon dioxide adsorbed when contacted with a mixed gas composed of carbon dioxide, nitrogen, and water vapor for 15 hours is 0.1 mmol / cm3 or more, an acidic gas adsorbent. Here, the concentration of carbon dioxide in the mixed gas is 400 volppm, the mixed gas has a temperature of 20°C, and a humidity of 50% RH.

3. The porous sheet contains continuous pores formed continuously in three dimensions, the acidic gas adsorbent according to claim 1 or 2.

4. The porous sheet contains the polymer as a main component, the acidic gas adsorbent according to claim 1 or 2.

5. The amino group contains a secondary amino group, the acidic gas adsorbent according to claim 1 or 2.

6. The polymer is an epoxy polymer containing a structural unit derived from an amine monomer, the acidic gas adsorbent according to claim 1 or 2.

7. The specific surface area of the porous sheet is 1.0 m 2 / g or more, and the acidic gas adsorbent according to claim 1 or 2.

8. The porosity of the porous sheet is 20% or more, the acidic gas adsorbent according to claim 1 or 2.

9. The acidic gas adsorbent according to claim 1 or 2 further includes a support for supporting the porous sheet.

10. The acidic gas adsorbent according to claim 1 or 2 has a flat plate shape or a corrugated shape.

11. The acidic gas adsorbent according to claim 1 or 2, a ventilation path, and a structure.

12. An adsorption part having a gas inlet and a gas outlet, wherein the adsorption part houses the acidic gas adsorbent according to claim 1 or 2, an acidic gas adsorption device.

13. The acidic gas adsorbent according to claim 1 or 2, a medium path, and, during a desorption operation for desorbing the acidic gas adsorbed by the acidic gas adsorbent from the acidic gas adsorbent, a heat medium for heating the acidic gas adsorbent passes through the medium path, an acidic gas recovery device.

14. The medium path penetrates the acidic gas adsorbent in the thickness direction of the acidic gas adsorbent, the acidic gas recovery device according to claim 13.

15. comprising the two acidic gas adsorbents, The acidic gas recovery apparatus according to claim 13, wherein the medium path is formed between the two acidic gas adsorbents.

16. The acidic gas recovery apparatus according to claim 13, wherein after the desorption operation, a cooling medium for cooling the acidic gas adsorbent passes through the medium path.

17. A method for producing the acidic gas adsorbent according to claim 1 or 2, a step (I) of curing a mixed solution containing a compound group containing an amine monomer and a porogen to obtain a cured body; a step (II) of removing the porogen from the sheet-like cured body to obtain the porous sheet; A method for producing an acidic gas adsorbent, comprising:

18. In the step (I), the manufacturing method according to claim 17, wherein the mixed solution is applied onto a support, and the obtained coating film is cured to obtain the sheet-like cured body.

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