Porous member

Abstract

A porous member disclosed herein is used for adsorbing a target substance. This porous member includes a resin matrix and functional particles which adsorb the target substance. The resin matrix has a three-dimensional mesh structure including pores. The functional particles are held inside the three-dimensional mesh structure of the resin matrix.

Description

Porous material

[0001] This disclosure relates to a porous material used for adsorbing a target substance. This international application claims priority to Japanese Patent Application No. 2025-031138, filed on 28 February 2025, the entire contents of which are incorporated herein by reference.

[0002] Exhaust gases emitted from thermal power plants, factories, automobiles, etc., contain various harmful components, and there is a need to develop materials and technologies for selectively separating and recovering them. For example, carbon dioxide (CO2) ２ ) can be a cause of global warming. Also, nitrogen dioxide (NOx) ２ NOx such as ) can cause photochemical smog and have adverse effects on the human body. To efficiently separate and recover such components, materials comprising an active substance such as an adsorbent or catalyst and a carrier that supports the active substance are used. Related technologies are disclosed, for example, in Japanese Patent Publication No. 2014-533195 and Japanese Patent Publication No. 2018-505071.

[0003] Furthermore, not only exhaust gases from factories and other facilities, but also wastewater may contain components that can have adverse effects on human health and the environment. For example, wastewater may contain PFAS (a general term for perfluoroalkyl compounds and polyfluoroalkyl compounds). Because PFAS are difficult to decompose in living organisms, they accumulate in the environment for long periods, raising concerns about adverse effects on ecosystems and human health. Activated carbon, for example, is used to adsorb PFAS.

[0004] Special table No. 2014-533195 Publication No. 2018-505071

[0005] Functional particles with the ability to adsorb the target substance are widely used to adsorb it. Functional particles can include those that carry active substances such as adsorbents or catalysts, or those that possess adsorption capabilities themselves. The smaller the functional particle, the larger its specific surface area, and therefore the higher its adsorption capacity. However, smaller functional particles are difficult to handle, leading to challenges such as the risk of exposure to workers and difficulties in placement and recovery. When functional particles are placed in exhaust pipes, drainage pipes, etc., they can block the flow path and cause increased pressure loss. On the other hand, if relatively large functional particles are used to facilitate handling, the specific surface area decreases, and the adsorption capacity of the functional particles tends to be not fully exhibited. Furthermore, even when relatively large functional particles are used, the flow path tends to narrow, and pressure loss tends to increase. Therefore, there is a need for technology that utilizes functional particles with adsorption capacity while suppressing the increase in pressure loss.

[0006] One aspect of the technology disclosed herein is a porous member used for adsorbing a target substance. This porous member comprises a resin matrix and functional particles that adsorb the target substance. The resin matrix has a three-dimensional network structure including pores. The functional particles are held within the three-dimensional network structure of the resin matrix.

[0007] With this configuration, the resin matrix has a three-dimensional network structure containing pores, thus ensuring a pathway for fluids such as gases and liquids to flow. Furthermore, the functional particles are held within the three-dimensional network structure of the resin matrix. Therefore, clogging by the functional particles can be prevented, and an increase in pressure loss can be suppressed.

[0008] In one preferred embodiment of the porous member disclosed herein, the ratio (B / A) of the average particle diameter B (μm) of the functional particles to the average pore diameter A (μm) of the resin matrix is ​​0.1 or more and 10 or less. This allows the functional particles to exhibit their adsorption capacity suitably while suppressing an increase in pressure loss.

[0009] In a preferred embodiment of the porous member disclosed herein, the average pore diameter A of the resin matrix is 1 µm or more and 85 µm or less. This can further suppress an increase in pressure loss.

[0010] In a preferred embodiment of the porous member disclosed herein, the ratio (B / A) of the average particle diameter B (µm) of the functional particles to the average pore diameter A (µm) of the resin matrix is 0.7 or more. This makes it difficult for the functional particles to fall off from the resin matrix.

[0011] In a preferred embodiment of the porous member disclosed herein, the hot water resistance is 120°C or more and 250°C or less. This allows the porous member to be used even in high-temperature environments.

[0012] In a preferred embodiment of the porous member disclosed herein, the resin matrix contains a resin having a glass transition temperature of 70°C or more and 250°C or less. This allows the porous member to be used even in high-temperature environments.

[0013] In a preferred embodiment of the porous member disclosed herein, the resin matrix is formed into a network structure by three-dimensional bonding of crystalline resin particles or amorphous resin. This increases the amount of functional particles per volume retained inside the three-dimensional network structure of the resin matrix, and improves the efficiency of adsorbing the target substance.

[0014] The porous member disclosed herein may be used for adsorbing the target substance contained in a liquid.

[0015] Fig. 1 is a diagram schematically showing the structure of a porous member according to an embodiment.

[0016] Some embodiments of the technology disclosed herein will be described below. Matters other than those specifically mentioned herein but necessary for implementation can be understood based on the technical content taught herein and the common technical knowledge of those skilled in the art. The technology disclosed herein can be implemented based on the content disclosed herein and the common technical knowledge of the art. In this specification, the designation "A to B" indicates a range of A to B.

[0017] <Porous Member> Figure 1 is a schematic diagram showing the structure of a porous member 10 according to one embodiment. Figure 1 is a schematic diagram of the porous member 10 as viewed from the surface. As shown in Figure 1, the porous member 10 disclosed herein includes a resin matrix 20 and functional particles 30. The resin matrix 20 has a three-dimensional network structure including pores 22. The functional particles 30 are held inside the three-dimensional network structure of the resin matrix 20. The porous member 10 is used to adsorb a target substance. The target substance may be, for example, a component contained in a gas or a component contained in a liquid. Examples of gases that may contain the target substance include air, exhaust gas, flue gas, biogas, gases generated in the cement manufacturing process, gases generated in the ironmaking process or the manufacturing process of steel products, etc. Examples of components contained in gases that may be the target substance include CO ２ Examples include greenhouse gases, harmful components that can affect living organisms such as NOx and VOCs (volatile organic compounds), etc. Components that can be contained in the liquid as the target substance include, for example, persistent components such as PFAS, and industrially usable components such as ammonia and metals. Examples of liquids that may contain such target substances include industrial wastewater, industrial wastewater, domestic wastewater, sewage, river water, seawater, dam water, and chemical solutions.

[0018] The porous member 10 can be molded into a sheet, a rectangular parallelepiped, a cube, a prismatic shape, a cylindrical shape, a sphere, or the like. While not particularly limited, the porous member 10 is preferably in the form of a sheet. When the porous member 10 is in the form of a sheet, for example, it is preferable that its thickness is 0.3 mm or more and 5 mm or less. Also, while not particularly limited, it is preferable that each side of the sheet-shaped porous member 10 is, for example, 0.3 mm or more, or 1 mm or more. This makes it easier to handle the porous member 10. The upper limit of each side of the sheet-shaped porous member 10 is not particularly limited and can be adjusted as appropriate according to the location where the porous member 10 is placed, but from the viewpoint of manufacturing efficiency, for example, the upper limit of each side may be, for example, 1000 mm or less, 500 mm or less, 200 mm or less, 100 mm or less, 50 mm or less, or 30 mm or less.

[0019] <Resin Matrix> As shown in Figure 1, the resin matrix 20 has a three-dimensional network structure including pores 22. That is, the resin matrix 20 has a plurality of pores 22 and has a porous structure. The resin matrix 20 can function as a framework in the porous member 10. The pores 22 of the resin matrix 20 may be interconnected pores. The pores 22 of the resin matrix 20 may include through-holes that penetrate from one side of the porous member 10 to the other.

[0020] The average pore diameter A of the resin matrix 20 is, for example, 0.5 μm or more, preferably 1 μm or more, more preferably 1.2 μm or more, and particularly preferably 1.3 μm or more. This allows for a suitable reduction in the pressure loss of the porous member 10. If the average pore diameter A of the resin matrix 20 is too large, the strength of the porous member 10 may become insufficient. From this viewpoint, the average pore diameter A of the resin matrix 20 is preferably, for example, 100 μm or less, 81.1 μm or less, 35 μm or less, 15 μm or less, 12 μm or less, 10.6 μm or less, 9 μm or less, or 8.6 μm or less. The "average pore diameter of the resin matrix" can be determined by the mercury intrusion method using a commercially available mercury porosimeter on the porous member 10.

[0021] The resin matrix 20 contains resin and may be constructed by bonding crystalline particles of the resin or by bonding amorphous resin. In other words, unlike an aggregate of resin fibers, the resin matrix 20 is preferably a matrix of resin binders constructed in a three-dimensional network by bonding crystalline particles of resin or amorphous resin in three dimensions. With such a configuration, the amount of functional particles 30 per unit volume held inside the three-dimensional network structure of the resin matrix 20 can be increased, and the efficiency of adsorption of the target substance can be improved. The resin matrix 20 may have both a portion in which crystalline particles of resin are bonded and a portion composed of amorphous resin.

[0022] While not particularly limited, the resin matrix 20 preferably contains a resin with a glass transition temperature (Tg) of 70°C or higher. This improves the heat resistance of the porous member 10. The glass transition temperature of the resin contained in the resin matrix 20 is, for example, 70°C or higher, preferably 100°C or higher, more preferably 120°C or higher, and even more preferably 150°C or higher. The higher the glass transition temperature of the resin matrix 20, the higher the heat resistance of the porous member 10. This allows the porous member 10 to be used against high-temperature gases passing through the exhaust pipes of vehicles and factories, or against hot water. The glass transition temperature of the resin contained in the resin matrix 20 is not particularly limited, but may be, for example, 260°C or lower, or 250°C or lower. The "glass transition temperature of the resin" can be measured according to conventionally known differential scanning calorimetry (DSC) measurement or dynamic viscoelasticity measurement (DMA method).

[0023] Furthermore, although not particularly limited, the resin matrix 20 preferably contains a resin with high heat water resistance. This improves the heat water resistance of the porous member 10. The heat water resistance of the resin contained in the resin matrix 20 is preferably 120°C or higher, more preferably 140°C or higher, and may be 150°C or higher, or 160°C or higher. The heat water resistance of the resin contained in the resin matrix 20 is preferably, for example, 300°C or lower, may be 250°C or lower, or 200°C or lower. Note that the "heat water resistance of the resin" can be determined by measuring the deflection temperature under load in accordance with JIS K 7191-2:2015.

[0024] The resin content is not particularly limited, but is preferably 10% to 90% by mass, more preferably 20% to 80% by mass, and even more preferably 20% to 40% by mass, when the total mass of the porous member 10 is considered as 100% by mass. This allows for a favorable improvement in the balance between the strength of the porous member 10 and the pressure loss reduction effect.

[0025] While not particularly limited, the resin components included in the resin matrix 20 include acrylic resins, cellulose resins, and resins classified as super engineering plastics. The resin matrix 20 may contain one of the above-mentioned resins alone, or it may contain two or more in combination.

[0026] The term "acrylic resin" encompasses all polymers and their derivatives that contain alkyl (meth)acrylate as a constituent monomer component. In this specification, the terms "(meth)acrylate," etc., are used to comprehensively mean acrylate and / or methacrylate. Examples of acrylic resins include polymers containing alkyl (meth)acrylate as a main monomer (a component accounting for 50% or more by mass of the total monomer) and copolymers containing such main monomer and sub-monomers copolymerizable with the main monomer. Specifically, examples include poly(meth)acrylic acid, poly(meth)acrylamide, and polymethyl methacrylate (PMMA). Among these, the acrylic resin used in the resin matrix 20 preferably contains methacrylic acid and / or PMMA.

[0027] Cellulose resins encompass all compounds derived from cellulose (cellulose derivatives). Specifically, examples include ethylcellulose (EC), hydroxyethylcellulose (HEC), ethylmethylcellulose (EMC), hydroxyethylmethylcellulose (HEMC), nitrocellulose, and diacetylcellulose. Among these, the cellulose resin used in the resin matrix 20 preferably contains ethylcellulose.

[0028] Super engineering plastics are resins characterized by, for example, excellent heat resistance and excellent mechanical strength. Examples of super engineering plastics include fluorine-based resins such as polytetrafluoroethylene (PTFE), tetrafluoroethylene perfluorovinyl ether copolymer (PFA), tetrafluoroethylene hexafluoropropylene copolymer (FEP), chlorotrifluoroethylene homopolymer (PCTFE), ethylene tetrafluoroethylene copolymer (ETFE), ethylene chlorotrifluoroethylene copolymer (ECTFE), and vinylidene fluoride homopolymer (PVDF); thermoplastic polyimides such as polybenzimidazole (PBI), polyimide (PI), polyetherimide (PEI), and polyamideimide (PAI); and polyethersulfone (PES), polyetheretherketone (PEEK), polyphenylene sulfide (PPS), PSU (polysulfone), and polyphenylsulfone (PPSU). The super engineering plastic used in the resin matrix 20 preferably includes PEI, PI, PES, PVDF, PSU, and / or PPSU.

[0029] <Functional Particles> In the porous member 10 disclosed herein, functional particles 30 are held within the three-dimensional network structure of the resin matrix 20. That is, the functional particles 30 are held in the voids between the meshes of the three-dimensional network structure of the resin matrix 20. The functional particles 30 may be held by being surrounded by the resin matrix 20. Alternatively, the functional particles 30 may be arranged and held inside the pores 22 of the resin matrix 20. The functional particles 30 may or may not be adhered to the resin matrix 20. Furthermore, a portion of the functional particles 30 may be present on the surface of the resin matrix 20 (outside the three-dimensional network structure). The presence of the resin matrix 20 and functional particles 30 in the porous member 10 can be confirmed, for example, by observing the surface or cross-section of the porous member 10 with a scanning electron microscope (SEM).

[0030] As shown in Figure 1, the functional particles 30 are dispersed in the resin matrix 20. In other words, most of the functional particles 30 contained in the porous member 10 are spaced apart from each other. For example, more than 70% of the functional particles 30 may be spaced apart from each other, or more than 80% may be spaced apart from each other. Conventional structures employ methods such as forming particle necks by firing or binding particles together with a binder, which can reduce the surface area of ​​the functional particles. However, in this technology, the reduction in the surface area of ​​the functional particles 30 due to contact between the functional particles 30 is suppressed, so that the adsorption capacity of the functional particles 30 can be fully exhibited.

[0031] Functional particles 30 have the ability to adsorb the target substance. Functional particles 30 may themselves have the ability to adsorb the target substance. Alternatively, functional particles 30 may be particles on which an adsorbent or catalyst having the ability to adsorb the target substance is supported on the surface of a particle acting as a carrier. Furthermore, particles having the ability to adsorb the target substance may have an additional adsorbent or catalyst added to them.

[0032] The type of functional particle 30 is not particularly limited, as it is appropriately selected according to the target substance to be adsorbed. Examples of functional particles 30 that themselves have adsorption capacity include zeolites, activated carbon, and metal-organic frames (MOFs). Zeolites can adsorb, for example, NOx, ammonia, ammonium ions, and metal ions. Activated carbon can adsorb, for example, PFAS, VOCs, and metal ions. MOFs can adsorb, for example, CO ２ It can adsorb VOCs, ammonia, hydrogen sulfide, and other substances.

[0033] When the functional particles 30 are particles on which an adsorbent or catalyst having the ability to adsorb a target substance is supported on the surface of the particles serving as a carrier, in addition to the above-mentioned particles, for example, silica particles, alumina particles, ceria particles, zirconia particles, titania particles, etc. can be used as the carrier. As for the adsorbent supported on the particles, for example, when the target substance to be adsorbed is an acidic gas (for example, CO ２ , H ２S, etc.), for example, an amine compound can be preferably used as the adsorbent. In addition, when the target substance to be adsorbed is a basic gas, iron (III) sulfate (FeSO ４ ), metaphosphoric acid (HPO ３ ) can be used. The method for supporting an adsorbent, a catalyst, or the like on the particles may follow known methods.

[0034] The amine compound is, for example, various compounds having at least one primary amino group (NH ２ -). The amine compound may contain a secondary amino group and / or a tertiary amino group in addition to the primary amino group. The amine compound may be solid or liquid at normal temperature. For the amine compound, during gas adsorption (for example, CO ２ adsorption), it becomes solid, and during gas desorption (CO ２ desorption), it becomes liquid (for example, isophoronediamine, etc.). Such an amine compound may be used as the amine compound serving as the adsorbent.

[0035] Examples of amine compounds include amines, polyamines, and compounds having primary to tertiary amino groups such as aminoorganosilanes. Examples of amines include monoethanolamine, diethanolamine, triethanolamine, and isoholodiamine. Examples of polyamines include polyethyleneimine, polypropyleneimine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine. Examples of aminoorganosilanes include (3-aminopropyl)trimethoxysilane (APTMS), N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-amino-propyltriethoxysilane, N-(2-aminoethyl)-3-amino-propylmethyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and N-(n-butyl)-3-aminopropyltrimethoxysilane. Furthermore, compounds with partially modified functional groups may be used as amine compounds. The amine compound may be used individually or in combination of two or more. In particular, the amine compound preferably contains polyalkylene imines such as polyethyleneimine and polypropyleneimine.

[0036] The functional particles 30 may contain only one type of the above-mentioned particles, or they may contain two or more types.

[0037] The shape of the functional particles 30 is not particularly limited and may be spherical or non-spherical. Examples of non-spherical functional particles 30 include plate-like, flaky, or irregularly shaped particles.

[0038] The average particle diameter B of the functional particles 30 is not particularly limited. If the average particle diameter B of the functional particles 30 is too small, they tend to detach easily from the resin matrix 20. From this viewpoint, the average particle diameter B of the functional particles 30 may be, for example, 100 nm or more, 1 μm or more, 3 μm or more, or 5 μm or more. On the other hand, from the viewpoint of increasing the specific surface area of ​​the functional particles 30, the average particle diameter B of the functional particles 30 is, for example, 100 μm or less, preferably 50 μm or less, more preferably 15 μm or less, and even more preferably 12 μm or less. In this specification, "average particle diameter of functional particles" refers to the arithmetic mean of the equivalent circle diameter measured based on optical microscope observation. Here, the equivalent circle diameter refers to the diameter of a circle having the same area as the area of ​​an ellipse formed by the longest diameter of the functional particles observed in the microscope image, which is the major axis, and the longest diameter of the line intersecting the major axis at a right angle, which is the minor axis. In this specification, the average particle diameter of functional particles refers to the arithmetic mean of the equivalent circular diameters of 200 randomly selected functional particles.

[0039] The ratio (B / A) of the average particle diameter B (μm) of the functional particles 30 to the average pore diameter A (μm) of the resin matrix 20 may be, for example, 0.1 or more, 0.3 or more, 0.7 or more, 1 or more, greater than 1, or 1.1 or more. B / A is preferably 0.7 or more. This makes it more difficult for the functional particles 30 to detach from the resin matrix 20. B / A is, for example, 20 or less, preferably 10 or less, and more preferably 9 or less. The lower the B / A, the more the pressure loss tends to be reduced.

[0040] While not particularly limited, the functional particles 30 may be porous particles having multiple pores. The porous nature of the functional particles 30 increases their specific surface area, which can improve their adsorption capacity. The functional particles 30 may, for example, be a mesoporous material having multiple mesopores. "Mesopore" refers to a pore with a diameter in the range of 2 nm or more and less than 50 nm, based on the IUPAC classification. When the functional particles 30 are a mesoporous material, the average pore diameter is preferably, for example, 2 nm or more, more preferably 10 nm or more, and even more preferably 12 nm or more. This allows for the appropriate introduction of adsorbents and the like into the pores. Furthermore, when the functional particles 30 are a mesoporous material, the average pore diameter is preferably, for example, 100 nm or less, more preferably 70 nm or less, even more preferably 50 nm or less, even more preferably less than 50 nm, for example 40 nm or less, and particularly preferably 30 nm or less. This allows for a favorable increase in the specific surface area of ​​the functional particles 30, further improving the adsorption capacity of the functional particles 30. The "average pore size of the functional particles" can be measured for a porous material using a commercially available pore size distribution measuring device and the pore size distribution by gas adsorption method based on the BJH method.

[0041] Furthermore, although not particularly limited, the functional particles 30 may be, for example, a microporous material having multiple micropores. "Micropore" refers to a pore with a diameter of 2 nm or less, based on the IUPAC classification. When the functional particles 30 are a microporous material, the average pore diameter is preferably, for example, 0.1 nm or more, more preferably 0.5 nm or more, and even more preferably 1 nm or more. This makes it easier for the target substance to be introduced into the pores, and the target substance can be adsorbed suitably. Alternatively, when the functional particles 30 are a microporous material, the average pore diameter may be, for example, 2 nm or less, 1.8 nm or less, or 1.6 nm or less. This increases the specific surface area of ​​the functional particles 30, and the target substance can be adsorbed more suitably.

[0042] From the viewpoint of increasing the contact area between the functional particles 30 and the target substance, it is preferable that the specific surface area of ​​the functional particles 30 is large. Although not particularly limited, the specific surface area of ​​the functional particles 30 measured by the BET method (BET specific surface area) is, for example, 100 m². ２ It is 1 / g or more, preferably 200m ２ It is 1 / g or more. Also, the specific surface area of ​​the functional particle 30 is, for example, 3000 m². ２ / g or less, 2000m ２ / g or less, 1000m ２ / g or less, or 500m ２ It may be less than or equal to / g. In this specification, the "BET specific surface area of ​​functional particles" can be measured by nitrogen adsorption using a commercially available specific surface area measuring device.

[0043] Furthermore, from the viewpoint of increasing the amount of adsorbent supported, it is preferable that the functional particles 30 have a high oil absorption capacity. Although not particularly limited, the oil absorption capacity of the functional particles 30 is preferably, for example, 100 mL / 100 g or more and 400 mL / 100 g or less, and more preferably 130 mL / 100 g or more and 380 mL / 100 g or less. The "oil absorption capacity of porous particles" can be measured using a general absorption capacity measuring device, with DBP (dibutyl phthalate) as the reagent liquid, in accordance with JIS K6217-4 (2008).

[0044] The amount of functional particles 30 when the total mass of the porous member 10 is 100% by mass may be, for example, 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, or 60% by mass or more. The greater the amount of functional particles 30, the better the adsorption capacity of the target substance. On the other hand, if the amount of functional particles 30 is too large, the pressure loss of the porous member 10 may increase. For this reason, the amount of functional particles 30 when the total mass of the porous member 10 is 100% by mass may be, for example, 90% by mass or less, 85% by mass or less, or 80% by mass or less.

[0045] While not particularly limited, in the porous member 10, the mass ratio of the functional particles 30 to the resin constituting the resin matrix 20 is preferably, for example, 10:90 to 90:10, more preferably 20:80 to 80:20, and even more preferably 60:40 to 80:20. This allows for a suitable balance between the adsorption capacity of the target substance and the reduction of pressure loss.

[0046] <Properties of the Porous Member> Although not particularly limited, the water absorption rate of the porous member 10 based on the Archimedes method is preferably 140% or more, more preferably 145% or more, even more preferably 147% or more, and may be 190% or more, or 200% or more. By having a high water absorption rate of the porous member 10, the adsorption of the target substance in the liquid can be improved. From this viewpoint, a higher water absorption rate is preferable, and there is no particular upper limit. For example, the water absorption rate of the porous member 10 based on the Archimedes method may be 400% or less, 370% or less, or 350% or less. Note that the "water absorption rate of the porous member" can be calculated based on the Archimedes method. More specifically, the dry weight W of the porous member Ａｉｒ , underwater weight W Ａｑ , water content W ａ＋ｗ The water absorption rate (Aw) can be calculated by measuring the water absorption rate and using the following formula (1). Aw (%) = (W ａ＋ｗ -W Ａｉｒ ) / W Ａｉｒ ×100 (1)

[0047] While not particularly limited, the porosity of the porous member 10 based on the Archimedes method is preferably 65% ​​or more, more preferably 70% or more, and even more preferably 75% or more. This can improve the adsorption of the target substance and reduce pressure loss. The porosity of the porous member 10 based on the Archimedes method is preferably 90% or less, and may be 86% or less. The "porosity of the porous member" can be calculated based on the Archimedes method. More specifically, the dry weight W of the porous member Ａｉｒ , underwater weight W Ａｑ, water content W ａ＋ｗ The porosity (P) can be calculated by measuring the following formula (2): P (%) = (W ａ＋ｗ -W Ａｉｒ ) / (W ａ＋ｗ -W Ａｑ ) × 100 (2)

[0048] Furthermore, although not particularly limited, the porous member 10 preferably has high resistance to hot water. The heat resistance of the porous member 10 is preferably 120°C or higher, more preferably 140°C or higher, and may be 150°C or higher, or even 160°C or higher. This allows the porous member 10 disclosed herein to be suitably used even in environments exceeding 100°C or in relatively humid environments. The heat resistance of the porous member 10 is preferably, for example, 250°C or lower, and may be 200°C or lower. The "heat resistance of the porous member" can be evaluated by drying the porous member immersed in hot water in an autoclave and measuring its strength by a conventionally known tensile test.

[0049] As described above, the porous member 10 has a three-dimensional network structure in the resin matrix 20 that includes pores 22, thus ensuring a path for fluids such as gases and liquids to flow. Furthermore, the functional particles 30 are held inside the three-dimensional network structure of the resin matrix 20. Therefore, clogging of the functional particles 30 can be prevented, and an increase in pressure loss can be suppressed. In addition, the functional particles 30 are larger in size than when handled as they are, making them easier to handle.

[0050] <Method for Manufacturing Porous Members> Next, an example of a method for manufacturing the porous member 10 disclosed herein will be described. The porous member 10 disclosed herein may include a preparation step of preparing a slurry for forming a molded body, a molding step of producing a molded body from the slurry for forming a molded body, an immersion step of immersing the molded body in an aqueous solvent, and a drying step of drying the molded body after the immersion step. However, the porous member 10 disclosed herein is not limited to those manufactured by the following manufacturing method.

[0051] In the preparation step, a slurry-like composition (slurry for forming molded articles) containing at least functional particles 30, a resin, and an organic solvent is prepared. As an example, in the preparation step, the functional particles 30 are added to the organic solvent and stirred. This disperses the functional particles 30 in the organic solvent. Next, the resin is added to the organic solvent in which the functional particles 30 are dispersed and stirred. This dissolves the resin in the organic solvent. Although not particularly limited, in the preparation step, it is preferable to add the functional particles 30 and the resin to the organic solvent and stir while heating it to 40°C to 60°C.

[0052] As the functional particles 30, the functional particles 30 described above can be suitably used. However, if the functional particles 30 contain an adsorbent, it is preferable to prepare only the particles as a carrier. As the resin, a resin that dissolves in an organic solvent and precipitates in a network structure in the immersion step described later can be suitably used. Among these, PEI, PI, PES, PVDF, PSU, and / or PPSU are preferred. The mass ratio of the functional particles 30 to the resin is preferably 10:90 to 70:30, more preferably 20:80 to 65:35, and even more preferably 55:45 to 65:35.

[0053] The organic solvent is not particularly limited as long as it can dissolve the resin. Examples of organic solvents include amides such as diethylformamide, dimethylacetamide, dimethylformamide, N-methylpyrrolidone (NMP), and dimethylimidazolidinone; alkyl ketones such as dimethyl sulfoxide (DMSO), acetone, and methyl ethyl ketone; ethers such as tetrahydrofuran, dioxane, and diglyme; and glycol ethers such as ethylene glycol and diethylene glycol. These may be used individually or in combination of two or more. The mass ratio of the organic solvent contained in the slurry for forming the molded article is not particularly limited. Preferably, the content of the organic solvent in the slurry for forming the molded article is, for example, 30% to 80% by mass. This allows for the production of a suitable molded article in the molding process.

[0054] Furthermore, the slurry for forming the molded article may contain conventionally known additives, provided that these additives do not significantly impair the effects of the technology disclosed herein. Examples of such additives include dispersants, plasticizers, defoamers, and thickeners. For example, nonionic surfactants such as polyethylene glycol (PEG), polyvinyl alcohol (PVA), and glycerin can be preferably used as additives. By adjusting the amount of nonionic surfactant, the pore size of the precipitated resin matrix 20 can be controlled. The additive content in the slurry for forming the molded article is preferably 30% by mass or less, but may also be 20% by mass or less, 10% by mass or less, 5% by mass or less, 3% by mass or less, 1.5% by mass or less, or 1% by mass or less.

[0055] In the molding process, the molded body is formed using the prepared slurry for molded body formation. For example, a sheet-like molded body can be produced by supplying the slurry for molded body formation to a glass substrate with a predetermined thickness using a doctor blade. Alternatively, a molded body of a desired shape can be produced by extruding the slurry for molded body formation into a predetermined shape, printing on a metal plate or metal mesh, or dip-coating a core material.

[0056] In the immersion step, the molded body prepared in the molding step is immersed in an aqueous solvent (for example, water). As a result, the organic solvent contained in the molded body is replaced by the aqueous solvent, and the resin precipitates. The areas where the organic solvent contained in the molded body is replaced by the aqueous solvent become pores 22, and when the resin precipitates, the resin matrix 20 described above is suitably formed. Since the functional particles 30 are dispersed in the organic solvent, the resin matrix 20 is formed to enclose the functional particles 30, and the functional particles 30 are arranged inside the three-dimensional network structure of the resin matrix 20.

[0057] The aqueous solvent used in the immersion process is not particularly limited. The aqueous solvent may be, for example, water, a mixed solution of water and alcohol, or water with a surfactant added. Preferably, ion-exchanged water (deionized water), pure water, ultrapure water, distilled water, etc., can be used as the aqueous solvent.

[0058] In the drying process, the molded body after the immersion process is dried to remove the aqueous solvent from the molded body. This allows for the suitable production of a porous member 10 having the structure described above. The drying means in the drying process are not particularly limited, and for example, a hot air dryer, a low-humidity air dryer, a vacuum dryer, various infrared dryers, an electromagnetic induction dryer, a microwave dryer, dry air, etc., or drying acceleration means such as blowing air, reducing pressure, and heating can be used alone or in combination. The drying temperature in the drying process (setting temperature of the drying device, etc.) can be appropriately selected depending on the type and amount of solvent in the mixture, but can be set to, for example, 60°C to 150°C, preferably 80°C to 120°C. The drying time can also be appropriately selected depending on the type and amount of aqueous solvent, and is not particularly limited.

[0059] As described above, the porous member 10 can be suitably manufactured. When using particles on which an adsorbent is supported as the functional particles 30, the adsorbent can be supported on the particles, for example, after the drying process, according to a known method for supporting the adsorbent on the particles.

[0060] <Test Examples> The following describes test examples related to the technology disclosed herein, but it is not intended that the technology disclosed herein is limited to these test examples.

[0061] [Test 1] In Test 1, the target substance was CO ２ CO ２ We conducted tests on porous materials used for adsorption.

[0062] <Fabrication of Porous Components> (Example 1) Porous silica particles having multiple mesopores as functional particles (manufactured by Grace, SiO2 ２190 g of silica particles (average particle size 9.5 μm), 100 g of polyetherimide (PEI) as the resin to form the resin matrix, 700 g of dimethyl sulfoxide (DMSO) as the organic solvent, and 30 g of polyethylene glycol (PEG) as an additive were prepared. This prepared the slurry for forming the molded body of Example 1. Next, the slurry for forming the molded body of Example 1 was applied to a glass substrate to a thickness of 2 mm using a doctor blade to obtain a sheet-like molded body. The sheet-like molded body was immersed in water for 24 hours. Then, the molded body after immersion in water was dried at 80°C for 5 hours to obtain the sheet-like carrier structure (carrier sheet) of Example 1. In this carrier sheet, it was confirmed that the prepared silica particles were held within the three-dimensional network structure of the resin matrix.

[0063] Next, ethanol and polyethyleneimine (Epomin, PEI012, manufactured by Nippon Shokubai Co., Ltd.) were mixed in a 1:1 mass ratio, and the mixture was stirred for 24 hours using a stirrer with a rotor rotated at 150 rpm. The carrier sheet obtained from Example 1 was cut to a size of φ6 mm, thickness 1 mm, and weight 1 g. This carrier sheet piece was added to 15 g of the stirred solution and shaken for 24 hours. The carrier sheet piece was recovered from the solution, and its surface was washed with ethanol. Then, it was dried at 80°C for 5 hours. This yielded the porous member (porous sheet) of Example 1 on which the amine compound was supported.

[0064] (Comparative Example 1) Porous silica beads having multiple mesopores (manufactured by Fuji Silicia Co., Ltd., average particle size 3.5 mm) were prepared. An amine compound was supported on these silica beads in the same manner as in Example 1 to obtain the porous member of Comparative Example 1. The porous member of Comparative Example 1 was in the form of beads and was not processed into a sheet.

[0065] <Measurement of Average Pore Diameter of Resin Matrix Before Amine Loading> The average pore diameter of the resin matrix in the porous member of Example 1 before amine loading was measured using the mercury intrusion method. Specifically, first, the porous member of Example 1 before amine loading was cut to a size of approximately 5 mm x 5 mm, placed in water, and ultrasonic waves were applied to remove powder through the mesh. Then, the porous member from which the powder had been removed was dried at 80°C for 4 hours. Next, mercury was introduced using a mercury porosimeter (Auto Pole IV 9500, manufactured by Micromeritic) in the range of 0.10 to 60000 psi to obtain the pore distribution. From the peak position of the obtained pore distribution, the average pore diameter A (μm) of the resin matrix in the porous member of Example 1 before amine loading was calculated. The results are shown in Table 1.

[0066] <CO ２ Measurement of adsorption rate > CO2 in porous material for each example ２ The adsorption rate was determined as follows: First, the porous material of each example after drying was placed in a glass tube. At this time, the CO2 of each example was ２ The amount of saturation adsorption was made to be the same. In Example 1, multiple pieces of porous material cut to approximately φ6 mm × 1 mm thick were prepared and placed in a glass tube. He gas was passed through the glass tube, and moisture and CO adsorbed on the porous material were removed. ２ and N ２ A pretreatment was performed to remove CO2. During this treatment, He gas was flowed for 3 hours at a temperature of 100°C and a gas flow rate of 30 mL / min. Subsequently, 5% CO2 was applied to each of the pretreated porous members. ２ -N ２ The gas was circulated. At this time, 5% CO2 was present. ２ -N ２ The gas was circulated under the conditions of temperature: 60°C and gas flow rate: 30 mL / min. A mass spectrometer (Microtrac-Bel, Belcat, BEL Mass) was used to analyze the CO content of the exhaust gas. ２ and N ２ CO was detected. ２ Concentration and CO2 emissions from the exhaust gas ２ The concentration becomes the same (i.e., CO of the porous material) ２ The gas is circulated until adsorption is saturated, CO２ A breakthrough curve was obtained. The CO2 gas used was... ２ Concentration and CO2 emissions from the exhaust gas ２ The time it took for the concentration to become the same was defined as the adsorption rate. The adsorption rate in Example 1 was converted as a relative value when the adsorption rate of Comparative Example 1 was set to 1. The results are shown in Table 1.

[0067] <Measurement of Pressure Loss> The porous material for each example was packed into a cylindrical column. At this time, the weight of the silica particles in the porous material for each example was made to be the same. In Example 1, multiple pieces of the porous material cut to approximately 4 mm x 20 mm were prepared and packed into the column. Nitrogen gas was circulated from the inlet side of the column, and the pressure at the inlet and outlet sides of the column was measured using a pressure gauge, and the differential pressure was determined. When the differential pressure was 50 Pa or less, it was marked as "○" (Good), and when it was greater than 50 Pa, it was marked as "×" (Bad), and the results are shown in Table 1.

[0068] Table 1 shows the ratio of the average particle diameter B of the functional particles (silica particles) to the average pore diameter A of the resin matrix in Example 1, expressed as "B / A".

[0069]

[0070] As shown in Table 1, the porous member of Example 1 has a higher CO2 content than the porous member of Comparative Example 1. ２ It can be seen that the adsorption rate is fast and the pressure loss is small.

[0071] [Test 2] In Test 2, a porous material using zeolite particles was tested.

[0072] <Preparation of Porous Material> (Example 2) Instead of the silica particles used in Example 1, powder-type porous zeolite particles (average particle size 3.1 μm, manufactured by Resonaq Universal Co., Ltd., product name: HiSiv3000) were prepared. The materials were mixed in a mass ratio of zeolite particles:polyimide (PI):DMSO = 37:10:53 to prepare the slurry for forming the molded body of Example 2. Next, the slurry for forming the molded body of Example 2 was applied to a glass substrate to a thickness of 1 mm using a doctor blade to obtain a sheet-like molded body. The sheet-like molded body was immersed in water for 24 hours. The molded body after immersion in water was dried at 80°C for 5 hours to obtain the porous material (porous sheet) of Example 2.

[0073] (Comparative Example 2) Pellet-type porous zeolite particles (φ1.5 mm, length 5 mm, manufactured by Resonaq Universal Co., Ltd., product name: HiSiv3000) were used as the porous material in Comparative Example 2. That is, the porous material in Comparative Example 2 was in pellet form and was not processed into a sheet form.

[0074] <NO ２ Measurement of adsorption amount > NO of porous members in Example 2 and Comparative Example 2 ２ The amount of adsorption was determined as follows. First, the porous material of each example after drying was placed in a glass tube. At this time, the amount of functional particles was made to be the same for each example. In Example 2, multiple pieces of the porous material were cut to a width of 4 mm, a length of 20 mm, and a thickness of approximately 1 mm, and placed in a glass tube. He gas was circulated through the glass tube to perform a pretreatment to remove moisture and gas adsorbed on the porous material. At this time, the He gas was circulated for 3 hours under the conditions of temperature: 100°C and gas flow rate: 30 mL / min. Next, 3000 ppm NO was added to the porous material of each example after pretreatment. ２ Air gas was circulated. At this time, 3000 ppm NO ２ The air gas was circulated under the conditions of temperature: 60°C and flow rate: 30 mL / min. NO content in the exhaust gas was measured using a mass spectrometer (Microtrac-Bel, Belcat, BEL Mass). ２ and N included in air２ NO was detected. ２ Concentration and NO of the exhaust gas ２ The concentration becomes the same (i.e., NO in porous material) ２ The gas is passed through until adsorption is saturated, NO ２ A breakthrough curve was obtained. N2 was obtained from the exhaust gas. ２ The start time t1 is when it is detected (i.e., 3000 ppm NO from He gas) ２ After being switched to air gas, 3000 ppm NO ２ (When the air gas is first discharged from the glass tube), NO of the gas used ２ Concentration and NO of the exhaust gas ２ The point at which the concentration becomes equal to the final stage t2 is defined as the theoretically detectable NO from t1 to t2. ２ The difference from the total amount is the NO of each example of porous material. ２ The amount of adsorption was calculated. The amount of adsorption in Example 2 was converted as a relative value when the amount of adsorption in Comparative Example 2 was set to 1. The results are shown in Table 2.

[0075] The average pore size of the resin matrix in Example 2, and the pressure drop in Example 2 and Comparative Example 2, were measured in the same manner as in Test 1. However, for the measurement of pressure drop, 3000 ppm NO was used. ２ / air gas was used. The results are shown in Table 2.

[0076]

[0077] As shown in Table 2, the porous member of Example 2 has a smaller pressure loss than the porous member of Comparative Example 2. Furthermore, the porous member of Example 2 has a lower NO content than the porous member of Comparative Example 2. ２ It can be seen that the adsorption capacity is high.

[0078] [Test 3] In Test 3, the target substance was PFAS, and a porous material for PFAS adsorption was tested.

[0079] <Preparation of Porous Material> (Example 3) As functional particles, porous activated carbon having multiple mesopores (average particle size 11.7 μm, manufactured by MC Evatec Co., Ltd., product name: Amasove®) was prepared. The materials were mixed in a mass ratio of activated carbon particles:polysulfone (PSU):N-methylpyrrolidone (NMP) = 32:8:60 to prepare the slurry for forming the porous material of Example 3. Next, the slurry for forming the porous material of Example 3 was applied to a glass substrate to a thickness of 2 mm using a doctor blade to obtain a sheet-like molded body. The sheet-like molded body was immersed in water for 24 hours. Then, the molded body after immersion in water was dried at 80°C for 5 hours to obtain the porous material (porous sheet) of Example 3.

[0080] (Example 4) In Example 3, PSU was replaced with polyphenylsulfone (PPSU), and NMP was replaced with DMSO. The mass ratio of each material remained the same as in Example 3: 32:8:60. The porous member (porous sheet) of Example 4 was obtained in the same manner as in Example 3.

[0081] (Example 5) In Example 3, PSU was replaced with polyetherimide (PEI), NMP was replaced with DMSO, and polyvinyl alcohol (PVA) was used as an additive. The porous member (porous sheet) of Example 5 was obtained in the same manner as in Example 3, except that the mass ratio of each material was changed to activated carbon particles:PEI:DMSO:PVA = 29:18:52.9:0.1.

[0082] (Example 6) A porous member (porous sheet) of Example 6 was obtained in the same manner as in Example 5, except that the mass ratio of each material was changed to activated carbon particles:PEI:DMSO:PVA = 29:18:51.5:1.5.

[0083] (Example 7) A porous member (porous sheet) of Example 7 was obtained in the same manner as in Example 5, except that the mass ratio of each material was changed to activated carbon particles:PEI:DMSO:PVA = 29:18:52:1.

[0084] (Comparative Example 3) Granular activated carbon (average particle size 500 μm, manufactured by MC Evatec Co., Ltd., product name: Amasorb) was prepared as the porous material for Comparative Example 3.

[0085] (Reference Example 1) The activated carbon particles used in Examples 3 to 7 were used as a porous material in powder form.

[0086] <Measurement of average pore diameter of resin matrix> The average pore diameter of the resin matrix in Examples 3 to 7 was measured in the same manner as in Test 1.

[0087] <Measurement of Pressure Loss> The porous material for each example was packed into a cylindrical column. At this time, the weight of the activated carbon particles in the porous material for each example was made to be the same. For the porous material of Examples 3 to 7, multiple pieces cut to approximately 2 mm x 6 mm were prepared and packed into the column. Water was passed through the inlet side of the column, and the pressure at the inlet and outlet sides of the column was measured with a pressure gauge, and the differential pressure was determined. When the differential pressure was 0.1 MPa or less, it was marked as "○" (Good), and when it was greater than 0.1 MPa, it was marked as "×" (Bad), and the results are shown in Table 3.

[0088] <Measurement of PFAS adsorption amount> PFAS water containing 1500 ng / L of PFAS was prepared. The porous material of each example was mixed into this PFAS water and shaken for 5 minutes. At this time, the weight of activated carbon particles in the porous material of each example was made to be the same. For the porous material of Examples 3 to 7, multiple pieces cut to approximately 2 mm x 6 mm were prepared and used. After shaking, the PFAS water mixed with the porous material was filtered by suction filtration through filter paper to remove the porous material from the PFAS water. The PFAS water after suction filtration was analyzed by LC / MS / MS to measure the remaining amount of PFAS. The results are shown in Table 3.

[0089]

[0090] In Reference Example 1, the activated carbon was in powder form and had a large surface area, resulting in high adsorption capacity for PFAS. However, its powdery form made it difficult to handle, and suction filtration was time-consuming due to clogging of the filter paper. On the other hand, in Examples 3 to 7, the sheet-like porous material consisted of activated carbon particles supported on a resin matrix with a three-dimensional network structure containing pores, resulting in low pressure loss and easy recovery from PFAS. Furthermore, the porous material in Examples 3 to 7 exhibited higher PFAS adsorption capacity than the granular activated carbon particles in Comparative Example 3.

[0091] The specific examples of the technology disclosed herein have been described in detail above, but these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples described above.

[0092] The technologies disclosed herein include the following sections 1 to 8. Sections 1 to 8 are not limited to the embodiments described above.

[0093] Item 1: A porous member used for adsorbing a target substance, comprising a resin matrix and functional particles for adsorbing the target substance, wherein the resin matrix has a three-dimensional network structure including pores, and the functional particles are held inside the three-dimensional network structure of the resin matrix.

[0094] Item 2: The porous member according to Item 1, wherein the ratio (B / A) of the average particle diameter B (μm) of the functional particles to the average pore diameter A (μm) of the resin matrix is ​​0.1 or more and 10 or less.

[0095] Item 3: The porous member according to item 1 or 2, wherein the average pore diameter A of the resin matrix is ​​1 μm or more and 85 μm or less.

[0096] Item 4: The porous member according to any one of items 1 to 3, wherein the ratio (B / A) of the average particle diameter B (μm) of the functional particles to the average pore diameter A (μm) of the resin matrix is ​​0.7 or more.

[0097] Item 5: A porous member according to any one of items 1 to 4, wherein the hot water resistance is 120°C or higher and 250°C or lower.

[0098] Item 6: A porous member according to any one of items 1 to 5, wherein the resin matrix contains a resin having a glass transition temperature of 70°C or more and 250°C or less.

[0099] Item 7: The porous member according to any one of items 1 to 6, wherein the resin matrix is ​​configured in a mesh-like structure by three-dimensional bonding of crystalline resin particles or amorphous resin.

[0100] Item 8: A porous member according to any one of items 1 to 7, used for adsorbing the above-mentioned target substance contained in a liquid.

[0101] 10 Porous material 20 Resin matrix 22 Pores 30 Functional particles

Claims

1. A porous member used for adsorbing a target substance, comprising a resin matrix and functional particles for adsorbing the target substance, wherein the resin matrix has a three-dimensional network structure including pores, and the functional particles are held within the three-dimensional network structure of the resin matrix.

2. The porous member according to claim 1, wherein the ratio (B / A) of the average particle diameter B (μm) of the functional particles to the average pore diameter A (μm) of the resin matrix is ​​0.1 or more and 10 or less.

3. The porous member according to claim 1, wherein the average pore size A of the resin matrix is ​​1 μm or more and 85 μm or less.

4. The porous member according to claim 1, wherein the ratio (B / A) of the average particle diameter B (μm) of the functional particles to the average pore diameter A (μm) of the resin matrix is ​​0.7 or more.

5. The porous member according to claim 1, wherein the heat resistance of water is 120°C or higher and 250°C or lower.

6. The porous member according to claim 1, wherein the resin matrix comprises a resin having a glass transition temperature of 70°C or higher and 250°C or lower.

7. The porous member according to claim 1, wherein the resin matrix is ​​configured in a mesh-like structure by three-dimensional bonding of crystalline resin particles or amorphous resin.

8. A porous member according to any one of claims 1 to 7, used for adsorbing the target substance contained in a liquid.

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