Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
  • B01J20/20—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising free carbon; comprising carbon obtained by carbonising processes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
  • B01J20/30—Processes for preparing, regenerating, or reactivating
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B32/00—Carbon; Compounds thereof
  • C01B32/30—Active carbon
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B32/00—Carbon; Compounds thereof
  • C01B32/30—Active carbon
  • C01B32/354—After-treatment
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/28—Treatment of water, waste water, or sewage by sorption

Definitions

• Activated carbon has excellent adsorption capabilities for various pollutants, odorous and harmful substances, and has traditionally been used as an adsorbent in a variety of fields, both domestically and industrially.
• a demand for delicious water that is free of chlorine odors, moldy odors, etc. and various water purifiers using activated carbon have been proposed to meet this demand.
• safety and health issues related to water quality such as trihalomethanes, environmental hormones, and heavy metals.
• activated carbon alone is insufficient, and it has become necessary to use it in conjunction with an adsorbent with unique adsorption capabilities.
• activated carbon with introduced functional groups is generally known as activated carbon with improved metal removal capabilities.
• Patent Document 1 describes activated carbon that has been given metal removal capabilities by introducing a predetermined amount of acidic functional groups such as carboxylic acid.
• Patent Document 2 describes activated carbon that has improved metal removal performance through a synergistic effect by setting the specific surface area, the total amount of acidic functional groups, and the ratio of the total amount of hydroxyl groups and carboxyl groups to the total amount of acidic functional groups within predetermined ranges.
• the present invention aims to solve the above-mentioned problems and provide activated carbon with excellent metal removal performance.
• the total amount of surface functional groups is 2.50 mmol/g or more,
• the amount of functional groups derived from a carboxylate metal salt is 0.30 mmol/g or more, and Activated carbon having a BET specific surface area of 300 m 2 /g or more.
• Item 2 The activated carbon according to Item 1, wherein the metal constituting the functional group derived from the metal carboxylate is at least one metal selected from the group consisting of alkali metals and alkaline earth metals.
• Item 3 The activated carbon according to Item 1 or 2, wherein the metal constituting the functional group derived from the metal carboxylate is at least one metal selected from the group consisting of sodium, potassium, calcium, and magnesium.
• Item 4 The activated carbon according to any one of Items 1 to 3, wherein the amount of functional groups derived from the metal carboxylate is 10 mol % or more, with the total number of all functional groups being 100 mol %.
• Item 5 The activated carbon described in any one of Items 1 to 4, which is granular activated carbon.
• Item 6 The activated carbon described in any one of Items 1 to 5, having a median diameter of 1 to 130 ⁇ m.
• Item 7 The activated carbon according to any one of Items 1 to 6, wherein the activated carbon generates 200 ⁇ mol/g or more of CO 2 between 100 and 400°C in temperature programmed desorption spectrometry (TPD analysis).
• Item 8 The activated carbon described in any one of Items 1 to 7, having an oxygen content of 10% by mass or more.
• Item 9 The activated carbon described in any one of Items 1 to 8, having a free chlorine adsorption capacity of 10 to 100 L/g as measured in accordance with the analytical method described in JIS S3201.
• Item 10 The activated carbon described in any one of Items 1 to 9, which is a chemically activated activated carbon.
• Item 11 The activated carbon described in any one of items 1 to 10, having an average pore diameter of 2.30 nm or less.
• Item 12 The activated carbon according to any one of Items 1 to 11, wherein the decomposition onset temperature measured in thermogravimetric analysis under atmospheric conditions at a temperature rise rate of 10°C/min is 850°C or less.
• Item 13 A metal adsorbent containing the activated carbon described in any one of items 1 to 12.
• Item 14 The metal adsorbent according to Item 13, which adsorbs metal ions belonging to Groups 1 to 16 of the periodic table.
• Item 15 A filter medium for a water purifier containing the metal adsorbent described in Item 13 or 14.
• Item 16 A water purifier filter containing the water purifier filter material described in Item 15.
• Item 17 A water purifier cartridge equipped with the water purifier filter described in Item 16.
• Item 18 A water purifier equipped with the water purifier cartridge described in Item 17.
• Item 19 A system kitchen equipped with the water purifier cartridge described in Item 18.
• Item 20 A method for producing activated carbon according to any one of Items 1 to 12, A production method comprising: (1) a step of oxidizing raw activated carbon; (2) a step of washing the oxidized activated carbon obtained in the step (1) with a basic solution and adjusting the pH of the filtrate after washing to 4 or higher; and (3) a step of washing the activated carbon obtained in the step (2) that has been washed with the basic solution.
• the activated carbon of the present invention can have excellent metal removal performance.
• the activated carbon of the present invention has a total surface functional group amount of 2.50 mmol/g or more, a functional group amount derived from a metal carboxylate of 0.30 mmol/g or more, and a BET specific surface area of 300 m 2 /g or more.
• activated carbon can be used as long as they meet the above conditions.
• Examples include plant-based or fossil-based raw materials such as wood, wood flour (sawdust, etc.), bamboo, fruit shells (coconut shells, etc.), pulp manufacturing by-products, bagasse, blackstrap molasses, graphite, coal (peat, lignite, brown coal, bituminous coal, etc.), anthracite, coal pitch, petroleum (especially petroleum distillation residue components), petroleum pitch, coke, and coal tar; various synthetic resins such as phenolic resin, polyvinyl chloride resin, vinyl acetate resin, melamine resin, urea resin, resorcinol resin, celluloid, epoxy resin, polyurethane resin, polyester resin, acrylic resin (polyacrylonitrile (PAN), etc.), and polyamide resin; synthetic rubbers such as polybutylene, polybutadiene, and polychloroprene; polysaccharides such as cellulose and regenerated
• plant-based activated carbon is preferred from the viewpoints of easily improving metal (particularly lead) removal performance and preventing deterioration of the activated carbon's pore structure, with coconut shell activated carbon, sawdust activated carbon, coal-based activated carbon, phenol-based activated carbon, polyacrylonitrile (PAN)-based activated carbon, cellulose-based activated carbon, etc. being more preferred, and coconut shell activated carbon being even more preferred.
• These activated carbons can be used alone or in combination of two or more types.
• Activated carbon can be obtained by carbonizing or infusibilizing these raw materials as needed, followed by an activation treatment.
• carbonization method infusibilization method, or activation treatment method, and conventional methods can be used.
• activation treatment can be performed using a gas activation method (gas-activated activated carbon), in which the carbon raw material (or its carbonized or infusibilized form) is heat-treated in an activation gas (water vapor, carbon dioxide, etc.) at approximately 500-1000°C; or a chemical activation method (chemically activated activated carbon), in which the carbon raw material (or its carbonized or infusibilized form) is mixed with an activator (phosphoric acid, zinc chloride, potassium hydroxide, sodium hydroxide, etc.) and heat-treated at approximately 300-800°C.
• gas activation method gas-activated activated carbon
• an activation gas water vapor, carbon dioxide, etc.
• an activator phosphoric acid, zinc chloride, potassium hydroxide, sodium hydroxide, etc.
• the activated carbon of the present invention can be obtained by subjecting these activated carbons (raw carbons) to the treatment described below in the manufacturing method.
• Activated carbon typically has acidic groups present on its surface.
• the type of acidic group on the surface of activated carbon varies depending on the activated carbon, but the activated carbon of the present invention has a total surface functional group amount (particularly, a total surface acidic functional group amount) of 2.50 mmol/g or more, preferably 2.70 to 9.00 mmol/g, and more preferably 2.80 to 8.00 mmol/g. If the total surface functional group amount (particularly, a total surface acidic functional group amount) is less than 2.50 mmol/g, it will be difficult to adsorb metals (particularly lead) and will have poor metal (particularly lead) removal performance.
• the total surface functional group amount (particularly, a total surface acidic functional group amount) of the activated carbon of the present invention is measured by acid-base neutralization titration (Boehm method).
• the types of acidic groups on the surface of activated carbon vary depending on the activated carbon.
• the metal removal performance of the activated carbon is improved by replacing the hydrogen ions of the carboxylic acids in the activated carbon with metal ions. Therefore, the amount of functional groups derived from metal carboxylates is 0.30 mmol/g or more, preferably 0.35 to 5.00 mmol/g, more preferably 0.45 to 4.00 mmol/g, and particularly preferably 0.60 to 3.50 mmol/g. If the amount of functional groups derived from metal carboxylates is less than 0.30 mmol/g, the adsorption of metals (especially lead) will be difficult, resulting in inferior metal (especially lead) removal performance.
• the amount of acidic functional groups on the surface of activated carbon is usually determined by acid-base neutralization titration (Boehm method), which can determine the amount of quinone groups, carboxyl groups, lactone groups, phenolic hydroxyl groups, etc. present on the surface.
• This acid-base neutralization titration method involves adding various alkalis to activated carbon to cause a reaction, and then back-titrating the alkali concentration after the reaction with an acid to quantify the amount of acidic functional groups present on the surface of the activated carbon.
• the amount of functional groups derived from metal carboxylates is calculated from the difference between the amount of carboxylic acid determined by titration for activated carbon after washing with an alkaline aqueous solution and the amount of carboxylic acid determined by titration for activated carbon before washing with an alkaline aqueous solution.
• the median diameter of the activated carbon of the present invention is not particularly limited, but from the viewpoints of easily improving metal (particularly lead) removal performance and preventing deterioration of the activated carbon's pore structure, it is preferably 1 to 130 ⁇ m, more preferably 5 to 100 ⁇ m, and even more preferably 10 to 75 ⁇ m.
• the median diameter of the activated carbon is calculated from the particle size distribution obtained by laser diffraction/scattering method.
• the amount of CO 2 generated between 100 and 400°C depends on the functional group derived from the metal carboxylate imparted to the activated carbon. From the viewpoints of easily improving the metal (particularly lead) removal performance of the activated carbon and preventing deterioration of the pore structure of the activated carbon, the amount of CO 2 generated between 100 and 400°C in temperature programmed desorption spectroscopy (TPD analysis) is preferably 200 ⁇ mol/g or more, more preferably 300 to 4000 ⁇ mol/g, even more preferably 500 to 3000 ⁇ mol/g, and particularly preferably 1000 to 3000 ⁇ mol/g.
• TPD analysis is measured using a mass spectrometer.
• the oxygen content of the activated carbon of the present invention is not particularly limited, but from the standpoint of easily improving metal (particularly lead) removal performance and preventing deterioration of the activated carbon's pore structure, it is preferably 10% by mass or more, more preferably 11 to 25% by mass, and even more preferably 12 to 20% by mass, of the total amount of activated carbon (100% by mass).
• the oxygen content of the activated carbon is measured using energy dispersive X-ray spectroscopy.
• the amount of free chlorine adsorbed by the activated carbon of the present invention is not particularly limited, but from the viewpoints of easily improving metal (particularly lead) removal performance and preventing deterioration of the activated carbon's pore structure, it is preferably 10 to 100 L/g, more preferably 20 to 80 L/g, and even more preferably 40 to 60 L/g.
• the amount of free chlorine adsorbed by activated carbon is measured in accordance with the analytical method described in JIS S3201.
• the average pore diameter of the activated carbon of the present invention is not particularly limited, but from the viewpoint of easily improving metal (particularly lead) removal performance and preventing deterioration of the activated carbon's pore structure, it is preferably 2.30 nm or less, more preferably 1.60 to 2.20 nm, and even more preferably 1.70 to 2.10 nm.
• the average pore diameter of the activated carbon is measured by the nitrogen adsorption method.
• the sites where functional groups are introduced are edge sites, so it is preferable to select activated carbon with many edge sites and a well-developed pore structure.
• the decomposition onset temperature measured in thermogravimetric analysis (TGA) in air at a temperature rise rate of 10°C/min is preferably 850°C or lower, more preferably 300 to 800°C, and even more preferably 400 to 700°C.
• the method for producing the activated carbon of the present invention is not particularly limited, but may be, for example,
• the activated carbon can be produced by a method comprising: (1) a step of oxidizing raw activated carbon; (2) a step of washing the oxidized activated carbon obtained in the step (1) with a basic solution and adjusting the pH of the filtrate after washing to 4 or higher; and (3) a step of washing the activated carbon obtained in the step (2) that has been washed with the basic solution.
• the oxidation treatment that can be used in step (1) is not particularly limited, and oxidizing agents such as nitric acid, sulfuric acid, hydrogen peroxide, ammonium peroxydisulfide, sodium peroxodisulfate, and ozone can be used. Alternatively, heat treatment in air under an oxygen gas atmosphere or oxidation treatment using oxygen plasma and ultraviolet rays can be performed. These oxidation treatments can be performed alone or in combination of two or more. In particular, when hydrogen peroxide is used as the oxidizing agent, it is preferable to use it in combination with nitric acid, sulfuric acid, ammonium peroxydisulfide, sodium peroxodisulfate, etc. Among these, from the viewpoint of mass production, it is preferable to use an oxidizing agent.
• oxidizing agents such as nitric acid, sulfuric acid, hydrogen peroxide, ammonium peroxydisulfide, sodium peroxodisulfate, etc.
• the amount of oxidizing agent used is preferably 5 to 50 parts by mass, and more preferably 10 to 30 parts by mass, per 100 parts by mass of activated carbon, from the viewpoints of making it easier to increase the amount of functional groups derived from the metal carboxylate, making it less likely to reduce the specific surface area, and making it less likely to cause deterioration of the pore structure.
• the reaction temperature in step (1) is not particularly limited and can be adjusted appropriately depending on the oxidizing power of the oxidizing agent. However, from the viewpoints of easily increasing the amount of functional groups derived from the metal carboxylate, minimizing a decrease in the specific surface area, and minimizing deterioration of the pore structure, a temperature of 50 to 100°C is preferred, and 70 to 90°C is more preferred.
• the reaction temperature in step (1) is not particularly limited, and can be set to a time sufficient to sufficiently oxidize the raw material activated carbon and increase the total amount of surface functional groups (particularly the total amount of surface acidic functional groups), but can be, for example, 10 minutes to 6 hours, preferably 30 minutes to 3 hours.
• the degree of washing with the basic solution should be adjusted so that the pH of the filtrate after washing is 4 or higher, preferably 5 to 10, and more preferably 6 to 9. If the pH of the filtrate after washing is less than 3, the amount of functional groups derived from the metal carboxylate will be insufficient, resulting in poor metal (particularly lead) removal performance.
• Washing with water can be carried out by a conventional method, which can remove the oxidizing agent and basic solution remaining in the pores, and the products formed by the reaction between the oxidizing agent and the basic solution, as well as metals contained in the activated carbon and foreign matter attached to the surface.
• the activated carbon of the present invention can be obtained by drying it using conventional methods.
• the activated carbon of the present invention is particularly useful as a metal adsorbent because of its excellent metal removal performance, as described above.
• the metals that can be removed by the activated carbon of the present invention are not particularly limited, but examples include metal ions belonging to Groups 1 to 16 of the periodic table, such as lead, mercury, cadmium, copper, arsenic, zinc, selenium, nickel, manganese, chromium, iron, barium, and aluminum, preferably metal ions belonging to Groups 6 to 16 of the periodic table, and preferably metal ions belonging to Groups 10 to 15 of the periodic table.
• the adsorbent of the present invention is useful as an adsorbent for metals such as lead, and can therefore be used as a filter medium for water purifiers.
• the activated carbon of the present invention described above can be filled into a cartridge case as is, or as a filter-like water purifier filter, or the activated carbon of the present invention can be added to a desired binder and molded to obtain the water purifier cartridge of the present invention. Either dry molding or wet molding can be used as a molding method for producing the water purifier cartridge of the present invention.
• the composition containing the activated carbon of the present invention and a thermoplastic resin be molded into a hollow cylindrical or disc shape. More specifically, it is preferable that the composition containing the activated carbon of the present invention and a thermoplastic resin be placed in a mold made of aluminum or the like as needed, and heated to mold into a hollow cylindrical or disc shape.
• thermoplastic resins include, for example, polyethylene, polypropylene, polystyrene, ethylene-vinyl acetate copolymer, acrylonitrile-butadiene-styrene copolymer resin, polyethylene terephthalate, polybutylene terephthalate, ethylene-acrylic resin, polymethyl methacrylate, nylon, mesophase pitch, and hydrophilic resins (e.g., polyvinyl alcohol resin, ethylene-vinyl alcohol resin, etc.).
• the amount of thermoplastic resin is preferably 5 to 20 parts by mass, and more preferably 8 to 18 parts by mass, per 100 parts by mass of the activated carbon of the present invention.
• the composition containing the activated carbon of the present invention and the fibrous binder be molded into a hollow cylindrical or disc shape. More specifically, it is preferable that the composition containing the activated carbon of the present invention and the fibrous binder be dispersed in water to prepare a slurry, and then molded into a hollow cylindrical or disc shape while suctioning the slurry as needed.
• the fibrous binder is not particularly limited, as long as it can be used to entangle and shape the fibrous activated carbon and powdered activated carbon through fibrillation, and a wide range of materials, both synthetic and natural, can be used.
• fibrous binders include acrylic fibers, polyethylene fibers, polypropylene fibers, polyacrylonitrile fibers, cellulose fibers, nylon fibers, and aramid fibers.
• an average fiber length of 0.5 to 4 mm is preferred, and 0.7 to 2 mm is more preferred.
• the amount of fibrous binder contained is preferably 2 to 15 parts by mass, and more preferably 5 to 10 parts by mass, per 100 parts by mass of the activated carbon for a water purifier of the present invention.
• the phosphoric acid-activated carbon used was phosphoric acid-activated activated carbon (manufactured by Jacobi Carbons; BET specific surface area: 2445 m 2 /g; pore diameter: 2.5 nm).
• the coconut shell activated carbon used was coconut shell activated carbon (manufactured by Jacobi Carbons; steam-activated; BET specific surface area: 1093 m 2 /g; pore diameter: 1.7 nm), classified coconut shell activated carbon, or coconut shell activated carbon pulverized with a roll mill.
• the zinc chloride-activated activated carbon used was commercially available zinc chloride-activated activated carbon (Carborafine, manufactured by Osaka Gas Chemicals Co., Ltd.; BET specific surface area: 1497 m 2 /g; pore diameter: 3.4 nm).
• Example 2 100 mL of water was added to 5 g of coconut shell activated carbon (1093 m 2 /g; median diameter 66 ⁇ m), and the temperature was raised to 80°C while stirring. A solution of 20 g of sodium peroxodisulfate dissolved in 160 mL of water was slowly added, and the mixture was allowed to react for 90 minutes. It was then suction filtered, and the residue was washed with 35 g of a 1% by mass aqueous sodium hydroxide solution so that the pH of the filtrate became 8. After washing with water, the mixture was dried at 100°C to obtain the activated carbon of Example 2, which was used as a lead adsorbent.
• Example 3 300 mL of water was added to 60 g of phosphoric acid-activated activated carbon (2420 m2 /g; median diameter 34 ⁇ m), and while stirring, 46 mL of hydrogen peroxide solution (30% by mass) and 14 mL of nitric acid (60% by mass) were slowly added, and the mixture was then heated to 80°C and reacted for 90 minutes. This was then subjected to suction filtration, and the residue was washed with 420 g of a 1% by mass aqueous sodium hydroxide solution so that the pH of the filtrate was 8. After washing with water, the mixture was dried at 100°C to obtain the activated carbon of Example 3, which was used as a lead adsorbent.
• Example 6 100 mL of water was added to 5 g of coconut shell activated carbon (1093 m 2 /g; median diameter 19 ⁇ m), and the mixture was heated to 80°C while stirring. A solution of 20 g of sodium peroxodisulfate dissolved in 160 mL of water was slowly added, and the mixture was allowed to react for 90 minutes. The mixture was then suction filtered, and the residue was washed with 35 g of a 1% by mass aqueous sodium hydroxide solution so that the pH of the filtrate became 7. After washing with water, the mixture was dried at 100°C to obtain the activated carbon of Example 6, which was used as a lead adsorbent.
• Example 8 100 mL of water was added to 5 g of coconut shell activated carbon (1093 m 2 /g; median diameter 4 ⁇ m), and the mixture was heated to 80°C while stirring. A solution of 20 g of sodium peroxodisulfate dissolved in 160 mL of water was slowly added, and the mixture was allowed to react for 90 minutes. The mixture was then suction filtered, and the residue was washed with 35 g of a 1% by mass aqueous sodium hydroxide solution so that the pH of the filtrate became 8. After washing with water, the mixture was dried at 100°C to obtain the activated carbon of Example 8, which was used as a lead adsorbent.
• Example 9 100 mL of water was added to 5 g of coconut shell activated carbon (1093 m 2 /g; median diameter 111 ⁇ m), and the mixture was heated to 80°C while stirring. A solution of 20 g of sodium peroxodisulfate dissolved in 160 mL of water was slowly added, and the mixture was allowed to react for 90 minutes. The mixture was then suction filtered, and the residue was washed with 530 mL of a 0.002% by mass aqueous calcium hydroxide solution so that the pH of the filtrate became 7. After washing with water, the mixture was dried at 100°C to obtain the activated carbon of Example 9, which was used as a lead adsorbent.
• Example 10 100 mL of water was added to 5 g of coconut shell activated carbon (1093 m 2 /g; median diameter 4 ⁇ m), and the mixture was heated to 80°C while stirring. A solution of 20 g of sodium peroxodisulfate dissolved in 160 mL of water was slowly added, and the mixture was allowed to react for 90 minutes. The mixture was then suction filtered, and the residue was washed with 32 mL of a 1% by mass aqueous sodium hydroxide solution so that the pH of the filtrate was 5. After washing with water, the mixture was dried at 100°C to obtain the activated carbon of Example 10, which was used as a lead adsorbent.
• Example 11 100 mL of water was added to 5 g of coconut shell activated carbon (1093 m 2 /g; median diameter 66 ⁇ m), and the mixture was heated to 80°C while stirring. A solution of 20 g of sodium peroxodisulfate dissolved in 160 mL of water was slowly added, and the mixture was allowed to react for 90 minutes. The mixture was then suction filtered, and the residue was washed with 35 mL of a 1% by mass aqueous sodium hydroxide solution so that the pH of the filtrate became 8. After washing with water, the mixture was dried at 100°C to obtain the activated carbon of Example 11, which was used as a lead adsorbent.
• Example 16 100 mL of water was added to 5 g of coconut shell activated carbon (1093 m 2 /g; median diameter 66 ⁇ m), and the temperature was raised to 80°C while stirring. A solution of 20 g of sodium peroxodisulfate dissolved in 160 mL of water was slowly added and allowed to react for 90 minutes. Thereafter, the mixture was suction filtered, and the residue was washed with 35 mL of a 1% by mass aqueous sodium hydroxide solution so that the pH of the filtrate became 8. After washing with water, the mixture was dried at 100°C to obtain the activated carbon of Example 16, which was used as an aluminum adsorbent.
• Comparative Example 2 The phosphoric acid-activated activated carbon (2420 m 2 /g; median diameter 34 ⁇ m) was used as the activated carbon of Comparative Example 2.
• Comparative Example 5 100 mL of water was added to 5 g of coconut shell activated carbon (1093 m 2 /g; median diameter 4 ⁇ m), and the temperature was raised to 80°C while stirring. A solution of 20 g of sodium peroxodisulfate dissolved in 160 mL of water was slowly added, and the mixture was allowed to react for 90 minutes. It was then suction filtered, and the residue was washed with 30 g of a 1% by mass aqueous sodium hydroxide solution so that the pH of the filtrate was 3. After washing with water, the mixture was dried at 100°C to obtain the activated carbon of Comparative Example 6.
• Comparative Example 7 The crushed and carbonized coconut shells were activated at a steam-carbon ratio of 0.9 to 1.3 and a temperature of 650 to 950°C for 18 to 20 hours, and then crushed and separated into pellets to obtain activated carbon (1093 m 2 /g; median diameter 66 ⁇ m) for use as a copper adsorbent.
• Comparative Example 8 The crushed and carbonized coconut shells were activated at a steam-carbon ratio of 0.9 to 1.3 and a temperature of 650 to 950°C for 18 to 20 hours, and then crushed and separated into pellets to obtain activated carbon (1093 m 2 /g; median diameter 66 ⁇ m) as a cadmium adsorbent.
• Comparative Example 9 The crushed and carbonized coconut shells were activated at a steam-carbon ratio of 0.9 to 1.3 and a temperature of 650 to 950°C for 18 to 20 hours, and then crushed and separated into pellets to obtain activated carbon (1093 m 2 /g; median diameter 66 ⁇ m) as a barium adsorbent.
• Comparative Example 10 The crushed and carbonized coconut shells were activated at a steam-carbon ratio of 0.9 to 1.3 and a temperature of 650 to 950°C for 18 to 20 hours, and then crushed and separated into pellets to obtain activated carbon (1093 m 2 /g; median diameter 66 ⁇ m) as a mercury adsorbent.
• Comparative Example 12 The crushed and carbonized coconut shells were activated at a steam-carbon ratio of 0.9 to 1.3 and a temperature of 650 to 950°C for 18 to 20 hours, and then crushed and separated into pellets to obtain activated carbon (1093 m 2 /g; median diameter 66 ⁇ m) as a chromium adsorbent.
• Test Example 1 Amount of Acidic Functional Groups Activated carbon was reacted with a 0.1 mol/L aqueous solution of sodium ethoxide to react with the acidic functional groups on the surface of the activated carbon. The alkaline aqueous solution obtained after the reaction was then back-titrated with hydrochloric acid to quantify the total amount of functional groups (total amount of acidic functional groups) present on the surface of the activated carbon.
• the acidic functional groups on the surface of activated carbon were reacted with an aqueous sodium bicarbonate solution.
• the alkaline aqueous solution obtained after the reaction was then back-titrated with hydrochloric acid to quantify the amount of carboxyl groups present on the surface of the activated carbon.
• 0.1 mol/L hydrochloric acid was reacted with the activated carbon to convert the metal salt of the carboxyl groups on the surface into carboxyl groups.
• This activated carbon was washed with distilled water in an amount 100 times the weight of the activated carbon and dried at 115°C.
• the acidic functional groups on the surface of the dried activated carbon were reacted with an aqueous sodium bicarbonate solution.
• the alkaline aqueous solution obtained after the reaction was back-titrated with 0.1 mol/L hydrochloric acid to quantify the amount of carboxyl groups present on the activated carbon surface.
• the amount of functional groups derived from the metal carboxylate was quantified from the difference in the amount of carboxyl groups before and after reaction with hydrochloric acid.
• Test Example 3 Median diameter The particle size distribution was measured by a laser diffraction/scattering method using a laser particle size distribution diameter (MT3300exII manufactured by Microtrac Bel) and the median diameter was calculated.
• MT3300exII manufactured by Microtrac Bel
• Test Example 4 Average pore diameter The average pore diameter was calculated from the nitrogen adsorption isotherm of the activated carbon.
• Test Example 5 Amount of soluble lead adsorption (Examples 1 to 10 and Comparative Examples 1 to 5) A plurality of Erlenmeyer flasks were prepared, and each flask was individually charged with the activated carbon of the Examples and Comparative Examples, except for one Erlenmeyer flask. 50 mL of raw water prepared by dissolving lead nitrate in ultrapure water and adjusting the concentration to 5 mg/L was added, and the mixture was shaken for 20 hours while being kept at 20° C. Thereafter, the raw water in each Erlenmeyer flask was filtered, and 60% by mass nitric acid was added in an amount of 1% by mass relative to the filtrate. The concentration of soluble lead was analyzed by an atomic absorption spectrophotometer, and the amount of adsorption when the concentration reached 1 ppb was confirmed from the adsorption isotherm.
• Test Example 6 Lead adsorption amount (Example 11 and Comparative Example 6) A number of Erlenmeyer flasks were prepared, and each flask was individually charged with the activated carbon from each of the Examples and Comparative Examples, except for one. 1000 mL of raw water prepared by diluting a lead standard solution (1000 ppm) with ultrapure water to a concentration of 500 ⁇ g/L was added, and the mixture was shaken at room temperature for 24 hours.
• a lead standard solution 1000 ppm
• Test Example 7 Copper adsorption amount (Example 12 and Comparative Example 7) A number of Erlenmeyer flasks were prepared, and each flask was individually charged with the activated carbon from each of the Examples and Comparative Examples, except for one. 1000 mL of raw water prepared by diluting a copper standard solution (1000 ppm) with ultrapure water to a concentration of 500 ⁇ g/L was added, and the mixture was shaken at room temperature for 24 hours.
• Test Example 8 Cadmium adsorption amount (Example 13 and Comparative Example 8) A number of Erlenmeyer flasks were prepared, and each flask was individually charged with the activated carbon from each of the Examples and Comparative Examples, except for one. 1000 mL of raw water prepared by diluting a cadmium standard solution (1000 ppm) with ultrapure water to a concentration of 500 ⁇ g/L was added, and the mixture was shaken at room temperature for 24 hours.
• a cadmium standard solution 1000 ppm
• Test Example 9 Barium adsorption amount (Example 14 and Comparative Example 9) A number of Erlenmeyer flasks were prepared, and each flask was individually charged with the activated carbon from each of the Examples and Comparative Examples, except for one Erlenmeyer flask. 1000 mL of raw water prepared by diluting a barium standard solution (1000 ppm) with ultrapure water to a concentration of 500 ⁇ g/L was added, and the mixture was shaken at room temperature for 24 hours.
• Test Example 10 Mercury adsorption amount (Example 15 and Comparative Example 10) Several Erlenmeyer flasks were prepared, and each flask was individually charged with the activated carbon from each of the Examples and Comparative Examples, except for one. 1000 mL of raw water prepared by diluting a mercury standard solution (1000 ppm) with ultrapure water to a concentration of 500 ⁇ g/L was added, and the mixture was shaken at room temperature for 24 hours.
• a mercury standard solution 1000 ppm
• Test Example 11 Aluminum adsorption amount (Example 16 and Comparative Example 11) A number of Erlenmeyer flasks were prepared, and each flask was individually charged with the activated carbon from each of the Examples and Comparative Examples, except for one. 1000 mL of raw water prepared by diluting an aluminum standard solution (1000 ppm) with ultrapure water to a concentration of 500 ⁇ g/L was added, and the mixture was shaken at room temperature for 24 hours.
• 1000 mL of raw water prepared by diluting an aluminum standard solution (1000 ppm) with ultrapure water to a concentration of 500 ⁇ g/L was added, and the mixture was shaken at room temperature for 24 hours.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Inorganic Chemistry (AREA)
• Analytical Chemistry (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Engineering & Computer Science (AREA)
• Hydrology & Water Resources (AREA)
• Life Sciences & Earth Sciences (AREA)
• Carbon And Carbon Compounds (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)
• Water Treatment By Sorption (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=97219962

Family Applications (1)

Country Status (3)

Families Citing this family (1)

Citations (7)

• 2025
  • 2025-03-28 JP JP2025544951A patent/JP7782104B1/ja active Active
  • 2025-03-28 WO PCT/JP2025/012983 patent/WO2025206377A1/ja active Pending
  • 2025-03-31 TW TW114112360A patent/TW202547785A/zh unknown
  • 2025-11-20 JP JP2025200962A patent/JP2026035664A/ja active Pending

Patent Citations (7)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events