Adsorption sheet, adsorption element, and adsorption / desorption treatment device

Abstract

Provided is an adsorption sheet containing a porous material, fibers, and an organic binder. The adsorption sheet further contains a cationic surfactant. With this adsorption sheet, a silica-based inorganic adhesive is less likely to permeate. An adsorption element can be provided using the adsorption sheet, and a adsorption / desorption treatment device can also be provided using the adsorption element.

Description

Adsorption sheet, adsorption element, and adsorption / desorption treatment device

[0001] The present disclosure relates to an adsorption sheet capable of adsorbing substances to be adsorbed, such as moisture, organic solvents, and malodorous components contained in a gas to be treated, an adsorption element using this adsorption sheet, and an adsorption / desorption treatment device using this adsorption element.

[0002] Adsorption sheets are sheets containing porous materials such as silica gel and zeolite. A known method for manufacturing adsorption sheets is, for example, a wet papermaking process, in which a porous material, fiber, and an organic binder are mixed together to form a sheet. Adsorption elements are manufactured by forming one or more adsorption sheets into a predetermined shape or structure. For example, a honeycomb-structured adsorption element is manufactured by laminating a corrugated adsorption sheet onto a liner-shaped adsorption sheet using an adhesive, and then winding the resulting sheet into a rotor. The adsorption element is installed in the flow path of the gas to be treated in an adsorption / desorption treatment device. The adsorption / desorption treatment device brings the gas to be treated into contact with the adsorption element, thereby adsorbing the target substance contained in the gas to be treated onto the porous material in the adsorption element.

[0003] Here, silica-based inorganic adhesives such as water glass and silica sol are commonly used as adhesives for manufacturing honeycomb-structured adsorption elements, taking heat resistance into consideration (see, for example, Patent Document 1). However, silica-based inorganic adhesives contain a large amount of moisture and tend to soak into the adsorption sheets when applied to the adsorption sheets for lamination. If the adhesive soaks into the adsorption sheets before curing, the adsorption sheets cannot be bonded together, making it difficult to manufacture the adsorption element. Furthermore, if the adhesive soaks into the adsorption sheets before curing, the adhesive may penetrate the pores of the porous material in the adsorption element, blocking the pores and potentially reducing the adsorption performance of the porous material for the target substance.

[0004] Patent Publication No. 2021-181072

[0005] In order to solve the above-mentioned problems, the present disclosure aims to provide an adsorption sheet that is resistant to penetration by silica-based inorganic adhesives, an adsorption element using this adsorption sheet, and an adsorption / desorption treatment device using this adsorption element.

[0006] The present inventors have discovered that adding a cationic surfactant to the adsorbent sheet during the manufacturing process provides the adsorbent sheet with water repellency, which makes it difficult for the silica-based inorganic adhesive to penetrate into the adsorbent sheet. The adsorbent sheet, adsorption element, and adsorption / desorption treatment device of the present disclosure were invented based on this finding.

[0007] That is, in order to solve the above-mentioned problems, the present disclosure encompasses as its subject the adsorbent sheet described in the following item 1.

[0008] Item 1. An adsorbent sheet containing a porous material, fibers, and an organic binder, further containing a cationic surfactant.

[0009] The present disclosure also encompasses the adsorbent sheet described in the following item 2 as a preferred embodiment of the adsorbent sheet described in item 1 above.

[0010] Item 2. The adsorption sheet according to Item 1, wherein the cationic surfactant has a long alkyl chain and an amide moiety, and when analyzed by pyrolysis gas chromatography mass spectrometry, peaks of fragment ions at m / z=59 and 72, which are characteristic of a compound having an amide moiety containing a long alkyl chain, are detected.

[0011] The present disclosure also encompasses the adsorption sheet described in the following item 3 as a preferred embodiment of the adsorption sheet described in item 1 or 2 above.

[0012] Item 3. The adsorption sheet according to Item 1 or 2, wherein the cationic surfactant comprises a partial structure represented by the following chemical formula 1:

[0013]

[0014] (In chemical formula 1, R １ R contains an alkyl chain having 5 to 30 carbon atoms. ２ and R ３represents C or H.) The present disclosure also encompasses the adsorbent sheet described in the following item 4 as a preferred embodiment of the adsorbent sheet described in item 3 above.

[0015] Item 4. R in the cationic surfactant １ Item 4. An adsorbent sheet according to Item 3, wherein the alkyl chain and the amide moiety are present as a single compound or as separate compounds.

[0016] The present disclosure also encompasses the adsorbent sheet described in the following item 5 as a preferred embodiment of the adsorbent sheet described in any one of items 1 to 4 above.

[0017] Item 5. The adsorption sheet according to any one of Items 1 to 4, containing 40% by mass or more and 85% by mass or less of the porous material.

[0018] The present disclosure also encompasses the adsorbent sheet described in the following item 6 as a preferred embodiment of the adsorbent sheet described in any one of items 1 to 5 above.

[0019] Item 6. The adsorbent sheet according to any one of Items 1 to 5, wherein the fibers include non-fibrillated fibers and / or fibrillated fibers.

[0020] The present disclosure also encompasses the adsorption sheet described in the following item 7 as a preferred embodiment of the adsorption sheet described in any one of items 1 to 6 above.

[0021] Item 7. The adsorption sheet according to any one of Items 1 to 6, containing 3% by mass or more and 15% by mass or less of the organic binder.

[0022] In order to solve the above problems, the present disclosure encompasses as its subject the adsorption element described in the following item 8.

[0023] Item 8. An adsorption element that is a processed product comprising at least one adsorption sheet according to any one of items 1 to 7 and a silica-based inorganic adhesive.

[0024] In order to solve the above problems, the present disclosure includes as its subject the adsorption / desorption treatment device described in the following item 9.

[0025] Item 9. An adsorption / desorption treatment device comprising the adsorption element according to Item 8, configured to bring a gas to be treated into contact with the adsorption element so that at least a portion of the substance to be adsorbed contained in the gas to be treated is adsorbed by the porous material, and to bring a regeneration gas into contact with the adsorption element so that the substance to be adsorbed is desorbed from the porous material.

[0026] According to the present disclosure, it is possible to provide an adsorption sheet into which silica-based inorganic adhesives are resistant to penetration, an adsorption element using the adsorption sheet, and an adsorption / desorption treatment device using the adsorption element.

[0027] Figure 1 is an explanatory diagram illustrating a porous metal complex having open metal sites. Figure 2 is an explanatory diagram illustrating a porous metal complex having OH groups in the metal core unit. Figure 3(A) is a perspective view of a liner-shaped adsorption sheet, Figure 3(B) is a perspective view of a corrugated adsorption sheet, and Figure 3(C) is a perspective view of an adsorption sheet in which a corrugated adsorption sheet is laminated on a liner-shaped adsorption sheet. Figure 4(A) is a perspective view showing the procedure for forming an adsorption element, and Figure 4(B) is a perspective view of the adsorption element. Figure 5 is a schematic diagram of an adsorption / desorption treatment device.

[0028] Embodiments of the adsorption sheet, adsorption element, and adsorption / desorption treatment device of the present disclosure will be described below with reference to the accompanying drawings. The adsorption sheet, adsorption element, and adsorption / desorption treatment device of the present disclosure are used for various applications, such as air dehumidification, air deodorization, air purification, and gas separation. For example, they are used to reduce odorous components indoors, in vehicles, wallpaper, furniture, interior materials, resin molded bodies, electrical equipment, etc. Or they are used to separate and recover organic solvents in the air emitted from factories, etc. Or they are used to condition or dehumidify the air in spaces such as homes, buildings, condominiums, hospitals, factories, and commercial facilities, as well as various vehicles such as automobiles, trains, and airplanes.

[0029] <Adsorbent Sheet> The adsorbent sheet of the present disclosure adsorbs some of the gases contained in the gas to be treated, such as moisture, organic solvents, and malodorous components.

[0030] The adsorption sheet of the present disclosure contains a porous material, fibers, and an organic binder. The porous material is a material for adsorbing a target substance. The fibers are a material that forms the skeleton of the adsorption sheet. The organic binder is a material that fixes the porous material to the adsorption sheet and improves the strength, flexibility, etc. of the adsorption sheet.

[0031] <Porous Material> The porous material contained in the adsorption sheet is not particularly limited as long as it has the ability to adsorb the substance to be adsorbed, and can be appropriately selected from known porous materials depending on the substance to be adsorbed. Preferred examples of the porous material include zeolite, silica gel, and porous materials called porous metal complexes (PCPs) or metal-organic frameworks (MOFs).

[0032] Preferred examples of zeolite include natural zeolite, synthetic zeolite (also called molecular sieve), and artificial zeolite. The zeolite may be selected from the above-mentioned types depending on the purpose, but it is preferable to select synthetic zeolite from the viewpoint of stability of quality and performance.

[0033] Preferred examples of silica gel include type A silica gel and type B silica gel. When the substance to be adsorbed is a polar substance such as water or carbon dioxide, type A silica gel with a small average pore size or type RD silica gel with physical properties similar to type A silica gel are preferred from the viewpoint of improving the adsorption performance for the substance to be adsorbed. On the other hand, type B silica gel with a large average pore size is preferred from the viewpoint of improving the desorption performance for the substance to be adsorbed. In order to achieve both adsorption performance and desorption performance, type A silica gel or type RD silica gel and type B silica gel may be mixed in any ratio depending on the desired performance.

[0034] Porous metal complexes are porous materials formed by the self-assembly of metal ions, which can take various coordination forms, and organic ligands with two or more coordination sites. The organic ligands bridge the metal ions that serve as nodes, creating a framework structure, and the pores within this framework act as spaces for capturing the target substance.

[0035] Compared to inorganic porous materials such as silica gel or zeolite, porous metal complexes have characteristics such as a high specific surface area, a sharp pore distribution, and high structural designability, which offer the advantages of a fast adsorption rate and a large amount of the target substance. Furthermore, because the target substance is adsorbed and desorbed using weak bonding forces such as coordination interactions and hydrogen bonds, the heat of adsorption generated during adsorption is small, and the adsorbed target substance can be desorbed even at low regeneration gas temperatures, resulting in low energy requirements for regeneration. Therefore, by using porous metal complexes as the porous material, the adsorption sheet can effectively adsorb the target substance in the gas to be treated.

[0036] The metal ions constituting the porous metal complex are not particularly limited, and examples thereof include titanium ions, manganese ions, iron ions, cobalt ions, nickel ions, copper ions, zinc ions, aluminum ions, zirconium ions, etc. Among these, titanium ions, iron ions, copper ions, zinc ions, aluminum ions, and zirconium ions, which have low toxicity in consideration of environmental pollution, are preferred examples of the metal ions.

[0037] The compound having an organic ligand is not particularly limited, and examples thereof include dicarboxylic acids such as terephthalic acid, isophthalic acid, 2-aminoterephthalic acid, 2,5-diaminoterephthalic acid, 2,5-dihydroxyterephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 3,3'-biphenyldicarboxylic acid, fumaric acid, 1H-pyrazole-3,5-dicarboxylic acid, and 2,5-furandicarboxylic acid; tricarboxylic acids such as trimesic acid; tetracarboxylic acids such as azobenzene-3,3'-5,5'-tetracarboxylic acid; and imidazoles such as 2-methylimidazole.

[0038] Specific examples of porous metal complexes include: a porous metal complex (MOF303) composed of aluminum ions and 1H-pyrazole-3,5-dicarboxylic acid; a porous metal complex (MIL160) composed of aluminum ions and 2,5-furandicarboxylic acid; a porous metal complex (PCN250) composed of iron ions and azobenzene-3,3'-5,5'-tetracarboxylic acid; a porous metal complex (MIL100) composed of iron ions and trimesic acid; porous metal complexes (MIL53, MIL101) composed of iron ions and terephthalic acid; a porous metal complex (MOF801) composed of zirconium ions and fumaric acid; a porous metal complex (UiO66) composed of zirconium ions and terephthalic acid; and a porous metal complex (UiO66-NH ２ ), a porous metal complex (MIL125) composed of titanium ions and terephthalic acid, and a porous metal complex (MIL125-NH) composed of titanium ions and 2-aminoterephthalic acid. ２ ), a porous metal complex composed of nickel and 2,5-dihydroterephthalic acid (MOF74-Ni), a porous metal complex composed of magnesium and 2,5-dihydroterephthalic acid (MOF74-Mg), a porous metal complex composed of chromium and terephthalic acid (MIL101), etc. These porous metal complexes vary in BET specific surface area depending on the synthesis method and purity, even if they are the same porous metal complex.

[0039] When the substance to be adsorbed is a polar substance such as water or carbon dioxide, the porous metal complex preferably has adsorption sites, from the viewpoint of improving the adsorption performance for the substance to be adsorbed. Examples of adsorption sites include open metal sites. Open metal sites exhibit high adsorption activity. Therefore, porous metal complexes having open metal sites have a very high adsorption rate for the substance to be adsorbed in the gas to be treated, and exhibit high adsorption performance.

[0040] One example of an open metal site is a metal ion that is coordinatively unsaturated and has at least one vacant site in its coordination state, i.e., a coordinatively unsaturated site. In a porous metal complex having a coordinatively unsaturated site, as shown in FIG. 1, the ligand of the metal ion (Fe ion in FIG. 1) is unsaturated, and the metal ion has one or more vacant ligands (vacant sites). The substance to be adsorbed is adsorbed onto these vacant sites. Therefore, a porous metal complex having a coordinatively unsaturated site exhibits high adsorption performance.

[0041] Specific examples of porous metal complexes having coordinatively unsaturated sites include PCN250, MOF74-Ni, MOF74-Mg, and MIL101. Among these, PCN250 is preferred because it has a fast adsorption / desorption rate and uses a metal that is water-resistant and has low toxicity.

[0042] In addition to porous metal complexes having open metal sites, porous metal complexes that exhibit high adsorption performance, i.e., porous metal complexes having adsorption sites, include porous metal complexes having OH groups (hydroxy groups) near the metal. Porous metal complexes having OH groups near the metal have OH groups in the metal core unit, as shown in FIG. 2. When a porous metal complex has OH groups in the metal core unit, it exhibits excellent adsorption activity for the substance to be adsorbed. Therefore, porous metal complexes having OH groups near the metal have a very fast adsorption / desorption rate for the substance to be adsorbed in the gas to be treated, and exhibit high adsorption performance.

[0043] The metal core unit refers to a metal cluster that constitutes a porous metal complex represented by MxOyHz (x and y are integers other than 0, and z is an integer including 0). Some oxygen atoms in the metal core unit MxOyHz are carboxyl group oxygen atoms of the organic ligand, and the metal core unit forms a framework by the organic ligand sharing oxygen atoms.

[0044] Specific examples of porous metal complexes having OH groups in the vicinity of the metal include MOF801 and MOF303.

[0045] The porous material may be in various forms, such as powder, granules, fibers, etc. The adsorption sheet contains a large number of powder or granular porous materials.

[0046] The size of the porous material is not particularly limited, but is preferably 0.1 μm or more, more preferably 0.5 μm or more, and more preferably 1 μm or more. On the other hand, the size of the porous material is not particularly limited, but is preferably 200 μm or less, more preferably 150 μm or less, more preferably 100 μm or less, and more preferably 80 μm or less. When the size of the porous material is 0.1 μm or more and 200 μm or less, the gas to be treated can be brought into good contact with the porous material, thereby improving the adsorption performance of the porous material. Furthermore, the pressure loss when the gas to be treated comes into contact with the porous material can be reduced. Furthermore, the porous material can be supported on the adsorption sheet at a high density, while the detachment of the porous material from the adsorption sheet can be reduced. The size of the porous material can be measured by the D50 value of a laser diffraction particle size analyzer or the average particle diameter using a scanning electron microscope.

[0047] The pore structure of the porous material is not particularly limited. When the porous material is a porous metal complex, the pore structure of the porous metal complex may be one-dimensional pores or three-dimensional pores. From the viewpoint of a high adsorption rate of the substance to be adsorbed and ease of adsorption of the substance to be adsorbed, the pores of the porous metal complex are preferably one-dimensional pores. Specific examples of porous metal complexes having one-dimensional pores include PCN250, MOF303, MOF74, etc. In addition, when the porous metal complex has three-dimensional pores but does not have open metal sites, it is preferable that the crystallite size of the porous metal complex is small in order to facilitate adsorption of the substance to be adsorbed all the way to the inside of the pores. Specific examples of porous metal complexes having three-dimensional pores but no open metal sites include MOF801, etc.

[0048] The pore size of the porous material is not particularly limited. When the porous material is a porous metal complex and the substance to be adsorbed is a polar substance of relatively small size, such as water or carbon dioxide, the pore size of the porous metal complex is not particularly limited, but is preferably 3.0 Å or more, more preferably 3.5 Å or more, from the viewpoint of improving the adsorption performance for the substance to be adsorbed. On the other hand, the pore size of the porous metal complex is not particularly limited, but is preferably 10 Å or less, more preferably 8 Å or less. When the pore size of the porous metal complex is 3.0 Å or more and 10 Å or less, the substance to be adsorbed can be well adsorbed into the pores, thereby improving the adsorption performance of the porous metal complex. Furthermore, when the porous metal complex is regenerated, the adsorbed substance to be adsorbed can be easily desorbed from the porous metal complex. Note that, when prioritizing the improvement of the adsorption performance of the porous metal complex by increasing the desorption rate of the porous metal complex, the pore size of the porous metal complex is preferably greater than 10 Å. The pore size of the porous metal complex can be obtained by measuring the cage diameter or window diameter of the pores by X-ray structural analysis.

[0049] When the porous material is silica gel and the substance to be adsorbed is a polar substance such as water or carbon dioxide, the pore size of the silica gel is not particularly limited, but an average pore size of 30 Å or less is preferred from the viewpoint of improving the adsorption performance for the substance to be adsorbed. On the other hand, the pore size of the silica gel is not particularly limited, but an average pore size of 70 Å or less is preferred from the viewpoint of improving the desorption performance for the substance to be adsorbed. In order to achieve both adsorption performance and desorption performance, multiple types of silica gel having average pore sizes in the range of 10 Å to 70 Å may be mixed and used in any ratio depending on the desired performance.

[0050] When the porous material is zeolite, the pore size of the zeolite is determined largely by the crystal structure. Therefore, the crystal structure of the zeolite may be selected according to the purpose, and two or more types of zeolite may be mixed and used.

[0051] The specific surface area of ​​the porous material measured by the BET method (BET specific surface area) is not particularly limited. When the porous material is a porous metal complex, the specific surface area of ​​the porous metal complex measured by the BET method (BET specific surface area) is not particularly limited, but is preferably 200 m ２ / g or more, more preferably 300m ２ / g or more, more preferably 500m ２ / g or more, more preferably 900m ２ / g or more, more preferably 1000m ２ / g or more, more preferably 1500m ２ / g or more, more preferably 1800m ２ The BET specific surface area of ​​the porous metal complex is not particularly limited, but is preferably 6000 m ２ / g or less, and more preferably 2500m ２ / g or less, and more preferably 2000m ２ / g or less. The specific surface area of ​​the porous metal complex is 200 m ２ / g or more 6000m ２ When the specific surface area of ​​the porous metal complex is 2500 m / g or less, the substance to be adsorbed can be well adsorbed into the pores, and the adsorption performance of the porous metal complex can be improved. In addition, the porous metal complex can be easily produced. ２ When the pore size is 1 / g or less, the strength of the porous metal complex can be sufficiently ensured.

[0052] When the porous material is silica gel, the specific surface area of ​​the silica gel measured by the BET method is not particularly limited, but is preferably 200 m ２ / g or more, more preferably 300m ２ / g or more, more preferably 400m ２ / g or more.

[0053] When the porous material is zeolite, the specific surface area of ​​the zeolite measured by the BET method is not particularly limited, but is preferably 200 ２ / g or more 900m ２ / g or less.

[0054] The bulk density of the porous material is not particularly limited, but is preferably 0.2 g / cc or more, more preferably 0.23 g / cc or more. When the bulk density of the porous material is 0.2 g / cc or more, the voids between the multiple porous materials can be reduced, and the porous materials can be supported on the adsorption sheet at a high density. Therefore, the adsorption sheet can effectively adsorb the target substances in the gas to be treated. The bulk density of the porous material can be measured by dividing the volume of a container of known volume by the weight of the porous material when the porous material is filled to the top.

[0055] When the porous material is a porous metal complex, the moisture adsorption rate of the porous metal complex at 25°C and a relative pressure of 0.5 is not particularly limited, but is preferably 30% by mass or more, more preferably 35% by mass or more, and more preferably 40% by mass or more. Here, the pressure at which the progress of adsorption appears to have stopped under a constant pressure (number of adsorbed molecules = number of desorbed molecules) is called the adsorption equilibrium pressure, and the relative pressure is the ratio of the adsorption equilibrium pressure to the saturated vapor pressure.

[0056] By including a porous metal complex with a moisture adsorption rate of 30% by mass or more at 25°C and a relative pressure of 0.5, the adsorbent sheet can retain a large amount of the substance to be adsorbed, and the adsorbent sheet is endowed with high flexibility during processing. Furthermore, because the porous metal complex imparts sufficient flexibility to the adsorbent sheet, the content of organic binders that have traditionally been included in adsorbent sheets to impart flexibility can be reduced. As a result, the rate at which side chains of the organic binder adsorb into the pores of the porous material and block the pores can be reduced, thereby improving the adsorption performance of the porous material.

[0057] The water adsorption rate of a porous metal complex at 25°C and a relative pressure of 0.5 was determined by collecting approximately 100 mg of the porous metal complex (before treatment with water or an organic solvent), vacuum drying it at 120°C for 12 hours, and weighing it. Then, using a high-precision gas / vapor adsorption measuring device (BELSORP-max, manufactured by BEL Japan Co., Ltd.), the amount of water vapor adsorption at 25°C was measured at 40 points while gradually increasing the relative pressure in the range of 0.02 to 0.95, and an adsorption isotherm was created. At this time, the target relative pressure was set to 0.001, 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, and 0.9, and the adsorption amount increase / decrease tolerance was set to 30 cm at a relative pressure of 0 to 0.3. ２ / g, 50 cm at relative pressures of 0.3 to 0.5 ２ / g, relative pressure 0.5 - 30 cm ２ The water adsorption rate [%] can be calculated from the amount of water adsorbed [g] per 1 g of porous metal complex at a relative pressure of 0.5 using the following formula 1:

[0058] Moisture adsorption rate = moisture adsorption amount per 1 g of porous metal complex [g] × 100 (Equation 1) The content of the porous material in the adsorbent sheet is not particularly limited, but is preferably 40 mass% or more, more preferably 50 mass% or more. On the other hand, the content of the porous material is not particularly limited, but is preferably 85 mass% or less, more preferably 83 mass% or less. When the content of the porous material is 40 mass% or more and 85 mass% or less, the adsorbent sheet can support a high content of porous material, so that the adsorbent sheet can effectively adsorb the target substance to be adsorbed in the gas to be treated, while reducing the detachment of the porous material from the adsorbent sheet and ensuring sufficient strength of the adsorbent sheet.

[0059] The porous material may contain one or more of the above-mentioned silica gel, zeolite, and porous metal complex. The porous material may also contain a porous material other than the above-mentioned silica gel, zeolite, and porous metal complex, such as an organic polymer porous material such as activated carbon, activated alumina, aluminophosphate, silicoaluminophosphate, or styrene-divinylbenzene copolymer.

[0060] <Fibers> The fibers constituting the adsorption sheet are not particularly limited, and examples thereof include natural fibers, synthetic fibers, regenerated fibers, semi-synthetic fibers, and inorganic fibers. Specific examples of natural fibers include cotton, hemp, and pulp. Specific examples of synthetic fibers include aramid fibers, meta-aramid fibers, polybenzimidazole fibers, polybenzoxazole fibers, polyimide fibers, polyamideimide fibers, polyether ketone fibers, polyethylene terephthalate fibers, nylon fibers, and polyvinyl alcohol fibers. Specific examples of regenerated fibers include rayon, polynosic, and cupra. Specific examples of semi-synthetic fibers include acetate fibers and triacetate fibers. Specific examples of inorganic fibers include glass fibers, ceramic fibers, and rock wool fibers. The fibers constituting the adsorption sheet may be a combination of two or more of the above-mentioned fibers.

[0061] The fibers constituting the adsorption sheet preferably contain non-fibrillated fibers and / or fibrillated fibers. The inclusion of non-fibrillated fibers in the adsorption sheet allows the adsorption sheet to maintain a corrugated shape when, for example, the adsorption sheet is corrugated. On the other hand, the inclusion of fibrillated fibers in the adsorption sheet allows the adsorption sheet to efficiently support the porous material, and also allows for a reduction in the amount of organic binder contained in the adsorption sheet to fix the porous material to the adsorption sheet, thereby preventing the organic binder from blocking the pores of the porous material and improving the adsorption performance of the porous material.

[0062] The fiber diameter of the non-fibrillated fibers is not particularly limited, but is preferably 5 μm or more and 30 μm or less. The fiber length of the non-fibrillated fibers is not particularly limited, but is preferably 1 mm or more, more preferably 2 mm or more. On the other hand, the fiber length of the non-fibrillated fibers is not particularly limited, but is preferably 10 mm or less, more preferably 8 mm or less. When the non-fibrillated fibers have a fiber diameter of 5 μm or more and a fiber length of 1 mm or more, the strength of the adsorbent sheet can be sufficiently ensured, and when the adsorbent sheet is subjected to, for example, a corrugated processing, the adsorbent sheet can maintain its corrugated shape. When the non-fibrillated fibers have a fiber diameter of 30 μm or less and a fiber length of 10 mm or less, the adsorbent sheet has appropriate flexibility, and can easily be subjected to, for example, a corrugated processing. The non-fibrillated fibers may be a mixture of fibers of different fiber diameters or different fiber lengths.

[0063] The fibrillated fibers are, for example, fibers obtained by fibrillating the non-fibrillated fibers described above. The fibrillation method is not particularly limited, and any conventionally known method can be used, such as a beating method using a beating machine such as a beater or a refiner.

[0064] The fibrillated fibers are not particularly limited, but when the Canadian Standard Freeness (CSF) is measured in accordance with JIS P 8121-2, the value is preferably 50 ml or more and less than 800 ml.

[0065] The total content of non-fibrillated fibers and fibrillated fibers in the adsorbent sheet is not particularly limited, but is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more. On the other hand, the total content of non-fibrillated fibers and fibrillated fibers in the adsorbent sheet is not particularly limited, but is preferably 25% by mass or less. When the total content of non-fibrillated fibers and fibrillated fibers in the adsorbent sheet is 1% by mass or more and 25% by mass or less, it is possible to support a sufficient amount of porous material in the adsorbent sheet, reduce the detachment of porous metal complexes from the adsorbent sheet, and further ensure sufficient strength of the adsorbent sheet.

[0066] <Organic Binder> The organic binder contained in the adsorption sheet is not particularly limited as long as it can fix the porous material to the adsorption sheet. Examples of the organic binder that can be used include polyvinyl alcohol-based polymers, polyacrylonitrile-based polymers, polyethylene-based polymers, polyester-based polymers, and polyphenylene ether-based polymers. A preferred example of the organic binder is polyvinyl alcohol-based polymer, from the viewpoint of ease of handling.

[0067] The form of the organic binder is not particularly limited, but it is preferable to use a fibrous organic binder, since this allows the adsorption sheet to be easily produced.

[0068] The content of the organic binder in the adsorption sheet is not particularly limited, but is preferably 3% by mass or more, more preferably 4% by mass or more. On the other hand, the content of the organic binder in the adsorption sheet is not particularly limited, but is preferably 15% by mass or less, more preferably 12% by mass or less. When the content of the organic binder in the adsorption sheet is 3% by mass or more and 15% by mass or less, the supportability and flexibility of the porous material in the adsorption sheet can be sufficiently ensured. Furthermore, the rate at which side chains of the organic binder are adsorbed into the pores of the porous material and block the pores can be reduced, thereby improving the adsorption performance of the porous material.

[0069] The organic binder functions to improve the flexibility of the adsorbent sheet, but even if the organic binder content in the adsorbent sheet is low, the adsorbent sheet can exhibit good support for the porous material by containing fibrillated fibers, and the high moisture adsorption rate of the porous material allows the adsorbent sheet to exhibit flexibility. This not only allows the organic binder content in the adsorbent sheet to be reduced, but also, as a result of being able to reduce the organic binder content, it is possible to prevent the organic binder from clogging the pores of the porous material, thereby improving the adsorption performance of the porous material.

[0070] The water dissolution temperature of the organic binder is not particularly limited, but is preferably 65°C or higher, more preferably 70°C or higher. On the other hand, the water dissolution temperature of the organic binder is not particularly limited, but is preferably 100°C or lower. When the water dissolution temperature of the organic binder is 65°C or higher and 100°C or lower, the proportion of side chains of the organic binder adsorbing into the pores of the porous material and blocking the pores can be reduced, and the adsorption performance of the porous material can be improved. Furthermore, the adhesive strength of the organic binder can be well exhibited, and the organic binder can effectively support the porous material on the adsorption sheet.

[0071] The dissolution temperature of the organic binder in water can be measured by a conventionally known method. For example, 100 ml of pure water is placed in a beaker, stirred, and heated in an oil bath until the water temperature reaches 50° C. 0.5 g of organic binder is added to the heated water, the temperature is increased at a rate of 2° C. / min, and the temperature is measured when the organic binder begins to dissolve and becomes translucent by visual observation.

[0072] <Cationic Surfactant> In addition to the porous material, fibers, and organic binder described above, the adsorbent sheet contains a cationic surfactant as a water repellent to provide water repellency. The water repellent imparts water repellency to the adsorbent sheet. When the adsorbent sheet is water repellent, even if a silica-based inorganic adhesive is attached to the adsorbent sheet when manufacturing an adsorbent element, such as a honeycomb structure, using the adsorbent sheet, the silica-based inorganic adhesive can be prevented from penetrating into the adsorbent sheet before curing. Since the adhesive is less likely to penetrate into the adsorbent sheet before curing, the adsorbent sheets can be bonded together well, facilitating the manufacture of adsorbent elements. Furthermore, the adhesive can be prevented from penetrating into the adsorbent sheet and blocking the pores of the porous material, thereby preventing a decrease in the adsorption performance of the porous material in the adsorbent element.

[0073] The cationic surfactant is not particularly limited, and examples thereof include amine salt types and quaternary ammonium salt types. Examples of amine salt types include aliphatic amidoamines. Examples of quaternary ammonium salt types include monoalkyl types, monoalkyl ether types, dialkyl types, dialkyl ester types, and benzalkonium types.

[0074] The cationic surfactant preferably has a long alkyl chain and an amide moiety in its primary structure. The long alkyl chain and the amide moiety may exist in a single compound or as separate compounds. A preferred example of a cationic surfactant having a long alkyl chain and an amide moiety is "Santol KL-2" manufactured by Nicca Chemical Co., Ltd.

[0075] <Cationic surfactant having a long alkyl chain and an amide moiety> A cationic surfactant having a long alkyl chain and an amide moiety has a partial structure of Chemical Formula 1 (R ２ and R ３ = C or H), and R １ contains an alkyl chain having 5 to 30 carbon atoms. １ and the alkyl chain of CO—NR in Chemical Formula 1 ２ R ３ The amide moieties may be present within a single compound or as separate compounds.

[0076]

[0077] When the adsorbent sheet contains a cationic surfactant having a long-chain alkyl chain and an amide moiety, the long-chain alkyl chain moiety provides the adsorbent sheet with good water repellency. Furthermore, the inclusion of an amide moiety in the cationic surfactant improves the dispersibility of the cationic surfactant in solvents such as water and the adsorbability of the cationic surfactant to fibers and other materials during the manufacturing process of the adsorbent sheet, thereby enabling the cationic surfactant to be uniformly supported on the adsorbent sheet.

[0078] In this embodiment, a cationic surfactant having a long alkyl chain and an amide moiety is added as a water repellent to the raw materials, that is, the porous material, fibers, and organic binder, when producing an adsorbent sheet by the wet papermaking method described below.

[0079] Whether or not an adsorbent sheet or an adsorbent element manufactured using the adsorbent sheet contains a cationic surfactant having a long-chain alkyl chain and an amide moiety can be confirmed by pyrolysis gas chromatography mass spectrometry (pyrolysis GC-MS). Specifically, 1 mL of chloroform is added to 0.1 g of sheet material cut from the adsorbent sheet or adsorbent element, and ultrasonic extraction is then performed at room temperature for 30 minutes. Then, 0.5 g of the extract obtained by ultrasonic extraction is placed in a sample cup for pyrolysis GC-MS, and the chloroform is removed from the extract, followed by pyrolysis GC-MS. The pyrolysis GC-MS conditions are as follows: Gas chromatography mass spectrometry (GC-MS) of the gas components generated by the pyrolysis reaction of the sample is performed, and the presence of a cationic surfactant having a long-chain alkyl chain and an amide moiety is confirmed by detecting fragment ion peaks at m / z = 59 and 72, which are characteristic of compounds having an amide moiety containing a long-chain alkyl chain, in the adsorbent sheet or adsorbent element.

[0080] [Conditions for pyrolysis GC-MS] Apparatus: PY-2020iD (Frontier LAB) / QP-2010Plus (Shimadzu Corporation) Sample heating conditions: 550°C x 0.5 min Column: Ultra ALLOY-5 (MS / HT) (length 30 m, inner diameter 0.25 mm, film thickness 0.25 μm) Column temperature: 50°C (2 min) - 20°C / min - 320°C (10 min) Injection port pressure: 80 kPa Injection port temperature: 320°C Split ratio: 30 Ion source: EI method Ion source temperature: 250°C Ionization voltage: 70 eV Interface temperature: 320°C MS measurement mode: SIM and / or SCAN Measurement ions: m / z 29-550 in SCAN mode, m / z 59, 72 in SIM mode.

[0081] <Method for Producing Adsorbent Sheet> The method for producing an adsorbent sheet is not particularly limited, but a preferred example is a wet papermaking method. When producing an adsorbent sheet by a wet papermaking method, first, a porous material, fibers, and an organic binder are dispersed and mixed in a solvent such as water or an organic solvent at a predetermined blending ratio (preparation of a dispersion slurry). Next, the obtained dispersion slurry is made into a sheet using a papermaking machine to obtain a sheet-like material (sheeting process). The obtained sheet-like material is then dehydrated and dried to obtain an adsorbent sheet (dehydration and drying process). The dehydration and drying methods are not particularly limited, and conventionally known methods can be used. Examples of dehydration methods include a method of pressurized dehydration by passing a sheet-like material between a pair of rolls, and a method of pulling an adsorbent sheet onto a net and removing moisture under its own weight. Examples of drying methods include sun drying and a method of blowing hot air onto the sheet-like material after dehydration.

[0082] In the sheet-forming process, it is preferable to mix the porous material with other materials while solvent molecules have penetrated into the pores of the porous material. If the porous material does not have solvent molecules in its pores, the organic binder that constitutes the adsorption sheet may be trapped in the pores. In this case, it is difficult to remove the organic binder trapped in the pores of the porous material after sheet formation, which may result in a decrease in the adsorption performance of the adsorption sheet. In contrast, by trapping solvent molecules in the pores of the porous material, the organic binder is prevented from penetrating and being trapped in the pores of the porous material during the sheet-forming process. After the sheet-forming process, the solvent molecules are removed from the pores by a desolvation treatment described below, thereby ensuring the adsorption performance of the adsorption sheet.

[0083] As described above, when an adsorption sheet is manufactured with solvent molecules trapped in the pores of a porous material, if solvent molecules remain in the pores of the porous material, the porous material will not exhibit sufficient adsorption performance, so the solvent removal treatment is performed on the adsorption sheet to enable the porous material to fully exhibit its adsorption performance.

[0084] The conditions for the solvent removal treatment are not particularly limited. For example, the temperature for the solvent removal treatment is not particularly limited, but is preferably 50°C or higher, more preferably 80°C or higher. On the other hand, the temperature for the solvent removal treatment is not particularly limited, but is preferably 300°C or lower, more preferably 200°C or lower. When the temperature for the solvent removal treatment is 50°C or higher and 300°C or lower, there is little risk that the pore structure of the porous material will be destroyed, and the solvent can be efficiently removed from the pores of the porous material.

[0085] The solvent removal treatment is preferably carried out under reduced pressure. This allows the solvent to be removed from the pores of the porous material more efficiently. The pressure for the solvent removal treatment is not particularly limited and may be adjusted appropriately depending on the physical properties and amount of the porous material. ３ Pa or less, more preferably 10 －１ On the other hand, the pressure of the solvent removal treatment is not particularly limited, but is preferably 10 －５The pressure is at least Pa. The time for the solvent removal treatment is not particularly limited, but is preferably at least 20 seconds, more preferably at least 30 seconds. On the other hand, the time for the solvent removal treatment is not particularly limited, but is preferably at most 5 minutes, more preferably at most 3 minutes, and more preferably at most 1 minute. The most preferred conditions for the solvent removal treatment are a temperature of 80° C. to 200° C. under vacuum conditions, and a treatment time of 20 seconds to 5 minutes.

[0086] When producing the adsorption sheet, a polymer flocculant may be added as an additive in addition to the raw materials of the porous material, fibers and organic binder, and the water repellent agent.

[0087] The polymer flocculant is a chemical used to aggregate and precipitate the porous material, fibers, and organic binder dispersed in a solvent when producing an adsorbent sheet. As the polymer flocculant, any conventionally known flocculant can be used, and one example is the organic polymer flocculant "Tetsuflock (registered trademark)" manufactured by Nittetsu Mining Co., Ltd.

[0088] <Shape and properties of adsorbent sheet> The adsorbent sheet can be used in a liner-like (flat) form as shown in Figure 3(A), but can also be used in a desired shape by appropriately applying pleating, honeycomb processing, corrugation, or the like. When processing the adsorbent sheet into a pleated, honeycomb, corrugated, or other shape, flexibility may be imparted to the adsorbent sheet by allowing the porous material to absorb sufficient moisture so that the adsorbent sheet can be easily folded. Alternatively, the adsorbent sheet may be processed in a semi-dry state where it is completely dried, and then completely dried after processing.

[0089] Fig. 3(B) shows an example of a processed suction sheet, i.e., a corrugated suction sheet 1B. Fig. 3(C) shows an suction sheet 1C obtained by laminating the corrugated suction sheet 1B shown in Fig. 3(B) on the liner-like suction sheet 1A shown in Fig. 3(A). The suction sheet 1C is produced by bonding multiple bottom portions 10 of the corrugated suction sheet 1B to the surface 11 of the liner-like suction sheet 1A using an adhesive 12.

[0090] The adhesive 12 is not particularly limited, but from the viewpoint of heat resistance, a silica-based inorganic adhesive is preferably used. Specific examples of silica-based inorganic adhesives include water glass, silica sol, and alumina sol. The adhesive 12 may be a mixture of the above-mentioned inorganic adhesive and an organic adhesive. Specific examples of organic adhesives include one or more organic adhesives selected from phenolic resins, epoxy resins, acrylic resins, urethane resins, polyester resins, melamine resins, silicone resins, fluororesins, and copolymers thereof.

[0091] The flexibility of the adsorbent sheet is not particularly limited, but is preferably 5% m / g or more, where the tensile elongation index is used as an indicator of flexibility. If the tensile elongation index of the adsorbent sheet is 5% m / g or more, the adsorbent sheet has good processability, and when the adsorbent sheet is used to manufacture an adsorbent element having a honeycomb structure, for example, cracks can be suppressed from occurring in the adsorbent sheet even if the adsorbent sheet is corrugated.

[0092] The tensile elongation index of the adsorption sheet is determined by drying a 15 mm x 100 mm sample piece cut from the adsorption sheet at 120°C for 1 hour and measuring its weight. The dried sample piece is then left to stand in an atmosphere of 25°C and 75% RH for 1 hour, and the maximum point elongation [%] is measured using a tensile / compression testing machine (TENSILON RTG-1310, manufactured by A&D). The chuck distance is 50 mm and the tensile speed is 15 mm / min. From the obtained data, the tensile elongation index [% m / g] is calculated using the following formula 2.

[0093] Specific tensile elongation = Maximum point elongation [%] / Sample width [m] / Basis weight of adsorption sheet [g / m ２ ] (Formula 2) The thickness of the adsorption sheet is not particularly limited, but is preferably 0.1 mm or more. On the other hand, the thickness of the adsorption sheet is preferably 0.9 mm or less, and more preferably 0.7 mm or less. When the thickness of the adsorption sheet is 0.1 mm or more and 0.9 mm or less, the strength of the adsorption sheet can be sufficiently ensured when the adsorption sheet is processed to manufacture an adsorption element, and an increase in pressure loss in the adsorption element manufactured by processing the adsorption sheet can be suppressed.

[0094] The basis weight of the adsorption sheet is not particularly limited, but is preferably 25 g / m ２ More preferably, 40 g / m ２ On the other hand, the basis weight of the adsorption sheet is preferably 200 g / m ２ and preferably 150 g / m ２ The basis weight of the adsorption sheet is 25 g / m ２ More than 200g / m ２ If this is the case, the thickness of the adsorption sheet can be ensured and a decrease in strength can be suppressed, making it easier to process the adsorption sheet to manufacture an adsorption element, and since the thickness of the adsorption sheet can be prevented from becoming too large, an increase in pressure loss in the adsorption element manufactured by processing the adsorption sheet can be suppressed.

[0095] <Adsorption element> An adsorption element is manufactured by using one or more adsorption sheets to create a structure suited to the application or purpose. The adsorption sheet of the present disclosure can prevent a silica-based inorganic adhesive from penetrating the adsorption sheet before hardening, even if the silica-based inorganic adhesive is attached to the adsorption sheet during the manufacturing of the adsorption element. Therefore, the adsorption element of the present disclosure can be a processed product including at least one adsorption sheet of the present disclosure and a silica-based inorganic adhesive. Furthermore, the type of the adsorption element is not particularly limited, and any conventionally known type can be used.

[0096] For example, a cross-flow type adsorption element can be manufactured by using a pleated adsorption sheet, or a parallel-flow type adsorption element can be manufactured by using a honeycomb-shaped adsorption sheet. Cross-flow type adsorption elements and parallel-flow type adsorption elements have a large contact area with the gas to be treated, which allows for high adsorption performance of the adsorption target substance and also reduces pressure loss of the adsorption element. Furthermore, parallel-flow type adsorption elements are superior to cross-flow type adsorption elements in terms of preventing clogging due to mist and debris, reducing pressure loss, and reducing weight, making them more suitable for use in adsorption / desorption treatment devices.

[0097] An example of an adsorption element is shown in Fig. 4. The adsorption element 4 shown in Fig. 4(B) is formed by winding the adsorption sheet 1C shown in Fig. 3(C) into a rotor shape as shown in Fig. 4(A), and has a honeycomb shape.

[0098] <Adsorption / Desorption Treatment Device> The adsorption / desorption treatment device is a device that includes the above-described adsorption element, and is configured to bring the gas to be treated into contact with the adsorption element to adsorb the substance to be adsorbed contained in the gas to be treated onto a porous material, and to bring the regeneration gas into contact with the adsorption element that has adsorbed the substance to be adsorbed, thereby desorbing the substance to be adsorbed from the porous material.

[0099] The adsorption / desorption treatment device is, for example, a rotor-rotating type continuous adsorption / desorption treatment device 3 as shown in Fig. 5. The continuous adsorption / desorption treatment device 3 includes a cylindrical adsorption rotor 4 that can be rotated about a rotation axis L by driving a motor. The adsorption rotor 4 includes, for example, adsorption elements 2 with a honeycomb structure as shown in Fig. 4(B). The adsorption rotor 4 is partitioned into an adsorption zone 40 and a desorption zone 41 in the circumferential direction around the rotation axis L, and the adsorption elements 2 move alternately between the adsorption zone 40 and the desorption zone 41 as the adsorption rotor 4 rotates.

[0100] The gas to be treated is supplied to the adsorption zone 40 of the adsorption rotor 4 by the drive of the fan 5, and as it passes through the adsorption elements 2 located in the adsorption zone 40, the adsorbent substances contained in the gas to be treated are adsorbed by the porous material contained in the adsorption elements 2. The regeneration gas, heated by a heat source 6 such as a heater, is supplied to the desorption zone 41 of the adsorption rotor 4 by the drive of the fan 7, and as it passes through the adsorption elements 2 located in the desorption zone 41, the adsorbent substances are desorbed from the porous material. This regenerates the porous material.

[0101] The rotor rotation type continuous adsorption / desorption treatment device is not limited to the above-mentioned example, and other conventionally known devices can be used. Furthermore, the adsorption / desorption treatment device is not limited to the rotor rotation type continuous adsorption / desorption treatment device.

[0102] According to the above-described adsorption sheet, adsorption element, and adsorption / desorption treatment device, the adsorption sheet contains a porous material, fibers, and an organic binder, and further contains a cationic surfactant, thereby exhibiting water-repellent properties. Furthermore, because the cationic surfactant has a long-chain alkyl chain and an amide moiety, the adsorption sheet exhibits good water-repellent properties due to the presence of the cationic surfactant having a long-chain alkyl chain and an amide moiety. This prevents the silica-based inorganic adhesive from penetrating the adsorption sheet before curing when adsorbing an adsorption element using one or more adsorption sheets. Since the adhesive is less likely to penetrate the adsorption sheet before curing, the adsorption sheets can be bonded well, facilitating the manufacture of the adsorption element. Furthermore, since the adhesive is prevented from penetrating the adsorption sheet and blocking the pores of the porous material, the adsorption performance of the porous material in the adsorption element is prevented from decreasing. Therefore, the adsorption performance of an adsorption / desorption treatment device using an adsorption element is also prevented from decreasing.

[0103] The above describes one embodiment of the adsorption sheet, adsorption element, and adsorption / desorption processing device of the present disclosure, but the adsorption sheet, adsorption element, and adsorption / desorption processing device of the present disclosure are not limited to the above-described embodiment, and various modifications are possible as long as they do not deviate from the spirit of the present disclosure.

[0104] The functions and effects of the adsorption sheet of the present disclosure will be specifically explained below by showing examples thereof, but the adsorption sheet of the present disclosure is not limited to the following examples.

[0105] Example 1: 0.5 g of Fe(NO ３ ) ３ ・9H ２ PCN250 was synthesized by dissolving 0 and 0.1 g of azobenzene-3,3'-5,5'-tetracarboxylic acid in 20 mL of N,N-dimethylformamide and 10 mL of acetic acid and heating at 150°C for 24 hours. The physical properties of the obtained PCN250 were evaluated by nitrogen adsorption measurement, and the BET specific surface area was found to be 1227 m. ２ / g.

[0106] The synthesized PCN250 was then immersed in water for 24 hours and filtered to obtain a PCN250 sample with solvent molecules adsorbed in the pores. This PCN250 sample was mixed at 80% by mass (excluding solvent molecules), 8% by mass of aramid fiber as non-fibrillated fiber, 5% by mass of aramid fiber as fibrillated fiber, and 7% by mass of polyvinyl alcohol (PVA) fiber with a water dissolution temperature of 70°C (catalog value) as an organic binder. Santol KL-2 (manufactured by Nicca Chemical Co., Ltd., hereinafter the same) was added as a water repellent, and the mixture was stirred in a mixer for approximately 3 minutes. Then, a polymer flocculant, Tetsuflock (manufactured by Nittetsu Mining Co., Ltd., hereinafter the same) was added as a flocculant, and the resulting mixture had a basis weight of 75 g / m. ２ An adsorption sheet was produced using a wet papermaking machine (manufactured by Toyobo Engineering Co., Ltd.; the same applies hereinafter) with a mass of 0.01g. The adsorption sheet was then subjected to a solvent removal treatment at 130°C under vacuum conditions for 1 minute to obtain an adsorption sheet sample. The obtained adsorption sheet sample was subjected to gas chromatography mass spectrometry to detect compounds having an amide moiety containing a long-chain alkyl group and to measure water repellency.

[0107] Example 2: 75% by mass (excluding solvent molecules) of the PCN250 sample obtained in the same manner as in Example 1, 10% by mass of aramid fiber as non-fibrillated fiber, 6.3% by mass of aramid fiber as fibrillated fiber, and 8.7% by mass of polyvinyl alcohol (PVA) fiber as an organic binder having a water dissolution temperature of 70°C (catalog value) were mixed, and after adding Santol KL-2 as a water repellent, the mixture was stirred in a mixer for about 3 minutes. Thereafter, a polymer flocculant Tetsuflock was added as a flocculant, and the mixture was mixed to a weight of 75 g / m. ２ An adsorbent sheet was produced using a wet papermaking machine with a mass of 1000 kJ / g. The adsorbent sheet was then subjected to a solvent removal treatment at 130°C under vacuum for 1 minute to obtain an adsorbent sheet sample. The obtained adsorbent sheet sample was subjected to gas chromatography mass spectrometry to detect compounds having an amide moiety containing a long-chain alkyl group and to measure water repellency.

[0108] Example 3 A-type silica gel (manufactured by Toyota Chemical Industry Co., Ltd.) was used as the porous material. The physical properties were evaluated by nitrogen adsorption measurement and water vapor adsorption measurement, and the BET specific surface area was found to be 730 m ２ / g. After immersing the A-type silica gel in water for 24 hours, it was filtered to obtain an A-type silica gel sample with solvent molecules adsorbed in the pores. This A-type silica gel sample was mixed at 80 mass % (excluding solvent molecules), 8 mass % of aramid fiber as non-fibrillated fiber, 5 mass % of aramid fiber as fibrillated fiber, and 7 mass % of polyvinyl alcohol (PVA) fiber as an organic binder with a water dissolution temperature of 70°C (catalog value), and after adding Santol KL-2 as a water repellent agent, the mixture was stirred in a mixer for about 3 minutes. Thereafter, a polymer flocculant Tetsuflock was added as a flocculant, and the mixture had a basis weight of 75 g / m. ２ An adsorbent sheet was prepared using a wet papermaking machine with a mass of 1000 kJ / g. The obtained adsorbent sheet sample was subjected to gas chromatography mass spectrometry to detect compounds having an amide moiety containing a long-chain alkyl group and to measure water repellency.

[0109] Example 4: 75% by mass (excluding solvent molecules) of the A-type silica gel sample obtained in the same manner as in Example 3, 10% by mass of aramid fiber as non-fibrillated fiber, 6.3% by mass of aramid fiber as fibrillated fiber, and 8.7% by mass of polyvinyl alcohol (PVA) fiber as an organic binder having a water dissolution temperature of 70°C (catalog value) were mixed, and after adding Santol KL-2 as a water repellent, the mixture was stirred in a mixer for about 3 minutes. Thereafter, a polymer flocculant Tetsuflock was added as a flocculant, and the mixture was mixed to a weight of 75 g / m. ２ An adsorbent sheet was produced using a wet papermaking machine with a mass of 1000 kJ / g. The adsorbent sheet was then subjected to a solvent removal treatment at 130°C under vacuum for 1 minute to obtain an adsorbent sheet sample. The obtained adsorbent sheet sample was subjected to gas chromatography mass spectrometry to detect compounds having an amide moiety containing a long-chain alkyl group and to measure water repellency.

[0110] Example 5 Synthetic zeolite (ZSM-5) was used as the porous material. The physical properties were evaluated by nitrogen adsorption measurement and water vapor adsorption measurement. As a result, the BET specific surface area was 500 m ２ The viscosity was 1 / g. The synthetic zeolite (ZSM-5) was immersed in water for 24 hours and then filtered to obtain a synthetic zeolite (ZSM-5) sample with solvent molecules adsorbed in the pores. This synthetic zeolite (ZSM-5) sample was mixed at 80 mass% (excluding solvent molecules), 8 mass% of aramid fiber as non-fibrillated fiber, 5 mass% of aramid fiber as fibrillated fiber, and 7 mass% of polyvinyl alcohol (PVA) fiber as an organic binder having a water dissolution temperature of 70°C (catalog value), and then Santol KL-2 was added as a water repellent agent, followed by stirring in a mixer for approximately 3 minutes. Thereafter, a polymer flocculant Tetsuflock was added as a flocculant, and the mixture was mixed to a basis weight of 75 g / m. ２ An adsorbent sheet was prepared using a wet papermaking machine with a mass of 1000 kJ / g. The obtained adsorbent sheet sample was subjected to gas chromatography mass spectrometry to detect compounds having an amide moiety containing a long-chain alkyl group and to measure water repellency.

[0111] Comparative Example 1: 80% by mass (excluding solvent molecules) of the PCN250 sample obtained in the same manner as in Example 1, 8% by mass of aramid fiber as a non-fibrillated fiber, 5% by mass of aramid fiber as a fibrillated fiber, and 7% by mass of polyvinyl alcohol (PVA) fiber as an organic binder having a water dissolution temperature of 70°C (catalog value) were mixed and stirred in a mixer for about 3 minutes. Then, a polymer flocculant, Tetsuflock, was added as a flocculant, and the resulting mixture had a basis weight of 75 g / m. ２ An adsorbent sheet was produced using a wet papermaking machine with a mass of 1000 kJ / g. The adsorbent sheet was then subjected to a solvent removal treatment at 130°C under vacuum for 1 minute to obtain an adsorbent sheet sample. The obtained adsorbent sheet sample was subjected to gas chromatography mass spectrometry to detect compounds having an amide moiety containing a long-chain alkyl group and to measure water repellency.

[0112] Comparative Example 2: 80% by mass (excluding solvent molecules) of the A-type silica gel sample obtained in the same manner as in Example 3, 8% by mass of aramid fiber as non-fibrillated fiber, 5% by mass of aramid fiber as fibrillated fiber, and 7% by mass of polyvinyl alcohol (PVA) fiber as an organic binder having a water dissolution temperature of 70°C (catalog value) were mixed and stirred in a mixer for about 3 minutes. Then, a polymer flocculant, Tetsuflock, was added as a flocculant, and the resulting mixture had a basis weight of 75 g / m. ２ An adsorbent sheet was prepared using a wet papermaking machine with a mass of 1000 kJ / g. The obtained adsorbent sheet sample was subjected to gas chromatography mass spectrometry to detect compounds having an amide moiety containing a long-chain alkyl group and to measure water repellency.

[0113] Comparative Example 3: 80% by mass (excluding solvent molecules) of the zeolite (ZSM-5) sample obtained in the same manner as in Example 5, 8% by mass of aramid fiber as non-fibrillated fiber, 5% by mass of aramid fiber as fibrillated fiber, and 7% by mass of polyvinyl alcohol (PVA) fiber as an organic binder having a water dissolution temperature of 70°C (catalog value) were mixed and stirred in a mixer for about 3 minutes. Thereafter, a polymer flocculant, Tetsuflock, was added as a flocculant, and the resulting mixture had a basis weight of 75 g / m. ２ An adsorbent sheet was prepared using a wet papermaking machine with a mass of 1000 kJ / g. The obtained adsorbent sheet sample was subjected to gas chromatography mass spectrometry to detect compounds having an amide moiety containing a long-chain alkyl group and to measure water repellency.

[0114] To measure water repellency, 10 μL of pure water was dropped using a micropipette onto a paper piece approximately 2.5 cm × 4 cm in size cut out from the adsorbent sheet sample. The time when the pure water came into contact with the paper piece was defined as 0 seconds, and the time until the puddle of pure water on the paper piece disappeared was measured to evaluate water repellency. Samples that took longer than 600 seconds for the puddle of pure water to disappear were evaluated as being over 600 seconds (denoted as >600).

[0115] Table 1 shows the results of detecting compounds having an amide moiety containing a long-chain alkyl group and the results of measuring water repellency for Examples 1 to 5 and Comparative Examples 1 to 3.

[0116]

[0117] According to Table 1, comparing Examples 1-2 and Comparative Example 1, comparing Examples 3-4 and Comparative Example 2, and comparing Example 5 and Comparative Example 3, it was confirmed that the adsorbent sheet in which a compound having an amide moiety containing a long-chain alkyl group was detected had better water repellency than the adsorbent sheet in which a compound having an amide moiety containing a long-chain alkyl group was not detected. Therefore, it can be seen that the adsorbent sheet of the present disclosure is less susceptible to adhesive penetration into the adsorbent sheet before curing.

Claims

1. An adsorbent sheet comprising a porous material, fibers, and an organic binder, the adsorbent sheet further comprising a cationic surfactant.

2. The adsorption sheet according to claim 1, wherein the cationic surfactant has a long alkyl chain and an amide moiety, and when pyrolysis gas chromatography mass spectrometry is performed, fragment ion peaks at m / z = 59 and 72, which are characteristic of compounds having an amide moiety containing a long alkyl chain, are detected.

3. The adsorbent sheet according to claim 1 or 2, wherein the cationic surfactant comprises a partial structure shown in the following chemical formula 1: (In chemical formula 1, R １ R contains an alkyl chain having 5 to 30 carbon atoms. ２ and R ３ represents C or H.

4. R in the cationic surfactant １ 4. The adsorbent sheet according to claim 3, wherein the alkyl chain and the amide moiety are present as a single compound or as separate compounds.

5. An adsorption sheet according to any one of claims 1 to 4, containing 40% by mass or more and 85% by mass or less of the porous material.

6. An adsorbent sheet according to any one of claims 1 to 5, wherein the fibers comprise non-fibrillated fibers and / or fibrillated fibers.

7. An adsorbent sheet according to any one of claims 1 to 6, containing 3% by mass or more and 15% by mass or less of the organic binder.

8. An adsorption element, which is a processed product comprising at least one adsorption sheet according to any one of claims 1 to 7 and a silica-based inorganic adhesive.

9. An adsorption / desorption treatment device comprising the adsorption element according to claim 8, configured to adsorb at least a portion of the substance to be adsorbed contained in the gas to be treated by the porous material by bringing the gas to be treated into contact with the adsorption element, and to desorb the substance to be adsorbed from the porous material by bringing a regeneration gas into contact with the adsorption element.

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