Carbonaceous materials and their manufacturing methods, materials for removing fluoride-containing organic compounds, water filters and water purifiers.

Abstract

One aspect of this invention relates to a carbonaceous material, which has a benzene adsorption capacity of 30-60%, a vitamin B12 adsorption capacity of more than 50.0 mg / g, and a mesopore volume of 0.13-0.30 cm³ / g calculated from the nitrogen adsorption isotherm using the BJH method.

Description

Technical Field

[0001] This invention relates to carbonaceous materials. Furthermore, it relates to methods for manufacturing the aforementioned carbonaceous materials, materials for removing fluoride-containing organic compounds using the aforementioned carbonaceous materials, water filters, and water purifiers. Prior Technology

[0002] In recent years, there has been increasing attention paid to the safety and hygiene of tap water, with the aim of removing various harmful substances.

[0003] Fluorinated organic compounds possess unique properties unmatched by other substances (excellent heat and chemical resistance, usability under harsh conditions, and insufficient light absorption), and are therefore used in various applications such as surfactants, emulsifiers, water-repellent agents, fire extinguishing agents, waxes, carpet cleaners, and coatings. In recent years, their application as surface treatment agents for semiconductors and components of fuel cells has been gradually increasing.

[0004] However, several years ago, researchers, primarily in the United States and Canada, began reporting that some fluorinated organic compounds (PFAS) had accumulated in environmental water and in the bodies of wildlife. Typical examples include perfluorooctanoic acid (PFOA): C7F15COOH, representing perfluoroalkyl carboxylic acids, and perfluoroalkyl sulfonic acids (PFOS): C8F17SO3H, representing perfluoroalkyl sulfonic acids. Subsequently, researchers from Europe and Japan also conducted environmental analyses, confirming that these compounds exist in the environment on a global scale, including in Japan. Based on this situation, efforts are underway to reduce the environmental risks of fluorinated organic compounds (perfluoroalkyl and polyfluoroalkyl compounds; hereinafter also referred to as "PFAS").

[0005] For example, there are reports indicating that fluoride-containing surfactants can be removed from water by contacting activated carbon, in which more than 90% of the particles passing through a 75μm filter are present, with the water containing fluoride surfactants (Patent Document 1).

[0006] As described in Patent Document 1, there have been reports to date regarding the use of activated carbon to remove fluoride-containing organic compounds from water. However, the technology described in Patent Document 1 is mainly for batch applications (treatment / purification of industrial wastewater). The technologies reported so far are methods for removing PFAS from raw water (river water, etc.) in such batch applications and water treatment plants, while there has been little progress in research on methods for removing fluoride-containing organic compounds using water purifiers.

[0007] The water being treated differs between water treatment plants and water purifiers (raw water and tap water), and the treatment time also varies greatly. Therefore, the PFAS removal methods used in water treatment plants cannot be directly applied to household water purifiers.

[0008] Therefore, the main objective of this invention is to provide a carbonaceous material with high PFAS (PFOS, PFOA, etc.) removal performance that can also be used in water purifiers. [Previous Technical Documents] [Patent Literature]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2010-158662 Summary of the Invention

[0010] [The problem the invention aims to solve]

[0011] The inventors devoted themselves to studying the aforementioned problems and discovered that the problems could be solved by a carbonaceous material having the following structure. Based on this discovery, they conducted further research and thus completed the present invention.

[0012] That is, the carbonaceous material of one aspect of the present invention is characterized by: a benzene adsorption capacity of 30-60%, a vitamin B12 adsorption capacity of more than 50.0 mg / g, and a mesopore volume of 0.13-0.30 cm³ / g calculated by the BJH method from the nitrogen adsorption isotherm.

[0013] According to another aspect of the present invention, a method for manufacturing carbonaceous materials is characterized by: using a fluidized bed furnace; and introducing oxygen-containing gas into the fluidized bed furnace in a manner different from introducing flowing gas from the hearth, such that the oxygen concentration in the total gas of the flowing gas and the oxygen-containing gas is 0.004 to 1% by volume.

[0014] According to another aspect of the present invention, a water purifier is characterized by comprising: a carbonaceous material as described above and a fibrous binder; the fibrous binder having a CSF value of 10 to 150 mL; and containing 4 to 10 parts by weight of the fibrous binder relative to 100 parts by weight of the carbonaceous material. Simple Explanation of the Diagram

[0015] Figure 1 is a schematic diagram illustrating a method for manufacturing carbonaceous materials using a fluidized bed furnace in one embodiment of the present invention. Figure 2 is a schematic diagram illustrating a method for manufacturing carbonaceous materials using a fluidized bed furnace in one embodiment of the present invention. Figure 3 is a graph showing the relationship between the removal rates of PFOS and PFOA and the bed volume in the embodiments and comparative examples of the present invention. Implementation [The form in which the invention is carried out]

[0016] The following describes specific embodiments of the present invention, but the present invention is not limited thereto. [Carbon-based materials]

[0017] The carbonaceous material of the first embodiment of the present invention is characterized by: a benzene adsorption capacity of 30-60%, a vitamin B12 adsorption capacity greater than 50.0 mg / g, and a mesopore volume of 0.13-0.30 cm3 / g calculated by the BJH method from the nitrogen adsorption isotherm.

[0018] Based on the aforementioned structure, a carbonaceous material with high PFAS (PFOS, PFOA, etc.) removal performance can be provided, which can also be used in water purifiers. (Benzene adsorption capacity)

[0019] Benzene adsorption capacity is an indicator of the degree of activation of carbonaceous materials. The carbonaceous material of this embodiment has a benzene adsorption capacity in the range of 30-60%, making it suitable for adsorbing PFAS.

[0020] From the perspective of excellent PFAS adsorption performance, the benzene adsorption capacity of carbonaceous materials is in the range of 30-60%, with the upper limit preferably below 58%, more preferably below 56%, and even more preferably below 55%. The lower limit is preferably above 40%, more preferably above 42%, and even more preferably above 44%.

[0021] The amount of benzene adsorbed on carbonaceous materials can be determined by the method described in [Determination of Benzene Adsorption] below.

[0022] (Vitamin B12 adsorption capacity) Vitamin B12 (cyanocobalamin) has a large molecular weight, approximately 1355, and the adsorption capacity of vitamin B12 is an indicator of its adsorption characteristics for large molecules. The carbonaceous material of this embodiment has a vitamin B12 adsorption capacity exceeding 50 mg / g, making it a suitable carbonaceous material for adsorbing PFAS.

[0023] From the perspective of achieving excellent PFAS adsorption performance, the adsorption capacity of carbonaceous materials for vitamin B12 is greater than 50 mg / g, preferably above 60 mg / g, more preferably above 70 mg / g, and even more preferably above 80 mg / g. There is no particular upper limit to the adsorption capacity of vitamin B12, but from the perspective of balancing benzene adsorption and other physical properties, it is generally below 500 mg / g, more preferably below 460 mg / g, and even more preferably below 420 mg / g.

[0024] The amount of vitamin B12 adsorbed by carbonaceous materials can be determined by the method described in [Determination of Vitamin B12 Adsorption] below.

[0025] (Volume of the central hole) The pores of carbonaceous materials can be classified according to their diameter into micropores (diameter less than 2 nm), mesopores (diameter 2-50 nm), and macropores (diameter greater than 50 nm) (the values ​​in parentheses indicate the IUPAC classification criteria). Mesopores are larger than micropores, and the volume of mesopores is mainly used as an indicator of the adsorption characteristics of macromolecules. The mesopore volume of the carbonaceous material in this embodiment is in the range of 0.130-0.30 cm³ / g, thereby making the carbonaceous material more suitable for adsorbing PFAS.

[0026] From the viewpoint of achieving excellent PFAS adsorption performance, the mesopore volume of carbonaceous materials is preferably in the range of 0.130~0.300 cm³ / g, with the lower limit preferably above 0.140 cm³ / g, and more preferably above 0.145 cm³ / g. The upper limit is preferably below 0.280 cm³ / g, and more preferably below 0.250 cm³ / g.

[0027] The mesopore volume of carbonaceous materials can be calculated from nitrogen adsorption isotherms using the BJH (Barrett-Joyner-Halenda) method. The determination of nitrogen adsorption isotherms and the calculation of mesopore volume can be carried out by the methods described later in [Determination of Nitrogen Adsorption Isotherms] and [Determination of Mesopore Volume Using the BJH Method].

[0028] As described above, the technical significance of benzene adsorption capacity, vitamin B12 adsorption capacity, and mesopore volume in this embodiment has been explained. However, the relationship between the structure of the carbonaceous material (adsorbent) and its adsorption characteristics for the adsorbate is complex, and there may be cases where the benzene adsorption capacity, vitamin B12 adsorption capacity, and mesopore volume are independently independent and not directly related to the adsorption characteristics for the adsorbate. To achieve a carbonaceous material that can effectively remove PFAS, a balance between these benzene adsorption capacity, vitamin B12 adsorption capacity, and mesopore volume is considered extremely important. As will be described later, in this embodiment, a carbonaceous material possessing the aforementioned characteristics was successfully manufactured using a specific manufacturing method in a fluidized bed furnace.

[0029] As described above, the carbonaceous material of this embodiment only needs to have benzene adsorption capacity, vitamin B12 adsorption capacity, and mesopore volume within the aforementioned ranges. There are no particular limitations on other characteristics. However, it is believed that in order to reliably obtain the effects of the present invention, it is also preferable to have the following characteristics.

[0030] (Specific surface area) From the perspective of achieving the high standards of adsorption / removal performance required for water purifiers, the optimal specific surface area of ​​carbonaceous materials is in the range of 1200~2000 m² / g. The lower limit of the specific surface area is preferably above 1300 m² / g or 1400 m² / g, and the upper limit is preferably below 1900 m² / g or 1800 m² / g.

[0031] The specific surface area of ​​carbonaceous materials can be calculated from nitrogen adsorption isotherms using the BET method. The determination of nitrogen adsorption isotherms and the calculation of specific surface area can be performed by the methods described later in [Determination of Nitrogen Adsorption Isotherms] and [Determination of Specific Surface Area].

[0032] (Average pore diameter) From the perspective of achieving superior PFAS adsorption performance, the average pore diameter of carbonaceous materials is preferably in the range of 1.85~1.90 nm. The lower limit of the average pore diameter is preferably above 1.86 nm or 1.87 nm, and the upper limit is preferably below 1.89 nm or 1.88 nm.

[0033] The average pore diameter of carbonaceous materials can be calculated from nitrogen adsorption isotherms. The determination of nitrogen adsorption isotherms and the calculation of average pore diameter can be carried out by the methods described later in [Determination of Nitrogen Adsorption Isotherms] and [Determination of Total Pore Volume / Average Pore Diameter].

[0034] (Conductivity) The conductivity of the carbonaceous material in this embodiment, as measured by powder resistivity under a 12kN load, is preferably in the range of 3 to 9 S / cm. Specifically, if the conductivity is within this range, the carbonaceous material can achieve the adsorption and removal performance required by a water purifier at a high level. The upper limit of the conductivity is preferably 8.7 S / cm or less, more preferably 8.3 S / cm or less, even more preferably 8 S / cm or less, and the lower limit is preferably 5.3 S / cm or more, more preferably 5.6 S / cm or more, and more preferably 6 S / cm or more.

[0035] The aforementioned conductivity of carbonaceous materials can be measured using the methods described in the section on [Measurement of Conductivity] below.

[0036] There are no particular limitations on the shape of carbonaceous materials; they can be any shape, such as particles, fibers (threads, woven fabrics, felts), etc., and can be appropriately selected according to the specific application. However, because the adsorption capacity per unit volume is relatively high, granular materials are preferred. In the case of granular carbonaceous materials, there are no particular limitations on their size, and the particle size can be appropriately adjusted according to the specific application.

[0037] There are no particular limitations on the raw materials (carbon precursors) for carbonaceous materials. Examples include: plant-based carbon precursors (e.g., wood, shavings, charcoal, coconut or walnut shells, fruit seeds, pulp manufacturing byproducts, lignin, waste molasses, etc.), mineral-based carbon precursors (e.g., peat, lignite, brown coal, bituminous coal, anthracite, coal tar, coal pitch, petroleum distillation residues, petroleum asphalt, etc.), synthetic resin-based carbon precursors (e.g., phenolic resins, polyvinylidene chloride, acrylic resins, etc.), and natural fiber-based carbon precursors (e.g., cellulose and other natural fibers, rayon and other regenerated fibers, etc.). Among these, plant-based carbon precursors are preferred due to their excellent adsorption properties for substances to be removed, as specified in the Household Goods Quality Labelling Act. Therefore, in a preferred embodiment, the carbonaceous material is derived from plant-based carbonaceous precursors. From the viewpoint of achieving more effective removal of PFAS from the carbonaceous material, coconut shells are preferred as the raw material. Therefore, in a particularly preferred embodiment, coconut shells are used as a plant-based carbonaceous precursor.

[0038] The carbonaceous material of this embodiment is suitable for the adsorption of PFAS, and performs particularly well in water purifier applications. Therefore, the carbonaceous material of this embodiment can be used as a carbonaceous material for water purification (carbonaceous material for water purification), and can also be used as a carbonaceous material for purifying tap water (carbonaceous material for tap water purification).

[0039] In particular, the removal performance of the carbonaceous material of this embodiment, under the following test conditions, is better than 12,000 in terms of bed volume for removing fluorinated organic compounds.

[0040] (Measurement conditions) A stainless steel column with a diameter of 6.2 mm, a height of 25.4 mm, and an internal volume of 0.77 mL, filled with carbonaceous material, was used as test water. Water with a PFOA concentration of 50 ± 10 ppt and a PFOS concentration of 50 ± 10 ppt (containing 1.2 ppm TOC) was used. The water was passed through in an upflow at a rate of 7.2 mL / min and a space velocity (SV) of 560 hr⁻¹. The flow rate (bed volume) from the start of the flow to the breakthrough point, where the removal rate was less than 80%, was used as the removal performance. This indicates that the aforementioned excellent removal effect can be obtained more reliably.

[0041] The carbonaceous material of this embodiment can effectively adsorb fluorinated organic compounds, and is therefore suitable as a material for removing fluorinated organic compounds. Therefore, this invention also includes a fluorinated organic compound removal material made from the aforementioned carbonaceous material.

[0042] [Manufacturing Methods for Carbonaceous Materials] One embodiment of the present invention provides a carbonaceous material manufactured by activating the aforementioned carbonaceous precursor. Furthermore, when carbonization is required prior to activation, oxygen or air can generally be excluded, and carbonization can be carried out at, for example, 400-800°C (preferably 500-800°C, more preferably 550-750°C). Under such conditions, the raw carbon obtained by carbonizing the carbonaceous precursor is activated to manufacture the carbonaceous material.

[0043] Activation methods are important for achieving specific ranges of benzene adsorption capacity, vitamin B12 adsorption capacity, and mesopore volume (and optionally, specific surface area, average pore diameter, conductivity, etc., if desired). The method for manufacturing carbonaceous materials of this embodiment (hereinafter also referred to as "the manufacturing method of this embodiment") is characterized by using a fluidized bed furnace (fluidized activation furnace) as the activation furnace; and introducing oxygen-containing gas into the fluidized bed furnace, unlike the flowing gas introduced from the furnace bed. This allows the carbonaceous material to achieve benzene adsorption of 40%–60% and vitamin B12 adsorption of greater than 50 mg / g, which are difficult to achieve using conventional methods that use rotary kilns as activation furnaces or conventional methods that only introduce flowing gas from the furnace bed into the fluidized bed furnace.

[0044] The flowing gas, as long as it has the function of activating the flow of carbon in the raw material, is not particularly limited and can be any conventionally known substance. Examples include gases containing water vapor and / or carbon dioxide as flowing gas systems. Industrially, since the presence of water vapor and carbon dioxide is appropriate, combustion gases of hydrocarbons (such as light gases like methane, propane, and butane, and liquid fuels like light oil, kerosene, and heavy oil) are preferred.

[0045] From the viewpoint of effectively activating the raw carbon, the water vapor concentration in the flowing gas is preferably 10-40% by volume. The upper limit is more preferably 35% or less or 30% by volume, and the lower limit is more preferably 12% or more, 14% or more, or 15% or more by volume. Furthermore, when the flowing gas contains carbon dioxide, the carbon dioxide concentration in the flowing gas is preferably 15% or less by volume. The upper limit is more preferably 14% or less or 13% by volume, and the lower limit is more preferably 8% or more, 9% or more, or 10% or more by volume.

[0046] In the manufacturing method of this embodiment, in addition to the flowing gas introduced from the hearth, an oxygen-containing system is introduced into the fluidized furnace. The oxygen-containing gas is introduced into the fluidized furnace such that the oxygen concentration in the total gas mixture of the flowing gas and the oxygen-containing gas is 0.004 to 1% by volume. From the viewpoint of obtaining a carbonaceous material that can more effectively remove PFAS, the oxygen concentration in the total gas mixture of the flowing gas and the oxygen-containing gas is preferably 0.005% by volume or more, 0.01% by volume or more, 0.02% by volume or more, 0.03% by volume or more, 0.04% by volume or more, or 0.05% by volume or more. The upper limit of this oxygen concentration is preferably 0.95% by volume or less, 0.9% by volume or less, 0.85% by volume or less, or 0.8% by volume or less. In this embodiment, the oxygen concentration in the total gas mixture of the flowing gas and the oxygen-containing gas is the feed conversion concentration calculated based on the composition and amount of the flowing gas and the composition and amount of the oxygen-containing gas.

[0047] There are no particular limitations on the oxygen-containing gas as long as it contains oxygen; for example, air or air diluted with other gases (such as inert gases like nitrogen) can be used. The oxygen concentration in the oxygen-containing gas is not particularly limited as long as the oxygen concentration in the flowing gas and the total oxygen-containing gas is in the range of 0.004 to 1% by volume. Preferably, it is below 20% by volume, more preferably below 15%, 10%, 8%, 6%, 5%, 4%, 3%, or 2% by volume. The lower limit of the oxygen concentration in the oxygen-containing gas is generally above 0.1% by volume, above 0.2% by volume, etc. Furthermore, the flowing gas introduced from the furnace bed may contain oxygen; however, when combustion gas is used as the flowing gas, it is usually difficult to control the trace oxygen concentration in the combustion gas. Therefore, it is preferable to control the oxygen concentration by controlling the oxygen from the oxygen-containing gas.

[0048] The manufacturing method of this embodiment will now be described with reference to the drawings.

[0049] Figure 1 shows a schematic diagram of the fluidized bed furnace (fluidized activation furnace) 100 used in the manufacturing method of this embodiment. In the following description, the symbols represent: 1. Flowing gas inlet, 2. Oxygen-containing gas inlet, 3. Exhaust port, 4. Gas dispersion layer, 5. Raw material carbon, 6. Raw material carbon (during fluidized bed activation), 7. Flowing gas, 8. Oxygen-containing gas, 9. Exhaust gas, 10. Gas dispersion section, 20. Fluidized bed section, 100. Fluidized bed furnace (fluidized activation furnace).

[0050] The fluidized bed furnace 100 includes a flowing gas inlet 1, an oxygen-containing gas inlet 2, an exhaust port 3, and a gas dispersion layer 4. The flowing gas inlet 1 is typically located inside the furnace bed. The flowing gas (not shown) introduced into the fluidized bed furnace 100 contacts the raw material carbon 5 through the gas dispersion layer 4 to perform fluid activation on the raw material carbon. Then, the flowing gas is discharged outside the furnace through the exhaust port 3, which is typically located at the furnace top. In Figure 1, the mainstream direction of the aforementioned flowing gas (i.e., the flow direction from the furnace bed to the furnace top) is represented as direction Z.

[0051] The gas dispersion layer 4 is not particularly limited as long as it has the function of dispersing the flow of the flowing gas introduced from the flowing gas inlet 1 and making the flowing gas contact uniformly with the raw material carbon 5, and a conventionally known layer can be used. For example, when a perforated plate is used to disperse the flowing gas, it is called a gas dispersion layer 4 including a buffer zone from the furnace bottom to the perforated plate. As shown in FIG. 1, when observed from the main flow direction Z of the flowing gas, the gas dispersion layer 4 is arranged on the upstream side in the fluidized furnace. In this embodiment, the area formed by the gas dispersion layer 4 is called the gas dispersion part 10. Therefore, when observed along the main flow direction Z of the flowing gas, the fluidized furnace 100 has the gas dispersion part 10 on the upstream side in the fluidized furnace.

[0052] When the fluidized furnace 100 is observed along the main flow direction Z of the flowing gas, the fluidized furnace further has a fluidized bed part 20 on the downstream side in the fluidized furnace. In the fluidized bed part 20, the raw material carbon 5 and the flowing gas contact each other to activate the flow of the raw material carbon 5.

[0053] As described above, the manufacturing method of this embodiment is characterized in that, different from the flowing gas introduced from the furnace bottom, an oxygen-containing gas is introduced into the fluidized furnace. In addition, when realizing a carbonaceous material with the benzene adsorption amount and the vitamin B12 adsorption amount within a specific range, the position where the oxygen-containing gas is introduced is important. That is, when the upstream end position of the gas dispersion part in the main flow direction Z of the flowing gas is set to 0 (m), the downstream end position is set to t1 (m) (t1 > 0), and the introduction position of the oxygen-containing gas is set to t2 (m), it is preferably to satisfy the relationship of 0.5t1 ≤ t2. When 0.5t1 > t2, it is difficult to realize the carbonaceous material of this embodiment with the benzene adsorption amount and the vitamin B12 adsorption amount within a specific range. Preferably, 0.7t1 ≤ t2, more preferably 0.8t1 ≤ t2, 0.9t1 ≤ t2 or t1 ≤ t2, and particularly preferably t1 < t2, 1.2t1 ≤ t2, 1.4t1 ≤ t2 or 1.5t1 ≤ t2. As long as the oxygen-containing gas can contact the raw material carbon during the flow activation, the upper limit of t2 is not particularly limited and can be any position below the furnace top. However, when the height (thickness) of the fluidized bed part 20 is set to T (m) when observed from the direction Z (that is, T = (furnace top height - t1)), it is preferably t2 ≤ 0.8T, t2 ≤ 0.7T, t2 ≤ 0.6T, or t2 ≤ 0.5T. The introduction position t2 of the oxygen-containing gas refers to the central position of the width (thickness) when the oxygen-containing gas inlet 2 has a width (thickness) when observed from the direction Z.

[0054] FIG. 2 shows a schematic diagram of the state of flowing activation of the raw material carbon using the fluidized furnace shown in FIG. 1. In FIG. 2, the components / parts denoted by the same reference numerals as those in FIG. 1 represent the same components / parts as those in FIG. 1.

[0055] In Figure 2, flowing gas 7 is introduced into the fluidized bed furnace 100 from the hearth, and oxygen-containing gas 8 is introduced into the fluidized bed furnace 100 from the furnace side. The flowing gas 7 passes through the gas dispersion section 10, which is composed of a gas dispersion layer 4, and contacts the raw material carbon in the fluidized bed section 20, thereby activating the raw material carbon. Additionally, the oxygen-containing gas 8 (specifically, oxygen in the gas) contacts the activated raw material carbon 6, thereby locally activating the raw material carbon. By locally activating the raw material carbon with such oxygen-containing gas, it is speculated that mesopores can be locally developed while maintaining micropores, resulting in the advantageous production of carbonaceous materials with benzene and vitamin B12 adsorption capacities within specific ranges.

[0056] The activation conditions for the raw carbon can be any conventional conditions, except for introducing an oxygen-containing gas that is different from the flowing gas. For example, the activation temperature can be 700~1000°C (preferably 800~1000°C, even more preferably 850~950°C), and the activation time can be any time that achieves the desired amount of benzene adsorption (the desired degree of activation).

[0057] As described above, in the manufacturing method of this embodiment, by utilizing an oxygen-containing gas different from that introduced by the flowing gas, a desired carbonaceous material with a specific range of benzene adsorption capacity, vitamin B12 adsorption capacity, and mesopore volume can be manufactured. Here, the raw material carbon is activated by water vapor or carbon dioxide in the flowing gas in an endothermic reaction, while the raw material carbon is activated by oxygen in the oxygen-containing gas in a rapid exothermic reaction. Therefore, the manufacturing method of this embodiment, which brings the oxygen-containing gas into contact with the raw material carbon during the flowing activation process, can reduce the external heat supply required to maintain the activation of the raw material carbon, which is also highly advantageous from the viewpoint of energy balance.

[0058] After the flowing gas 7 and the oxygen-containing gas 8 are used to activate the raw material carbon, they are discharged from the furnace through the exhaust port (exhaust gas 9 in Figure 2). Some or all of the exhaust gas can be recycled or heat exchanged to reuse the heat energy of the exhaust gas.

[0059] Figures 1 and 2 illustrate a fluidized bed furnace, which has one flowing gas inlet 1, one oxygen-containing gas inlet 2, and one exhaust port 3, respectively. However, Figures 1 and 2 are only schematic diagrams, and the fluidized bed furnace can be provided with multiple flowing gas inlets 1, oxygen-containing gas inlets 2, and exhaust ports 3. When multiple oxygen-containing gas inlets 2 are provided, they can be positioned at the same position (height) or different positions (heights) along the mainstream direction Z of the flowing gas.

[0060] When activated carbonaceous materials are processed using plant-based carbonaceous precursors such as coconut shells or mineral-based carbonaceous precursors containing impurities such as alkali metals, alkaline earth metals, and transition metals, they are cleaned to remove ash and chemicals. Therefore, in one embodiment, the manufacturing method of the present invention may include a step of cleaning the activated carbonaceous material. In this case, an inorganic acid or water is used for cleaning, and hydrochloric acid, which has high cleaning efficiency, is preferred. When cleaning (acid washing) the carbonaceous material with an inorganic acid such as hydrochloric acid, it is preferable to perform water washing or similar treatment after acid washing, followed by deacidification.

[0061] After cleaning, the obtained carbonaceous material is dried, and then crushed and sieved as needed to obtain carbonaceous material products.

[0062] [Water Purifier Filter] Water filters can be manufactured using carbonaceous materials. The following describes a preferred embodiment of a water filter.

[0063] In a preferred embodiment, the water purification filter comprises the carbonaceous material and fibrous binder of the present embodiment as described above.

[0064] Fibrous adhesives are not particularly limited in scope as long as they can be shaped by winding around carbonaceous materials through fibrosis; both synthetic and natural products can be widely used. Examples of such fibrous adhesives include: acrylic fibers, polyethylene fibers, polypropylene fibers, polyacrylonitrile fibers, cellulose fibers, nylon fibers, polyaramid fibers, and pulp. The fiber length of the fibrous adhesive is preferably 4 mm or less.

[0065] Two or more fibrous adhesives can be used in combination. A particularly good option is to use polyacrylonitrile fibers or pulp as an adhesive. This further increases the density and strength of the molded body and prevents performance degradation.

[0066] In a preferred embodiment, the water permeability of the fibrous binder, expressed as a CSF value, is approximately 10-150 mL. In this embodiment, the CSF value is determined according to the Canadian Standard Filtration Method, JIS P8121 "Test Method for Filtration of Pulp". Furthermore, the CSF value can be adjusted, for example, by fibrillating the fibrous binder. When the CSF value of the fibrous binder is less than 10 mL, water permeability is not achieved, the strength of the molded body decreases, and there is a risk of increased pressure loss. On the other hand, when the aforementioned CSF value is greater than 150 mL, the powdered activated carbon cannot be adequately retained, the strength of the molded body decreases, and the adsorption performance may deteriorate.

[0067] From the viewpoint of removal performance and formability of the substances to be removed, a water purification filter preferably contains 4 to 10 parts by mass, and more preferably 4.5 to 6 parts by mass, of a fibrous binder relative to 100 parts by mass of carbonaceous material. Therefore, in a preferred embodiment, the water purification filter comprises the carbonaceous material and the fibrous binder of this embodiment, wherein the CSF value of the fibrous binder is 10 to 150 mL, and 4 to 10 parts by mass of the fibrous binder are contained relative to 100 parts by mass of carbonaceous material. Furthermore, when the water purification filter includes other functional components described later, the term "relative to 100 parts by mass of carbonaceous material" in the filter composition can be interpreted and applied as "the sum of 100 parts by mass of carbonaceous material and other functional components".

[0068] Without impairing the effects of the present invention, water purification filters may contain other functional components. Examples of other functional components include lead adsorbents such as titanates and zeolite powders that can adsorb and remove dissolved lead, ion exchange resins or chelating resins, or various adsorbents containing silver ions and / or silver compounds to impart antibacterial properties.

[0069] Since the water purification filter of this embodiment contains the carbonaceous material of this embodiment, it can remove PFAS very effectively. There are no particular limitations on the water flow conditions, but in order to avoid excessive pressure loss, it can be implemented at a space velocity (SV) of 300~6500 / hr. The performance of the water purification filter can be confirmed by plotting the relationship between the removal rates calculated from the concentrations of the substances to be removed in the raw water and the permeate, and the ratio of the volume of water flowing out from the beginning of the water flow (L) to the volume of the water purification filter cartridge (mL).

[0070] Water purifier Water purifiers can be manufactured using carbonaceous materials or water purification filters. In a preferred embodiment, the water purifier includes the carbonaceous materials or water purification filters of this embodiment as described above.

[0071] In a preferred embodiment, the water purifier includes a water purification filter element, which is constructed using the carbonaceous material or water purification filter of this embodiment. For example, the carbonaceous material of this embodiment can be filled into the housing to form the water purification filter element, and the water purification filter of this embodiment can also be filled into the housing to form the water purification filter element. In addition to the carbonaceous material or water purification filter of this embodiment, the water purification filter element can also be combined with conventional non-woven filters, various adsorbent materials, mineral additive materials, ceramic filter materials, hollow fiber membranes, etc.

[0072] As mentioned above, this specification discloses various techniques, among which the main techniques are summarized below.

[0073] That is, the carbonaceous material of one aspect of the present invention is characterized by: a benzene adsorption capacity of 30-60%, a vitamin B12 adsorption capacity of greater than 50.0 mg / g, and a mesopore volume of 0.13-0.30 cm³ / g calculated by the BJH method from the nitrogen adsorption isotherm.

[0074] This structure provides carbonaceous materials with high PFAS (PFOS, PFOA, etc.) removal performance that can also be used in water purifiers.

[0075] Furthermore, among the aforementioned carbonaceous materials, the preferred specific surface area, calculated using the BET method based on the nitrogen adsorption isotherm, is 1200~2000 m² / g. It is believed that this configuration enables the high-level adsorption and removal performance required by water purifiers.

[0076] Furthermore, in the aforementioned carbonaceous materials, the average pore diameter calculated from the nitrogen adsorption isotherm is preferably 1.85~1.90 nm. Therefore, it is believed that PFAS can be removed more effectively.

[0077] Furthermore, in carbonaceous materials, the conductivity measured by powder resistance under a 12kN load is preferably 3~9S / cm. It is believed that this configuration enables the high-level adsorption and removal performance required for water purifiers.

[0078] Furthermore, the aforementioned carbonaceous material is preferably a plant-based carbonaceous precursor. Therefore, it is believed that it is easy to produce a carbonaceous material with excellent adsorption performance for substances to be removed as specified in the Consumer Goods Quality Labelling Act. Additionally, coconut shell is a preferred plant-based carbonaceous precursor, as it is believed that this can lead to a carbonaceous material that can more effectively remove PFAS.

[0079] In addition, under the following test conditions, the preferred bed volume of the carbonaceous material for removing fluorinated organic compounds is 12,000 or more. Test conditions: A stainless steel column with a diameter of 6.2 mm, a height of 25.4 mm, and an internal volume of 0.77 mL, filled with carbonaceous material, was used as the test water. Water (containing 1.2 ppm TOC) with a PFOA concentration of 50 ± 10 ppt and a PFOS concentration of 50 ± 10 ppt was used. The water was passed through in an upflow at a rate of 7.2 mL / min and a space velocity (SV) of 560 hr⁻¹. The water flow rate (bed volume) from the start of the flow to the breakthrough point when the removal rate was less than 80% was taken as the removal performance. The results showed that the aforementioned effect could be obtained more reliably.

[0080] Another aspect of the present invention relates to a method for manufacturing carbonaceous materials, characterized by: using a fluidized bed furnace; and introducing oxygen-containing gas into the fluidized bed furnace in a manner different from the flowing gas introduced from the furnace bed, such that the oxygen concentration in the total gas of the flowing gas and the oxygen-containing gas is 0.004 to 1% by volume. With this configuration, the excellent carbonaceous materials described above can be obtained.

[0081] Furthermore, in the aforementioned manufacturing method, the concentration of water vapor in the flowing gas introduced from the aforementioned furnace bed is preferably 10 to 40% by volume. It is believed that this can effectively activate the raw material carbon.

[0082] Furthermore, in the aforementioned manufacturing method, when viewed along the mainstream direction Z of the flowing gas, the fluidized bed has a gas dispersion section on its upstream side. When the upstream end position of the gas dispersion section in the aforementioned direction Z is set to 0 (m), the downstream end position to t1 (m), and the oxygen-containing gas introduction position to t2 (m), it is preferable to introduce the oxygen-containing gas in a manner that satisfies the relationship 0.5t1≤t2. Therefore, it is believed that the excellent carbonaceous material described above can be obtained more reliably.

[0083] Another aspect of the present invention provides a water purifier filter characterized by comprising: a carbonaceous material as described above and a fibrous binder; the fibrous binder having a CSF value of 10-150 mL; and containing 4-10 parts by weight of the fibrous binder relative to 100 parts by weight of the carbonaceous material. Furthermore, the present invention also comprises: a water purifier comprising the carbonaceous material as described above, a fluoride-containing organic compound removal material composed of the carbonaceous material as described above, and a water purifier comprising the aforementioned water purifier filter. [Example]

[0084] The present invention will now be described in more detail with reference to embodiments, but the present invention is not limited to the embodiments.

[0085] <Assessment Methods> The physical property values ​​in the examples were determined by the methods shown below.

[0086] [Determination of Benzene Adsorption Capacity] The carbonaceous materials prepared in the examples and comparative examples were dried in a constant-temperature desiccator at 115°C for 3 hours, and then allowed to cool to room temperature in a desiccator using silicone as a desiccant. Next, dry air containing benzene at a concentration of 1 / 10 of the saturation concentration was introduced into the carbonaceous materials in a constant-temperature bath at 20°C. The amount of benzene adsorbed (mass %) was calculated according to the following formula (1) from the mass of the carbonaceous materials at adsorption equilibrium and the mass of the carbonaceous materials before adsorption (i.e., the mass of the carbonaceous materials after drying and cooling). [Equation (1)] Benzene adsorption capacity (mass%) = [{(mass of sample after benzene adsorption) - (mass of sample before benzene adsorption)} / (mass of sample before benzene adsorption)] × 100

[0087] [Determination of Vitamin B12 Adsorption Capacity] The carbonaceous materials prepared in the examples and comparative examples were pulverized to achieve a cumulative 50% particle size (D50) of approximately 9-11 μm on a volume basis. After drying in a constant-temperature desiccator at 115°C for 3 hours, the pulverized carbonaceous materials were allowed to cool to room temperature in a desiccator using silicone as a desiccant. The particle size of the pulverized carbonaceous materials was determined by laser diffraction. Specifically, the carbonaceous material to be tested was placed in ion-exchanged water along with a surfactant, and ultrasonic vibration was applied to create a uniform dispersion. The dispersion was then measured using a Microtrac MT3200 manufactured by Microtrac Bell Inc. The surfactant used was "polyoxyethylene (10) octylphenyl ether" manufactured by Fujifilm and Koden Pharmaceutical Co., Ltd. The analytical conditions are as follows.

[0088] (Analysis conditions) Number of measurements: 1 Measurement time: 30 seconds Distribution display: volume Particle size classification: Standard calculation mode: MT3000 Solvent name: Water Upper limit of detection: 1408 μm, lower limit of detection: 0.265 μm Remaining ratio: 0.00 Pass rate: 0.00 Remaining ratio setting: Invalid Particle permeability: Through Particle refractive index: 1.81 Particle shape: Non-spherical Solvent refractive index: 1.333, DV value: 0.0100~0.0500 Transmittance (TR): 0.750~0.920 Flow rate: 50%

[0089] 100 mL of an aqueous solution of vitamin B12 (C 63H 88N 14O 14PCo: molecular weight 1355.4) adjusted to approximately 300 ppm was added to 0.050 g of the obtained carbonaceous material, and the mixture was stirred at 25 °C for 24 hours. Then, the absorbance of the filtered carbonaceous material solution was measured at 330 nm with approximately 300 ppm of vitamin B12 in test water for adsorption experiments, and the concentration of vitamin B12 was calculated based on a pre-prepared calibration curve. The amount of vitamin B12 adsorbed per 1 g of carbonaceous material was calculated from the obtained vitamin B12 concentration using the following formula (2). [Equation (2)] Vitamin B12 adsorption capacity (mg / g) = {Vitamin B12 concentration before adsorption (ppm) - Vitamin B12 concentration after adsorption treatment (ppm)} × 0.1 / Mass of carbonaceous material (g)

[0090] Determination of Nitrogen Adsorption Isotherms Using the BELSORP-mini manufactured by Microtrac BEL Co., Ltd., carbonaceous materials were heated at 300°C for 3 hours under a nitrogen flow (nitrogen flow rate: 50 mL / min), and the nitrogen adsorption isotherm of the carbonaceous materials at 77 K was measured.

[0091] [Determination of specific surface area] The specific surface area was calculated from the nitrogen adsorption isotherm obtained by the aforementioned method using the BET method with multi-point analysis, and from the straight line in the region of relative pressure P / P0 = 0.01 to 0.1.

[0092] [Determination of Total Pore Volume / Average Pore Diameter] The nitrogen adsorption amount at a relative pressure P / P0 = 0.99 in the nitrogen adsorption isotherm obtained by the aforementioned method is used to calculate the total pore volume by the Gurvish method. Regarding the average pore diameter, it is calculated from the total pore volume and the specific surface area obtained by the BET method described above according to the following formula (3). [Formula (3)] Average pore diameter (nm) = total pore volume (cm3 / g) / specific surface area (m2 / g) × 4000

[0093] [Measurement of the mesopore volume using the BJH method] The BJH method is applied to the nitrogen adsorption isotherm obtained by the aforementioned method to calculate the pore volume of the mesopores. In addition, in the BJH method analysis, the reference curve 'NGCB - BEL.t' provided by Microtrack BEL Co., Ltd. is used.

[0094] [Measurement of conductivity] The conductivity of the carbonaceous material is measured using a powder resistivity measurement device (MCP - PD51 manufactured by Mitsubishi Chemical Analytical Technology Co., Ltd.). Since the particle size of the measurement sample has a great influence on the measurement of conductivity, it is pulverized so that the 50% particle size (D50) of the volume - based cumulative distribution of the carbonaceous material is about 5 - 8 μm. When a load of 12 kN is applied, the conductivity of the carbonaceous material particles is measured. In addition, the particle size of the pulverized carbonaceous material is measured by the laser diffraction measurement method. The measurement steps / analysis conditions of the particle size of the carbonaceous material are as described in the previous [Measurement of vitamin B12 adsorption amount].

[0095] <Example 1> The coconut shell carbon obtained by carbonizing coconut shells produced in the Philippines is adjusted in particle size from 30 mesh (0.5 mm) to 60 mesh (0.25 mm). 1 kg of this coconut shell carbon is put into a fluidized activation furnace heated to 900 °C, and a fluid gas containing 15 vol% of water vapor and 11 vol% of carbon dioxide is introduced from the furnace bed at a rate of 50 L / min, and a gas containing 0.5 vol% of oxygen and 99.5 vol% of oxygen - containing gas is introduced from the side of the furnace at a rate of 5 L / min for activation treatment until the benzene adsorption amount reaches about 53.3 wt% (the oxygen concentration in the total gas introduced into the fluidized activation furnace is about 0.045 vol%). In the fluidized activation furnace, a furnace having a gas dispersion layer on the upstream side in the furnace when observed in the main flow direction Z of the fluid gas is used. Moreover, the introduction position t2 of the oxygen - containing gas in the direction Z and the downstream end t1 of the gas dispersion layer satisfy the relationship t1 < t2. That is, the oxygen - containing gas is introduced into the fluidized bed part of the fluidized activation furnace.

[0096] The activated carbon was washed with dilute hydrochloric acid, then thoroughly washed with deion-exchanged water and dried to remove residual hydrochloric acid, thus obtaining carbonaceous material. The processing conditions and the physical properties of the obtained carbonaceous material are shown in Table 1.

[0097] <Example 2> Except for changing the concentration of oxygen-containing gas introduced during activation treatment to 1.0% by volume of oxygen and 99.0% by volume of nitrogen, and performing activation treatment until the benzene adsorption amount reached 45.7% by weight, the same operation as in Example 1 was performed to obtain carbonaceous material. The processing conditions and the physical properties of the obtained carbonaceous material are shown in Table 1.

[0098] <Example 3> Except for changing the concentration of oxygen-containing gas introduced during activation treatment to 3.0% by volume of oxygen and 97.0% by volume of nitrogen, and performing activation treatment until the benzene adsorption amount reached 52.6% by weight, the same operation as in Example 1 was performed to obtain carbonaceous material. The processing conditions and the physical properties of the obtained carbonaceous material are shown in Table 1.

[0099] <Comparative Example 1> Except for the activation treatment until the benzene adsorption amount reached 34.4% by weight, the same operation as in Example 1 was performed to obtain the carbonaceous material. The processing conditions and the physical properties of the obtained carbonaceous material are shown in Table 1.

[0100] <Comparative Example 2> Coconut shell carbon obtained by carbonizing coconut shells from the Philippines was adjusted in particle size from 30 mesh (0.5 mm) to 60 mesh (0.25 mm). 5 g of this coconut shell carbon was placed in a horizontal electric heating tube furnace equipped with a quartz tube with an inner diameter of 42 mm. Water vapor was introduced into the furnace by bubbling water at a rate of 1 L / min with 0.5% oxygen and 99.5% nitrogen, and the furnace was heated to 900°C for activation treatment until the benzene adsorption reached 32.3% by weight. The resulting activated carbon was washed with dilute hydrochloric acid, then thoroughly washed with deionized water and dried to remove residual hydrochloric acid, thus obtaining carbonaceous material. The processing conditions and the physical properties of the obtained carbonaceous material are shown in Table 1.

[0101] <Comparative Example 3> Except for changing the concentration of oxygen-containing gas introduced during activation treatment to 0.1% by weight of oxygen and 99.9% by weight of nitrogen, and performing activation treatment until the benzene adsorption amount reached 46.6% by weight, the same operation as in Example 1 was performed to obtain carbonaceous material. The processing conditions and the physical properties of the obtained carbonaceous material are shown in Table 1.

[0102] <Comparative Example 4> Except for changing the concentration of oxygen-containing gas introduced during activation treatment to 10.0% by volume of oxygen and 90.0% by volume of nitrogen, and continuing activation treatment until the benzene adsorption amount reached 53.0% by weight, the same operation as in Example 1 was performed to obtain carbonaceous material. The processing conditions and the physical properties of the obtained carbonaceous material are shown in Table 1.

[0103] <Comparative Example 5> Coconut shell carbon obtained by carbonizing coconut shells from the Philippines was adjusted in particle size from 10 mesh (1.7 mm) to 30 mesh (0.5 mm). One kg of this coconut shell carbon was placed in a rotary kiln heated to 900°C, and activated by introducing an active gas of 15% by volume water vapor and 11% by volume carbon dioxide at a rate of 10 L / min, along with an additional gas of 0.5% by volume oxygen and 99.5% by volume nitrogen at a rate of 1 L / min, until the benzene adsorption reached approximately 62.3% by weight.

[0104] The activated carbon was washed with dilute hydrochloric acid, then thoroughly washed with deion-exchanged water and dried to remove residual hydrochloric acid, thus obtaining carbonaceous material. The processing conditions and the physical properties of the obtained carbonaceous material are shown in Table 1.

[0105] <Comparative Example 6> 10g of Evoqua granular activated carbon (AquaCarb1240C) was impregnated in an aqueous solution of 0.28g calcium chloride and 0.96g citric acid dissolved in 18.8mL of ion-exchanged water and allowed to stand for 12 hours. Then, after filtration to remove the aqueous solution, approximately half of the resulting calcium / citric acid impregnated activated carbon was placed in a wet alumina boat and then into a horizontal electric heating tube furnace equipped with a quartz tube with an inner diameter of 42mm. Water vapor was introduced into the furnace by bubbling water with a gas concentration of 0.5% oxygen and 99.5% nitrogen at a rate of 1 L / min, and the furnace was heated to 900°C for activation treatment until the benzene adsorption reached 56.0% by weight.

[0106] The activated carbon was washed with dilute hydrochloric acid, then thoroughly washed with deion-exchanged water and dried to remove residual hydrochloric acid, thus obtaining carbonaceous material. The processing conditions and the physical properties of the obtained carbonaceous material are shown in Table 1.

[0107] <Comparative Example 7> Coconut shell carbon obtained by carbonizing coconut shells from the Philippines was adjusted in particle size from 10 mesh (1.7 mm) to 30 mesh (0.5 mm). One kg of this coconut shell carbon was placed in a rotary kiln heated to 900°C. An active gas consisting of 15% by volume water vapor and 11% by volume carbon dioxide was introduced at a rate of 10 L / min, along with an additional gas consisting of 0.5% by volume oxygen and 99.5% by volume nitrogen at a rate of 1 L / min, to activate the carbon until the benzene adsorption reached 31.0% by weight. The activated carbon was washed with dilute hydrochloric acid, then thoroughly washed with deion-exchanged water and dried to remove residual hydrochloric acid, thus obtaining carbonaceous material. The processing conditions and the physical properties of the obtained carbonaceous material are shown in Table 1.

[0108] [Table 1] Activation furnace During activation granularity oxygen-containing gas oxygen concentration In total gas oxygen concentration Fill density benzene adsorption capacity Vitamin B12 Adsorption capacity Medium pore volume (BJH method) Specific surface area Average pore diameter Powder conductivity Mesh vol.% vol.% g / mL % mg / g cm 3 / g m 2 / g nm S / cm Example 1 Fluidized bed furnace 30-60 0.5 0.045 0.405 53.3 183.0 0.149 1710 1.85 8.0 Example 2 Fluidized bed furnace 30-60 1 0.091 0.440 45.7 405.0 0.131 1538 1.84 9.5 Example 3 Fluidized bed furnace 30-60 3 0.27 0.410 52.6 205.0 0.164 1669 1.88 7.3 Comparative Example 1 Fluidized bed furnace 30-60 0.5 0.045 0.480 34.4 21.0 0.079 1132 1.77 7.8 Comparative Example 2 Tubular furnace 30-60 0.5 0.5 0.473 32.3 2.3 0.042 1210 1.75 10.3 Comparative Example 3 Fluidized bed furnace 30-60 0.1 0.0091 0.444 46.6 38.3 0.147 1571 1.88 6.5 Comparative Example 4 Fluidized bed furnace 30-60 10 0.91 0.412 53.0 305.0 0.320 1640 1.86 5.6 Comparative Example 5 rotary kiln 10-30 0.5 0.045 0.386 62.3 52.0 0.256 1815 1.85 12.1 Comparative Example 6 Tubular furnace 12-40 0.5 0.5 0.392 56.0 300.0 0.420 1680 1.96 8.2 Comparative Example 7 rotary kiln 10-30 0.5 0.045 0.474 31.0 2.0 0.036 1174 1.71 10.9

[0109] [Assessment of the filtration capacity of carbonaceous materials] The carbonaceous materials prepared in Examples 1-3 and Comparative Examples 1-7 were filled into stainless steel columns with a diameter of 6.2 mm, a height of 25.4 mm, and an internal volume of 0.77 mL. PFOA+PFOS filtration capacity tests were conducted according to the procedure shown below, as specified in ASTM D6586-03 (2014), "The Prediction of Contaminant Adsorption On GAC In Aqueous Systems Using Rapid Small-Scale Color Tests". Furthermore, the carbonaceous material used in this test was prepared with a particle size adjusted to 120 mesh (125 μm) to 200 mesh (74 μm) before the test.

[0110] [PFOA+PFOS filtration capacity test] Water with a PFOA concentration of 50±10 ppt and a PFOS concentration of 50±10 ppt (containing 1.2 ppm TOC) was used as the test water. The water was passed through an upflow at a rate of 7.2 mL / min and a space velocity (SV) of 560 hr⁻¹. The point where the removal rate was less than 80% was considered the breakthrough point for the filtration capacity test. In this test, a filtration capacity of 12000 (bed volume) or higher was considered passing. The water flow test conditions and results are shown in Table 2 and Figure 3.

[0111] [Table 2] Particle size during water flow test Fill volume Space velocity (SV) PFAS removal performance Mesh mL hr -1 BV Example 1 120-200 0.77 560 24000 Actual example 2 120-200 0.77 560 17500 Actual example 3 120-200 0.77 560 20000 Comparative Example 1 120-200 0.77 560 9500 Comparative Example 2 120-200 0.77 560 0 Comparative Example 3 120-200 0.77 560 8000 Comparative Example 4 120-200 0.77 560 6500 Comparative Example 5 120-200 0.77 560 7000 Comparative Example 6 120-200 0.77 560 10000 Comparative Example 7 120-200 0.77 560 0

[0112] (Exploration) As shown in Table 2 and Figure 3, the carbonaceous materials related to the embodiments of the present invention can all be used in water purifiers, confirming their excellent PFAS removal performance. In particular, Examples 1 and 3, with an average pore diameter of 1.85 nm or more, were found to exhibit even better removal capabilities.

[0113] On the other hand, Comparative Examples 1-7, in which at least one of the benzene adsorption amount, vitamin B12 adsorption amount, and mesopore volume did not meet the requirements of the present invention, could not sufficiently remove PFAS. In particular, in Comparative Examples 2 and 7, in which neither the vitamin B12 adsorption amount nor the mesopore volume met the requirements of the present invention, the removal rate was significantly lower than 80% from the start of water flow, indicating that the PFAS removal capacity was 0.

[0114] This application is based on Japanese Patent Application No. 2020-177898, filed on October 23, 2020, the contents of which are incorporated herein by reference.

[0115] To illustrate the invention, it has been adequately and sufficiently described above through specific embodiments. However, those skilled in the art will understand that modifications and / or improvements to the aforementioned embodiments are readily apparent. Therefore, unless a modification or improvement implemented by those skilled in the art deviates from the scope of the claims stated in the patent application, such modification or improvement shall be construed as being included within the scope of the claims. [Potential for industrial application]

[0116] The carbonaceous material of this invention is particularly useful for removing fluoride-containing organic compounds. Therefore, this invention has broad industrial applicability in water purification technologies such as water filters and water purifiers.

[0117] 1: Flowing gas inlet 2: Oxygen-containing gas inlet 3: Exhaust port 4: Gas dispersion layer 5: Raw material carbon 6: Raw material carbon (during flow activation) 7: Flowing gas 8: Oxygen-containing gas 9: Expel gas 10: Gas Dispersion Section 20: Fluidized Bed Section 100: Fluidized bed furnace (fluidized activation furnace) 0: Upstream position of the gas dispersion section t1: Downstream position of the gas dispersion section t2: Location for introducing oxygen-containing gas Z: Mainstream Direction

Claims

1. A carbonaceous material having a benzene adsorption capacity of 30-60% by mass, a vitamin B12 adsorption capacity greater than 50.0 mg / g, and a mesopore volume of 0.13-0.30 cm³ / g calculated from the nitrogen adsorption isotherm using the BJH method.

2. The carbonaceous material as requested in item 1, wherein the specific surface area calculated by the BET method from the nitrogen adsorption isotherm is 1200~2000 m2 / g.

3. The carbonaceous material as claimed in item 1 or 2, wherein the average pore diameter calculated from the nitrogen adsorption isotherm is 1.85~1.90 nm.

4. Carbonaceous materials as requested in item 1 or 2, wherein, The conductivity measured by the powder resistance method under a 12kN load is 3~9S / cm.

5. The carbonaceous material in claim 1 or 2 is derived from plant-based carbonaceous precursors.

6. The carbonaceous material as requested in item 5, wherein the carbonaceous precursor of the plant-based material is coconut shell.

7. For carbonaceous materials as requested in item 1 or 2, the removal performance of fluorinated organic compounds obtained under the following test conditions is 12000 or higher in bed volume. Test conditions: A stainless steel column with a diameter of 6.2 mm, a height of 25.4 mm, and an internal volume of 0.77 mL is filled with carbonaceous material. Water (containing 1.2 ppm TOC) adjusted to a PFOA concentration of 50 ± 10 ppt and a PFOS concentration of 50 ± 10 ppt is used as test water. The water is passed through in an upflow at a rate of 7.2 mL / min and a space velocity (SV) of 560 hr⁻¹. The water flow rate (bed volume) from the start of the flow to the breakpoint when the removal rate is less than 80% is taken as the removal performance.

8. A method for manufacturing carbonaceous material as claimed in any one of claims 1 to 7, wherein the method for manufacturing carbonaceous material using a fluidized bed furnace is different from the method of introducing flowing gas from the hearth, wherein the oxygen-containing gas is introduced into the fluidized bed furnace in such a way that the oxygen concentration in the total gas of the flowing gas and the oxygen-containing gas is 0.004 to 1% by volume.

9. The method for manufacturing carbonaceous materials as claimed in claim 8, wherein the concentration of water vapor in the flowing gas introduced from the furnace bed is 10 to 40% by volume.

10. A method for manufacturing carbonaceous materials as claimed in claim 8 or 9, wherein when viewed along the mainstream direction Z of the flowing gas, the fluidizing furnace has a gas dispersion section on the upstream side of the fluidizing furnace, and when the upstream end position of the gas dispersion section in the Z direction is set to 0 (m), the downstream end position is set to t1 (m), and the oxygen-containing gas is introduced at the position of t2 (m), the oxygen-containing gas is introduced in a manner that satisfies the relationship of 0.5t1t2.

11. A water filter comprising a carbonaceous material as claimed in any one of claims 1 to 7 and a fibrous binder, wherein the fibrous binder has a CSF value of 10 to 150 mL and contains 4 to 10 parts by weight of the fibrous binder relative to 100 parts by weight of the carbonaceous material.

12. A water purifier comprising a carbonaceous material as claimed in any one of claims 1 to 7.

13. A water purifier comprising a water filter as claimed in claim 11.

14. A material for removing fluorinated organic compounds, comprising a carbonaceous material of any one of claims 1 to 7.

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