Dispersion, adsorption material for pfas, method for improving environment, powder for environment-improving liquid, method for dispersing porous carbon material, porous carbon material, and filter

Abstract

The present invention relates to a technique for appropriately adsorbing an organic fluorine compound (PFAS) represented by PFOA / PFOS, harmful organic chemical substances such as BTEX, agrochemical substances, heavy metals, and the like, which have flowed out into an environment such as soil. The main purpose of the present invention is to provide a technique capable of effectively dispersing a porous carbon material, which is an adsorbent material, in a liquid. As a result of in-depth studies, the present inventors have found that a porous carbon material can be effectively dispersed in a liquid by using an ionic biodegradable polymer as a dispersant.

Description

Technical Field

[0001] This technology relates to a dispersion, an adsorbent for PFAS, an environmental improvement method, a powder for an environmental improvement solution, a method for dispersing a porous carbon material, a porous carbon material, and a filter. More specifically, this technology relates to a method for dispersing a porous carbon material using a charged compound, a dispersion prepared by dispersing the porous carbon material, an adsorbent for PFAS using the dispersion, an environmental improvement method using the dispersion, a powder for an environmental improvement solution, a porous carbon material, and a filter containing the porous carbon material. Background Art

[0002] Soil contamination by chemical substances has long been a social problem. In particular, organofluorine compounds (PFAS, a generic term for chemical substances known as perfluoroalkyl and polyfluoroalkyl compounds), such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), are virtually indegradable in the environment and are harmful to living organisms. Therefore, technologies for adsorbing these substances (soil remediation technologies) that escape into the environment are in high demand.

[0003] For example, Patent Document 1 below discloses using an activated carbon adsorbent having a surface oxide content of a certain ratio or less to adsorb perfluoroalkyl compounds and polyfluoroalkyl compounds in a water sample, but the adsorbent itself is not dispersed in the liquid. Citation List Patent Literature

[0004] Patent Document 1: Japanese Patent Application Publication No. 2021-079376 Summary of the Invention Problems to be solved by the present invention

[0005] The main purpose of this technology is to provide a technology that can effectively disperse porous carbon materials as adsorption materials in dispersions, compared with the adsorption technology of harmful chemical substances that flow into the environment such as soil. Solution to the problem

[0006] As a result of intensive studies, the present inventors have found that a porous carbon material can be efficiently dispersed in a dispersion by using an ionic biodegradable polymer as a dispersant.

[0007] That is, the present technology provides a dispersion comprising a porous carbon material and a compound having an electric charge, wherein the porous carbon material has a 10 m 2 / g and above specific surface area values and 0.1 cm measured by BJH method and MP method 3 / g or more pore volume. In the dispersion according to the present technology, the porous carbon material in the dispersion preferably has a zeta potential of +25 mV to +100 mV measured at 25°C. In the dispersion according to the present technology, a compound having an anionic or cationic charge can be used as the compound having a charge. In the case of using a compound having a cationic charge as the compound having a charge, the compound includes a compound having an amino group or an aluminum alcohol group. In the dispersion according to the present technology, the porous carbon material and the compound having a charge may be bonded, and the bonding may be chemical bonding. In the dispersion according to the present technology, the compound having a charge may include an ionic biodegradable polymer, and a compound having a polysaccharide skeleton may be used as the biodegradable polymer. In the dispersion according to the present technology, the porous carbon material may include a porous carbon material subjected to cationization treatment, and a surface of the porous carbon material may be substituted with an amino group. In the dispersion according to the present technology, the porous carbon material may be contained in an amount of 0.01 to 25 wt %, and the ionic biodegradable polymer may be contained in an amount of 0.1 to 20 wt % relative to the porous carbon material. In the dispersion according to the present technology, the ionic biodegradable polymer may have a 1% solution viscosity of 0.1 Pa·s or more. In the dispersion according to the present technology, the porous carbon material may have a cumulative pore volume of 0.4 cc / g or more in the range of 0.05 μm to 5 μm as measured by mercury intrusion porosimetry. In the dispersion according to the present technology, the porous carbon material may have an average particle size of 0.1 to 500 μm. In the dispersion according to the present technology, the porous carbon material may have a zeta potential of -50 to +100 mV at pH 7.0. In the dispersion according to the present technology, the porous carbon material may have a 500 m 2 / g or more BET specific surface area. The dispersion according to this technology is -1 The viscosity at the shear rate may be 1000 Pa·s or less. Dispersions according to the present technology may include a liquid.

[0008] Next, the present technology provides an adsorbent material for PFAS using the dispersion according to the present technology. Here, PFAS may include an anionic organic fluorine compound, and the anionic organic fluorine compound may include an organic fluorine compound having 8 or more carbon atoms. The present technology also provides a method for improving an environment, wherein the dispersion according to the present technology is used.

[0009] The present technology provides a powder for environmental improvement liquid, wherein the powder comprises a porous carbon material and a compound having an electric charge, wherein the porous carbon material has a 10m 2 / g and above specific surface area values and 0.1 cm measured by BJH method and MP method 3 Here, the compound having a charge may include an ionic biodegradable polymer, and a compound having a polysaccharide skeleton may be used as the biodegradable polymer.

[0010] The present technology provides a method for dispersing a porous carbon material, wherein the method comprises dispersing the porous carbon material in a dispersion by using a compound having an electric charge, and the porous carbon material has a 10 m 2 / g and above specific surface area values and 0.1 cm measured by BJH method and MP method 3 Here, the compound having a charge may include an ionic biodegradable polymer, and a compound having a polysaccharide skeleton may be used as the biodegradable polymer.

[0011] The present technology provides a porous carbon material having a 10m 2 / g and above specific surface area values and 0.1 cm measured by BJH method and MP method 3 The porous carbon material has a pore volume of 1000 Å / g or more, wherein a compound having a charge is bound to the porous carbon material. The porous carbon material dispersed in water in an amount of 1 wt % has a zeta potential of +25 mV or more measured at 25° C. The porous carbon material of the present technology can be used for dispersion. Furthermore, the present technology provides a filter containing the porous carbon material of the present technology. DETAILED DESCRIPTION

[0012] Hereinafter, preferred embodiments of the present technology will be described. However, the following embodiments illustrate examples of representative embodiments of the present technology, and the present technology is not limited to the following preferred embodiments and can be freely changed within the scope of the present technology.

[0013] The dispersion according to the present technology contains a porous carbon material having a 10 m 2 / g and above specific surface area values and 0.1 cm measured by BJH method and MP method 3 The contained charged compound enables the porous carbon material to be effectively dispersed in the dispersion.

[0014] Here, the "dispersion" refers to a dispersion in which a single compound, a substance containing a plurality of compounds, or the like is uniformly dispersed in a dispersion medium, and generally refers to a liquid or gel form.

[0015] That is, the porous carbon material and the charged compound contained in the dispersion according to the present technology can each be dispersed in the dispersion medium as a single independent compound, or can be dispersed in the dispersion medium as a substance in which the porous carbon material and the charged compound are physically or chemically combined.

[0016] For the example of material dispersion in which a porous carbon material and a compound having a charge are physically or chemically bonded, the compound having a charge can be physically or chemically bonded to the surface of the porous carbon material, and the porous carbon material can be properly dispersed in the dispersion by the repulsive force generated by the charge.

[0017] Since the dispersion of the present technology contains a compound having an electric charge, the porous carbon material can be appropriately dispersed. Therefore, when the porous carbon material in the dispersion has cationic properties, the zeta potential of the porous carbon material measured at 25°C can be, for example, +25 mV to +100 mV. Note that in this case, the concentration of the porous carbon material in the dispersion is, for example, 1% by weight. The zeta potential can be appropriately measured in accordance with JIS Z 8836:2017.

[0018] <Charged Compounds> In the present technology, a "charged compound" is a compound having a positive or negative charge within the molecule. A charged compound preferably has ionic properties. Whether a compound has ionic properties can be determined, for example, based on whether the compound has anionic or cationic properties in water at pH 7.0.

[0019] The charge contained in the compound having a charge that the dispersion of the present technology may contain may be a positive charge or a negative charge, and both anionic charge and cationic charge may be appropriately used.

[0020] In the case where the compound having a charge that the dispersion of the present technology may contain has, for example, a cationic charge, the dispersion of the present technology may appropriately adsorb anionic chemical substances.

[0021] When the compound having a charge that may be included in the dispersion of the present technology has a cationic charge, the compound has, for example, an amino group, an imino group, an ammonium group, an aluminol group, etc. It is particularly preferred to have an amino group or an aluminol group, which can be easily introduced by synthesis.

[0022] The charged compound that can be included in the dispersion of the present technology is not particularly limited as long as it is a compound that meets the above requirements. In particular, from the perspective of reducing the risk of environmental pollution, examples include: biodegradable polymers described below, and cationic compounds such as amino group-containing polymer-type silane coupling materials that are unlikely to be released into the environment due to strong bonding with the porous carbon material, and disiloxanes containing quaternary ammonium salts.

[0023] Examples of the above-mentioned amino-containing compounds include amino-containing polymeric silane coupling agents. In addition, examples of low-molecular compounds having an aluminum alcohol group include aluminum alcoholates such as aluminum sec-butoxide, aluminum ethyl acetoacetate diisopropylate, aluminum isopropylate, mono-sec-butoxy aluminum diisopropylate, aluminum sec-butoxide, and aluminum ethoxide; aluminum alkylates such as aluminum ethyl acetoacetate diisopropylate, aluminum triethyl acetoacetate, alkyl acetoacetate diisopropylate, aluminum monoacetoacetate, and aluminum tris(acetylacetonate); and cyclic aluminum oligomers such as cyclic aluminum oxide isopropylate and cyclic aluminum oxide stearate, all of which undergo hydrolysis in the presence of atmospheric moisture or in water to produce aluminum alcohol groups.

[0024] <Biodegradable Polymer> In the present technology, a "biodegradable polymer" refers to a polymer that can be decomposed by the action of an organism, and is not particularly limited as long as it can be decomposed by the action of an organism. Examples of the organism include various microorganisms.

[0025] Specific examples of "biodegradable polymers" include polymers in which one or more structural units (monomers) are bonded via glycosidic bonds (which are ether bonds) or dehydration condensation (such as ester bonds). Examples of such polymers include compounds having a polysaccharide backbone, compounds having a polyvinyl alcohol structure, and compounds having a polyethylene glycol structure. In the present technology, compounds having a polysaccharide backbone can be suitably used among these.

[0026] Furthermore, the "biodegradable polymer" is preferably an ionic biodegradable polymer.

[0027] The ionic biodegradable polymer contained in the dispersion according to the present technology adheres to the surface of the porous carbon material, and it is expected that the porous carbon material will be properly dispersed in the liquid due to the repulsive force generated by the charge of the ionic dissociation group. In the case of the liquid according to the present technology, since the porous carbon material is properly dispersed in the liquid, it is expected that harmful chemicals that have been released into the soil, etc., will be effectively adsorbed by the use of the liquid. In addition, since the biodegradable polymer contained in the liquid according to the present technology is decomposed by the action of the organism, the risk of the biodegradable polymer remaining in the environment for a long time, thereby minimizing the risk of environmental pollution.

[0028] The charge contained in the ionic biodegradable polymer contained by the dispersion of the present technology can be a positive charge or a negative charge, and both anionic and cationic charges can be appropriately used. In the case of using anionic biodegradable polymers, it can be expected that porous carbon materials with a positive surface charge, in particular, will be effectively dispersed in small amounts. In the case of using cationic biodegradable polymers, it can be expected that porous carbon materials with a negative surface charge, in particular, will be effectively dispersed in small amounts.

[0029] When the dispersion according to the present technology contains a compound having a polysaccharide backbone as the biodegradable polymer, the "compound having a polysaccharide backbone" is preferably a compound having a main chain composed of one or more monosaccharides linked by glycosidic bonds. Here, in the polymer constituting the polymeric material, the "main chain" refers to the longest repeating structure of covalently bonded atoms.

[0030] Examples of compounds having a polysaccharide backbone that may be included in the dispersion according to the present technology include cellulose, guar gum, carrageenan, pectin, gum arabic, xanthan gum, gellan gum, agar, tragacanth gum, and chitosan. These compounds may be modified with substituents. Furthermore, these compounds may be used alone or in combination.

[0031] Examples of methods for converting the polysaccharide-backbone compound into an anionic compound include synthesizing the compound as a salt with an alkali metal, alkaline earth metal, etc. Examples of methods for converting the polysaccharide-backbone compound into a cationic compound include halogenating, aminating, or aluminolating the compound.

[0032] At 25 degrees Celsius and 10s -1At a shear rate of , the 1% solution viscosity of the charged compound (such as the ionic biodegradable polymer) contained in the dispersion according to the present technology is preferably 0.1 Pa·s or more, more preferably 0.5 Pa·s or more, and particularly preferably 1.0 Pa·s or more, thereby reducing the sedimentation rate of the porous carbon material and expecting to maintain the dispersed state of the porous carbon material for a long time. The 1% solution viscosity can be appropriately adjusted by the degree of polymerization of the charged compound (such as the ionic biodegradable polymer). Here, the "1% solution viscosity" refers to the viscosity of an aqueous solution containing 1% by mass of a charged compound (such as the biodegradable polymer). The viscosity can be appropriately measured according to JIS Z 8803: 2011 (Method for determining the viscosity of a liquid).

[0033] <Porous Carbon Materials> In the present technology, "porous carbon material" refers to a solid substance having pores of various sizes and refers to a material containing carbon. The specific surface area of the porous carbon material can be appropriately measured by, for example, the nitrogen BET method. In addition, the pore volume of the porous carbon material can be measured by, for example, the BJH method and the MP method.

[0034] The raw material of the porous carbon material according to the present technology is not particularly limited, for example, any carbonaceous material can be used, such as activated carbon derived from rice husks and coconut shells. In addition, other porous materials such as zeolites, metal organic frameworks (MOFs), ion exchange resins and mesoporous silica can be used in combination. In particular, from the viewpoint of reducing environmental load, plant-derived materials can be appropriately used. In addition, microbial materials containing any microorganisms can also be used in these materials.

[0035] The plant-derived material that can be used for the porous carbon material of the present technology is not particularly limited as long as it is a plant-derived material. For example, plants containing silicon components (referred to as "silicate plants" or "silicon-accumulating plants") can be suitably used. Here, examples of silicon components contained in plants include silicon oxides such as silicon dioxide, silicon oxide, and silicon oxide salts.

[0036] Examples of silicate plants include, but are not limited to, rice (paddy), barley, wheat, rye, Japanese barnyard grass (barnyard grass), millet (fowl), as well as reeds, kelp stems, coffee beans, tea stems, bagasse and bamboo. Other examples include vascular plants, ferns, mosses, algae and seaweeds grown on land. Note that these materials can be used as raw materials alone, or two or more of them can be used in combination. In addition, the shape and form of the plant-derived material are not particularly limited, and can be, for example, its shell or stalk, or can be a dried product. In addition, in food and beverage processing such as beer and foreign liquor, materials that have undergone various treatments such as fermentation, baking and extraction can also be used. In particular, from the perspective of reusing industrial waste, it is preferred to use the rods or shells after processing such as threshing. Such processed rods or shells can be easily obtained in large quantities from, for example, agricultural cooperatives, alcoholic beverage production companies, food companies, etc.

[0037] The porous carbon material according to the present technology can be produced by any suitable production method. For example, in the case of using plant-derived materials as raw materials to produce the porous carbon material, the raw materials can be subjected to any combination of the steps of pulverization, shaping, carbonization, silicon oxide removal, activation, washing, and screening according to the application to produce the porous carbon material. For each of the above steps, known conditions can be used as appropriate.

[0038] The porous carbon materials suitable for this technology have a 10m 2 / g or more (hereinafter referred to as "specific surface area value"), and having a specific surface area of 0.1 cm measured by the BJH method and the MP method 3 / g or more pore volume.

[0039] The specific surface area value of the porous carbon material according to the present technology is preferably 10 m 2 / g or more, more preferably 50m 2 / g or more, more preferably 100m 2 / g or more, particularly preferably 500m 2 / g or more. As the specific surface area of the porous carbon material increases, improvement in functionality can be expected. Note that the above-mentioned specific surface area refers to the specific surface area of the porous carbon material itself, rather than the specific surface area in a state where the porous carbon material has adsorbed a compound to be adsorbed, such as a harmful organic compound.

[0040] The nitrogen BET method is a method comprising measuring an adsorption isotherm by allowing nitrogen as an adsorbed molecule to adsorb and desorb on a porous carbon material, and analyzing the measured data based on the BET equation represented by equation (1). Specific surface area, pore volume, etc. can be calculated based on this method.

[0041] Specifically, in the case of calculating the specific surface area value by the nitrogen BET method, first, an adsorption isotherm is obtained by causing nitrogen as an adsorbed molecule to adsorb and desorb on the porous carbon material. Then, from the obtained adsorption isotherm, [p / {V a (p0-p)}], and the result is plotted against the equilibrium relative pressure (p / p0). Then, the curve is considered as a straight line, and the slope s (=[(C-1) / (C·V m )]) and intercept i(=[1 / (C·V m )]). Then, V is calculated from the obtained slope s and intercept i based on equations (2-1) and (2-2). m and C. In addition, based on equation (3) (see BELSORP-mini and BELSORP analysis software manual produced by Bayer Japan, pages 62-66) from V m Calculate the specific surface area a sBET .

[0042] Note that the nitrogen BET method is a measurement method according to JIS R 1626-1996 "Determination of specific surface area of fine ceramic powder by gas adsorption using the BET method".

[0043] V a = (V m ·C·p) / [ (p0-p) {1 + (C-1) (p / p0)}] (1) [p / {V a (p0-p)}]=[(C-1) / (C·V m )](p / p0)+[1 / (C·V m )](1') V m = 1 / (s + i) (2-1) C = (s / i) + 1 (2-2) a sBET = (V m ·L·σ) / 22414 (3)

[0044] here, V a : adsorption capacity; V m : adsorption capacity of monolayer; p: pressure of nitrogen at equilibrium; p0: saturated vapor pressure of nitrogen; L: Avogadro's constant; and σ: adsorption cross-sectional area of nitrogen.

[0045] The pore volume V was calculated by the nitrogen BET method. p In the case of, for example, linear interpolation is performed on the adsorption isotherm to determine the adsorption amount V at the relative pressure set by the pore volume calculation relative pressure. The pore volume V can be calculated from the adsorption amount V based on equation (4): p (See BELSORP-mini and BELSORP analysis software manual produced by Bayer Japan, pages 62-65.) Note that, hereinafter, the pore volume based on the nitrogen BET method may be simply referred to as "pore volume."

[0046] V p = (V / 22414)×(M g / ρ g ) (4)

[0047] here, V: adsorption capacity under relative pressure; M g : molecular weight of nitrogen; and ρ g : Density of nitrogen.

[0048] The pore volume of the porous carbon material according to the present technology obtained by the BJH method and the MP method is preferably 0.1 cm 3 / g or more, more preferably 0.15cm 3 / g or more, more preferably 0.2cm 3 / g or more. As the pore volume of the porous carbon material obtained by the BJH method and the MP method increases, improved functionality can be expected. Note that the above-mentioned pore volume refers to the pore volume of the porous carbon material itself, and does not refer to the pore volume in a state where the porous carbon material has adsorbed a compound to be subjected to adsorption, such as a harmful organic compound.

[0049] The pore diameter of the pores in the porous carbon material can be calculated as a pore distribution from the pore volume change rate relative to the pore diameter based on, for example, the BJH method. The BJH method is a widely used method for pore distribution analysis.

[0050] In the case of pore distribution analysis based on the BJH method, first, a desorption isotherm is obtained by adsorbing and desorbing nitrogen as an adsorbed molecule on a porous carbon material. Then, based on the obtained desorption isotherm, the thickness of the adsorption layer when the pores are filled with adsorbed molecules (e.g., nitrogen) and the adsorbed molecules are gradually adsorbed and desorbed, and the inner diameter of the pores generated during adsorption and desorption (twice the core radius) is determined, and the pore radius r is calculated based on equation (5) p, and the pore volume is calculated based on equation (6). Then, the pore radius and pore volume are plotted relative to the pore diameter (2r p ) of the pore volume change rate (dV p / dr p ), thereby obtaining the pore distribution curve (see BELSORP-mini and BELSORP analysis software manual produced by Bayer Japan, pages 85 to 88).

[0051] r p = t + r k (5) V pn = R n ·dV n - R n ·dt n ·c·ΣA pj (6) in, R n = r pn 2 / (rkn-1 + dt n ) 2 (7)

[0052] here, r p : hole radius; r k :Under this pressure, the hole radius is r p The core radius (inner diameter / 2) in the case where an adsorption layer with a thickness of t is adsorbed on the inner wall of the pore; V pn : the pore volume when the nth nitrogen adsorption and desorption occurs; dV n : the amount of change at this time; dt n : The thickness t of the adsorption layer when the nth nitrogen adsorption and desorption occurs n The amount of change; r kn : the core radius at this time; c: a fixed value; and r pn : The pore radius when the nth nitrogen adsorption and desorption occurs. In addition, ∑A pj Indicates the integrated value of the wall surface area of the holes from j=1 to j=n-1.

[0053] The pore diameter of pores can be calculated, for example, based on the MP method, as a pore distribution by the pore volume change rate relative to the pore diameter. In the case of performing pore distribution analysis by the MP method, first, an adsorption isotherm is determined by adsorbing nitrogen to the porous carbon material. The adsorption isotherm is then converted into a pore volume relative to the adsorption layer thickness t (t curve). The pore distribution curve can then be obtained based on the curvature of the curve (the amount of change in pore volume relative to the amount of change in adsorption layer thickness t). The pore distribution curve can be obtained (see BELSORP-mini and BELSORP analysis software manuals produced by Bayer Japan, pages 72, 73, and 82).

[0054] In the porous carbon material contained in the dispersion according to the present technology, the cumulative pore volume in the range of 0.05 μm to 5 μm, as measured by mercury intrusion porosimetry, is preferably 0.4 cc / g or more, more preferably 0.5 cc / g or more, and particularly preferably 0.7 cc / g or more. As the pore volume increases, improved functionality can be expected. The mercury intrusion porosimetry can be appropriately measured in accordance with JIS R 1655:2003.

[0055] The upper limit of the average particle size of the porous carbon material contained in the dispersion according to the present technology is, for example, preferably 500 μm or less, more preferably 50 μm or less, and even more preferably 5 μm or less. Since the average particle size is adjusted within the above range or less, it is expected that the sedimentation rate of the porous carbon material will be reduced, and the porous carbon material will remain dispersed in the liquid for a longer period of time. Furthermore, since the average particle size is set within the above range or less, it is expected that the diffusion of the porous carbon material into soil or ambient water will be improved when the dispersion according to the present technology is used for environmental improvement, etc.

[0056] There is no particular lower limit on the average particle size of the porous carbon material contained in the dispersion according to the present technology. From the perspective of ease of manufacturing, appropriate production can be achieved, for example, by setting the average particle size to be greater than 0.1 μm, more preferably greater than 0.5 μm, and even more preferably greater than 1.0 μm.

[0057] Note that the average particle size of the porous carbon material can be appropriately adjusted by performing sieving or the like at any point in the production process of the porous carbon material to make the average particle size uniform.

[0058] The porous carbon material contained in the dispersion according to the present technology can be expected to effectively adsorb organic fluorine compounds (PFAS) represented by PFOA / PFOS, so that the amount of cations present on the surface of the porous carbon material is increased by cationization treatment.

[0059] For the cations present on the surface of the porous carbon material contained in the dispersion according to the present technology, the surface of the porous carbon material can be replaced by cationic groups (the cationic groups are covalently bound to the porous carbon material), thereby making the porous carbon material cationic as a single molecular entity, or the porous carbon material can be covered with a cationic substance different from the porous carbon material, thereby being cationic.

[0060] When the porous carbon material is coated with a cationic substance different from the porous carbon material, the surface of the porous carbon material and the surface of the cationic substance are bound by interfacial bonding forces. Here, "interfacial bonding forces" depend on chemical interactions and / or mechanical bonding between molecules on the two surfaces.

[0061] The cationic groups used in the cationization treatment of the porous carbon material contained in the dispersion according to the present technology are not particularly limited as long as they are cationic groups, examples of which include amino groups, imino groups, ammonium groups and aluminum alcohol groups, and amino groups or aluminum alcohol groups can be particularly suitably used.

[0062] There is no limitation on the cationization method of the porous carbon material contained in the dispersion according to the present technology, and any method can be used. In the case of cationization treatment by coating the porous carbon material with a cationic substance, as the cationic substance, for example, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-8-aminooctyltrimethoxysilane, N-2-(aminoethyl)-3-aminoethyltrimethoxysilane, etc. can be suitably used. In this case, by mixing the porous carbon material and the cationic substance under heating conditions, the porous carbon material can be appropriately coated with the cationic substance.

[0063] The degree of cationization treatment of the porous carbon material contained in the dispersion according to the present technology can be determined by X-ray photoelectron spectroscopy (XPS) surface analysis. XPS surface analysis can be appropriately measured in accordance with JIS K0162:2010.

[0064] The lower limit of the zeta potential of the porous carbon material contained in the dispersion according to the present technology at pH 7.0 is preferably -50 mV or higher, more preferably -20 mV or higher, and even more preferably 10 mV or higher, and the upper limit is +100 mV or lower, more preferably 70 mV or lower, and even more preferably 50 mV or lower. The degree of cationization treatment can be controlled within an appropriately adjusted range. Note that, depending on the harmful organic compound to be adsorbed, it is expected that the adsorption performance can be improved by appropriately adjusting the zeta potential range. The zeta potential can be appropriately measured in accordance with JIS Z 8836:2017.

[0065] <Dispersion> The dispersion according to the present technology is used to dissolve or disperse the following components in a dispersion medium such as water: a porous carbon material and a compound having an electric charge, such as an ionic biodegradable polymer. Here, the term "dissolved" refers to a state in which a component such as a solute is mixed with a dispersion medium to form a uniform phase. In addition, the term "dispersion" is a state in which a component is dispersed in a substance (dispersion medium) that forms one phase in the form of fine particles. Note that, as described above, the dispersion according to the present technology is generally in the form of a liquid or a gel. In addition, in this specification, in the case where the porous carbon material and the compound having an electric charge are dissolved in a dispersion medium, the dispersion is a solution, and the dispersion medium is a solvent.

[0066] The dispersion medium that can be used for the dispersion according to the present technology is not particularly limited, and for example, water can be suitably used.

[0067] In the dispersion according to the present technology, the upper limit of the content of the porous carbon material is not particularly limited, and for example, it is preferably 25% by weight or less, more preferably 15% by weight or less, and even more preferably 10% by weight or less. The lower limit of the content of the porous carbon material is not particularly limited, and for example, it is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and even more preferably 1.0% by weight or more.

[0068] In the dispersion according to the present technology, when a compound having a charge, such as an ionic biodegradable polymer, is contained in an amount of 0.1% by weight or more, more preferably 0.5% by weight or more, and even more preferably 1% by weight or more, relative to 100% by weight of the porous carbon material, the porous carbon material can be appropriately dispersed in the dispersion. The upper limit of the content of the compound having a charge is not particularly limited, and the compound having a charge can be contained in an amount of 20% by weight or less, more preferably 15% by weight or less, and even more preferably 10% by weight or less, relative to 100% by weight of the porous carbon material.

[0069] The dispersion according to this technology is -1 The viscosity at the shear rate is preferably 1000 Pa·s or less, more preferably 100 Pa·s or less, and particularly preferably 10 Pa·s or less. -1 The viscosity at the shear rate is set within the above range, and the dispersion can be expected to be suitable for environmental improvement applications such as soil, environmental water, etc. described later, and thus the dispersion exhibits excellent ease of use.

[0070] <Other ingredients> The dispersion according to the present technology may contain ingredients other than those mentioned above as needed, as long as the desired various physical properties are not significantly impaired. Examples of other ingredients include low molecular weight surfactants. One of these ingredients may be included, or two or more of these ingredients may be included in any combination and ratio.

[0071] <Adsorbent> With the dispersion according to the present technology, since the porous carbon material is appropriately dispersed in the dispersion, it can be expected that harmful chemicals flowing out to the environment such as soil are effectively adsorbed using the dispersion.

[0072] The chemical substances adsorbed by the dispersion according to the present technology are not particularly limited. For example, it is expected that the dispersion can appropriately adsorb harmful organic compounds such as organic fluorine compounds (PFAS) represented by PFOA / PFOS and benzene / toluene / ethylbenzene / xylene (BTEX), agricultural chemicals, heavy metals, etc. In particular, the dispersion according to the present technology can be used as an adsorbent material for PFAS because the dispersion is unlikely to decompose in the environment and can be expected to appropriately adsorb PFAS, which is a substance harmful to living organisms.

[0073] The PFAS to be adsorbed by the dispersion according to the present technology is not particularly limited, and the dispersion is expected to appropriately adsorb, for example, anionic organic fluorine compounds. As anionic organic fluorine compounds, for example, the dispersion is expected to adsorb relatively high molecular weight organic fluorine compounds having 8 or more carbon atoms, 9 or more carbon atoms, or 10 or more carbon atoms, and can also adsorb low molecular weight organic fluorine compounds having less than 8 carbon atoms that cannot be effectively adsorbed by activated carbon or the like.

[0074] <Environmental improvement methods> The environmental improvement method for soil, environmental water, etc. using the dispersion according to the present technology is not particularly limited, and the dispersion according to the present technology can be appropriately used in any environmental improvement method. For any environmental improvement method, examples of soil improvement methods and environmental water improvement methods include in-situ purification (on site) in which the target soil or environmental water is improved without moving the target soil or environmental water from its location, and in-situ treatment (in site) in which the target soil or environmental water is moved from its location and then improved.

[0075] Note that the term "soil" herein refers to the outermost layer of the Earth's crust, a mixture of inorganic components including rock fragments and organic components resulting from the decomposition of animal and plant bodies, and includes groundwater contained in the soil. The term "environmental water" refers to water and groundwater in public waters such as rivers, lakes, and oceans. Furthermore, terms such as "soil improvement" and "environmental water improvement" refer to general technologies used to improve the properties of target soil or environmental water, and include, for example, remediation, which is the process of returning contaminated soil or contaminated environmental water to a more pristine state.

[0076] Examples of on-site methods for improving soil or environmental water include: an in-situ stirring method, in which a treatment liquid is sprayed onto contaminated soil or contaminated environmental water and stirred using a backhoe or the like; and an in-situ injection method, in which a well (injection well) is set up and a treatment liquid is injected. Examples of in-site methods for improving soil or environmental water include: a soil cultivation method, in which contaminated soil, etc. is excavated, moved to a predetermined location, stirred while adding a treatment liquid and mixing; and the contaminated soil is piled into a pile shape, and a treatment liquid is injected through a pipe buried therein. The dispersion according to the present technology can be appropriately used as the above-mentioned treatment liquid, or used in combination with other reagents, etc. In addition, a treatment liquid adjusted as follows can also be used: a powder of an environmental improvement liquid containing a porous carbon material and a compound having a charge such as an ionic biodegradable polymer according to the present technology is mixed with any dispersion medium.

[0077] The powder used in the environmental improvement liquid of this technology can contain components equivalent to the dispersion of this technology. The environmental improvement powder used in this technology can be a powdery mixture obtained by mixing the raw materials constituting the environmental improvement powder according to the usage conditions, or can be formed into any shape, such as pills or tablets.

[0078] When soil or environmental water is improved using a treatment liquid containing the powder or dispersion for environmental improvement liquid according to the present technology, whether the powder or dispersion for environmental improvement liquid according to the present technology is used can be confirmed by the following method, for example.

[0079] First, particles containing porous carbon materials, etc. are recovered by filtering soil, etc. under reduced pressure. Then, the recovered porous carbon material is filled into an HPLC column and a UV detector is connected downstream. Ultrapure water is flowed while the column is heated to 150°C using a column oven and cleaned until the value from the UV detector asymptotically approaches 0. The conditions for circulating ultrapure water at this stage are, for example, a pressure of 3MPa, a liquid volume of 2mL / min, etc. Under these conditions, cleaning can be appropriately achieved, but the conditions are not limited thereto. Then, the above-mentioned particles are taken out and fully dried at 150°C until the weight does not change. Then, they can be confirmed. According to the above method, the specific surface area is measured by the nitrogen BET method, and the pore volume is measured by the BJH method and the MP method.

[0080] Furthermore, compounds having a charge such as ionic biodegradable polymers can be confirmed by drying and removing the dispersion medium from the filtrate after filtration, and then combining infrared spectroscopy, potentiometric titration, and a general biodegradability evaluation method represented by JIS K 6953-1:2011.

[0081] <Porous Carbon Material Incorporating a Charged Compound> The porous carbon material and the compound having an electric charge contained in the powder for the environmental improvement liquid according to the present technology may be bonded to each other. More specifically, the porous carbon material may have a 10 m 2 / g and above specific surface area values and 0.1 cm measured by BJH method and MP method 3 / g or more porous carbon material, and a compound having an electric charge is bonded thereto.

[0082] The bonding between the porous carbon material and the compound having a charge may be physical bonding, but is more preferably chemical bonding from the viewpoint of increasing the bonding strength.

[0083] When the porous carbon material incorporating the charged compound of the present technology is mixed with any dispersion medium and used as a dispersion, for example, the porous carbon material is appropriately dispersed in the dispersion due to the charged compound being incorporated. For example, when the porous carbon material has cationic properties, the charged compound is incorporated into the porous carbon material. Therefore, when the porous carbon material is dispersed in water at 1% by weight, the zeta potential measured at 25°C can be +25 mV or higher.

[0084] As described above, the porous carbon material incorporating the charged compound of the present technology can also be used as a powder for environmental improvement liquids, and can also be used as a material for, for example, filters due to its high adsorption properties for chemical substances such as organic fluorine compounds.

[0085] In this specification, "filter" refers to a device that removes chemical substances such as organic fluorine compounds from a fluid. Depending on the use case, the filter can be obtained by molding the raw material containing the porous carbon material with a charged compound combined with the present technology into any form according to the use purpose. It can be a powder of the raw material containing the porous carbon material with a charged compound combined with the present technology, it can be in a form combined with other components, or it can be in a form in which other raw materials are dispersed as a medium. Examples of the form of combination with other components include the following: a form in which components such as non-woven fabrics are combined, and the non-woven fabrics are stacked with the porous carbon material with a charged compound combined with the present technology. In addition, examples of the form in which other raw materials are dispersed as a medium include: paper or resin sheets, in which the porous carbon material with a charged compound combined with the present technology is added during the papermaking process to disperse the porous carbon material; fibers containing the porous carbon material with a charged compound combined with the present technology by a method such as dispersing the porous carbon material, and the like. Example

[0086] Hereinafter, the present technology will be described more specifically using embodiments. Note that the present technology is not limited at all to the contents of the following embodiments.

[0087] <Preparation of porous carbon material> As the plant-derived materials used in the examples, husks of rice (paddy) (husks of Indian rice and Indica rice) were used to prepare the following carbon materials 1 to 4.

[0088] 10 g of rice husk was placed in an alumina crucible, heated to 500°C at a heating rate of 5°C / min in a nitrogen flow (10 L / min), carbonized at the carbonization temperature for 6 h to convert the rice husk into a carbonaceous substance (porous carbon material precursor), and then cooled to room temperature to obtain a porous carbon material precursor.

[0089] The porous carbon material precursor was pulverized and mixed using an agate mortar so that potassium bromide (KBr) was about 5 wt % relative to 100 wt % of each sample to adjust the sample.

[0090] Then, the porous carbon material precursor was immersed in an aqueous sodium hydroxide solution with a concentration of 18 mol / L at 105°C and 1.0 MPa for 10 hours to obtain a porous carbon material. Note that when the carbonized material is immersed in the aqueous sodium hydroxide solution, the aqueous sodium hydroxide solution is stirred to adjust the concentration and temperature of the aqueous sodium hydroxide solution to be substantially uniform.

[0091] The porous carbon material obtained as described above was washed with RO water filtered through a reverse osmosis (RO) membrane until it became neutral, and then dried at 120° C. for 24 hours.

[0092] The porous carbon material that had been subjected to the alkali treatment was subjected to activation treatment based on a gas activation method, specifically, activation treatment using oxygen / water vapor at 800° C. to 950° C. for 2 hours.

[0093] Table 1 shows the specific surface area calculated using the nitrogen BET method and the pore volume calculated using the BJH method for each material using the above-mentioned method. Note that the specific surface area and pore volume calculated using the nitrogen BET method were measured using a surface area / pore distribution measurement device (product name: BELSORP mini, manufactured by Bayer Japan). Reference Materials 1 and 2 in Table 1 represent data for coconut shell activated carbon used as a reference.

[0094] The zeta potential in Table 1 was measured by mixing 0.15 g of each porous carbon material with 15 mL of water, subjecting the mixture to ultrasonic treatment for 5 minutes, and then measuring the sample by electrophoresis. This measurement was performed using a Zetasizer ULTRA (Malvern Analytical Ltd.) at 25°C.

[0095] In addition, the removal rates of PFAS in Table 1 were measured by the following method. (1) 20 mL of a mixed aqueous solution of 28 PFAS prepared at a concentration of 5000 ng / L and 10 mg of each porous carbon material were stirred in a 50 mL PP tube for 1 hour. (2) Then, the porous carbon material was filtered using a syringe filter having a diameter of 0.22 μm, and the PFAS concentration of the obtained filtrate was analyzed using LC-MS / MS. (3) The total removal rate of PFAS having a carbon chain of 4 or more carbon atoms was determined from the PFAS concentration values measured without an adsorbent by similar operations as in (1) and (2) above and the concentrations after treatment with the adsorbent.

[0096] In the determination of PFAS removal rate, the quantified PFAS with carbon chains of more than 4 carbon atoms include: PFBS, PFHxS, PFHpS, PFOS, PFDS, FOSA, N-MeFOSAA, N-EtFOSAA, 6:2FTSA, 8:2FTSA, PFBA, PFPeA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnDA, PFDoDA, PFTrDA, and PFTeDA.

[0097] [Table 1]

[0098] Next, as porous carbon materials to which a compound having a charge is bonded, carbon materials A to D are adjusted. In addition to the conditions of carbon materials 1 to 4 described above, the conditions for adjustment include the following method.

[0099] <Cationic Coating of Porous Carbon Materials> Using carbon material 4 as a raw material, 10 ml of a reaction solution having an effective concentration of 1 wt % of each compound was added to 1 g of the carbon material, and the mixture was mixed at room temperature for 30 minutes. Then, only the carbon material was recovered by centrifugal separation, and heated at 110 ° C for 1 hour to react each compound. Subsequently, ethanol was used for two washings and dried again at 110 ° C for 4 hours to prepare carbon materials A to D. For each material, the specific surface area by the nitrogen BET method and the pore volume by the BJH method calculated by the above method are shown in Table 2. Note that the specific surface area by the nitrogen BET method and the pore volume are measured by a specific surface area / pore distribution measuring device (product name: BELSORP mini, manufactured by Bayer Japan).

[0100] The measurement conditions for carbon materials A to D were the same as those for the above-mentioned carbon materials 1 to 4. The results are shown in Table 2.

[0101] [Table 2]

[0102] <Evaluation of dispersion stability> A dispersant such as an ionic biodegradable polymer shown in Table 3 is used to prepare 6 mL of a 0.1 wt % aqueous dispersion, to which 60 mg of the carbon material 3 shown in Table 1 is added, and the mixture is gently shaken to adjust the liquid (the liquid contains 10 wt % of the dispersant compared to the porous carbon material).

[0103] The liquid was then dispersed for 15 minutes using an ultrasonic cleaner (trade name: W-113, manufactured by Honda Electronics Co., Ltd.). The dispersion state was visually observed 6 days and 1 month after the dispersion and evaluated according to the following criteria.

[0104] [Evaluation Criteria] A. No obvious concentration gradient was observed. B. A concentration gradient begins to form. C. A clear concentration gradient is observed.

[0105] [Table 3]

[0106] For the dispersants such as ionic biodegradable polymers shown in Table 3, the dispersion material was dissolved in water to a concentration of 1 wt %, and the 1% solution viscosity of the dispersion material was measured as the viscosity in 10 s.-1 The viscosity at a shear rate of 1000 nm was determined using a digital viscometer DV2T (AMETEK Brookfield). The results are shown in Table 4.

[0107] Similarly, for the dispersants such as ionic biodegradable polymers shown in Table 3, the solvents were mixed at a weight ratio of porous carbon material: dispersant: solvent = 1:0.1:98.9 or 10:1:89 to obtain samples. The samples were subjected to ultrasonic treatment for 5 minutes, and the viscosity of the dispersion containing 1% by weight of the porous carbon material and the viscosity of the dispersion containing 10% by weight of the porous carbon material were measured. For this measurement, a digital viscometer DV2T (AMETEK Brookfield) was used. The results are shown in Table 4.

[0108] [Table 4]

[0109] Each of the carbon materials A to D was added to water in an amount of 60 mg, and the mixture was gently shaken to adjust the liquid.

[0110] The liquid was then dispersed for 15 minutes using an ultrasonic cleaner (trade name W-113 / manufactured by Honda Electronics Co., Ltd.), and the dispersion state was visually observed 6 days and 1 month after dispersion. The dispersibility of the porous carbon material to which the charged compound was bound was evaluated based on the same criteria as in Examples 1 to 3. The results are shown in Table 5.

[0111] [Table 5]

[0112] <Evaluation of Adsorption Characteristics> Adsorption characteristics were evaluated using an anionic dye, alizarin cyanine green (1,4-N,N'-bis(4-methyl-2-sulfophenyl)aminoanthraquinone disodium salt / Fujifilm Wako Pure Chemical Industries, Ltd.), which is used as an alternative to anionic PFAS, which are substances harmful to living organisms.

[0113] 60 mg of the porous carbon material listed in Table 1 was added to 6 mL of a 0.1 wt% sodium carboxymethylcellulose aqueous solution. 1 mL of a solution prepared similarly to the dispersion stability evaluation test described above and 20 mL of Alizarin Cyanine Green (concentration: 75 mg / L) were stirred in a container at room temperature for 6 hours. The porous carbon material was then removed by filtration, and the absorbance of the filtrate at a wavelength of 611 nm was measured using an absorbance meter (U-3900, manufactured by Hitachi High-Technologies Corporation) to calculate the adsorption capacity. The results are shown in Table 6.

[0114] [Table 6]

[0115] Note that the present technology can have the following configurations. (1) A dispersion comprising: A porous carbon material having a 10 m 2 / g and above specific surface area values and 0.1 cm measured by BJH method and MP method 3 / g or more pore volume; and A compound with an electric charge. (2) The dispersion according to (1), wherein the porous carbon material in the dispersion preferably has a zeta potential of +25 mV to +100 mV measured at 25°C. (3) The dispersion according to (1) or (2), wherein the compound having a charge is a compound having a cationic charge. (4) The dispersion according to (3), wherein the compound having a cationic charge is a compound having an amino group or an aluminol group. (5) The dispersion according to any one of (1) to (4), wherein the porous carbon material and the compound having a charge are bound to each other. (6) The dispersion according to (5), wherein the bonding is chemical bonding. (7) The dispersion according to any one of (1) to (6), wherein the compound having a charge is an ionic biodegradable polymer. (8) The dispersion according to (7), wherein the biodegradable polymer is a compound having a polysaccharide skeleton. (9) The dispersion according to any one of (1) to (8), wherein the porous carbon material is a porous carbon material subjected to cationization treatment. (10) The dispersion according to any one of (1) to (9), wherein the surface of the porous carbon material is substituted with an amino group. (11) The dispersion according to any one of (1) to (10), wherein the content of the porous carbon material is 0.01% by weight to 25% by weight. (12) The dispersion according to any one of (7) to (11), wherein the content of the ionic biodegradable polymer relative to the porous carbon material is 0.1% by weight to 20% by weight. (13) The dispersion according to any one of (7) to (12), wherein the ionic biodegradable polymer has a 1% solution viscosity of 0.1 Pa·s or more. (14) The dispersion according to any one of (1) to (13), wherein the porous carbon material has a cumulative pore volume of 0.4 cc / g or more in the range of 0.05 μm to 5 μm as measured by mercury intrusion porosimetry. (15) The dispersion according to any one of (1) to (14), wherein the porous carbon material has an average particle size of 0.1 to 500 μm. (16) The dispersion according to any one of (1) to (15), wherein the porous carbon material has a zeta potential of -50 to +100 mV at pH 7.0. (17) The dispersion according to any one of (1) to (16), wherein the porous carbon material has a 500 m 2 / g or more BET specific surface area. (18) The dispersion according to any one of (1) to (17), wherein the dispersion is -1 The viscosity is 1000 Pa·s or less at a shear rate. (19) The dispersion according to any one of (1) to (18), wherein the dispersion is a liquid. (20) An adsorbent material for PFAS, wherein the dispersion according to any one of (1) to (19) is used. (21) The adsorbent material for PFAS according to (20), wherein PFAS is an anionic organic fluorine compound. (22) The adsorbent material for PFAS according to (21), wherein the anionic organic fluorine compound is an organic fluorine compound having 8 or more carbon atoms. (23) An environmental improvement method, wherein the dispersion according to any one of (1) to (19) is used. (24) The environmental improvement method according to (23), wherein the environmental improvement is soil improvement or environmental water improvement. (25) A powder for environmental improvement liquid, comprising: A porous carbon material having a 10 m 2 / g and above specific surface area values and 0.1 cm measured by BJH method and MP method 3 / g or more pore volume; and A compound with an electric charge. (26) The powder for environmental improvement liquid according to (25), wherein the compound having a charge is an ionic biodegradable polymer. (27) The powder for environmental improvement liquid according to (26), wherein the biodegradable polymer is a compound having a polysaccharide skeleton. (28) A method for dispersing a porous carbon material, the method comprising: The porous carbon material having a 10 m³ / min measured by a nitrogen BET method is dispersed in a dispersion by using a compound having an electric charge. 2 / g and above specific surface area values and 0.1 cm measured by BJH method and MP method 3 / g or more pore volume. (29) The method for dispersing a porous carbon material according to (28), wherein the compound having a charge is an ionic biodegradable polymer. (30) The method for dispersing a porous carbon material according to (29), wherein the biodegradable polymer is a compound having a polysaccharide skeleton. (31) A porous carbon material having: 10m3 measured by nitrogen BET method 2 / g or more specific surface area value; and 0.1 cm measured by BJH method and MP method 3 / g or more pore volume, of which A compound having an electric charge is combined with the porous carbon material. (32) The porous carbon material according to (31), wherein the porous carbon material dispersed in water in an amount of 1 wt % has a zeta potential of +25 mV or more measured at 25°C. (33) The porous carbon material according to (31) or (32), wherein the porous carbon material is used for dispersion. (34) A filter comprising the porous carbon material according to any one of (31) to (33).

Claims

1. A dispersion comprising: A porous carbon material having a 10 m 2 / g and above specific surface area values and 0.1 cm measured by BJH method and MP method 3 / g or more pore volume; and A compound with an electric charge.

2. The dispersion according to claim 1, wherein The porous carbon material in the dispersion has a zeta potential of +25 mV to +100 mV measured at 25°C.

3. The dispersion according to claim 1, wherein The compound having a charge is a compound having a cationic charge.

4. The dispersion according to claim 3, wherein The compound having a cationic charge is a compound having an amino group or an aluminum alcohol group.

5. The dispersion according to claim 1, wherein The porous carbon material and the compound having a charge are bonded to each other.

6. The dispersion according to claim 5, wherein The binding is chemical binding.

7. The dispersion according to claim 1, wherein The compound having a charge is an ionic biodegradable polymer.

8. The dispersion according to claim 7, wherein The biodegradable polymer is a compound having a polysaccharide backbone.

9. The dispersion according to claim 1, wherein The porous carbon material is a porous carbon material that has been cationized.

10. The dispersion according to claim 1, wherein The surface of the porous carbon material is substituted with amino groups.

11. The dispersion according to claim 1, wherein The content of the porous carbon material is 0.01 wt % to 25 wt %.

12. The dispersion according to claim 7, wherein The content of the ionic biodegradable polymer relative to the porous carbon material is 0.1 wt % to 20 wt %.

13. The dispersion according to claim 7, wherein The ionic biodegradable polymer has a 1% solution viscosity of 0.1 Pa·s or more. 14 . The dispersion according to claim 1 , wherein the porous carbon material has a cumulative pore volume of 0.4 cc / g or more in the range of 0.05 μm to 5 μm as measured by mercury intrusion porosimetry.

15. The dispersion according to claim 1, wherein The porous carbon material has an average particle size of 0.1 to 500 μm.

16. The dispersion according to claim 1, wherein The porous carbon material has a 500 m 2 / g or more BET specific surface area.

17. The dispersion according to claim 1, wherein The dispersion was stirred for 10 s. -1 The viscosity is 1000 Pa·s or less at a shear rate.

18. The dispersion according to claim 1, wherein The dispersion is a liquid.

19. An adsorption material for PFAS, wherein: The liquid according to claim 1 is used.

20. The adsorption material for PFAS according to claim 19, wherein The PFAS are anionic organofluorine compounds.

21. The adsorption material for PFAS according to claim 20, wherein: The anionic organic fluorine compound is an organic fluorine compound having 8 or more carbon atoms.

22. A method for improving an environment, wherein: A dispersion according to claim 1 is used.

23. A powder for environmental improvement liquid, comprising: A porous carbon material having a 10 m 2 / g and above specific surface area values and 0.1 cm measured by BJH method and MP method 3 / g or more pore volume; and A compound with an electric charge.

24. The powder for environmental improvement liquid according to claim 23, wherein The compound having a charge is an ionic biodegradable polymer.

25. The powder for environmental improvement liquid according to claim 24, wherein The biodegradable polymer is a compound having a polysaccharide backbone.

26. A method for dispersing a porous carbon material, the method comprising: The porous carbon material having a 10 m³ / min measured by a nitrogen BET method is dispersed in a dispersion by using a compound having an electric charge. 2 / g and above specific surface area values and 0.1 cm measured by BJH method and MP method 3 / g or more pore volume.

27. The method for dispersing a porous carbon material according to claim 26, wherein The compound having a charge is an ionic biodegradable polymer.

28. The method for dispersing a porous carbon material according to claim 27, wherein The biodegradable polymer is a compound having a polysaccharide backbone.

29. A porous carbon material comprising: 10m3 measured by nitrogen BET method 2 / g or above; and 0.1 cm measured by BJH method and MP method 3 / g or more pore volume, where A compound having an electric charge is combined with the porous carbon material.

30. The porous carbon material according to claim 29, wherein The porous carbon material dispersed in water in an amount of 1 wt % has a zeta potential of +25 mV or more measured at 25°C.

31. The porous carbon material according to claim 29, wherein The porous carbon material is used for dispersion.

32. A filter comprising the porous carbon material according to claim 29.

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