PFAS-removing material, method for producing PFAS-removing material, method for regenerating PFAS-removing material, method for producing regenerated PFAS-removing material, PFAS-removed regenerated activated carbon, water purification facility, and method for maintaining water purification facility

Abstract

This PFAS-removing material contains a carbonaceous material. The pore volume of the carbonaceous material is determined by the CI method from the N2 adsorption isotherm at -196°C. The ratio ((A) / (B)) of the pore volume (A) having a pore diameter of 2-4 nm to the pore volume (B) having a pore diameter of 1.2 nm or less is 0.085-0.410, inclusive. The ratio ((C) / (B)) of the pore volume (C) having a pore diameter of 9-25 nm to the pore volume (B) having a pore diameter of 1.2 nm or less is 0.04-0.45, inclusive.

Description

PFAS removal material, method for manufacturing PFAS removal material, method for regenerating PFAS removal material, method for manufacturing regenerated PFAS removal material, PFAS removal regenerated activated carbon, water purification equipment, and maintenance method for water purification equipment.

[0001] The present invention relates to a PFAS removal material, an object, a method for manufacturing a PFAS removal material, a method for regenerating a PFAS removal material, a method for manufacturing a regenerated PFAS removal material, PFAS-regenerated activated carbon, water purification equipment, and a method for maintaining water purification equipment.

[0002] In various industrial fields, there is a demand for PFAS removers to remove organofluorine compounds (perfluoroalkyl compounds and polyfluoroalkyl compounds (hereinafter referred to as PFAS)). As PFAS removers, for example, PFAS adsorbents capable of adsorbing PFAS have been proposed, and more specifically, carbonaceous materials having pores have been proposed.

[0003] As a carbonaceous material, for example, fibrous activated carbon obtained by the following method has been proposed. First, coal pitch-based carbon fibers and an alkali activator are mixed, and this mixture is heated under a nitrogen atmosphere to obtain alkali-activated carbon. Next, the alkali-activated carbon is washed, dried, and heat-treated to produce fibrous activated carbon.

[0004] International Publication No. 2024 / 180739

[0005] On the other hand, carbonaceous materials are required to have superior durability. Furthermore, carbonaceous materials are required to have superior PFAS removal performance.

[0006] The present invention relates to a PFAS removal material containing a carbonaceous material having excellent durability and PFAS removal performance, an object, a method for manufacturing the PFAS removal material, a method for regenerating the PFAS removal material, a method for manufacturing the regenerated PFAS removal material, PFAS-removing regenerated activated carbon, water purification equipment, and a method for maintaining the water purification equipment.

[0007] The present invention [1] relates to N at -196°C ２The PFAS removal material contains a carbonaceous material in which, based on the pore volume determined by the CI method from adsorption isotherms, the ratio of the pore volume of pores with a diameter of 2 to 4 nm (A) to the pore volume of pores with a diameter of 1.2 nm or less (B) ((A) / (B)) is 0.085 to 0.410, and the ratio of the pore volume of pores with a diameter of 9 to 25 nm (C) to the pore volume of pores with a diameter of 1.2 nm or less (B) ((C) / (B)) is 0.04 to 0.45.

[0008] The present invention [2] relates to N at -196°C ２ The specific surface area determined by the BET method from the adsorption isotherm is 900 m². ２ / g or more 1760m ２ The PFAS removal material contains a carbonaceous material with a concentration of less than or equal to / g, where the pore volume (A) for pores with a diameter of 2 to 4 nm is 0.030 mL / g or more and 0.100 mL / g or less, the pore volume (B) for pores with a diameter of 1.2 nm or less is 0.230 mL / g or more and 0.350 mL / g or less, and the pore volume (C) for pores with a diameter of 9 to 25 nm is 0.011 mL / g or more and 0.140 mL / g or less.

[0009] The present invention [3] includes the PFAS removal material described in [1] or [2] above, wherein the MS hardness of the carbonaceous material is 80.0% or more.

[0010] The present invention [4] includes a PFAS removal material according to any one of the above [1] to [3], wherein the fluorine content of the carbonaceous material is 0.010 mg / kg or more and 50.000 mg / kg or less.

[0011] The present invention [5] includes a PFAS removal material according to any one of the above [1] to [4], wherein the MS hardness of the carbonaceous material is 80.0% or more, and the fluorine content of the carbonaceous material is 0.010 mg / kg or more and 50.000 mg / kg or less.

[0012] The present invention [6] includes an object selected from the group consisting of an adsorption filter, a water purifier cartridge, a water purifier, and a water purification system, which contains a PFAS removal material as described in any one of the above items [1] to [5].

[0013] The present invention [7] is a method for producing a PFAS removal material according to any one of the above items [1] to [5], comprising a carbonization step of carbonizing raw material components for obtaining the carbonaceous material by heat treatment to obtain a carbide, and an activation step of activating the carbide to obtain the carbonaceous material, wherein in the carbonization step, the heat treatment temperature in the heat treatment is increased at a heating rate of 5°C / min or more and 10°C / min or less.

[0014] The present invention [8] further includes a method for producing the PFAS remover described in [7] above, comprising: an adsorption step of adsorbing an organofluorine compound onto a carbonaceous material to obtain a carbonaceous material on which the organofluorine compound has been adsorbed; a thermal decomposition step of heating the carbonaceous material on which the organofluorine compound has been adsorbed to thermally decompose the organofluorine compound; and a removal step of removing impurities from the carbonaceous material after the thermal decomposition.

[0015] The present invention [9] includes a method for producing a PFAS remover as described in [8] above, wherein in the thermal decomposition step, the carbonaceous material on which the organofluorine compound has been adsorbed is heated in an inert gas atmosphere to a temperature of 300°C to 950°C to thermally decompose the organofluorine compound.

[0016] The present invention

[10] further includes a method for producing a PFAS removal material according to [8] or [9] above, comprising a cooling step of cooling the carbonaceous material after the thermal decomposition step.

[0017] The present invention

[11] includes a method for removing PFAS, which involves bringing a PFAS removal material described in any one of the above items [1] to [5] into contact with a workpiece containing an organofluorine compound, thereby removing the organofluorine compound from the workpiece.

[0018] The present invention

[12] is a method for regenerating a PFAS removal material according to any one of the above items [1] to [5], comprising the steps of: preparing the PFAS removal material containing the carbonaceous material on which an organofluorine compound has been adsorbed; and heating the carbonaceous material on which the organofluorine compound has been adsorbed to a temperature of 300°C to 950°C to thermally decompose the organofluorine compound.

[0019] The present invention

[13] is a method for producing a recycled PFAS removal material obtained by regenerating a PFAS removal material described in any one of the above items [1] to [5], comprising the steps of: preparing the PFAS removal material containing the carbonaceous material on which an organofluorine compound has been adsorbed; and heating the carbonaceous material on which the organofluorine compound has been adsorbed to cause thermal decomposition of the organofluorine compound.

[0020] The present invention

[14] is a regenerative PFAS removal material containing recycled carbonaceous material, wherein the recycled carbonaceous material has N at -196°C ２ The specific surface area determined by the BET method from the adsorption isotherm is 900 m². ２ / g or more 1760m ２ It contains a recycled PFAS removal material that is less than or equal to 0.010 mg / kg, has a pore volume (A) of pores with a diameter of 2 to 4 nm of 0.030 mL / g or more and 0.100 mL / g or less, a pore volume (B) of pores with a diameter of 1.2 nm or less of 0.230 mL / g or more and 0.350 mL / g or less, a pore volume (C) of pores with a diameter of 9 to 25 nm of 0.011 mL / g or more and 0.140 mL / g or less, and a fluorine content of 0.010 mg / kg or more and 50.000 mg / kg or less.

[0021] The present invention

[15] includes the recycled PFAS removal material described in

[14] above, wherein the MS hardness of the recycled carbonaceous material is 80.0% or more.

[0022] The present invention

[16] includes an object selected from the group consisting of an adsorption filter, a water purifier cartridge, a water purifier, and a water purification system, which contains the recycled PFAS removal material described in

[14] or

[15] above.

[0023] The present invention

[17] includes a method for removing PFAS, in which the recycled PFAS removal material described in

[14] or

[15] above is brought into contact with a workpiece containing an organofluorine compound, thereby removing the organofluorine compound from the workpiece.

[0024] The present invention

[18] includes PFAS-removed regenerated activated carbon having a fluorine content of 0.010 mg / kg or more and less than 1,000 mg / kg.

[0025] The present invention

[19] comprises a water purification facility comprising a packed bed containing a packed PFAS removing material, wherein the packed PFAS removing material comprises the PFAS removing material according to any one of the above [1] to [5] and / or the regenerated PFAS removing material according to the above

[14] .

[0026] The present invention

[20] comprises the water purification facility according to the above

[19] , wherein the packed bed further contains an adsorbent other than the packed PFAS removing material.

[0027] The present invention

[21] comprises a method for maintaining the water purification facility according to the above

[19] or

[20] , comprising: a regeneration step of regenerating the PFAS removing material and / or the regenerated PFAS removing material used in the packed bed by heating; and a reuse step of reusing the regenerated PFAS removing material and / or the regenerated PFAS removing material in the packed bed, wherein the regeneration step comprises: continuously measuring the PFAS concentration of treated water that has passed through the packed bed; calculating a cumulative PFAS adsorption amount of the PFAS removing material and / or the regenerated PFAS removing material when the PFAS concentration is equal to or higher than a predetermined value; setting a heating temperature based on the cumulative PFAS adsorption amount; and heating the PFAS removing material and / or the regenerated PFAS removing material at the set heating temperature.

[0028] The PFAS removing material, article, method for producing a PFAS removing material, method for regenerating a PFAS removing material, method for producing a regenerated PFAS removing material, PFAS-removing activated carbon, and water purification facility of the present invention contain the above-mentioned carbonaceous material. The above-mentioned carbonaceous material has excellent durability and excellent PFAS removal performance. Therefore, the above-mentioned PFAS removing material, article, method for producing a PFAS removing material, method for regenerating a PFAS removing material, method for producing a regenerated PFAS removing material, PFAS-removing activated carbon, and water purification facility have excellent durability and excellent PFAS removal performance. Furthermore, according to the maintenance method for a water purification facility of the present invention, the above-mentioned water purification facility can be operated efficiently.

[0029] Figure 1 is a schematic side view of a rotary kiln. Figure 2 is a schematic cross-sectional view of a rotary kiln. Figure 3 shows a container used for measuring MS hardness.

[0030] 1. Carbonaceous Material (1) First Embodiment In the first embodiment, the carbonaceous material contains a carbide obtained by carbonizing a raw material component (described later), as will be described in detail later.

[0031] The carbonaceous material has pores. The pores of the carbonaceous material are classified based on pore diameter in accordance with the standards of IUPAC (International Union of Pure and Applied Chemistry). More specifically, pores having a pore diameter of less than 2.0 nm are micropores. Pores having a pore diameter of 2.0 nm or more and 50.0 nm or less are mesopores. Pores having a pore diameter exceeding 50.0 nm are macropores.

[0032] Mesopores are larger pores than micropores. Therefore, mesopores are effective for adsorption of PFAS (described later) having a relatively large molecular size.

[0033] On the other hand, PFAS (described later) may include a plurality of types of compounds having different molecular sizes (for example, PFOA (described later) and PFOS (described later)). Therefore, if the carbonaceous material merely has pores (mesopores) with a pore diameter of 2.0 nm or more and 50.0 nm or less, sufficient PFAS adsorption performance may not be obtained in some cases.

[0034] Therefore, in the first embodiment, the specific surface area and pore volume of the carbonaceous material are adjusted from the viewpoint of achieving both PFAS adsorption performance and durability of the carbonaceous material.

[0035] In other words, in the first embodiment, the carbonaceous material has a predetermined specific surface area and a predetermined pore volume. More specifically, in the first embodiment, the specific surface area of the carbonaceous material is adjusted to a predetermined range, the pore volume (A) of pores with a pore diameter of 2 to 4 nm is adjusted to a predetermined range, the pore volume (B) of pores with a pore diameter of 1.2 nm or less is adjusted to a predetermined range, and further, the pore volume (C) of pores with a pore diameter of 9 to 25 nm is adjusted to a predetermined range. Each of these will be described in detail below.

[0036] [Specific Surface Area] The specific surface area is N at -196°C ２ It is the specific surface area determined by the BET method from the adsorption isotherm (hereinafter referred to as BET specific surface area). The BET specific surface area is used, for example, as an indicator of the adsorption capacity of a carbonaceous material. The BET specific surface area can be determined in accordance with the examples described later.

[0037] From the viewpoint of securing an adsorption area, the BET specific surface area of the carbonaceous material is 900 m ２ / g or more, preferably 1000 m ２ / g or more, more preferably 1200 m ２ / g or more. Further, from the viewpoint of controlling the pore size of the carbonaceous material, the BET specific surface area of the carbonaceous material is, for example, 1760 m ２ / g or less. That is, the BET specific surface area of the carbonaceous material is 900 m ２ / g or more and 1760 m ２ / g or less, preferably 1000 m ２ / g or more and 1760 m ２ / g or less, more preferably 1200 m ２ / g or more and 1760 m ２ / g or less.

[0038] [Pore Volume] The pore volume is N at -196°C ２ It is determined from the adsorption isotherm by the CI (Cranston-Inkley) method. More specifically, the pore volume for each interval (each pore diameter) is calculated by the CI method. Further, the total pore volume of the carbonaceous material is calculated as the sum of the pore volumes of each interval (each pore diameter). The pore volume can be determined in accordance with the examples described later.

[0039] [Pore Volume of Pores with Diameter of 2 to 4 nm (A)] The carbonaceous material includes pores having a pore diameter of 2 nm or more and 4 nm or less (hereinafter referred to as pores with a pore diameter of 2 to 4 nm).

[0040] In the carbonaceous material, the cumulative pore volume of pores with a diameter of 2 to 4 nm contained in 1 g of the carbonaceous material (hereinafter referred to as pore volume of pores with a diameter of 2 to 4 nm (A)) is adjusted to a predetermined range from the viewpoint of achieving both PFAS (particularly PFOA (described later)) adsorption performance and the durability of the carbonaceous material.

[0041] More specifically, N at -196°C ２ In the pore volume (hereinafter the same) determined by the CI method from the adsorption isotherm, the pore volume (A) for pores with a diameter of 2 to 4 nm is 0.030 mL / g or more, preferably 0.040 mL / g or more, more preferably 0.050 mL / g or more, and even more preferably 0.060 mL / g or more. Furthermore, the pore volume (A) for pores with a diameter of 2 to 4 nm is 0.100 mL / g or less, preferably 0.098 mL / g or less, more preferably 0.095 mL / g or less, and even more preferably 0.090 mL / g or less. In other words, the pore volume (A) of pores with a diameter of 2 to 4 nm is 0.030 mL / g or more and 0.100 mL / g or less, preferably 0.040 mL / g or more and 0.098 mL / g or less, more preferably 0.050 mL / g or more and 0.095 mL / g or less, and even more preferably 0.060 mL / g or more and 0.090 mL / g or less.

[0042] [Pore volume of pores with a diameter of 1.2 nm or less (B)] Carbonaceous materials have pores with a diameter of 1.2 nm or less (hereinafter referred to as pores with a diameter of 1.2 nm or less).

[0043] In carbonaceous materials, the cumulative pore volume of pores with a diameter of 1.2 nm or less contained in 1 g of carbonaceous material (hereinafter, pore volume of pores with a diameter of 1.2 nm or less (B)) is adjusted to a predetermined range from the viewpoint of achieving both PFAS (particularly PFOA (described later) and PFOS (described later)) adsorption performance and durability of the carbonaceous material.

[0044] More specifically, N at -196°C ２In the pore volume (hereinafter the same) determined by the CI method from the adsorption isotherm, the pore volume (B) for pores with a diameter of 1.2 nm or less is 0.230 mL / g or more, preferably 0.250 mL / g or more, more preferably 0.270 mL / g or more, and even more preferably 0.280 mL / g or more. Furthermore, the pore volume (B) for pores with a diameter of 1.2 nm or less is 0.350 mL / g or less, preferably 0.340 mL / g or less, more preferably 0.330 mL / g or less, and even more preferably 0.320 mL / g or less. In other words, the pore volume (B) of pores with a diameter of 1.2 nm or less is 0.230 mL / g or more and 0.350 mL / g or less, preferably 0.250 mL / g or more and 0.340 mL / g or less, more preferably 0.270 mL / g or more and 0.330 mL / g or less, and even more preferably 0.280 mL / g or more and 0.320 mL / g or less.

[0045] If the pore volume (B) of pores with a diameter of 1.2 nm or less is within the above range, competition between PFAS and other adsorbents can be suppressed, thereby preventing a decrease in the amount of PFAS adsorbed onto the carbonaceous material. As a result, PFAS can be adsorbed efficiently.

[0046] [Pore volume (C) of pores with a diameter of 9 to 25 nm] Carbonaceous materials have pores with a diameter of 9 nm to 25 nm (hereinafter referred to as pores with a diameter of 9 to 25 nm).

[0047] In carbonaceous materials, the cumulative pore volume of pores with a diameter of 9 to 25 nm contained in 1 g of carbonaceous material (hereinafter referred to as the pore volume of pores with a diameter of 9 to 25 nm (C)) is adjusted to a predetermined range from the viewpoint of achieving both PFAS (particularly PFOS (described later)) adsorption performance and durability of the carbonaceous material.

[0048] More specifically, N at -196°C ２In the pore volume (hereinafter the same) determined by the CI method from the adsorption isotherm, the pore volume (C) for pores with a diameter of 9 to 25 nm is 0.011 mL / g or more, preferably 0.015 mL / g or more, more preferably 0.020 mL / g or more, and even more preferably 0.025 mL / g or more. Furthermore, the pore volume (C) for pores with a diameter of 9 to 25 nm is 0.140 mL / g or less, preferably 0.100 mL / g or less, more preferably 0.090 mL / g or less, and even more preferably 0.080 mL / g or less. In other words, the pore volume (C) for pores with a diameter of 9 to 25 nm is 0.011 mL / g or more and 0.140 mL / g or less, preferably 0.015 mL / g or more and 0.100 mL / g or less, more preferably 0.020 mL / g or more and 0.090 mL / g or less, and even more preferably 0.025 mL / g or more and 0.080 mL / g or less.

[0049] [Effects] The carbonaceous material described above has excellent durability and excellent PFAS removal performance. More specifically, if the carbonaceous material has the above-mentioned specific surface area and the above-mentioned pore volumes (A) to (C), the carbonaceous material can possess excellent PFOA adsorption performance, excellent PFAS adsorption performance, and excellent durability.

[0050] In the first embodiment, the carbonaceous material is not particularly limited in terms of pore volume ratio (described later), as long as it has the above-mentioned specific surface area and pore volumes (A) to (C).

[0051] (2) Second Embodiment In the second embodiment, the carbonaceous material contains a carbide (described later) obtained by carbonizing the raw material components (described later), similar to the first embodiment. Unless otherwise specified below, the carbonaceous material of the second embodiment and the carbonaceous material of the first embodiment are the same.

[0052] In the second embodiment, the ratio of the above-mentioned pore volumes of the carbonaceous material (hereinafter referred to as the pore volume ratio) is adjusted from the viewpoint of achieving both PFAS adsorption performance and durability of the carbonaceous material.

[0053] In other words, in the second embodiment, the carbonaceous material has a predetermined pore volume ratio. More specifically, in the second embodiment, the ratio of the pore volume of pores with a diameter of 2 to 4 nm (A) to the pore volume of pores with a diameter of 1.2 nm or less (B) ((A) / (B)) is adjusted to a predetermined range, and the ratio of the pore volume of pores with a diameter of 9 to 25 nm (C) to the pore volume of pores with a diameter of 1.2 nm or less (B) ((C) / (B)) is adjusted to a predetermined range. Each of these will be described in detail below.

[0054] [Pore Volume Ratio (A) / (B)] In carbonaceous materials, the ratio of the pore volume (A) of pores with a diameter of 2 to 4 nm to the pore volume (B) of pores with a diameter of 1.2 nm or less ((A) / (B)) is adjusted, in particular, from the viewpoint of achieving both PFOA (described later) adsorption performance and the durability of the carbonaceous material.

[0055] Specifically, the ratio of the pore volume (A) with a pore diameter of 2 to 4 nm to the pore volume (B) with a pore diameter of 1.2 nm or less ((A) / (B)) is 0.085 or more, preferably 0.150 or more, and more preferably 0.250 or more. Also, the ratio of the pore volume (A) with a pore diameter of 2 to 4 nm to the pore volume (B) with a pore diameter of 1.2 nm or less ((A) / (B)) is 0.410 or less, preferably 0.350 or less, and more preferably 0.310 or less. In other words, the ratio of the pore volume (A) with a pore diameter of 2 to 4 nm to the pore volume (B) with a pore diameter of 1.2 nm or less ((A) / (B)) is 0.085 or more and 0.410 or less, preferably 0.150 or more and 0.350 or less, and more preferably 0.250 or more and 0.310 or less.

[0056] [Pore Volume Ratio (C) / (B)] In carbonaceous materials, the ratio of the pore volume (C) of pores with a diameter of 9 to 25 nm to the pore volume (B) of pores with a diameter of 1.2 nm or less (pore volume ratio (C) / (B)) is adjusted, in particular, from the viewpoint of achieving both PFOS (described later) adsorption performance and the durability of the carbonaceous material.

[0057] The ratio of the pore volume of pores with a diameter of 9 to 25 nm (C) to the pore volume of pores with a diameter of 1.2 nm or less (B) ((C) / (B)) is 0.04 or more, preferably 0.08 or more, and more preferably 0.10 or more. Also, the ratio of the pore volume of pores with a diameter of 9 to 25 nm (C) to the pore volume of pores with a diameter of 1.2 nm or less (B) ((C) / (B)) is 0.45 or less, preferably 0.40 or less, and more preferably 0.35 or less. That is, the ratio of the pore volume of pores with a diameter of 9 to 25 nm (C) to the pore volume of pores with a diameter of 1.2 nm or less (B) ((C) / (B)) is 0.04 or more and 0.45 or less, preferably 0.08 or more and 0.40 or less, and more preferably 0.10 or more and 0.35 or less.

[0058] [Pore Volume Ratio (C) / (A)] In carbonaceous materials, the ratio of the pore volume (C) of pores with a diameter of 9 to 25 nm to the pore volume (A) of pores with a diameter of 2 to 4 nm (pore volume ratio (C) / (A)) is not particularly limited and is adjusted as appropriate depending on the purpose and application.

[0059] The ratio of the pore volume (C) of pores with a diameter of 9 to 25 nm to the pore volume (A) of pores with a diameter of 2 to 4 nm is, for example, 0.100 or more, preferably 0.200 or more. Also, the ratio of the pore volume (C) of pores with a diameter of 9 to 25 nm to the pore volume (A) of pores with a diameter of 2 to 4 nm is, for example, 2.000 or less, preferably 1.000 or less. That is, the ratio of the pore volume (C) of pores with a diameter of 9 to 25 nm to the pore volume (A) of pores with a diameter of 2 to 4 nm is, for example, 0.100 or more and 2.000 or less, preferably 0.200 or more and 1.000 or less.

[0060] [Effects] The carbonaceous material described above has excellent durability and excellent PFAS removal performance. More specifically, if the pore volume ratio (A) / (B) and pore volume ratio (C) / (B) of the carbonaceous material are within the above range, the carbonaceous material can possess excellent PFOA adsorption performance, excellent PFAS adsorption performance, and excellent durability.

[0061] In the second embodiment, the specific surface area and the individual pore volumes (A) to (C) of the carbonaceous material are not particularly limited, as long as it has the above-mentioned pore volume ratios (A) / (B) and (C) / (B).

[0062] In other words, in the second embodiment, the specific surface area and each pore volume (A) to (C) of the carbonaceous material may be within the above range (i.e., the range of the specific surface area and each pore volume (A) to (C) of the carbonaceous material in the first embodiment), or may not be within the above range. Preferably, in the second embodiment, the specific surface area and each pore volume (A) to (C) are within the above range.

[0063] (3) Physical properties [Shape] The shape of the carbonaceous material of the first and second embodiments (hereinafter collectively referred to as carbonaceous material) is not particularly limited, but examples include particulate, lump, rod, pellet, substrate, sheet, and block shapes. Examples of rod shapes include cylindrical, elliptical, frustoplethysmal, and polygonal prism shapes, and examples of polygonal prism shapes include triangular, quadrangular, pentagonal, and hexagonal prism shapes. Examples of pellet shapes include honeycomb pellets and hollow pellets. Preferably, the carbonaceous material is particulate. Examples of particulate shapes include powder, spherical, and crushed chip shapes, and preferably, crushed chip shapes.

[0064] Examples of powdered forms include fine powder, powder, fine granules, and granules. Powdered carbonaceous material is suitably used, for example, as an adsorbent for batch contact with and adsorption to PFAS (described later) in batch processing. Powdered carbonaceous material is also suitably used, for example, as a raw material for molded articles.

[0065] Spherical carbonaceous material, for example, has multiple particles with substantially uniform shapes, and each particle is close to a perfect sphere. Crushed chip-type carbonaceous material, for example, has multiple particles with non-uniform shapes, and each particle has an arbitrary shape with corners. Spherical carbonaceous material and crushed chip-type carbonaceous material are suitably used, for example, as adsorbents for continuous contact with and adsorption of PFAS (described later) in column treatment and flow treatment. More specifically, spherical carbonaceous material and crushed chip-type carbonaceous material are suitably used in water purifier adsorption filters (described later) and water purification equipment (described later).

[0066] [Particle size] When carbonaceous material is in particulate form, the 50% particle size of the cumulative distribution based on volume (D ５０ The particle size is, for example, 1 μm or more and 150 μm or less. Note that the 50% particle size (D ５０ The diameter is measured as the median diameter based on volume using a laser diffraction light scattering particle size distribution analyzer (the same applies hereinafter).

[0067] Furthermore, when the carbonaceous material is in particulate form, the average particle size (representative diameter) of the carbonaceous material is, for example, 0.15 mm or more, preferably 0.20 mm or more. The average particle size (representative diameter) of the carbonaceous material is, for example, 1.70 mm or less, preferably 1.50 mm or less. That is, the average particle size (representative diameter) of the carbonaceous material is, for example, 0.15 mm or more and 1.70 mm or less, preferably 0.20 mm or more and 1.50 mm or less.

[0068] If the average particle size of the carbonaceous material is within the above range, even better adsorption performance can be obtained. In other words, when the carbonaceous material is used in a liquid (such as treated water), if the average particle size of the carbonaceous material is above the lower limit, pressure loss during liquid flow can be suppressed. Also, if the average particle size of the carbonaceous material is below the upper limit, the contact area between the carbonaceous material and the liquid can be increased. Therefore, if the average particle size of the carbonaceous material is within the above range, even better adsorption performance can be obtained.

[0069] Furthermore, the average particle size (representative diameter) is synonymous with the mass-average particle size in JIS K 1474 (2014). In other words, the average particle size (representative diameter) of carbonaceous materials is calculated according to the method for calculating the mass-average particle size in JIS K 1474 (2014).

[0070] [Sphericity] When the carbonaceous material is spherical, the sphericity (longest diameter / shortest diameter) of the carbonaceous material is, for example, 1.00 or more and 1.10 or less, preferably 1.00 or more and 1.09 or less, and more preferably 1.02 or more and 1.08 or less.

[0071] Furthermore, sphericity (longest diameter / shortest diameter) can be determined from imaging taken with a digital microscope.

[0072] [Mechanical Strength (MS Hardness)] Carbonaceous materials preferably have relatively high MS (microstrength) hardness.

[0073] The MS hardness of the carbonaceous material is, for example, 80.0% or more, preferably 85.0% or more, more preferably 90.0% or more, and particularly preferably 95.0% or more. Alternatively, the MS hardness of the carbonaceous material is, for example, 100.0% or less. That is, the MS hardness of the carbonaceous material is, for example, 80.0% or more and 100.0% or less, preferably 85.0% or more and 100.0% or less, more preferably 90.0% or more and 100.0% or less, and particularly preferably 95.0% or more and 100.0% or less.

[0074] If the MS hardness of the carbonaceous material is within the above range, even greater durability can be obtained. That is, when the carbonaceous material is used in a liquid (such as treated water), the carbonaceous materials may come into contact with each other as the liquid flows. In such cases, if the MS hardness of the carbonaceous material is above the lower limit above, the generation of fine particles due to contact between carbon fibers can be suppressed. As a result, clogging by fine particles in the filter placed downstream of the carbonaceous material can be suppressed. Furthermore, if the MS hardness of the carbonaceous material is within the above range, the finening of the carbonaceous material due to the above contact can be suppressed, the increase in the packing density of the carbonaceous material can be suppressed, and as a result, the increase in pressure loss during liquid flow can be suppressed. That is, if the MS hardness of the carbonaceous material is within the above range, the frequency of replacement of the carbonaceous material can be reduced. As a result, particularly excellent durability can be obtained.

[0075] The MS hardness is measured in accordance with the examples described later.

[0076] [Packing Density] The carbonaceous material preferably has a packing density within a predetermined range.

[0077] The packing density of the carbonaceous material is, for example, 0.350 g / mL or more, preferably 0.400 g / mL or more, and more preferably 0.425 g / mL or more. Alternatively, the packing density of the carbonaceous material is, for example, 0.550 g / mL or less, preferably 0.500 g / mL or less, and more preferably 0.480 g / mL or less. In other words, the packing density of the carbonaceous material is, for example, 0.350 g / mL or more and 0.550 g / mL or less, preferably 0.400 g / mL or more and 0.500 g / mL or less, and more preferably 0.425 g / mL or more and 0.480 g / mL or less.

[0078] If the packing density of the carbonaceous material is within the above range, even greater durability can be obtained. In other words, when the carbonaceous material is used in a liquid (such as treated water), if the packing density of the carbonaceous material is within the range, the leakage of the carbonaceous material can be suppressed. Furthermore, if the packing density of the carbonaceous material is within the range, excellent mechanical strength can be obtained even in liquids. Therefore, if the packing density of the carbonaceous material is within the above range, even greater durability can be obtained.

[0079] The packing density can be determined in accordance with the examples described later and JIS K 1474 (2014).

[0080] (4) Adsorption performance [Reactive Black Pentavalent] The carbonaceous material preferably has a reactive black pentavalent within a predetermined range. The reactive black pentavalent is an indicator of adsorption performance.

[0081] More specifically, Reactive Black pentavalent (g / L) is the amount of carbonaceous material required to remove 99% of Reactive Black 5 (also known as C.I. Reactive Black-5) contained in 1 L of the test solution (described later). Reactive Black 5 is represented by the following formula (1).

[0082]

[0083] As shown in formula (1) above, reactive black 5 has a relatively high molecular weight (molecular weight 995.88) and a relatively bulky structure. Therefore, reactive black 5 can be used, for example, as an indicator of the adsorption properties of PFOS (described later).

[0084] The reactive black pentavalent of the carbonaceous material is, for example, 2.0 g / L or more, preferably 3.0 g / L or more, and more preferably 4.0 g / L or more. Alternatively, the reactive black pentavalent of the carbonaceous material is, for example, 15.0 g / L or less, preferably 10.0 g / L or less, and more preferably 8.0 g / L or less. In other words, the reactive black pentavalent of the carbonaceous material is, for example, 2.0 g / L or more and 15.0 g / L or less, preferably 3.0 g / L or more and 10.0 g / L or less, and more preferably 4.0 g / L or more and 8.0 g / L or less.

[0085] If the reactive black pentavalent value of the carbonaceous material is above the lower limit, the carbonaceous material has pores of a size particularly suitable for the adsorption of PFOS (described later). Furthermore, if the reactive black pentavalent value of the carbonaceous material is below the upper limit, the carbonaceous material has a pore capacity particularly suitable for the adsorption of PFOS (described later). Therefore, if the reactive black pentavalent value of the carbonaceous material is within the above range, even better PFOS adsorption performance can be obtained.

[0086] The reactive black pentavalent is measured using reactive black 5 by known methods.

[0087] More specifically, in the measurement of reactive black pentavalent, first, a test solution containing reactive black 5 (pre-adsorption sample) is prepared. Next, a carbonaceous material is mixed with the test solution to allow sufficient adsorption of reactive black 5 onto the carbonaceous material. After that, the carbonaceous material and the reactive black 5 adsorbed onto it are removed to obtain the remaining solution (post-adsorption sample). Preferably, the carbonaceous material has a 50% particle size (D) of the cumulative distribution by volume. ５０ A carbonaceous material with a diameter of 9.0 μm or more and 11.0 μm or less is used.

[0088] In this method, the absorbance of the test solution (sample before adsorption) and the absorbance of the remaining solution (sample after adsorption) are measured separately. The absorbance is measured using a UV-Vis spectrophotometer at a wavelength of 594 nm and a path length (cell length) of 10 mm. Subsequently, from the measured absorbance, the remaining percentage (%) of Reactive Black 5 in the remaining solution (sample after adsorption) can be calculated, and the amount of Reactive Black 5 adsorbed per gram of carbonaceous material ( / g) can also be calculated. Then, using these values, the Reactive Black 5 valency can be calculated.

[0089] Furthermore, reactive black pentavalent can be determined more specifically according to the examples described later.

[0090] [2-MIB number] Carbonaceous materials preferably have a 2-MIB number within a predetermined range. The 2-MIB number is an indicator of adsorption performance.

[0091] More specifically, 2-methylisoborneol has a relatively low molecular weight (168.28) but a relatively bulky structure. Such 2-methylisoborneol is adsorbed into relatively large pores within micropores and relatively small pores within mesopores. For this reason, 2-methylisoborneol is used, in particular, as an indicator of the adsorption characteristics of PFOA (described later).

[0092] The 2-MIB number of carbonaceous materials is, for example, 1.0 or higher, preferably 1.5 or higher, and more preferably 1.6 or higher. Alternatively, the 2-MIB number of carbonaceous materials is, for example, 3.0 or lower, preferably 2.0 or lower, and more preferably 1.8 or lower. In other words, the 2-MIB number of carbonaceous materials is, for example, 1.0 or higher and 3.0 or lower, preferably 1.5 or higher and 2.0 or lower, and more preferably 1.6 or higher and 1.8 or lower.

[0093] If the 2-MIB value of the carbonaceous material is above the lower limit, the pore size of the carbonaceous material is particularly suitable for PFOA (described later) adsorption. Also, if the 2-MIB value of the carbonaceous material is below the upper limit, the pore capacity of the carbonaceous material is particularly suitable for PFOA (described later) adsorption. Therefore, if the 2-MIB value of the carbonaceous material is within the above range, even better PFOA adsorption performance can be obtained.

[0094] The 2-MIB value is measured using 2-methylisoborneol (abbreviated as 2-MIB) by known methods. More specifically, the 2-MIB value is measured in accordance with the examples described below and JWWAK 113 (2005).

[0095] [Iodine adsorption capacity] The carbonaceous material preferably has an iodine adsorption capacity within a predetermined range. The iodine adsorption capacity is an indicator of the surface area of ​​the pores for adsorbing PFOS (described later) and PFOA (described later).

[0096] The amount of iodine adsorbed by the carbonaceous material is, for example, 950 mg / g or more, preferably 1,050 mg / g or more. Alternatively, the amount of iodine adsorbed by the carbonaceous material is, for example, 1,600 mg / g or less. In other words, the amount of iodine adsorbed by the carbonaceous material is, for example, 950 mg / g or more and 1,600 mg / g or less, preferably 1,050 mg / g or more and 1,600 mg / g or less.

[0097] If the amount of iodine adsorbed by the carbonaceous material is above the lower limit mentioned above, the surface area of ​​the pores capable of adsorbing PFOS (described later) and PFOA (described later) is relatively large, thus enabling even better PFOA adsorption performance and superior PFOS adsorption performance. Furthermore, if the amount of iodine adsorbed by the carbonaceous material is below the upper limit mentioned above, even better strength can be obtained.

[0098] The amount of iodine adsorbed can be determined in accordance with the examples described later and JIS K 1474 (2014).

[0099] 2. Method for producing carbonaceous materials The method for producing carbonaceous materials is not particularly limited. Examples of methods for producing carbonaceous materials include pyrolysis, activation, coating, and vapor deposition.

[0100] From the viewpoint of adjusting the specific surface area and pore volume, and adjusting the pore volume ratio, an activation method is preferred. Below, a method for producing the above carbonaceous material by the activation method will be described in detail.

[0101] (1) Preparation process: In this method, first, the raw material components for obtaining carbonaceous material are prepared (preparation process).

[0102] The raw material components are not particularly limited, as long as they are components that can be used to obtain the above-mentioned carbonaceous material by carbonization (described later) and activation (described later). For example, the raw material components include known raw material compounds.

[0103] The raw material compounds are carbonizable compounds (uncarbonized materials). Examples of raw material compounds include natural compounds and synthetic compounds. Examples of natural compounds include wood, wood flour, fruit shells (e.g., coconut shells), seeds (palm kernels, plum seeds, and peach seeds), by-products of pulp production, bagasse, molasses, coal (peat, lignite, brown coal, sub-bituminous coal, and bituminous coal), anthracite, petroleum distillation residue components, petroleum pitch, coke, and coal tar. Examples of synthetic compounds include synthetic resins, synthetic rubber, synthetic wood, and synthetic pulp. Examples of synthetic resins include phenolic resins, vinyl chloride resins, vinyl acetate resins, melamine resins, urea resins, resorcinol resins, celluloid, epoxy resins, polyurethane resins, polyester resins, acrylic resins, and polyamide resins. Examples of synthetic rubbers include polybutylene, polybutadiene, and polychloroprene. These can be used individually or in combination of two or more types.

[0104] From the viewpoint of adjusting the specific surface area and pore volume, and adjusting the pore volume ratio, the raw material compounds are preferably natural compounds, more preferably wood, wood flour, fruit shells, and coal, even more preferably coconut shells and coal, and particularly preferably coconut shells, sub-bituminous coal, and bituminous coal.

[0105] The raw material components may contain additives as needed. In other words, the raw material components may contain both the raw material compound and additives. Examples of additives include water, coal tar, anhydrous tar, hard pitch, coal tar-based pitch, petroleum-based pitch, thickening polysaccharides, and water-soluble polymers. Additives can be used individually or in combination of two or more types.

[0106] The method for mixing the raw material compound and the additive is not particularly limited. For example, the raw material compound and the additive can be mixed by heating them at an appropriate temperature (e.g., 150°C to 300°C) while adjusting the oxygen concentration. The content ratio of the additive is not particularly limited and can be set appropriately according to the purpose and application. For example, the content ratio (total amount) of the additive is, for example, 1 part by mass or more and 100 parts by mass or less, relative to 100 parts by mass of the total amount of the raw material compound and the additive.

[0107] Furthermore, the raw materials may be pulverized as necessary. The pulverization method is not particularly limited. For example, a known pulverizer may be used to pulverize the raw materials.

[0108] The raw materials may be molded as needed. The molding method is not particularly limited. For example, a known molding machine may be used to mold the raw materials.

[0109] The shape of the raw material component is not particularly limited and includes, for example, particulate, lump, rod, pellet, substrate, sheet, and block, with particulate being preferred. Examples of particulate form include powder, spherical, and crushed chip form. When the raw material component is in particulate form, the 50% particle size (D) of the cumulative distribution by volume is used. ５０ For example, the particle size is between 1 μm and 150 μm.

[0110] (2) Carbonization process Next, in this method, the raw material components are carbonized to obtain carbonized material (carbonization process).

[0111] The carbonization method is not particularly limited, and known methods may be used. Examples of carbonization methods include pyrolysis carbonization, chemical decomposition carbonization, automated low-temperature carbonization, and superheated steam carbonization.

[0112] From the viewpoint of adjusting the specific surface area and pore volume, and adjusting the pore volume ratio, a preferred method of carbonization is thermal decomposition carbonization. In thermal decomposition carbonization, for example, the raw material compound is heat-treated by a known method. That is, in the carbonization step, the raw material components are preferably carbonized by heat treatment to obtain a carbide.

[0113] More specifically, this process uses, for example, known equipment. Examples of such equipment include a rotary kiln, a single-stage carbonization apparatus, and a circular agitated carbonization furnace.

[0114] From the viewpoint of adjusting the specific surface area and pore volume of the carbonaceous material, and from the viewpoint of adjusting the pore volume ratio, a rotary kiln is preferably used.

[0115] By using a rotary kiln, the raw material compounds can be fluidized and heat-treated simultaneously, thereby improving the uniformity of the carbides. This allows for efficient adjustment of the specific surface area, pore volume, and pore volume ratio of the carbonaceous material, resulting in superior adsorption performance.

[0116] A rotary kiln will be described with reference to Figures 1 and 2. The rotary kiln 1 has a known configuration, and specifically comprises a tubular body 2 and stirring blades 3.

[0117] The tube 2 is a cylindrical member extending along its longitudinal direction and is rotatably arranged along its circumferential direction. The material of the tube 2 is not particularly limited, and stainless steel is one example. The inner radius L1 of the tube 2 (i.e., half of the inner diameter (hereinafter the same)) is not particularly limited and is set according to the purpose and application. The thickness T1 of the tube 2 is also not particularly limited and is set appropriately according to the purpose and application.

[0118] The stirring blades 3 have a plate shape that extends along the longitudinal direction. The number of stirring blades 3 is adjusted as appropriate depending on the purpose and application. The number of stirring blades 3 is, for example, 1 to 20, preferably 3 to 12, more preferably 5 to 10, and particularly preferably 6. Figures 1 and 2 show six stirring blades 3, which are distinguished as stirring blades 3A to 3F.

[0119] The stirring blades 3 are arranged along the longitudinal direction of the pipe 2 on the inner circumferential surface of the pipe 2. More specifically, each stirring blade 3 is positioned to protrude from the inner wall surface of the pipe 2 toward the inside (hollow side) of the pipe 2.

[0120] The stirring blades 3 are arranged at equal intervals around the circumferential direction of the pipe 2. For example, if there are 6 stirring blades 3, they are arranged at intervals of one blade every 60° around the circumferential direction of the pipe 2.

[0121] The length L2 of the stirring blade 3 (i.e., the length along the protruding direction of the stirring blade 3) is not particularly limited and is adjusted from the viewpoint of stirring efficiency of the raw material components 5. The length L2 of the stirring blade 3 is, for example, 10% to 30% of the inner radius L1 of the pipe body 2. The length L2 of the stirring blade 3 is also adjusted, for example, according to the amount of raw material components 5 (see Figure 2). For example, the length L2 of the stirring blade 3 is adjusted so that a part of the stirring blade 3 at the bottom of the pipe body 2 (preferably 1 / 2 to 2 / 3 of the length L2 of the stirring blade 3) is covered with the raw material components 5.

[0122] The thickness T2 of the stirring blade 3 (length along the circumferential direction of the tube 2) is, for example, 1% to 100%, preferably 20% to 90%, and more preferably 30% to 95%, of the thickness T1 of the tube 2.

[0123] The stirring blade 3 has a predetermined angle α with respect to, for example, a perpendicular line (dashed line in Figure 2) from the inner wall of the pipe 2 toward the central axis of the pipe 2. From the viewpoint of stirring efficiency, the angle α of the stirring blade 3 is, for example, 15° to 45°.

[0124] The method of heat treatment using a rotary kiln is not particularly limited, but for example, as shown in the left diagram of Figure 2, the raw material component 5 is introduced into the tube 2. Then, as shown by the arrow R in the left and right diagrams of Figure 2, the tube 2 is rotated circumferentially, and the raw material component 5 is heat-treated while being stirred by the stirring blade 3, thereby carbonizing the raw material compound. The rotation speed of the tube 2 is, for example, 1.0 rpm or more and 5.0 rpm or less.

[0125] The heat treatment conditions are set appropriately from the viewpoint of adjusting the specific surface area and pore volume of the carbonaceous material, and from the viewpoint of adjusting the pore volume ratio.

[0126] For example, the raw material components are heat-treated in an oxygen-free atmosphere. The oxygen-free atmosphere may be, for example, a reduced-pressure atmosphere with air removed, or an inert gas atmosphere with an inert gas (for example, nitrogen) introduced. Preferably, an inert gas atmosphere is used, and more preferably, a nitrogen atmosphere is used.

[0127] The heat treatment temperature is, for example, 150°C to 800°C, preferably 200°C to 800°C, and more preferably 300°C to 800°C.

[0128] The heat treatment temperature may be constant, for example, or it may be increased continuously or gradually during the heat treatment.

[0129] The temperature is increased continuously or in stages from the viewpoint of adjusting the specific surface area and pore volume, and from the viewpoint of adjusting the pore volume ratio.

[0130] If the heat treatment temperature is increased during the heat treatment, the heat treatment temperature at the start of the heat treatment (for example, the inlet temperature of the rotary kiln) is, for example, 150°C to 400°C, preferably 200°C to 350°C.

[0131] If the heat treatment temperature is increased during the heat treatment, the highest temperature reached during the heat treatment (for example, the outlet temperature of the rotary kiln) is, for example, 400°C to 700°C, preferably 500°C to 600°C.

[0132] If the heat treatment temperature is increased during the heat treatment, the rate of increase is, for example, 2°C / min or more and 15°C / min or less, preferably 5°C / min or more and 10°C / min or less.

[0133] By increasing the heat treatment temperature during the heat treatment process, the specific surface area, pore volume, and pore volume ratio of carbonaceous materials can be adjusted particularly effectively. More specifically, when the raw material compound (uncarburized material that can be carbonized) is heat-treated, the organic matter contained in the raw material compound vaporizes, forming voids. When the heat treatment temperature is increased in stages, vaporization proceeds gradually, causing the formed voids to contract and the density to increase. In addition, some of the organic matter remains without vaporizing during the heat treatment process and vaporizes in the activation process described later, creating voids. Therefore, activation is promoted, and the development of mesopores can be accelerated. In particular, if the heat treatment start temperature is below the above upper limit, the rapid vaporization of organic matter can be suppressed, allowing for more efficient void contraction and accelerating the development of mesopores.

[0134] The heat treatment time is, for example, 30 minutes or more and 300 minutes or less, preferably 60 minutes or more and 150 minutes or less.

[0135] As described above, by heat-treating the raw material components, the raw material compounds can be carbonized, and as a result, a carbonized product can be obtained.

[0136] Furthermore, this method allows for the addition of the above-mentioned additives to the carbide as needed. The amount of additives added is not particularly limited and can be set appropriately according to the purpose and application.

[0137] The carbides (and additives (hereinafter the same)) may be pulverized as needed. The pulverization method is not particularly limited. For example, a known pulverizer may be used to pulverize the raw material components.

[0138] The carbide may be molded if necessary. The molding method is not particularly limited. For example, a known molding machine may be used to mold the carbide.

[0139] The carbides may be washed as needed. The washing method and washing conditions are not particularly limited and should be set appropriately according to the purpose and application.

[0140] The carbides may be dried as needed. The drying method and conditions are not particularly limited and can be set as appropriate depending on the purpose and application.

[0141] (3) Activation process Next, in this method, the carbide is subjected to an activation treatment to obtain an activated product (activation process).

[0142] The activation method is not particularly limited, and known methods can be employed. An example of an activation method is to use an activated gas to activate the carbide. Examples of activated gases include water vapor, oxygen, and carbon dioxide, with water vapor being preferred. An inert gas (e.g., nitrogen) can also be supplied along with the activated gas.

[0143] More specifically, known equipment is used in this process. Examples of such equipment include rotary kilns, fluidized bed furnaces, and sleep furnaces (vertical furnaces). From the viewpoint of adjusting the specific surface area and pore volume of the carbonaceous material, and adjusting the pore volume ratio, a rotary kiln is preferred, and more preferably, a rotary kiln similar to the rotary kiln used in the carbonization process (see Figures 1 and 2).

[0144] By using a rotary kiln, the scattering of activated material, which has been lightened during the activation process, outside the furnace can be suppressed, thereby improving the activation efficiency. Furthermore, using a rotary kiln allows for efficient contact between the carbide and the activated gas. Therefore, by using a rotary kiln, the specific surface area, pore volume, and pore volume ratio of the carbonaceous material can be efficiently adjusted, resulting in excellent adsorption performance.

[0145] The method of activation treatment using a rotary kiln is not particularly limited, but for example, carbides are placed in the tube 2, and while the tube 2 is rotated along its circumference, an active gas is supplied to the tube 2 to activate the carbides. The rotation speed of the tube 2 is, for example, 1.0 rpm or more and 5.0 rpm or less.

[0146] The activation conditions are set appropriately from the viewpoint of adjusting the specific surface area and pore volume of the carbonaceous material, and from the viewpoint of adjusting the pore volume ratio.

[0147] For example, the carbide is activated under the oxygen-free atmosphere described above. Preferably, the oxygen-free atmosphere is an inert gas atmosphere, and more preferably, a nitrogen atmosphere.

[0148] The supply rate of the active gas is set appropriately according to the type of active gas. For example, if the active gas is water vapor, the supply rate of the active gas is between 10 L / min and 300 L / min.

[0149] The activation temperature is, for example, 750°C to 1,200°C, preferably 800°C to 1,100°C. The activation time is, for example, 20 minutes to 48 hours, preferably 30 minutes to 36 hours, more preferably 40 minutes to 24 hours, even more preferably 45 minutes to 120 minutes, and most preferably 50 minutes to 100 minutes.

[0150] As described above, activated materials can be obtained by activating carbides. The resulting activated materials are the carbonaceous materials mentioned above.

[0151] Furthermore, in this method, the above-mentioned additives can be added to the activator as needed. The amount of additive added is not particularly limited and can be set appropriately according to the purpose and application.

[0152] The activators (and additives (hereinafter the same)) may be pulverized as necessary. The pulverization method is not particularly limited. For example, a known pulverizer may be used to pulverize the raw material components.

[0153] The activator may be molded as needed. The molding method is not particularly limited. For example, a known molding machine may be used to mold the activator.

[0154] (4) Washing step Next, in this method, preferably, the above-mentioned activating substance is washed (washing step).

[0155] One method for cleaning the activator is acid cleaning. In acid cleaning, the activator is cleaned with a known acid. Examples of acids include inorganic acids and organic acids. Examples of inorganic acids include hydrochloric acid and nitric acid. Examples of organic acids include formic acid and acetic acid. These can be used individually or in combination of two or more. In acid cleaning, the cleaning temperature and cleaning time are not particularly limited and are set appropriately according to the purpose and application.

[0156] Furthermore, after washing the activator with acid, it is preferable to wash the activator with water to remove the acid. The washing temperature and washing time are not particularly limited and are set as appropriate according to the purpose and application.

[0157] (5) Drying step Next, in this method, preferably the above-mentioned activator (preferably the washed activator) is dried (drying step).

[0158] Methods for drying the activated material include, for example, natural drying, heat drying, and vacuum drying. From the viewpoint of adjusting the specific surface area and pore volume of the carbonaceous material, and adjusting the pore volume ratio, preferred drying methods include heat drying and vacuum drying, and more preferably, heat drying.

[0159] In heat drying, known heating devices are used. Examples of heating devices include constant temperature dryers, hot air dryers, vacuum dryers, rotary evaporators, conical dryers, and Nauter dryers. The drying temperature in heat drying is, for example, between 40°C and 300°C.

[0160] In vacuum drying, known vacuum devices are used. Examples of vacuum devices include oil pumps, oil-less pumps, and aspirators. The drying pressure in vacuum drying is, for example, 0.00001 MPa to 0.05 MPa.

[0161] The drying time is not particularly limited, but for example, it is between 1 minute and 20 hours. Preferably, drying is continued until the moisture content of the dried activated material falls below a predetermined value. At the end of drying, the moisture content of the dried activated material is, for example, 20% by mass or less, preferably 10% by mass or less.

[0162] As described above, carbonaceous materials are produced by heat-treating and activating the raw material components, and, if necessary, washing and / or drying them.

[0163] The carbonaceous material obtained by the above method has, for example, the above specific surface area and above pore volume, and / or above pore volume ratio.

[0164] (6) Fluorine treatment step The carbonaceous material described above may be treated with fluorine (hereinafter referred to as fluorine treatment) as necessary (fluorine treatment step).

[0165] Fluorine-treated carbonaceous materials have excellent affinity for PFAS (described later), and therefore possess excellent PFAS adsorption performance. For this reason, carbonaceous materials are preferably fluorine-treated.

[0166] One example of fluorine treatment is the regeneration treatment of carbonaceous materials. This regeneration treatment involves adsorbing PFAS (described later) onto the carbonaceous material, and then removing the PFAS (described later).

[0167] More specifically, in the regeneration process, PFAS (described later) is first adsorbed onto the carbonaceous material mentioned above (i.e., the carbonaceous material that has not been regenerated). This results in obtaining a carbonaceous material that has adsorbed PFAS (described later) (adsorption step).

[0168] The method for adsorbing PFAS (described later) onto the carbonaceous material described above is not particularly limited, but for example, the carbonaceous material may be immersed in a treatment solution containing PFAS (described later).

[0169] The processing solution containing PFAS (described later) contains, for example, an aqueous solvent and PFAS (described later). Examples of aqueous solvents include water and lower alcohols. Examples of lower alcohols include alcohols having 1 to 4 carbon atoms, preferably methanol, ethanol, and isopropanol, and more preferably methanol. The content ratio of PFAS (described later) in the processing solution is not particularly limited. For example, the concentration of PFAS (described later) is 0.01% by mass or more and 10% by mass or less, preferably 0.1% by mass or more and 1% by mass or less.

[0170] The immersion conditions are not particularly limited and are set as appropriate so that a carbonaceous material having the fluorine content described later can be obtained. For example, the immersion temperature is, for example, 0°C to 50°C, preferably 5°C to 30°C. The immersion time is, for example, 1 hour to 100 hours, preferably 12 hours to 48 hours.

[0171] Subsequently, the carbonaceous material is dried as needed. Drying methods include natural drying, heat drying, and vacuum drying, with heat drying being preferred. In heat drying, the drying temperature is, for example, 40°C to 100°C, preferably 40°C to 90°C. The drying time is, for example, 10 minutes to 12 hours, preferably 1 hour to 6 hours.

[0172] By this method, a carbonaceous material with adsorbed PFAS (described later) can be obtained.

[0173] The amount of PFAS (described later) adsorbed is not particularly limited. For example, the amount of PFAS (described later) adsorbed is adjusted as appropriate so that a carbonaceous material having the amount of fluorine adsorbed described later is obtained. Preferably, the amount of PFAS (described later) adsorbed is adjusted as appropriate so that the amount of fluorine generated in the pyrolysis process described later is not excessive and the environmental burden and equipment burden can be suppressed.

[0174] Next, in this method, the carbonaceous material on which PFAS (described later) has been adsorbed is heated to thermally decompose the PFAS (described later) (thermal decomposition step).

[0175] The heating method is not particularly limited, and known methods can be used. For example, a carbonaceous material on which PFAS (described later) has been adsorbed is transferred to a known heating device (heating furnace) and heated. Examples of heating devices (heating furnaces) include batch heating devices and continuous heating devices. Examples of batch heating devices include tubular furnaces and box furnaces. Examples of continuous heating devices include rotary kilns.

[0176] The heating conditions are set appropriately within a range that yields carbonaceous materials having the various physical properties described above. Preferably, the heating conditions are set appropriately so that carbonaceous materials having the fluorine content described later are obtained. For example, the heating atmosphere can be an oxygen gas atmosphere, an air gas atmosphere, or an inert gas atmosphere. For example, the inert gas atmosphere can be a nitrogen gas atmosphere, a carbon dioxide gas atmosphere, or an argon gas atmosphere. Mixed gas atmospheres of these can also be used. For example, when air gas is used, the oxygen concentration can be reduced by mixing air gas with an inert gas to suppress the reaction between the carbonaceous material and oxygen. In such a case, the oxygen concentration is, for example, 5% or less, preferably 1% or less. Preferably, an inert gas atmosphere is used as the heating atmosphere. The heating temperature is, for example, 300°C to 950°C, preferably 500°C to 800°C. The heating time is, for example, 1 minute to 10,000 hours, preferably 1 minute to 10 hours, preferably 30 minutes to 5 hours.

[0177] As a result of the heating described above, the PFAS (described later) adsorbed on the carbonaceous material undergoes thermal decomposition, and the resulting fluorine is added to the carbonaceous material.

[0178] Furthermore, this method involves cooling the carbonaceous material as needed (cooling step).

[0179] The cooling method is not particularly limited. For example, after thermally decomposing the PFAS (described later) by the heating described above, the remaining carbonaceous material may be allowed to cool naturally. The cooling conditions in the cooling process are not particularly limited and can be set as appropriate depending on the purpose and application.

[0180] Furthermore, in the cooling process, for example, the carbonaceous material after the above-mentioned thermal decomposition can be cooled directly in a heating device. In such cases, the products (thermal decomposition products) from the thermal decomposition of PFAS (described later) generated by the above-mentioned thermal decomposition may be adsorbed onto the carbonaceous material, causing contamination of the carbonaceous material. Therefore, in the cooling process, it is preferable to continuously discharge the thermal decomposition products of PFAS (described later). The method for discharging the thermal decomposition products is not particularly limited, but examples include reduced pressure treatment, vacuum treatment, and aeration treatment, with aeration treatment being preferred. In the aeration treatment, any gas (e.g., oxygen gas, air gas, and inert gas) is passed through. The volume flow rate of the gas is set appropriately so that the thermal decomposition products of PFAS (described later) can be continuously discharged. For example, the gas flow rate is 0.1 volume parts / min or more and 100,000 volume parts / min or less for 100 volume parts of carbonaceous material.

[0181] Furthermore, in the cooling process, for example, the carbonaceous material after the above-mentioned thermal decomposition may be transferred from the heating device to a known cooling device (cooling furnace) (transfer process), and cooled within the cooling device. The transfer method is not particularly limited, and a known transfer method may be appropriately selected.

[0182] Furthermore, this method allows for the removal of impurities from the carbonaceous material after the thermal decomposition (and cooling, if necessary) described above (removal step).

[0183] More specifically, carbonaceous materials may contain trace amounts of impurities. Examples of impurities include thermal decomposition products of PFAS (described later), organic decomposition residues, metallic components, and fine powder of the carbonaceous material itself. These impurities may cause a decrease in the adsorption performance and durability of the carbonaceous material. Therefore, it is preferable to remove the impurities.

[0184] Methods for removing impurities include, for example, wet methods and dry methods. Wet methods include, for example, acid treatment and alkali treatment, with acid treatment being preferred. For acid treatment, for example, first, the carbonaceous material is immersed in an acid-containing solution (hereinafter referred to as the acid solution), stirred, and then removed and dried. Examples of acid solutions include hydrochloric acid solution, sulfuric acid solution, and phosphoric acid solution. The acid concentration in the acid solution is not particularly limited and is set appropriately so as to obtain a carbonaceous material having the fluorine content described later. Next, in this method, the carbonaceous material is immersed in water to remove the acid contained in the carbonaceous material. After that, in this method, the carbonaceous material is removed from the water and dried. Impurities can be removed by the above methods. In the dry method, for example, impurities are removed by blowing air. By removing impurities, a decrease in the adsorption performance and durability of the carbonaceous material can be suppressed.

[0185] By the method described above, a carbonaceous material from which PFAS (described later) has been adsorbed and removed (i.e., regenerated) can be obtained. The regenerated carbonaceous material is a regenerated carbonaceous material (hereinafter referred to as recycled carbonaceous material).

[0186] The method for obtaining recycled carbonaceous material is not limited to the above. For example, by using a carbonaceous material once or more to remove PFAS (described later) in any environment (e.g., underwater), PFAS (described later) can be adsorbed onto the carbonaceous material (adsorption step). Subsequently, recycled carbonaceous material can be obtained by subjecting the carbonaceous material to the heat treatment step described above, and, if necessary, to the cooling step (and transfer step) and / or the removal step described above.

[0187] Since the regenerated carbonaceous material contains fluorine functional groups derived from PFAS (described later), it is considered that the affinity between the carbonaceous material and PFAS (described later) can be improved, and the adsorption performance of PFAS (described later) can be improved. For this reason, the carbonaceous material preferably contains fluorine functional groups.

[0188] From the viewpoint of adsorption performance, the fluorine content of the carbonaceous material is, for example, 0.001 mg / kg or more and 60.000 mg / kg or less, preferably 0.010 mg / kg or more and 50.000 mg / kg or less, more preferably 0.030 mg / kg or more and 45.000 mg / kg or less, and even more preferably 0.050 mg / kg or more and 40.000 mg / kg or less. The fluorine content of the recycled carbonaceous material (also known as PFAS-removed recycled activated carbon) is particularly preferably 0.010 mg / kg or more and less than 1,000 mg / kg.

[0189] The fluorine content of a carbonaceous material is expressed as the mass (mg) of fluorine atoms contained per kilogram of the carbonaceous material. The fluorine content of a carbonaceous material can be measured according to the examples described later.

[0190] If the fluorine content of the carbonaceous material is within the above range, the affinity between the carbonaceous material and PFAS (described later) can be improved, and changes in the pore structure can be suppressed, thereby securing a diffusion pathway for PFAS (described later) within the pores, and thus improving the adsorption efficiency of PFAS (described later).

[0191] In particular, if the fluorine content of the carbonaceous material is within the above range and the MS hardness is within the above range, it is possible to improve the adsorption efficiency of PFAS (described later) while ensuring excellent mechanical strength, and to improve operational stability in various applications described later.

[0192] Furthermore, the above-described regeneration process allows for the adjustment of the fluorine functional group content while adjusting the various physical properties of the carbonaceous material (e.g., specific surface area, MS hardness, pore volume ratio and distribution) within the above-described range. As a result, excellent mechanical strength and PFAS adsorption performance can be obtained.

[0193] Furthermore, although not described in detail, the carbonaceous material may be sized by known methods. Also, the carbonaceous material may be purified by known methods. Also, the carbonaceous material may be given durability and its structure modified by known methods. 3. Applications (1) PFAS-treated materials The applications of the carbonaceous material are not particularly limited. An example of an application of the carbonaceous material is a PFAS-treated material for treating organofluorine compounds (perfluoroalkyl compounds and polyfluoroalkyl compounds (PFAS)).

[0194] Examples of PFAS include perfluoroalkanoic acid (PFAA), perfluoroalkanesulfonic acid (PFSA), perfluoroalkanesulfonamide (FASA), perfluoroalkanesulfonamideethanol (FASE), perfluoroalkanesulfonamideacetic acid (FASAA), N-methylperfluoroalkanesulfonamide (MeFASA), N-methylperfluoroalkanesulfonamideacetic acid (MeFASAA), N-methylperfluoroalkanesulfonamideethanol (MeFASE), N-ethylperfluoroalkanesulfonamide (EtFASA), and N-ethylperfluoroalkanesulfonamide. Examples include sulfonamide ethanol (EtFASE), N-ethyl perfluoroalkanesulfonamide acetate (EtFASAA), N-butyl perfluoroalkanesulfonamide (BuFASA), N-butyl perfluoroalkanesulfonamide ethanol (BuFASE), N-butyl perfluoroalkanesulfonamide acetate (BuFASAA), perfluoroalkanesulfonyl fluoride (PASF), fluoroprotein (FP), fluorotelomer carboxylic acid (FTCA), fluorotelomer alcohol (FTOH), fluorotelomer sulfonic acid (FTSA), derivatives thereof, and salts thereof. These are used alone or in combination of two or more types.

[0195] Specific examples of PFAS are not limited to perfluorobutanoic acid (PFBA), perfluorobutanesulfonic acid (PFBS), perfluoropentanoic acid (PFPeA), perfluoropentanesulfonic acid (PFPeS), perfluorohexanoic acid (PFHxA), perfluorohexanoic acid (PFHxS), perfluoroheptanoic acid (PFHpA), perfluoroheptanesulfonic acid (PFHpS), perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), and perfluoro Ammonium oroctanoate (APFO), perfluorooctanesulfonamide (PFOSA), perfluorooctanesulfonamide acetate (FOSAA), perfluorooctanesulfonamide ethanol (FOSE), perfluorononanoic acid (PFNA), perfluorononanosulfonic acid (PFNS), perfluorodecanoic acid (PFDA), perfluorodecanesulfonic acid (PFDS), perfluorododecanoic acid (PFDoA), perfluorododecanesulfonic acid (PFDoSA), perfluoroundecanoic acid (PF UnA), perfluoroundecanesulfonic acid (PFUnSA), perfluorotridecanoic acid (PFTrDA), perfluorotetradecanoic acid (PFTeDA), N-methylperfluorooctanesulfonamide (MeFOSA), N-ethylperfluorooctanesulfonamide (EtFOSA), N-ethylperfluorooctanesulfonamide ethanol (EtFOSE), perfluorobutylic acid, perfluorophosphonic acid (PFPA), perfluorophosphinic acid (PFpiA), 4,8-dioxa-3H-per Examples include fluorononanoic acid, 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy)propanoate, ammonium 2,3,3,3-tetrafluoroethyl-2-(heptafluoropropoxy)propanoate, 1,2,2,2-tetrafluoroethyl ether, polytetrafluoroethylene (PTFE), 4:2-fluorotelomersulfonic acid (4:2FtS), 6:2-fluorotelomersulfonic acid (6:2FtS), 8:2-fluorotelomersulfonic acid (8:2FtS), and salts thereof. These can be used alone or in combination of two or more types.

[0196] Preferred PFAS include perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS).

[0197] Examples of processing include removal, concentration, dilution, separation, and recovery, with removal being preferred.

[0198] More specifically, PFAS treatment materials include PFAS removal materials that remove PFAS (preferably PFOA and PFOS (hereinafter the same)).

[0199] [PFAS Removal Material] The PFAS removal material is a material used to remove PFAS. The PFAS removal material contains the above-mentioned carbonaceous material, and preferably consists of the above-mentioned carbonaceous material.

[0200] The method of using the PFAS removal material (i.e., the method of removing PFAS using a carbonaceous material) is not particularly limited. For example, the PFAS removal material can be brought into contact with a workpiece containing PFAS to remove the PFAS. The workpiece is not particularly limited and can be any known gaseous or liquid phase. More specifically, for example, the carbonaceous material contained in the PFAS removal material can be brought into contact with PFAS in the gaseous or liquid phase, and the PFAS can be adsorbed into the pores of the carbonaceous material to remove it.

[0201] More specifically, PFAS adsorbents can be used as PFAS removal materials.

[0202] [PFAS Adsorbent] The PFAS adsorbent is a material that adsorbs PFAS. The PFAS adsorbent contains the above-mentioned carbonaceous material, and preferably consists of the above-mentioned carbonaceous material.

[0203] The method of using the PFAS adsorbent (i.e., the method of adsorbing PFAS using a carbonaceous material) is not particularly limited. For example, similar to PFAS removal materials, PFAS can be removed by bringing the carbonaceous material contained in the PFAS adsorbent into contact with PFAS in the gas or liquid phase, and adsorbing the PFAS into the pores of the carbonaceous material.

[0204] [Method for regenerating PFAS-treated material, PFAS-removing material, and PFAS-adsorbing material] The above-mentioned PFAS-treated material, PFAS-removing material, and PFAS-adsorbing material can be regenerated after use.

[0205] More specifically, PFAS-treated materials, PFAS removal materials, and PFAS adsorbents that have been used at least once have adsorbed PFAS. Therefore, by removing the adsorbed PFAS, these materials can be regenerated and reused. In other words, regenerated PFAS-treated materials (hereinafter referred to as regenerated PFAS-treated materials), regenerated PFAS removal materials (hereinafter referred to as regenerated PFAS removal materials), and regenerated PFAS adsorbents (hereinafter referred to as regenerated PFAS adsorbents) can be manufactured.

[0206] The method for producing the regenerated material is, for example, the same as the regeneration process described above. More specifically, the used PFAS-treated material, PFAS-removing material, and / or PFAS-adsorbing material are subjected to the above-described thermal decomposition step to thermally decompose the PFAS. In this method, as described above, the PFAS-treated material, PFAS-removing material, and / or PFAS-adsorbing material after thermal decomposition can be subjected to a cooling step (and transfer step) and / or a removal step as needed. The regenerated material thus obtained contains the above-described recycled carbonaceous material, and preferably consists of the above-described recycled carbonaceous material.

[0207] (2)Specific examples: Carbonaceous materials, PFAS treated materials, PFAS removal materials, and PFAS adsorbents can be suitably used in any application in various industrial fields.

[0208] In particular, carbonaceous materials, PFAS-treated materials, PFAS-removing materials, and PFAS-adsorbing materials are suitably used to remove (adsorb) PFAS from water.

[0209] In other words, when carbonaceous materials are typically used in water treatment plants to remove (adsorb) PFAS from water, the carbonaceous materials are subjected to friction by water flow and pressure, and collisions between carbonaceous materials occur repeatedly. As a result, the carbonaceous materials may become pulverized in water, and this pulverized carbonaceous material may cause clogging of filters, increasing the number of work processes in water treatment plants. Furthermore, the pulverized carbonaceous material may increase the turbidity of the water. Therefore, from the viewpoint of efficiently and continuously removing (adsorbing) PFAS from water, suppressing the increase in work processes and the rise in water turbidity in water treatment plants, and achieving excellent environmental performance, carbonaceous materials used in water require particularly high durability. In contrast, the above-mentioned carbonaceous materials have excellent durability and are therefore suitable for use in removing (adsorbing) PFAS from water.

[0210] More specifically, applications of carbonaceous materials, PFAS-treated materials, PFAS-removing materials, and PFAS-adsorbing materials include, for example, adsorption filters, water purifier cartridges, water purifiers, packed columns, household drinking water treatment, and water purification equipment, with adsorption filters, water purifier cartridges, water purifiers, and water purification equipment being preferred. In other words, an object selected from the group consisting of adsorption filters, water purifier cartridges, water purifiers, and water purification equipment preferably contains the above-mentioned carbonaceous materials, PFAS-treated materials, PFAS-removing materials, and / or PFAS-adsorbing materials.

[0211] [Adsorption filter] The adsorption filter contains the above carbonaceous material, and more specifically, comprises the above PFAS adsorbent.

[0212] The specific configuration of the adsorption filter is not particularly limited. For example, the adsorption filter contains the carbonaceous material described above and a fibrous binder for holding the carbonaceous material.

[0213] The fibrous binder is not particularly limited as long as it can hold carbonaceous material, and known fibrous binders can be used. Examples of fibrous binders include acrylic fibers, polyethylene fibers, polypropylene fibers, polyacrylonitrile fibers, cellulose fibers, nylon fibers, aramid fibers, and pulp. These can be used individually or in combination of two or more types. From the viewpoint of improving the density and strength of the adsorption filter, polyacrylonitrile fibers and pulp are preferred.

[0214] Adsorption filters may contain other functional components. Examples of other functional components include adsorbents other than carbonaceous materials. Examples of adsorbents other than carbonaceous materials include titanosilicate, zeolite, silica gel, activated alumina, nonwoven fabric, ion exchange resin, chelate resin, porous organic compounds, silver ions, and silver compounds.

[0215] The method for obtaining the adsorption filter is not particularly limited. For example, an adsorption filter can be obtained by holding a carbonaceous material (and other functional components (hereinafter the same)) in a fibrous binder in a known manner. The ratio of carbonaceous material to fibrous binder is determined from the viewpoint of PFAS removal performance. For example, the amount of fibrous binder is, for example, 0.01 parts by mass or more and 20 parts by mass or less, preferably 0.01 parts by mass or more and 10 parts by mass or less, per 100 parts by mass of carbonaceous material.

[0216] There are no particular restrictions on how adsorption filters are used. For example, adsorption filters are used as adsorption filters for water purifiers. Specifically, water passes through the adsorption filter and is purified. The water passage rate is set appropriately according to the purification efficiency and pressure loss.

[0217] Furthermore, the above-mentioned adsorption filter contains the above-mentioned carbonaceous material. Therefore, the above-mentioned adsorption filter has excellent durability and excellent PFAS removal performance. Such an adsorption filter is suitably used as an adsorption filter for water purifiers to remove (adsorb) PFAS from water.

[0218] [Water purifier cartridge] The water purifier cartridge contains the above-mentioned carbonaceous material, and more specifically, comprises the above-mentioned PFAS adsorbent.

[0219] The specific configuration of the water purifier cartridge is not particularly limited. For example, the water purifier cartridge includes a housing for removing (adsorbing) PFAS. The housing has, for example, the carbonaceous material and / or the adsorption filter and is designed to remove (adsorb) PFAS from water.

[0220] Furthermore, the water purifier cartridge may include other components as needed. Examples of these other components include adsorbents other than carbonaceous materials, nonwoven fabric filters, mineral additives, ceramic filter media, and hollow fiber membranes. These can be used individually or in combination of two or more types. The method for obtaining the water purifier cartridge is not particularly limited. For example, a water purifier cartridge having a known configuration can be manufactured by a known method.

[0221] Furthermore, the above-mentioned water purifier cartridge contains the above-mentioned carbonaceous material. Therefore, the above-mentioned water purifier cartridge has excellent durability and excellent PFAS removal performance.

[0222] [Water Purifier] The water purifier contains the above-mentioned carbonaceous material, and more specifically, it is equipped with the above-mentioned PFAS adsorbent.

[0223] The specific configuration of the water purifier is not particularly limited. For example, the water purifier may include a water purifier cartridge (preferably the water purifier cartridge described above).

[0224] The water filter cartridge, for example, includes a housing for removing (adsorbing) PFAS. The housing, for example, has the carbonaceous material and / or the adsorption filter, and is designed to remove (adsorb) PFAS from water.

[0225] Furthermore, the water purifier may be equipped with other components as needed. The method of obtaining the water purifier is not particularly limited. For example, a water purifier having a known configuration may be manufactured by a known method.

[0226] Furthermore, the above water purifier contains the above carbonaceous material. Therefore, the above water purifier has excellent durability and excellent PFAS removal performance.

[0227] Therefore, water purifiers are suitably used, for example, as water purifiers for faucets and water purifiers for kitchens.

[0228] [Water purification equipment] The water purification equipment contains the above-mentioned carbonaceous material, and more specifically, it includes the above-mentioned PFAS adsorbent.

[0229] Examples of water purification equipment include water purification equipment, wastewater treatment equipment, and water purification equipment. Examples of water purification equipment include pure water production equipment, ultrapure water equipment, and water treatment plants. Examples of wastewater treatment equipment include industrial wastewater treatment equipment and industrial wastewater treatment equipment. Examples of water purification equipment include water purification equipment for pharmaceuticals and water purification equipment for food. The method of obtaining water purification equipment is not particularly limited. For example, water purification equipment having a known configuration can be manufactured by a known method.

[0230] The treatment method in a water purification facility is not particularly limited. Examples of treatment methods include batch treatment and flow treatment.

[0231] In a batch treatment method, for example, a PFAS removal agent is added to water containing PFAS (water to be treated), and the added PFAS removal agent (hereinafter sometimes referred to as the added PFAS removal agent) comes into contact with the PFAS in the water. This allows the PFAS to be adsorbed onto the added PFAS removal agent, and water with a reduced PFAS content (treated water) can be obtained. In a batch treatment method, the PFAS removal agent that has adsorbed the PFAS is recovered by known methods. Such methods include, for example, filtration and centrifugation.

[0232] In the flow-through treatment method, a water purification system equipped with a packed bed is used. More specifically, the water purification system includes, for example, a packed column and a PFAS removal material (sometimes referred to as packed PFAS removal material) as a packing material packed into the packed column. The packed PFAS removal material forms a packed bed within the packed column. That is, the water purification system is equipped with a packed bed containing the packed PFAS removal material. In such a water purification system, for example, water containing PFAS (water to be treated) is passed through the packed bed in an upward flow and / or downward flow, bringing the packed PFAS removal material and PFAS into contact in the water. This allows PFAS to be adsorbed onto the packed PFAS removal material, and water with a reduced PFAS content (treated water) can be obtained. In the flow-through treatment method, the packed PFAS removal material that has adsorbed PFAS is removed from the packed bed by known methods and regenerated as necessary.

[0233] There are no particular restrictions on the type of PFAS removal material used in water purification equipment. For example, examples of PFAS removal materials include unused PFAS removal material and recycled PFAS removal material. Unused PFAS removal material may or may not contain the above-mentioned fluorine-treated (recycled) carbonaceous material.

[0234] That is, the input PFAS removal material and the filled PFAS removal material contain, for example, the above PFAS removal material and / or the above recycled PFAS removal material, and preferably consist of the above PFAS removal material and / or the above recycled PFAS removal material. The input PFAS removal material and the filled PFAS removal material more preferably contain at least the above recycled PFAS removal material. The input PFAS removal material and the filled PFAS removal material more preferably contain the above PFAS removal material and the above recycled PFAS removal material.

[0235] In water purification equipment, a particularly preferred method of using PFAS removal material is the above-described flow-through treatment method, in which the packed PFAS removal material is used in the packed column, then recovered and regenerated, and the resulting regenerated PFAS removal material, together with unused PFAS removal material as needed, is packed into the original packed column or other packed column for reuse.

[0236] Furthermore, the amount of PFAS removal material supplied (input and / or filled) to the water purification equipment is not particularly limited and can be set appropriately, for example, according to the PFAS concentration of the water to be treated and the desired PFAS concentration of the treated water.

[0237] Furthermore, the treatment time in the water purification equipment is not particularly limited and can be set appropriately according to, for example, the PFAS concentration of the water to be treated and the desired PFAS concentration of the treated water.

[0238] Furthermore, the treatment temperature in the water purification equipment is not particularly limited and is set appropriately according to, for example, the PFAS concentration of the water to be treated and the desired PFAS concentration of the treated water. For example, from the viewpoint of ensuring the contact efficiency between the PFAS removal material and PFAS, and suppressing the concentration of PFAS, the treatment temperature is a temperature at which the water to be treated does not become a solid or gaseous state and can remain in a liquid state, and is usually between 0°C and 100°C.

[0239] The water purification system may also be equipped with adsorbents other than PFAS removal materials (hereinafter referred to as "other adsorbents").

[0240] More specifically, the treated water may contain substances that reduce the adsorption performance of the PFAS removal material. Examples of such substances include substances that oxidatively decompose the PFAS removal material and substances that clog the pores of the PFAS removal material. Examples of substances that oxidatively decompose the PFAS removal material include residual chlorine, hydrogen peroxide, and ozone. Examples of substances that clog the pores of the PFAS removal material include volatile organic compounds (VOCs), water-soluble organic compounds, and PFAS. Furthermore, the treated water may contain substances that inhibit the adsorption of PFAS to the PFAS removal material by chlorinating the PFAS. Examples of such substances include inorganic compounds and inorganic salts.

[0241] Therefore, the water purification equipment preferably includes other adsorbents, from the viewpoint of suppressing a decrease in the adsorption performance of the PFAS removal material and suppressing the inhibition of PFAS adsorption by the PFAS removal material.

[0242] Other adsorbents include, for example, porous inorganic minerals and ion exchange resins. Examples of porous inorganic minerals include synthetic zeolites, natural zeolites, acid clay, activated clay, and sepiolite. Other adsorbents include, for example, activated carbon and carbonaceous materials (carbonaceous materials that do not have the above-mentioned pore volume and pore volume ratio). These can be used individually or in combination of two or more types. Preferably, other adsorbents include activated carbon and carbonaceous materials. By adsorbing the above-mentioned impurities, the other adsorbents can suppress the decrease in the adsorption performance of the PFAS removal material and suppress the inhibition of PFAS adsorption.

[0243] The PFAS removal material and other adsorbents may be supplied to the water purification equipment individually or together. When the PFAS removal material and other adsorbents are supplied together to the water purification equipment, they may or may not be pre-mixed. For example, if the packed bed contains packed PFAS removal material and other adsorbents (adsorbents other than packed PFAS removal material), a mixed layer of PFAS removal material and other adsorbents may be formed, or a layer containing PFAS removal material and a layer containing other adsorbents may be laminated together.

[0244] The amount of other adsorbents is not particularly limited and is set as appropriate according to the purpose and application. For example, the amount of other adsorbents is 0.1 parts by mass to 100,000 parts by mass per 100 parts by mass of PFAS removal material.

[0245] Furthermore, the above water purification equipment contains the above carbonaceous material. Therefore, the above water purifier has excellent durability and excellent PFAS removal performance.

[0246] Furthermore, the above-mentioned water purification equipment may experience a decrease in the PFAS adsorption efficiency of the filled PFAS removal material as it continues to operate. Therefore, it is preferable to maintain the water purification equipment using the following maintenance method.

[0247] More specifically, the maintenance method for the water purification equipment comprises a regeneration step of regenerating the packed PFAS removal material (i.e., PFAS removal material and / or recycled PFAS removal material) used in the packed bed by heating, and a reuse step of reusing the regenerated PFAS removal material and / or recycled PFAS removal material as packed PFAS removal material in the packed bed.

[0248] In the regeneration process, for example, the treated water is first passed through a packed bed. Then, the PFAS concentration of the treated water that has passed through the packed bed is continuously measured. The measurement method is not particularly limited, and known methods can be used.

[0249] Next, in the regeneration process, it is determined whether the PFAS concentration in the treated water is above a predetermined value. The predetermined value of the PFAS concentration is not particularly limited, but for example, it is 4 ng / L.

[0250] If the PFAS concentration in the treated water is below the predetermined value mentioned above, it is determined that regeneration of the packed PFAS removal material is unnecessary. In this case, the operation of the water purification equipment is continued without removing the packed PFAS removal material (i.e., the PFAS removal material and / or regenerated PFAS removal material) from the packed column.

[0251] On the other hand, if the PFAS concentration in the treated water is above the predetermined value mentioned above, it is determined that the packed PFAS removal material needs to be regenerated. In such cases, for example, the packed PFAS removal material in the packed column (i.e., the PFAS removal material and / or regenerated PFAS removal material) is removed by any method.

[0252] Next, the total amount of PFAS adsorbed onto the extracted PFAS removal material and / or recycled PFAS removal material (hereinafter referred to as the cumulative PFAS adsorption amount) is calculated. More specifically, the total amount of PFAS adsorbed onto the packed PFAS removal material in the packed bed of the water purification equipment is calculated.

[0253] The cumulative amount of PFAS adsorbed can be calculated, for example, by a known method from the PFAS concentration of the water to be treated supplied to the packed bed, the PFAS concentration of the treated water that has passed through the packed bed, and the amount of packed PFAS treatment material.

[0254] Next, in the regeneration process, the heating temperature is set based on the cumulative amount of PFAS adsorbed. More specifically, for example, if the cumulative amount of PFAS adsorbed is relatively large, a relatively high heating temperature is selected. Conversely, if the cumulative amount of PFAS adsorbed is relatively small, a relatively low heating temperature is selected. The specific heating temperature is set appropriately, for example, within the range of the heating temperature in the thermal decomposition process in the regeneration treatment described above (preferably 300°C to 950°C).

[0255] Next, in the regeneration process, the PFAS removal material and / or regenerated PFAS removal material are heated at the above-set heating temperature to thermally decompose the PFAS adsorbed thereon. The heating conditions other than temperature are the same as, for example, the various conditions for the thermal decomposition process in the regeneration process described above. After heating, if necessary, the PFAS removal material and / or regenerated PFAS removal material are subjected to the above-mentioned cooling process (and transfer process) and / or the above-mentioned removal process.

[0256] Next, in this method, the regenerated PFAS removal material and / or the regenerated PFAS removal material is reused again in the packed bed. More specifically, the regenerated PFAS removal material and / or the regenerated PFAS removal material is packed into the packed column of the water purification equipment to form a packed bed. Then, by passing the treated water containing PFAS through the formed packed bed, PFAS can be adsorbed again onto the regenerated packed PFAS removal material.

[0257] According to the maintenance method for the water purification equipment described above, the water purification equipment can be operated efficiently. Furthermore, according to the maintenance method for the water purification equipment described above, the PFAS removal material can be reused efficiently, and the water can be purified efficiently.

[0258] Furthermore, with the above maintenance method, the filled PFAS removal material (PFAS removal material and / or recycled PFAS removal material) can be repeatedly regenerated and reused using the method described above. On the other hand, if the number of regeneration cycles becomes excessively large with the above maintenance method, it may become difficult to regenerate the filled PFAS removal material (PFAS removal material and / or recycled PFAS removal material).

[0259] Therefore, in the above maintenance method, preferably, whether or not regeneration is possible is determined based on the number of times the filled PFAS removal material (PFAS removal material and / or regenerated PFAS removal material) has been regenerated.

[0260] More specifically, in this method, for example, in the maintenance method for the water purification equipment described above, the history of the regeneration and reuse of the PFAS removal material and / or recycled PFAS removal material is preferably recorded as data.

[0261] Furthermore, in this method, preferably, in the regeneration process, the history of regeneration and reuse of the PFAS removal material and / or the regenerated PFAS removal material is referenced before heating the PFAS removal material and / or the regenerated PFAS removal material.

[0262] Next, preferably in this method, it is determined whether the number of regeneration cycles of the PFAS removal material and / or the recycled PFAS removal material is equal to or greater than a predetermined value. The predetermined value is not particularly limited and is set as appropriate according to the purpose and application.

[0263] Furthermore, this method determines, for example, whether regeneration is possible based on the number of times the PFAS removal material and / or the regenerated PFAS removal material has been regenerated.

[0264] For example, if the number of times the PFAS removal material and / or recycled PFAS removal material is recycled and reused is less than the predetermined value mentioned above, the packed PFAS removal material is deemed recyclable. In this case, the PFAS removal material and / or recycled PFAS removal material are subjected to the recycling process mentioned above. After that, the recycled PFAS removal material and / or recycled PFAS removal material are packed into the packed column to form a packed bed.

[0265] On the other hand, if the number of times the PFAS removal material and / or recycled PFAS removal material is recycled and reused exceeds the predetermined value mentioned above, it can be determined, for example, that the recycled packed PFAS removal material is difficult to recycle. In such cases, for example, the PFAS removal material and / or recycled PFAS removal material are removed from the water treatment facility without being subjected to the above-mentioned recycling process. Alternatively, in place of the removed PFAS removal material and / or recycled PFAS removal material, a separate PFAS removal material and / or recycled PFAS removal material is packed into the packed column to form a packed layer.

[0266] According to this maintenance method for water purification equipment, the above-mentioned PFAS removal material and / or recycled PFAS removal material can be reused more efficiently.

[0267] [Other Uses] The uses are not limited to those described above. For example, carbonaceous materials and PFAS treatment agents are suitably used in various treatment devices for treating PFAS by methods other than adsorption (e.g., removal, concentration, dilution, separation, and recovery).

[0268] Examples of treatment devices include those equipped with various filters (e.g., columns, tanks, tubes, bathtubs, cylinders, sheets, and films), such as known filtration devices, known adsorption devices, and known concentration devices. More specifically, examples of treatment devices include household drinking water treatment devices, water treatment devices in industrial processes, purification devices in industrial processes, and wastewater treatment devices in industrial processes.

[0269] Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited to the following examples. Unless otherwise specified, "parts" and "%" are based on mass. Furthermore, specific numerical values ​​such as blending ratios (content), physical properties, and parameters used in the following description may be replaced with the corresponding upper limits (numerical values ​​defined as "less than or equal to" or "less than") or lower limits (numerical values ​​defined as "greater than or equal to" or "greater than") of the blending ratios (content), physical properties, and parameters described in the "Modes for Carrying Out the Invention" above.

[0270] 1. Carbonaceous material [Example 1] (Preparation step) Coconut shells were prepared as a carbon raw material.

[0271] (Carbonization process) Using a rotary kiln with stirring blades (see Figures 1 and 2), the above raw material components were heat-treated under a nitrogen atmosphere to obtain carbides.

[0272] • Rotary kiln design Number of stirring blades: 6 (one blade every 60° around the circumference of the tube) Stirring blade angle: 15° to 45° Stirring blade length: 15% to 25% of the inner radius of the tube Stirring blade thickness: 40% to 80% of the thickness of the tube

[0273] Heat treatment conditions: Initial temperature: 150°C, Heating rate: 5°C / min, Heat treatment time: 90 minutes, Rotation speed: 3.0 rpm

[0274] (Activation Process) The carbide was placed into the rotary kiln described above, and while the rotary kiln was rotated, steam was introduced into the kiln to activate the carbide and obtain activated material. The amount of carbide was approximately 0.06 times the volume of the rotary kiln. The activation conditions are as follows.

[0275] Activation conditions: Activation temperature: 900°C, Activation time: 390 minutes, Rotation speed: 3.0 rpm

[0276] (Washing process) The activator was washed with dilute hydrochloric acid, and then the hydrochloric acid was removed by washing with water.

[0277] (Drying process) The washed activated material was dried to obtain a dried product. The dried product was then crushed to obtain a carbonaceous material.

[0278] [Example 2] A carbonaceous material was obtained using the same method as in Example 1, except that the activation time in the activation process was changed to 200 minutes.

[0279] [Example 3] (Preparation process) Bituminous coal was crushed to obtain coal powder. The coal powder and water were kneaded to obtain a mixture. The mixture was compacted using an extruder to obtain a molded product. The molded product was crushed, the crushed material was sieved through a sieve, and then dried to obtain raw material components containing bituminous coal.

[0280] (Carbonization Process) Using the same rotary kiln as in Example 1, the above raw material components were heat-treated under a nitrogen atmosphere to obtain carbides. The heat treatment conditions are as follows.

[0281] Heat treatment conditions: Initial temperature: 200°C, Heating rate: 10°C / min, Heat treatment time: 50 minutes, Rotation speed: 3.0 rpm

[0282] (Activation Process) The carbide was placed into the rotary kiln described above, and while the rotary kiln was rotated, steam was introduced into the kiln to activate the carbide and obtain activated material. The amount of carbide was approximately 0.06 times the volume of the rotary kiln. The activation conditions are as follows.

[0283] Activation conditions: Activation temperature: 950°C, Activation time: 260 minutes, Rotation speed: 3.0 rpm

[0284] (Washing and Drying Process) The activated material was washed and dried in the same manner as in Example 1, and then the dried material was crushed to obtain a carbonaceous material.

[0285] [Example 4] (Preparation process) Bituminous coal was crushed to obtain coal powder. The coal powder and water were kneaded to obtain a mixture. The mixture was molded into a spherical shape using a rolling granulator to obtain a molded product. By drying the molded product, raw material components containing bituminous coal were obtained.

[0286] (Carbonization Process) Using the same rotary kiln as in Example 1, the above raw material components were heat-treated under a nitrogen atmosphere to obtain carbides. The heat treatment conditions are as follows.

[0287] Heat treatment conditions: Initial temperature: 200°C, Heating rate: 10°C / min, Heat treatment time: 50 minutes, Rotation speed: 3.0 rpm

[0288] (Activation Process) The carbide was placed into the rotary kiln described above, and while the rotary kiln was rotated, steam was introduced into the kiln to activate the carbide and obtain activated material. The amount of carbide was approximately 0.06 times the volume of the rotary kiln. The activation conditions are as follows.

[0289] Activation conditions: Activation temperature: 900°C, Activation time: 100 minutes, Rotation speed: 3.0 rpm

[0290] (Washing and Drying Process) The activated material was washed and dried in the same manner as in Example 1, and then the dried material was crushed to obtain a carbonaceous material.

[0291] [Example 5] (Preparation step) 50 parts by mass of sub-bituminous coal and 50 parts by mass of bituminous coal were mixed, and the mixture was crushed to obtain coal powder. The coal powder, pitch, and water were kneaded to obtain a mixture. The mixture was molded into a spherical shape using a rolling granulator to obtain a molded product. The molded product was dried to obtain raw material components containing sub-bituminous coal and bituminous coal.

[0292] (Carbonization Process) Using the same rotary kiln as in Example 1, the above raw material components were heat-treated under a nitrogen atmosphere to obtain carbides. The heat treatment conditions are as follows.

[0293] Heat treatment conditions: Initial temperature: 200°C, Heating rate: 10°C / min, Heat treatment time: 50 minutes, Rotation speed: 3.0 rpm

[0294] (Activation Process) The carbide was placed into the rotary kiln described above, and while the rotary kiln was rotated, steam was introduced into the kiln to activate the carbide and obtain activated material. The amount of carbide was approximately 0.06 times the volume of the rotary kiln. The activation conditions are as follows.

[0295] Activation conditions: Activation temperature: 900°C, Activation time: 100 minutes, Rotation speed: 3.0 rpm

[0296] (Washing and Drying Process) The activated material was washed and dried in the same manner as in Example 1, and then the dried material was crushed to obtain a carbonaceous material.

[0297] [Example 6] (Preparation step) Coconut shells were prepared as raw material components.

[0298] (Carbonization Process) Using the same rotary kiln as in Example 1, the above raw material components were heat-treated under a nitrogen atmosphere to obtain carbides. The heat treatment conditions are as follows.

[0299] Heat treatment conditions: Initial temperature: 200°C, Heating rate: 5°C / min, Heat treatment time: 80 minutes, Rotation speed: 3.0 rpm

[0300] (Activation Process) The carbide was placed into the rotary kiln described above, and while the rotary kiln was rotated, steam was introduced into the kiln to activate the carbide and obtain activated material. The amount of carbide was approximately 0.06 times the volume of the rotary kiln. The activation conditions are as follows.

[0301] Activation conditions: Activation temperature: 900°C, Activation time: 400 minutes, Rotation speed: 3.0 rpm

[0302] (Washing and Drying Process) The activated material was washed and dried in the same manner as in Example 1, and then the dried material was crushed to obtain a carbonaceous material.

[0303] [Example 7] (Preparation Step) Sub-bituminous coal was crushed to obtain coal powder. The coal powder was mixed with pitch and water to obtain a mixture. The mixture was molded into a spherical shape using a rolling granulator to obtain a molded product. The molded product was dried to obtain raw material components containing sub-bituminous coal.

[0304] (Carbonization Process) Using the same rotary kiln as in Example 1, the above raw material components were heat-treated under a nitrogen atmosphere to obtain carbides. The heat treatment conditions are as follows.

[0305] Heat treatment conditions: Initial temperature: 200°C, Heating rate: 10°C / min, Heat treatment time: 50 minutes, Rotation speed: 3.0 rpm

[0306] (Activation Process) The carbide was placed into the rotary kiln described above, and while the rotary kiln was rotated, steam was introduced into the kiln to activate the carbide and obtain activated material. The amount of carbide was approximately 0.06 times the volume of the rotary kiln. The activation conditions are as follows.

[0307] Activation conditions: Activation temperature: 900°C, Activation time: 110 minutes, Rotation speed: 3.0 rpm

[0308] (Washing and Drying Process) The activated material was washed and dried in the same manner as in Example 1, and then the dried material was crushed to obtain a carbonaceous material.

[0309] [Comparative Example 1] (Preparation Step) Coconut shells were prepared as a raw material component.

[0310] (Carbonization Process) The above raw material components were heat-treated under a nitrogen atmosphere using a known rotary kiln (not shown) without stirring blades to obtain carbides. The heat treatment conditions are as follows.

[0311] Heat treatment conditions: Initial temperature: 150°C, Heating rate: 10°C / min, Heat treatment time: 70 minutes, Rotation speed: 3.0 rpm

[0312] (Activation Process) The carbide was placed into a known rotary kiln (not shown) that does not have the stirring blades described above, and the rotary kiln was rotated while steam was introduced into the kiln to activate the carbide and obtain activated material. The amount of carbide was approximately 0.06 times the volume of the rotary kiln. The activation conditions are as follows.

[0313] Activation conditions: Activation temperature: 900°C, Activation time: 130 minutes, Rotation speed: 3.0 rpm

[0314] (Washing and Drying Process) The activated material was washed and dried in the same manner as in Example 1, and then the dried material was crushed to obtain a carbonaceous material.

[0315] [Comparative Example 2] Wood powder obtained from cedar was dried to obtain dried wood powder. Next, 100 parts by mass of dried wood powder and 300 parts by mass of zinc chloride aqueous solution (concentration 70% by mass) were mixed to obtain a mixture. The mixture was heated in a rotary electric furnace to 700°C for 1 hour to activate the dried wood powder with zinc chloride and obtain an activated product.

[0316] (Washing and Drying Process) The activated material was washed and dried in the same manner as in Example 1, and then the dried material was crushed to obtain a carbonaceous material.

[0317] [Comparative Example 3] A carbonaceous material was obtained in the same manner as in Comparative Example 1, except that the heat treatment conditions in the carbonization process and the activation treatment conditions in the activation process were changed as follows.

[0318] Heat treatment conditions: Initial temperature: 150°C, Heating rate: 15°C / min, Heat treatment time: 30 minutes, Rotation speed: 3.0 rpm

[0319] Activation conditions: Activation temperature: 900°C, Activation time: 120 minutes, Rotation speed: 3.0 rpm

[0320] 2. Evaluation The carbonaceous materials were evaluated using the following method. The results are shown in Tables 1 to 3.

[0321] [N of carbonaceous materials at -196°C] ２ [Adsorption Isotherm] Using a specific surface area / pore distribution measuring device (BELSORP®-miniII (product name) manufactured by Microtrac-Bel), the carbonaceous material was heated under reduced pressure (vacuum level: 0.1 kPa or less) at 250°C for 3 hours. Subsequently, the N of the carbonaceous material at -196°C was measured. ２ Adsorption isotherms were measured.

[0322] [BET Specific Surface Area] Specific surface area of ​​carbonaceous materials (unit: m²) ２ ( / g) at -196°C N ２ The isotherms were obtained from the adsorption isotherms using the BET method.

[0323] That is, the above N ２ Using adsorption isotherms, relative pressure P / P is determined by BET analysis (multipoint method). ０ A straight line was obtained in the region between 0.01 and 0.10. Then, the BET specific surface area was calculated from the obtained straight line.

[0324] [Pore volume (A) of pores with a diameter of 2-4 nm] The cumulative pore volume of pores with a diameter of 2-4 nm contained in 1 g of carbonaceous material (i.e., pore volume (A) of pores with a diameter of 2-4 nm, unit: mL / g) is expressed as above N ２ The results were calculated from adsorption isotherms using the CI method.

[0325] [Pore volume of pores with a diameter of 1.2 nm or less (B)] The cumulative pore volume of pores with a diameter of 1.2 nm or less contained in 1 g of carbonaceous material (i.e., pore volume of pores with a diameter of 1.2 nm or less (B), unit: mL / g) is calculated as above N ２ The results were calculated from adsorption isotherms using the CI method.

[0326] [Pore Volume (C) of pores with a diameter of 9-25 nm] The cumulative pore volume of pores with a diameter of 9-25 nm contained in 1 g of carbonaceous material (i.e., pore volume (C) of pores with a diameter of 9-25 nm, unit: mL / g) is expressed as above N ２ The results were calculated from adsorption isotherms using the CI method.

[0327] [Pore Volume Ratio ((A) / (B))] From the above pore volumes (A) and (B), the ratio of the pore volume (A) with a pore diameter of 2 to 4 nm to the pore volume (B) with a pore diameter of 1.2 nm or less (pore volume ratio (A) / (B)) was calculated.

[0328] [Pore Volume Ratio ((C) / (B))] From the above pore volume (B) and pore volume (C), the ratio of the pore volume (C) with a pore diameter of 9 to 25 nm to the pore volume (B) with a pore diameter of 1.2 nm or less (pore volume ratio (C) / (B)) was calculated.

[0329] [Microstrength Hardness (MS Hardness)] The MS hardness of carbonaceous materials was measured using the following method. First, the carbonaceous material was sieved using a sieve with a predetermined particle size range. The particle size range of the sieve was selected based on the description of "hardness" in JIS K 1474 (2014).

[0330] Next, 10 g of sieved carbonaceous material was placed in the container shown in Figure 3 (inner diameter 25 mm x 300 mm, made of stainless steel). Ten steel balls with a diameter of 7.94 mm were also placed in the container. The container was then rotated at 25 revolutions per minute for 40 minutes. The contents of the container were then removed, separating the carbonaceous material from the steel balls.

[0331] Next, the carbonaceous material was sieved using a sieve having the specified particle size range. Then, the MS hardness was calculated according to the following formula.

[0332] MS hardness (%) = [Mass of carbonaceous material on the sieve] / [Mass of carbonaceous material on the sieve + Mass of carbonaceous material below the sieve] × 100 (%)

[0333] [Average particle size] The average particle size (representative diameter) of the carbonaceous material was calculated according to the method for calculating mass-average particle size specified in JIS K 1474 (2014).

[0334] Specifically, the carbonaceous material was dried for 3 hours in a constant-temperature drying oven (Yamato Scientific Co., Ltd., DVS402 (product name)) at 115°C to obtain a dried product. The dried carbonaceous material was then placed in a desiccator equipped with silica gel as a desiccant and allowed to cool to room temperature. Next, 100 g of the cooled carbonaceous material was taken and its mass was measured to the nearest 0.1 g.

[0335] Meanwhile, several sieves were stacked on a tray. The sieves were arranged so that the mesh size of the sieves decreased from the top to the bottom.

[0336] Then, the carbonaceous material was placed in the topmost sieve of the stacked sieves, and the lid was closed. After that, these were attached to a sieve shaker (manufactured by Iida Seisakusho Co., Ltd.) and sieved for 10 minutes (beats: 130-165 times / min, rotation speed: 240-295 times / min). After that, the mass of the carbonaceous material remaining on each sieve and in the receiving tray was measured to the nearest 0.1 g. Next, the particle size (%) of the carbonaceous material on each sieve was calculated using the following formula.

[0337] Particle size (%) = [Mass of carbonaceous material remaining on each sieve and in the tray] / [Total mass of carbonaceous material remaining on each sieve and in the tray] × 100 (%)

[0338] Furthermore, the average particle size (mm) of the carbonaceous material was calculated using the following formula. In the formula below, the total number of sieves was n, and the mesh size of the sieve with the smallest mesh size was defined as r1 (mm), with the mesh sizes being defined as r2, r3, ..., rn (mm) as the sieves progressed from smallest to largest mesh size.

[0339] Average particle size (mm) = ([average of r1 + r2 (mm)] × [grain size of carbonaceous material on sieve with mesh size r1 (%)] + [average of r2 + r3 (mm)] × [grain size of carbonaceous material on sieve with mesh size r2 (%)] + ... [average of rn-1 + rn (mm)] × [grain size of carbonaceous material on sieve with mesh size rn-1 (%)]) / [sum of grain sizes of carbonaceous material between the bottom and top sieves (%)]

[0340] [Packing Density] The packing density (g / mL) of the carbonaceous material was determined in accordance with JIS K 1474 (2014).

[0341] Specifically, the carbonaceous material was dried for 3 hours in a constant-temperature drying oven (Yamato Scientific Co., Ltd., DVS402 (product name)) at 115°C to obtain a dried product. The dried carbonaceous material was then left in a desiccator equipped with silica gel as a desiccant and allowed to cool to room temperature.

[0342] Next, the cooled carbonaceous material was introduced into the storage funnel of a bulk density meter (Tsutsui Chemical Instruments Co., Ltd.). Then, using the attached vibrator, the sample supply rate was adjusted to 0.75–1.0 mL / s while the carbonaceous material was filled to the mark of a 100 mL graduated cylinder (Shibata Chemical Co., Ltd. (product name)). The mass of the filled carbonaceous material was then measured to the nearest 0.1 g.

[0343] Next, the packing density (g / mL) of the carbonaceous material was calculated using the following formula.

[0344] Packing density (g / mL) = Mass of carbonaceous material (g) / Measured sample volume (mL)

[0345] [Reactive Black Pentavalent (RB5-valent)] The reactive black pentavalent (g / L) was measured using the following method.

[0346] In other words, carbonaceous material is defined as the 50% particle size (D) of the cumulative distribution by volume. ５０ The material was pulverized so that the particle size was 10.0 μm or less. The pulverized carbonaceous material was then dried for 3 hours in a constant-temperature drying oven (Yamato Scientific Co., Ltd., DVS402 (product name)) at 115°C to obtain a dried product. After that, the carbonaceous material was left in a desiccator equipped with silica gel as a desiccant and allowed to cool to room temperature.

[0347] On the other hand, test solution A, containing phosphate buffer and Reactive Black 5 (manufactured by Sigma-Aldrich), was prepared by the following method. Specifically, 7.26 g of potassium dihydrogen phosphate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and 28.66 g of disodium hydrogen phosphate dodecahydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were dissolved in 2 L of distilled water to prepare phosphate buffer (pH: 7.0). Then, Reactive Black 5 was added to 1 L of phosphate buffer to prepare test solution A.

[0348] The amount of Reactive Black 5 added to Test Solution A was determined by the following method. Specifically, the amount of Reactive Black 5 added to 1 L of phosphate buffer was adjusted so that when Test Solution A was diluted 20 times with distilled water, a diluted solution (hereinafter referred to as Test Solution B) with an absorbance of 1.18 to 1.23 was obtained. The amount of Reactive Black 5 was 0.5 to 1.2 g.

[0349] Next, the carbonaceous material and 50 mL of test solution A were placed in a 100 mL Erlenmeyer flask with a stopper, and the mixture was obtained by mixing them. Specifically, the carbonaceous material and test solution A were shaken at a rate of 150 times / minute for 5 hours in a 40°C water bath (Water Bath Shaker MM-10 (product name) manufactured by Taitec Co., Ltd.) to obtain the mixture.

[0350] The amount of carbonaceous material added to test solution A was adjusted so that the remaining amount of Reactive Black 5 in the filtrate, as described later, would be approximately 1%.

[0351] Next, the mixture was filtered using a membrane filter (DISMIC® 25HP045AN (product name) manufactured by Advantec Toyo Co., Ltd.) to obtain the filtrate.

[0352] Next, the absorbance of test solution B (i.e., a 20-fold dilution of test solution A) and the absorbance of the filtrate were measured. The absorbance is measured at a wavelength of 594 nm. The absorbance was measured using a glass cell with a path length of 10 mm and an ultraviolet-visible spectrophotometer (Hitachi High-Tech, double-beam spectrophotometer U-2910 (product name)).

[0353] Next, the amount of reactive black 5 adsorbed per gram of carbonaceous material (hereinafter referred to as "RB5 adsorbed per gram of carbonaceous material ( / g)") was calculated using the following formula.

[0354] RB5 adsorption amount per gram of carbonaceous material ( / g) = [(Absorbance of test solution B at a wavelength of 594 nm) × 20] - [Absorbance of filtrate at a wavelength of 594 nm] / Mass of carbonaceous material (g)

[0355] Furthermore, the residual rate of Reactive Black 5 contained in the filtrate (hereinafter referred to as "RB5 residual rate (%)") was calculated using the following formula.

[0356] RB5 retention rate (%) = [Absorbance of filtrate at a wavelength of 594 nm] / [(Absorbance of test solution B at a wavelength of 594 nm) × 20] × 100

[0357] Next, a power approximation curve was created using the RB5 retention rate (%) as the horizontal axis and the RB5 adsorption amount per gram of carbonaceous material ( / g) as the vertical axis.

[0358] Next, using the power approximation formula described above, the amount of reactive black 5 adsorbed when the reactive black 5 retention rate is 1% (hereinafter referred to as "RB5 adsorption amount ( / g) at RB5 retention rate of 1%") was determined.

[0359] Next, the reactive black pentavalent (g / L) was calculated using the following formula.

[0360] Reactive Black pentavalent (g / L) = [(Absorbance of test solution B at a wavelength of 594 nm) × 20] × 0.99 / [RB5 adsorption amount at 1% RB5 retention rate ( / g)] / 0.05 (L)

[0361] Note that 0.05 (L) in the above formula represents the volume of the test solution.

[0362] [2-MIB number] The 2-MIB number of carbonaceous materials was measured according to JWWA K 113 (2005-2) using the method described below.

[0363] In other words, carbonaceous material is defined as the 50% particle size (D) of the cumulative distribution by volume. ５０ The material was pulverized to a particle size of approximately 10.0 μm or less. Next, the pulverized carbonaceous material was dried for 3 hours in a constant-temperature drying oven (Yamato Scientific Co., Ltd., DVS402 (product name)) at 115°C to obtain a dried product. After that, the carbonaceous material was left in a desiccator equipped with silica gel as a desiccant and allowed to cool to room temperature.

[0364] On the other hand, test solution C containing methanol and 2-MIB (2-methylisoborneol) was prepared by the following method. Specifically, a 2-MIB standard solution (0.1 mg / mL methanol solution, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was diluted with methanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) to prepare a 1 mg / L 2-MIB solution. The resulting 2-MIB solution was used as test solution C.

[0365] Next, test solution C was diluted with distilled water to prepare the diluted solution (hereinafter referred to as test solution D). 100 mL of test solution D was transferred to a 200 mL Erlenmeyer flask with a stopper.

[0366] On the other hand, approximately 0.2 g of carbonaceous material was transferred to a 1 L volumetric flask and diluted to 1 L using distilled water to obtain a suspension containing carbonaceous material and water.

[0367] Next, the above suspension and 100 mL of test solution D were placed in a 200 mL Erlenmeyer flask with a stopper. Distilled water was then added to the Erlenmeyer flask until the total volume reached 200 mL, and these were mixed to obtain a mixture. More specifically, using a shaking thermostat (Tytec Water Bath Shaker MM-10 (product name)), the suspension, test solution D, and water were shaken at a rate of 150 times / min for 60 minutes in a 25°C water bath to obtain a mixture. The mixture was then allowed to stand for 30 minutes. The proportions of the suspension (i.e., carbonaceous material and water) were adjusted so that the "residual 2-MIB concentration" described later was approximately 20 ng / L.

[0368] Subsequently, the mixture was filtered using a membrane filter (DISMIC® 25HP045AN (product name) manufactured by Advantec Toyo Co., Ltd.) to obtain the filtrate.

[0369] Next, the 2-MIB content of the filtrate was measured using a calibration curve method with a gas chromatograph-mass spectrometer (GCMS-QP2020 (product name) manufactured by Shimadzu Corporation).

[0370] The calibration curve used for the measurement was prepared using the following method: Test solution C was divided into 100 mL volumes in stages from 1 to 50 mL, and these were diluted with distilled water to a total volume of 100 mL. Next, the 2-MIB content of the diluted solution was measured using a gas chromatograph-mass spectrometer (GCMS-QP2020 (product name) manufactured by Shimadzu Corporation), and a calibration curve was prepared based on these results.

[0371] The 2-MIB concentration in the filtrate was defined as the "residual 2-MIB concentration," and the amount of 2-MIB adsorbed per 1 mg of carbonaceous material was calculated using the following formula.

[0372] 2-MIB adsorption amount per gram of carbonaceous material (ng / mg) = [2-MIB concentration of test solution D (400 ng / L)] - [residual 2-MIB concentration of filtrate] × 0.2 (L) / 0.2 (mg)

[0373] Subsequently, an adsorption isotherm was created using Freundlich's adsorption isotherm, with "residual 2-MIB concentration" on the horizontal axis and "amount of 2-MIB adsorbed per 1 mg of carbonaceous material" on the vertical axis.

[0374] Next, using the adsorption isotherm described above, the amount of 2-MIB adsorbed per 1 mg of carbonaceous material (ng / mg) was calculated when the residual 2-MIB concentration was 20 ng / L. Subsequently, the 2-MIB value was calculated using the following formula.

[0375] 2-MIB value = [200 - 20] / [Amount of 2-MIB adsorbed per 1 mg of carbonaceous material (ng / mg) when the residual 2-MIB concentration is 20 ng / L]

[0376] [Iodine adsorption amount] The amount of iodine adsorbed by carbonaceous materials (mg / g) was determined in accordance with JIS K 1474 (2014).

[0377] Specifically, the carbonaceous material was pulverized in accordance with JIS Z 8801-1. Pulverization was continued until more than 90% of the pulverized carbonaceous material passed through a 45 μm sieve. Next, the pulverized carbonaceous material was dried for 3 hours in a constant-temperature drying oven (Yamato Scientific Co., Ltd., DVS402 (product name)) at 115°C. After that, the dried carbonaceous material was left in a desiccator equipped with silica gel as a desiccant and allowed to cool to room temperature.

[0378] On the other hand, 25.0 g of potassium iodide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and 13.0 g of iodine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were dissolved in approximately 1 L of distilled water to prepare an iodine solution.

[0379] The iodine solution was titrated with a 0.1 mol / L sodium thiosulfate solution (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) to determine its concentration. Distilled water was then added to the iodine solution to adjust its concentration. A 0.05 mol / L iodine solution was thus prepared.

[0380] Next, the carbonaceous material was weighed and placed in a 100 mL Erlenmeyer flask with a stopper. Then, 50 mL of the 0.05 mol / L iodine solution was added to the Erlenmeyer flask using a volumetric pipette. The amount of carbonaceous material was adjusted so that the residual iodine concentration in the supernatant of the filtrate (described later) was approximately 2.5 g / L.

[0381] Next, at room temperature (20°C to 30°C), the contents of the Erlenmeyer flask were shaken at 200 revolutions per minute for 15 minutes using a shaker (Tytec Co., Ltd., medium-sized reciprocating shaker NR-10 (product name)) to obtain a mixture. In addition, iodine was adsorbed onto a carbonaceous material in the mixture.

[0382] Next, the mixture was filtered using a cellulose mixed ester membrane filter (Advantec Toyo Co., Ltd., product name A045A025A) to obtain a filtrate.

[0383] Next, 10 mL of the supernatant of the filtrate was collected using a volumetric pipette and titrated with a 0.1 mol / L sodium thiosulfate solution (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., factor: 1.000).

[0384] The residual iodine concentration in the supernatant of the filtrate was then calculated using the following formula.

[0385] Iodine residual concentration (g / L) = [Amount of 0.1 mol / L sodium thiosulfate solution used in titration (mL)] × [Factor of 0.1 mol / L sodium thiosulfate solution] × 12.69 / 10

[0386] Then, the amount of iodine adsorbed per gram of carbonaceous material was calculated using the following formula.

[0387] Iodine adsorption per gram of carbonaceous material = (10 × [Factor of 0.05 mol / L iodine solution] - [Amount of 0.1 mol / L sodium thiosulfate solution used for titration (mL)] × [Factor of 0.1 mol / L sodium thiosulfate solution] × 12.69 × 5 / Mass of carbonaceous material (g)

[0388] The factor of a 0.05 mol / L iodine solution was calculated using the following formula.

[0389] Factor of 0.05 mol / L iodine solution = [Amount of 0.1 mol / L sodium thiosulfate solution used in titration (mL)] × [Factor of 0.1 mol / L sodium thiosulfate solution] / 10

[0390] Subsequently, an adsorption isotherm was created using Freundlich's adsorption isotherm, with "residual iodine concentration" on the horizontal axis and "amount of iodine adsorbed per gram of carbonaceous material" on the vertical axis.

[0391] Next, using the adsorption isotherm described above, the amount of iodine adsorbed per gram of carbonaceous material (mg / g) was calculated when the residual iodine concentration was 2.5 g / L.

[0392] [PFOS adsorption amount] The amount of PFOS adsorbed by carbonaceous materials (μg / mg) was determined using the following method.

[0393] In other words, carbonaceous material is defined as the 50% particle size (D) of the cumulative distribution by volume. ５０ The material was pulverized to a particle size of approximately 10.0 μm or less. Next, the pulverized carbonaceous material was dried for 3 hours in a constant-temperature drying oven (Yamato Scientific Co., Ltd., DVS402 (product name)) at 115°C to obtain a dried product. After that, the carbonaceous material was left in a desiccator equipped with silica gel as a desiccant and allowed to cool to room temperature.

[0394] On the other hand, test solution E containing perfluorooctanesulfonic acid (PFOS) was prepared by the following method. Specifically, commercially available perfluorooctanesulfonic acid (100 μg / mL in MeOH) (manufactured by AccuStandard) was diluted with ultrapure water to prepare a diluted solution with a PFOS concentration of 50 μg / L. The obtained diluted solution was used as test solution E.

[0395] Next, 100 mL of test solution E was transferred to a 200 mL stoppered Erlenmeyer flask.

[0396] Furthermore, carbonaceous material was added to the Erlenmeyer flask described above. The amount of carbonaceous material added was adjusted so that the "PFOS residual concentration," described later, would be approximately 10 μg / L.

[0397] Next, using a shaking constant temperature bath (Tytec Co., Ltd., Water Bath Shaker MM-10 (product name)), the contents of the Erlenmeyer flask were shaken at a rate of 148 times / minute for 5 hours in a 25°C water bath to obtain a mixture. Furthermore, PFOS was adsorbed onto the carbonaceous material by the above procedure.

[0398] Subsequently, the mixture was filtered using cellulose acetate filter paper with a pore size of 0.2 μm (DISMIC® 13CP020AN (product name) manufactured by Advantec Toyo Co., Ltd.) to obtain the filtrate.

[0399] Next, the PFOS concentration of the filtrate was quantified using a liquid chromatograph-mass spectrometer (Agilent Technologies, 1200 series / 6130 quadrupole LC / MS (trade name)) under the following conditions.

[0400] Delay column: ZORBAX Eclipse Plus C18 4.6 x 50 mm 3.5 μm (Agilent Technologies) Separation column: ZORBAX RRHD Eclipse Plus C18 2.1 x 100 mm 1.8 μm (Agilent Technologies) Mobile phase: Ammonium acetate solution (i.e., 10 mmol / L ammonium acetate solution prepared by diluting 1 mol / L ammonium acetate solution (Fujifilm Wako Pure Chemical Industries, Ltd.) with ultrapure water), and acetonitrile (for PFOA / PFOS analysis, Fujifilm Wako Pure Chemical Industries, Ltd.)

[0401] The PFOS concentration (measured value) of the filtrate obtained by the above measurements was defined as the "residual PFOS concentration," and the amount of PFOS adsorbed per 1 mg of carbonaceous material was calculated using the following formula.

[0402] PFOS adsorbed per 1 mg of carbonaceous material (μg / mg) = [PFOS concentration of test solution (50 μg / L) - residual PFOS concentration of filtrate (μg / L)] × 0.1 / [mass of carbonaceous material (mg)]

[0403] Subsequently, an adsorption isotherm was created using Freundlich's adsorption isotherm, with "PFOS residual concentration" on the horizontal axis and "PFOS adsorbed per 1 mg of carbonaceous material" on the vertical axis.

[0404] Next, using the adsorption isotherm described above, the amount of PFOS adsorbed per 1 mg of carbonaceous material (μg / mg) was calculated when the residual PFOS concentration was 10 μg / L. Furthermore, the amount of PFOS adsorbed was evaluated as the PFOS adsorption performance.

[0405] [PFOA Adsorption Amount] Perfluorooctanoic acid (100 μg / mL in MeOH) was used instead of perfluorooctanesulfonic acid (100 μg / mL in MeOH). Otherwise, the PFOA adsorption amount (μg / mg) was measured using the same method as for measuring PFOS adsorption.

[0406] The PFOA concentration (measured value) of the filtrate obtained by the above measurements was defined as the "residual PFOA concentration," and the amount of PFOA adsorbed per 1 mg of carbonaceous material was calculated using the following formula.

[0407] PFOA adsorption amount per 1 mg of carbonaceous material (μg / mg) = [PFOA concentration of test solution (50 μg / L) - residual PFOA concentration of filtrate (μg / L)] × 0.1 / [mass of carbonaceous material (mg)]

[0408] Subsequently, an adsorption isotherm was created using Freundlich's adsorption isotherm, with "PFOA residual concentration" on the horizontal axis and "PFOA adsorbed per 1 mg of carbonaceous material" on the vertical axis.

[0409] Next, using the adsorption isotherm described above, the amount of PFOA adsorbed per 1 mg of carbonaceous material (μg / mg) was calculated when the residual PFOA concentration was 10 μg / L. Furthermore, the amount of PFOA adsorbed was evaluated as the PFOA adsorption performance.

[0410]

[0411]

[0412]

[0413] 3. Fluorine treatment and regeneration of carbonaceous material [Example 8] (Adsorption process) A carbonaceous material was brought into contact with a solution containing PFAS to prepare a carbonaceous material on which PFAS was adsorbed. Specifically, perfluorooctanoic acid (PFOA, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was dissolved in methanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) to obtain a PFOA solution with a concentration of 20,000 mg / L. Next, the carbonaceous material obtained in Example 4 was placed in the above PFOA solution and shaken at a rate of 150 times / min for 24 hours in a water bath at 10°C using a shaking constant temperature bath (Tytec Corporation, Water Bath Shaker MM-10 (product name)). After that, methanol was removed in a conical flask while passing nitrogen gas through it in a constant temperature shaking bath maintained at 50°C, and the mixture was dried at 80°C for 2 hours to obtain a carbonaceous material on which PFOA was adsorbed.

[0414] (Thermal decomposition process) The obtained carbonaceous material was heat-treated for 30 minutes at a firing temperature of 850°C under a nitrogen atmosphere (1 L / min) in a quartz tubular firing furnace (manufactured by Koyo Thermo Systems Co., Ltd., small tube furnace (product name)) to thermally decompose the PFOA.

[0415] (Cooling process) Next, the heat-treated carbonaceous material was naturally cooled to room temperature under a nitrogen stream (1 L / min).

[0416] (Removal process) Next, impurities contained in the cooled carbonaceous material were removed with dilute hydrochloric acid and water. As a result, recycled carbonaceous material was obtained.

[0417] [Example 9] A carbonaceous material with adsorbed PFOA was obtained in the same manner as in Example 8, except that the carbonaceous material of Comparative Example 3 was used instead of the carbonaceous material obtained in Example 4. Subsequently, a recycled carbonaceous material was obtained in the same manner as in Example 8, except that the obtained carbonaceous material with adsorbed PFOA was used.

[0418] [Example 10] (Thermal Decomposition Process) The carbonaceous material from Example 4 was actually used in the adsorption of PFOA and recovered. The PFAS content of the recovered carbonaceous material from Example 4 was measured according to the procedure described in the Ministry of the Environment's "Technical Considerations Regarding the Treatment of Waste Containing PFOS and PFOA" (pages 38-39), and the PFOS content was 0.001 mg / kg-dry and the PFOA content was 0.512 mg / kg-dry.

[0419] Next, the carbonaceous material from Example 4, which had been recovered after use, was heat-treated in a rotary kiln without stirring blades (not shown) under a nitrogen atmosphere to thermally decompose the PFOA.

[0420] Heat treatment conditions: Heat treatment temperature: 900°C, Heat treatment time: 120 minutes, Rotation speed for both thermal decomposition and cooling processes: 3.0 rpm

[0421] (Transfer process) Next, the heat-treated carbonaceous material was transferred to a cooling kiln.

[0422] (Cooling process) Next, the carbonaceous material was cooled to near room temperature in a cooling kiln under an oxygen-free atmosphere.

[0423] (Removal process) Next, impurities contained in the cooled carbonaceous material were removed with dilute hydrochloric acid and water. As a result, recycled carbonaceous material was obtained.

[0424] 4. Evaluation Using the method described above, the BET specific surface area, pore volume (A) for pores with a diameter of 2-4 nm, pore volume (B) for pores with a diameter of 1.2 nm or less, pore volume (C) for pores with a diameter of 9-25 nm, pore volume ratio ((A) / (B)), and pore volume ratio ((C) / (B)) of the carbonaceous materials in Examples 8-10 were calculated. The results are shown in Table 4.

[0425] Furthermore, the microstrength hardness (MS hardness), PFOS adsorption amount, and PFOA adsorption amount of the carbonaceous materials in Examples 8 to 10 were measured using the method described above. The results are shown in Table 5.

[0426] Furthermore, the fluorine content of the carbonaceous materials in Examples 8 to 10 was measured by the method described below. The results are shown in Table 5.

[0427] [Fluorine Content] The content of fluorine contained in activated carbon was calculated by combustion ion chromatography. Specifically, the carbonaceous material was combusted and decomposed for 1 hour in a quartz tubular firing furnace (manufactured by Koyo Thermo Systems Co., Ltd., product name: Small Tube Furnace) under an air stream (1 L / min) at a combustion temperature of 900°C, and the generated gas was collected in a 0.5 mol / L sodium hydroxide solution (manufactured by Fujifilm Wako Pure Chemical Corporation). Subsequently, the collected liquid was passed through a solid-phase extraction cartridge (manufactured by Thermo Fisher Scientific, product name: Dionex OnGuard 2 H), and the fluorine concentration of the resulting solution was measured using ion chromatography (manufactured by Thermo Fisher Scientific, product name: Dionex Inuvion RFIC). Based on the obtained fluorine concentration (measured value) of the collected liquid, the fluorine content per 1 kg of the carbonaceous material was calculated by the following formula.

[0428] Fluorine content per 1 kg of carbonaceous material (mg / kg) = [Fluorine concentration of collected liquid (mg / L) × Volume of collected liquid (L)] / [Mass of carbonaceous material (kg)]

[0429]

[0430]

[0431] The above invention is provided as an exemplary embodiment of the present invention; however, this is merely an illustration and should not be construed as limiting. Variations of the present invention that are apparent to those skilled in the art are intended to be included within the scope of the following claims.

[0432] The PFAS removing material, article, method for producing a PFAS removing material, method for regenerating a PFAS removing material, method for producing a regenerated PFAS removing material, and regenerated PFAS-removing activated carbon of the present invention are suitably used particularly for removing (adsorbing) PFAS in water.

[0433] 1 Rotary kiln 2 Tube body 3 Stirring blade 5 Raw material component

Claims

1. N at -196°C ２ A PFAS removal material containing a carbonaceous material, wherein, in the pore volume determined by the CI method from adsorption isotherms, the ratio of the pore volume of pores with a diameter of 2 to 4 nm (A) to the pore volume of pores with a diameter of 1.2 nm or less (B) ((A) / (B)) is 0.085 or more and 0.410 or less, and the ratio of the pore volume of pores with a diameter of 9 to 25 nm (C) to the pore volume of pores with a diameter of 1.2 nm or less (B) ((C) / (B)) is 0.04 or more and 0.45 or less.

2. N at -196°C ２ The specific surface area determined by the BET method from the adsorption isotherm is 900 m². ２ / g or more 1760m ２ A PFAS removal material containing a carbonaceous material, wherein the amount is less than or equal to / g, the pore volume (A) for pores with a diameter of 2 to 4 nm is 0.030 mL / g or more and 0.100 mL / g or less, the pore volume (B) for pores with a diameter of 1.2 nm or less is 0.230 mL / g or more and 0.350 mL / g or less, and the pore volume (C) for pores with a diameter of 9 to 25 nm is 0.011 mL / g or more and 0.140 mL / g or less.

3. The PFAS removal material according to claim 1 or 2, wherein the MS hardness of the carbonaceous material is 80.0% or more.

4. The PFAS removal material according to claim 1 or 2, wherein the fluorine content of the carbonaceous material is 0.010 mg / kg or more and 50.000 mg / kg or less.

5. The PFAS removal material according to claim 1 or 2, wherein the MS hardness of the carbonaceous material is 80.0% or more, and the fluorine content of the carbonaceous material is 0.010 mg / kg or more and 50.000 mg / kg or less.

6. An object containing the PFAS removal material described in claim 1 or 2, selected from the group consisting of an adsorption filter, a water purifier cartridge, a water purifier, and a water purification system.

7. A method for producing a PFAS removal material according to claim 1 or 2, comprising: a carbonization step of carbonizing raw material components for obtaining the carbonaceous material by heat treatment to obtain a carbide; and an activation step of activating the carbide to obtain the carbonaceous material, wherein in the carbonization step, the heat treatment temperature in the heat treatment is increased at a heating rate of 5°C / min or more and 10°C / min or less.

8. The method for producing a PFAS remover according to claim 7, further comprising: an adsorption step of adsorbing an organofluorine compound onto a carbonaceous material to obtain a carbonaceous material on which the organofluorine compound has been adsorbed; a thermal decomposition step of heating the carbonaceous material on which the organofluorine compound has been adsorbed to thermally decompose the organofluorine compound; and a removal step of removing impurities from the carbonaceous material after thermal decomposition.

9. The method for producing a PFAS remover according to claim 8, wherein in the thermal decomposition step, the carbonaceous material on which the organofluorine compound has been adsorbed is heated in an inert gas atmosphere to 300°C or more and 950°C or less to thermally decompose the organofluorine compound.

10. The method for producing a PFAS removal material according to claim 8, further comprising a cooling step of cooling the carbonaceous material after the thermal decomposition step.

11. A method for removing PFAS, comprising contacting a workpiece containing an organofluorine compound with the PFAS removal material described in claim 1 or 2, and removing the organofluorine compound from the workpiece.

12. A method for regenerating a PFAS removal material according to claim 1 or 2, comprising the steps of: preparing the PFAS removal material containing the carbonaceous material on which an organofluorine compound has been adsorbed; and heating the carbonaceous material on which the organofluorine compound has been adsorbed to a temperature of 300°C to 950°C to thermally decompose the organofluorine compound.

13. A method for producing a recycled PFAS removal material obtained by regenerating the PFAS removal material described in claim 1 or 2, comprising the steps of: preparing the PFAS removal material containing the carbonaceous material on which an organofluorine compound has been adsorbed; and heating the carbonaceous material on which the organofluorine compound has been adsorbed to cause thermal decomposition of the organofluorine compound.

14. A regenerative PFAS removal material containing recycled carbonaceous material, with N at -196°C. ２ The specific surface area determined by the BET method from the adsorption isotherm is 900 m². ２ / g or more 1760m ２ A recycled PFAS remover having a concentration of 0.010 mg / kg or less, a pore volume (A) of pores with a diameter of 2 to 4 nm being 0.030 mL / g or more and 0.100 mL / g or less, a pore volume (B) of pores with a diameter of 1.2 nm or less being 0.230 mL / g or more and 0.350 mL / g or less, a pore volume (C) of pores with a diameter of 9 to 25 nm being 0.011 mL / g or more and 0.140 mL / g or less, and a fluorine content of 0.010 mg / kg or more and 50.000 mg / kg or less.

15. The recycled PFAS removal material according to claim 14, wherein the MS hardness of the recycled carbonaceous material is 80.0% or more.

16. An object containing the recycled PFAS removal material described in claim 14, selected from the group consisting of an adsorption filter, a water purifier cartridge, a water purifier, and a water purification system.

17. A method for removing PFAS, comprising contacting a workpiece containing an organofluorine compound with the recycled PFAS removal material described in claim 14, and removing the organofluorine compound from the workpiece.

18. PFAS-removed regenerated activated carbon with a fluorine content of 0.010 mg / kg or more and less than 1,000 mg / kg.

19. A water purification system comprising a packed bed containing a packed PFAS removal material, wherein the packed PFAS removal material contains the PFAS removal material described in claim 1 or 2, and / or the recycled PFAS removal material described in claim 14.

20. The water purification apparatus according to claim 19, wherein the packed layer further contains an adsorbent other than the packed PFAS removal material.

21. A method for maintaining a water purification system according to claim 19, comprising: a regeneration step of regenerating the PFAS removal material and / or the regenerated PFAS removal material used in the packed bed by heating; and a reuse step of reusing the regenerated PFAS removal material and / or the regenerated PFAS removal material in the packed bed, wherein the regeneration step comprises: a step of continuously measuring the PFAS concentration of the treated water that has passed through the packed bed; a step of calculating the cumulative amount of PFAS adsorbed by the PFAS removal material and / or the regenerated PFAS removal material when the PFAS concentration is above a predetermined value; a step of setting a heating temperature based on the cumulative amount of PFAS adsorbed; and a step of heating the PFAS removal material and / or the regenerated PFAS removal material at the set heating temperature.

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