Classifications

• • 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
  • C02F1/283—Treatment of water, waste water, or sewage by sorption using coal, charred products, or inorganic mixtures containing them
• • 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
• • 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
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
  • G01N30/02—Column chromatography
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
  • G01N30/02—Column chromatography
  • G01N30/62—Detectors specially adapted therefor
  • G01N30/72—Mass spectrometers
  • G01N30/7233—Mass spectrometers interfaced to liquid or supercritical fluid chromatograph
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2101/00—Nature of the contaminant
  • C02F2101/30—Organic compounds
  • C02F2101/36—Organic compounds containing halogen
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
  • G01N30/02—Column chromatography
  • G01N2030/022—Column chromatography characterised by the kind of separation mechanism
  • G01N2030/027—Liquid chromatography

Definitions

• the present invention relates to a perfluoroalkyl compound-adsorbing activated carbon that adsorbs perfluoroalkyl compounds in water containing contaminants.
• Per- and polyfluoroalkyl compounds are fluorine-substituted aliphatic compounds with high thermal stability, high chemical stability, and high surface modification activity.
• Per- and polyfluoroalkyl compounds are widely used in industrial applications such as surface treatment agents, packaging materials, and liquid fire extinguishing agents, and chemical applications, taking advantage of the above properties.
• per- and polyfluoroalkyl compounds are very stable chemical substances, so they are difficult to decompose under natural conditions after being released into the environment. For this reason, in recent years per- and polyfluoroalkyl compounds have been recognized as persistent organic pollutants (POPs) and perfluorooctanesulfonic acid (PFOS) (IUPAC names: 1,1,2,2,3,3,4, 4,5,5,6,6,7,7,8,8,8-heptadecafluorooctane-1-sulfonic acid) has been regulated by the Swedish Convention on Persistent Organic Pollutants (POPs Convention) since 2010. Use was restricted.
• POPs persistent organic pollutants
• PFOS perfluorooctanesulfonic acid
• PFOS perfluorooctane sulfonic acid
• PFOA perfluorooctane sulfonic acid
• a standard value was added that the combined value of acid (PFOS) and perfluorooctanoic acid (PFOA) is 50 ng/L or less.
• PFOS perfluorooctane sulfonic acid
• PFOA perfluorooctanoic acid
• ii perfluorooctanoic acid
• a polyfluoroalkyl compound is a substance in which a portion of hydrogen in an alkyl group is replaced with fluorine, and is represented by the chemical formula (ii).
• fluorotelomer alcohols and the like there are fluorotelomer alcohols and the like.
• per- and polyfluoroalkyl compounds continue to remain in the natural world (in water, in soil, in the air), so the establishment of a quantitative test method for per- and polyfluoroalkyl compounds is being considered.
• the subject of investigation of the quantitative test method is the development of adsorbents with high adsorption and desorption performance of per- and polyfluoroalkyl compounds.
• Water or air which is a sample containing a trace amount of per- and polyfluoroalkyl compounds, is brought into contact with a collecting material to collect the per- and polyfluoroalkyl compounds, and the compounds adsorbed by the collecting material are extracted by an extraction process. Desorb into the extract and concentrate. After concentration, it is possible to quantitatively measure with an apparatus such as LC-MS/MS or GC-MS/MS to measure the concentration of per- and polyfluoroalkyl compounds contained in the sample.
• Non-Patent Document 1 Regard the removal of residual organic fluorine compounds such as so-called perfluoroalkyl compounds in environmental water, due to the influence of contaminants such as organic substances contained in environmental water, residual organic fluorine compounds in environmental water can be treated with ozone or activated carbon. It has been reported that sufficient removal cannot be achieved by water purification treatment (see Non-Patent Document 1).
• the present invention provides a perfluoroalkyl compound-adsorbing activated carbon that can efficiently adsorb perfluoroalkyl compounds even in water containing contaminants such as so-called environmental water and waste water. .
• the first invention is an activated carbon adsorbent for adsorbing perfluoroalkyl compounds in water containing contaminants, the activated carbon adsorbent having a fine pore diameter of 2 to 50 nm as measured by the DH plot method.
• the sum of pore volumes in pores is 0.025 cm 3 /g or less, and the sum of pore volumes in pores with pore diameters of 1.5 to 2 nm is 0.014 cm 3 in the activated carbon adsorbent measured by the MP plot method. /g or more perfluoroalkyl compound-adsorbing activated carbon.
• a second invention relates to the perfluoroalkyl compound-adsorbing activated carbon according to the first invention, wherein the perfluoroalkyl compound is either one or both of perfluorooctane sulfonic acid and perfluorooctanoic acid.
• a third invention relates to the perfluoroalkyl compound-adsorbing activated carbon according to the first or second invention, wherein the perfluoroalkyl compound-adsorbing activated carbon has a tap specific gravity of 0.48 g/cc or more.
• the perfluoroalkyl compound adsorption performance per unit weight measured by the following perfluoroalkyl compound adsorption performance evaluation test method relates to a perfluoroalkyl compound-adsorbing activated carbon having a perfluorooctane sulfonic acid adsorption amount of 600 ⁇ g/g or more and a perfluorooctanoic acid adsorption amount of 300 ⁇ g/g or more.
• [Perfluoroalkyl compound adsorption performance evaluation test method] Potassium hydrogen phthalate and humic acid were added to ultrapure water to make total organic carbon 3.1 mg/L (inner humic acid: 0.1 mg/L). 500 ng/L (total concentration 1000 ng/L) to prepare test water. 2. 1 above. 0.1 mg of adsorbed activated carbon is added to 200 mL of the test water obtained in 1. and shaken at 140 rpm for 48 hours using a constant temperature shaker at 25°C. 3.
• the adsorbed activated carbon is removed by solid-liquid separation, extracted with a solvent containing methanol as the main component, and after concentration, the concentrations of perfluorooctanesulfonic acid and perfluorooctanoic acid are measured by LC-MS/MS.
• a fifth invention relates to the perfluoroalkyl compound-adsorbing activated carbon according to any one of the first to fourth inventions, wherein the perfluoroalkyl compound-adsorbing activated carbon is an adsorbent in a water purification filter of a water purifier.
• the perfluoroalkyl compound-adsorbing activated carbon is an activated carbon adsorbent for adsorbing perfluoroalkyl compounds in water containing contaminants, wherein the activated carbon adsorbent has a pore diameter of is 0.025 cm 3 /g or less, and the activated carbon adsorbent has a pore volume of 1.5 to 2 nm in pore diameter measured by the MP plot method. Since the sum is 0.014 cm 3 /g or more, even perfluoroalkyl compounds in water containing contaminants such as so-called environmental water and wastewater can be efficiently adsorbed.
• the perfluoroalkyl compound is either one or both of perfluorooctane sulfonic acid and perfluorooctanoic acid, which contributes to the removal of regulated compounds from water. can do.
• the tap specific gravity of the perfluoroalkyl compound adsorbent is 0.48 g/cc or more, the adsorption performance per unit volume It is expected to be used in existing facilities with a fixed volume such as water purification plants. Furthermore, it can also be used for filter bodies such as existing water purifiers, and is excellent in handling.
• the perfluoroalkyl compound adsorbent measured by the above-mentioned perfluoroalkyl compound adsorption performance evaluation test method Since the perfluorooctane sulfonic acid adsorption amount per unit weight of the compound is 600 ⁇ g/g or more and the perfluorooctanoic acid adsorption amount is 300 ⁇ g/g or more, even in water containing contaminants, It has good per- and polyfluoroalkyl compound adsorption performance and can efficiently remove said compounds.
• the perfluoroalkyl compound-adsorbing activated carbon in any one of the first to fourth inventions, since the perfluoroalkyl compound-adsorbing activated carbon is an adsorbent in a water filter of a water purifier, Even so, it has a high effect of selectively adsorbing perfluoroalkyl compounds, and is suitable as an adsorbent for water purification plants and water purification filters.
• the perfluoroalkyl compound-adsorbing activated carbon of the present invention consists of fibrous activated carbon or granular activated carbon.
• Fibrous activated carbon is activated carbon obtained by carbonizing and activating appropriate fibers, and includes, for example, phenol resin, acrylic resin, cellulose, coal pitch, and the like. The fiber length, cross-sectional diameter, etc. are appropriate.
• Raw materials for granular activated carbon include wood (waste wood, thinned wood, sawdust), coffee grounds, rice husks, coconut husks, tree bark, and fruit. Pores tend to develop in these naturally-derived raw materials by carbonization and activation. In addition, it can be procured cheaply because it is a secondary use of waste. In addition, fired products derived from synthetic resins such as tires, petroleum pitch, urethane resins and phenol resins, and coal can also be used as raw materials.
• the activated carbon raw material is heated and carbonized in the temperature range of 200°C to 600°C as necessary to form micropores. Subsequently, the activated carbon raw material is exposed to steam and carbon dioxide in a temperature range of 600° C. to 1200° C. for activation treatment. As a result, activated carbon having various pores is produced. In addition, zinc chloride activation and the like are also used for the activation. Sequential washes are also performed.
• the physical properties of the activated carbon produced in this way determine the adsorption performance of the target substance to be adsorbed.
• the adsorption performance of activated carbon for adsorbing a perfluoroalkyl compound, which is the substance to be adsorbed in the present invention is defined by the pore diameter and volume of pores formed in the activated carbon.
• the pore volume of pores with a pore diameter of 2 to 50 nm hereinafter referred to as "mesopores" in this specification
• the pores with a pore diameter of 1.5 to 2 nm hereinafter referred to as the present It is defined by the pore volume of "micropores" in the specification.
• the activated carbon of this application adsorbs perfluoroalkyl compounds in water samples containing contaminants, so-called environmental water and industrial or domestic wastewater.
• the activated carbon is excellent in adsorption performance of perfluoroalkyl compounds in water samples containing contaminants or impurities, rather than in adsorption performance in purified water such as pure water that does not contain impurities.
• Contaminants contained in environmental water or wastewater include organic substances and metal ions.
• Organic substances include, for example, volatile organic substances, fulvic acid, and humic acid. Point.
• organic substances with large molecules are adsorbed in the mesopores of the activated carbon and prevent the target adsorbate from reaching the micropores. For this reason, if too many mesopores are developed, the micropores for adsorbing contaminants and perfluoroalkyl compounds are blocked, and there is a tendency that the adsorption of the target substance to be adsorbed cannot be achieved.
• the adsorption efficiency of perfluoroalkyl compounds is improved by developing the micropores where the target adsorbate is adsorbed beyond a certain level.
• metal ions since they are hardly adsorbed by activated carbon, it is considered that they do not affect the adsorption of the intended adsorbate.
• the sum of pore volumes at pore diameters of 2 to 50 nm is 0.025 cm 3 /g or less, and the sum of pore volumes at pore diameters of 1.5 to 2 nm is By making it 0.014 cm 3 /g or more, it is possible to satisfactorily adsorb the target adsorbate while preventing the adsorption of contaminants that block the pores of the activated carbon and hinder the adsorption of the target adsorbate.
• the sum of the pore volumes of the pores of the perfluoroalkyl compound-adsorbing activated carbon having a pore diameter of 2 to 50 nm is 0.025 cm 3 /g or less, then the total organic matter as contaminants Even in water containing carbon, it is possible to suppress deterioration in the perfluoroalkyl compound adsorption performance of the activated carbon adsorbent.
• the pore volume sum in pores with a pore diameter of 2 to 50 nm was measured by the DH plot method.
• the activated carbon adsorbent Adsorption performance of perfluoroalkyl compounds is improved. Since pores with a pore diameter of 1.5 to 2 nm are considered to be suitable for adsorption of perfluoroalkyl compounds, it is preferable that pores with a pore diameter of 1.5 to 2 nm are developed to a certain extent or more. This is thought to contribute to good adsorption performance.
• the pore volume sum in pores with a pore diameter of 1.5 to 2 nm was measured by the MP plot method.
• the perfluoroalkyl compound-adsorbing activated carbon of the present application can exhibit good adsorption performance for per- and polyfluoroalkyl compounds in water containing contaminants.
• the tap specific gravity of the perfluoroalkyl compound activated carbon adsorbent it is preferable to set the tap specific gravity of the perfluoroalkyl compound activated carbon adsorbent to 0.48 g/cc or more.
• activated carbon with a high tap specific gravity the amount of adsorption of perfluoroalkyl compounds per unit volume is improved, so it is suitable as an adsorbent for equipment with a predetermined volume such as a water purification plant.
• the adsorbent activated carbon is used in the filter body of a water purifier, it is possible to prevent the volume of the filter body from increasing, to improve the handling, and to adsorb and remove perfluoroalkyl compounds with existing equipment. It becomes possible.
• the perfluoroalkyl compound activated carbon adsorbent has a perfluoroalkyl compound adsorption capacity per unit weight of 600 ⁇ g/g or more perfluorooctane sulfonic acid adsorption measured by the perfluoroalkyl compound adsorption performance evaluation test method described later, and perfluorooctane.
• the acid adsorption amount is 300 ⁇ g/g or more, the adsorption performance is good, and perfluoroalkyl compounds in water containing contaminants can be efficiently adsorbed and removed.
• Potassium hydrogen phthalate and humic acid were added to ultrapure water to make total organic carbon 3.1 mg/L (inner humic acid: 0.1 mg/L). 500 ng/L (total concentration 1000 ng/L) to prepare test water.
• total concentration 1000 ng/L total concentration 1000 ng/L
• activated carbon adsorbent used The inventors used the following activated carbon to evaluate the adsorption performance of perfluoroalkyl compounds in water containing contaminants.
• the specific surface area (m 2 /g) is obtained by measuring the nitrogen adsorption isotherm at 77 K using an automatic specific surface area / pore size distribution measuring device "BELSORP-miniII” manufactured by Microtrack Bell Co., Ltd., and determined by the BET method. (BET specific surface area).
• Pore volume The pore volume (cm 3 /g) was measured by nitrogen adsorption using an automatic specific surface area/pore size distribution analyzer (“BELSORP-miniII”, manufactured by Microtrac Bell Co.).
• the average pore diameter (nm) was obtained from the formula (iii) using the pore volume (cm 3 /g) and the specific surface area (m 2 /g), assuming that the pore shape is cylindrical. .
• the total pore volume of micropores (cm 3 /g) was measured using an automatic specific surface area/pore size distribution measuring device (“BELSORP-miniII”, manufactured by Microtrack Bell Co., Ltd.) in the same manner as the above pore volume. , determined by nitrogen adsorption.
• the pore volume sum (cm 3 /g) of pores with a pore diameter of 1.5 to 2 nm is the value of dV/dD in the range of pore diameters of 1.5 to 2 nm. It was obtained by analyzing from the plot by the MP method.
• the amount of surface oxides was obtained by applying Boehm's method, shaking the adsorbent activated carbon of each example in an aqueous 0.05N sodium hydroxide solution, filtering the mixture, and neutralizing and titrating the filtrate with 0.05N hydrochloric acid. It is the amount of sodium hydroxide when
• Methylene blue adsorption performance Methylene blue adsorption performance (mL/g) was measured according to JIS K 1474 (2014).
• the tap specific gravity (g/cc) was obtained by putting the adsorbent activated carbon of each prototype example into a 150 mL cylinder and measuring the weight. Next, the cylinder was set in a tapping machine (manufactured by Kuramochi Kagaku Kikai Seisakusho Co., Ltd.) and a shock was applied for 2 hours. The specific gravity of the activated carbon was calculated from the scale and weight of the cylinder, and was taken as the tap specific gravity.
• Tables 1 and 2 show the physical properties of the activated carbons of Prototype Examples 1-10. From the top of the table, specific surface area (m 2 /g), pore volume (cm 3 /g), average pore diameter (nm), total pore volume of micropores (cm 3 /g), mesopores They are sum of pore volume (cm 3 /g), surface oxide amount (meq/g), methylene blue adsorption performance (mL/g), pH, and tap specific gravity (g/cc).
• Potassium hydrogen phthalate manufactured by Kanto Chemical Co., Ltd.
• humic acid manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.
• Water and ultrapure water were prepared. Standard reagents of PFOA and PFOS of the object are added to test water and ultrapure water, respectively, and test solution 1 (test water) and test A solution 2 (ultra-pure water) was prepared.
• 0.1 mg of activated carbon pulverized to an average particle size of 10 ⁇ 4 ⁇ m was added to a container containing 200 mL of the test solutions 1 and 2, and the mixture was shaken at 25° C. with a constant temperature shaker (manufactured by Tokyo Rika Kikai Co., Ltd.). was shaken at 140 rpm for 48 hours. Thereafter, activated carbon was removed by solid-liquid separation, and an extract was collected using a solvent containing methanol as a main component.
• the extract After concentrating the collected extract to 1 mL with a nitrogen blowing concentrator, the extract is quantitatively measured in MRM mode using LC-MS/MS ("LCMS-8030", manufactured by Shimadzu Corporation), The concentrations of PFOA and PFOS were measured.
• Tables 3 and 4 show the amount of adsorption per unit weight ( ⁇ g/g) and the amount of adsorption per unit volume ( ⁇ g/cc) for each target substance in Prototype Examples 1 to 10 for each test solution.
• the adsorption amount per unit weight of PFOA ( ⁇ g/g) is 500 ⁇ g/g or more as “ ⁇ ”, 300 to 500 ⁇ g/g as “ ⁇ ”, and less than 300 ⁇ g/g as “ ⁇ ”. evaluated.
• the adsorption amount ( ⁇ g/cc) per unit volume of PFOA was evaluated as “ ⁇ ” when it was 300 ⁇ g/cc or more, “ ⁇ ” when it was 200 to 300 ⁇ g/cc, and “X” when it was less than 200 ⁇ g/cc.
• the adsorption amount ( ⁇ g/g) per unit weight of PFOS was evaluated as “ ⁇ ” when it was 800 ⁇ g/g or more, “ ⁇ ” when it was 600 to 800 ⁇ g/g, and “ ⁇ ” when it was less than 600 ⁇ g/g. .
• the adsorption amount ( ⁇ g/cc) per unit volume of PFOS was evaluated as “ ⁇ ” when it was 600 ⁇ g/cc or more, “ ⁇ ” when it was 400 to 600 ⁇ g/cc, and “X” when it was less than 400 ⁇ g/cc.
• the adsorption ratio (%) of the amount of adsorption in test solution 1 (test water) to the amount of adsorption in test solution 2 (ultrapure water) is shown for each target substance.
• the adsorption amount of PFOA was particularly low in test solution 1, and the adsorption of the target substance was insufficient.
• the adsorption amount of the test solution 1 containing contaminants with respect to the adsorption amount of the test solution 2 is about 10 to 20% for PFOA and 10% for PFOS. less than 70%, excluding In other words, it was shown that the adsorption of the target substance in water is not good in the presence of contaminants.
• the adsorption amount of PFOS was also low.
• both PFOA and PFOS in test solution 1 had a good adsorption amount, and it can be said that the adsorption of the target substance was sufficient.
• the adsorption amount of the test solution 1 containing contaminants with respect to the adsorption amount of the test solution 2 is 30% or more for PFOA and 70% or more for PFOS. there were. From the good adsorption performance in test solution 2 of Prototype Examples 1, 3 to 5, and 9, it was understood that good adsorption performance was exhibited even in water in the presence of contaminants.
• Prototype Examples 1, 3 to 5, and 9 are also good in the adsorption amount ( ⁇ g/cc) of the target substance per unit volume.
• ⁇ g/cc adsorption amount of the target substance per unit volume.
• the volume is more limited than the weight, so it is considered that the activated carbon adsorbent having a tap specific gravity of a certain value or more is preferable. .
• the perfluoroalkyl compound-adsorbing activated carbon of the present invention can efficiently adsorb perfluoroalkyl compounds in water containing contaminants. can be expected to contribute to

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• 2022
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