Activated carbon for adsorption of per- and polyfluoroalkyl compounds in atmospheric samples

Abstract

The present invention provides per- and polyfluoroalkyl compound-adsorbing activated carbon that has a high collection rate for per- and polyfluoroalkyl compounds in air samples, and a filter body using the same. Solution: BET specific surface area is 900m 2 / g or more, and the micropore volume (V mic ) is 0.35cm 3 / g or more, and the mesopore volume (V met ) is 0.02cm 3 / g or more, and the micropore volume (V mic ) and the sum of the mesopore volume (V met ) and the volume difference (V s ) is 0.45 or more and the surface oxide amount is 0.10 meq / g or more in an air sample consisting of an activated carbon adsorbent of For adsorption in air samples Activated carbon for adsorbing per- and polyfluoroalkyl compounds.

Description

[Technical Field]

[0001] The present invention relates to per- and polyfluoroalkyl compound adsorption activated carbon for capturing per- and polyfluoroalkyl compounds contained in atmospheric samples. [Background technology]

[0002] Perfluoroalkyl compounds are fluorine-substituted aliphatic compounds that possess high thermal stability, high chemical stability, and high surface modification activity. Taking advantage of these properties, perfluoroalkyl compounds are widely used in industrial and chemical applications such as surface treatment agents, packaging materials, and liquid fire extinguishing agents.

[0003] Some perfluoroalkyl compounds are highly stable chemicals and, after being released into the environment, do not easily decompose under natural conditions. For this reason, in recent years, perfluoroalkyl compounds have been recognized as persistent organic pollutants (POPs), and perfluorooctanesulfonic acid (PFOS) (IUPAC name: 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluorooctane-1-sulfonic acid) has been subject to regulations on the manufacture and use of under the Stockholm Convention on Persistent Organic Pollutants (POPs Convention) since 2010.

[0004] Perfluoroalkyl compounds have a fully fluorinated linear alkyl group and are substances represented by chemical formula (ii). Examples include perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) (IUPAC name: 2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecafluorooctanoic acid).

[0005]

number

[0006] A polyfluoroalkyl compound refers to a compound in which some of the hydrogens of an alkyl group are replaced by fluorine, and it is a substance represented by chemical formula (iii). For example, there are fluorotelomer alcohols and the like.

[0007] [Number]

[0008] Thus, since per- and polyfluoroalkyl compounds continue to remain in nature (in water, soil, and the atmosphere), the establishment of a quantitative test method for per- and polyfluoroalkyl compounds has been under consideration. The issue in the study of the quantitative test method is the development of a collection material having high adsorption and desorption performance for per- and polyfluoroalkyl compounds. Water or air, which is a sample containing trace amounts of per- and polyfluoroalkyl compounds, is brought into contact with the collection material to collect the per- and polyfluoroalkyl compounds, and the compound adsorbed on the collection material is desorbed into an extract by an extraction process and concentrated. After concentration, quantitative measurement can be performed using an apparatus such as LC-MS / MS or GC-MS / MS, and it becomes possible to measure the concentration of per- and polyfluoroalkyl compounds contained in the sample.

[0009] As an existing collection material, for example, an organic fluorine-based compound adsorbent made of cyclodextrin polymer has been proposed (Patent Document 1). This adsorbent is specialized only in adsorption and cannot desorb the compound, so it is not suitable for use as a collection material for quantitative measurement. In addition, cyclodextrin polymer is in powder or fine particle form, has poor handling, has a high resistance during liquid or gas flow, and has problems such as a risk of outflow of fine powder to the secondary side.

[0010] In addition, per- and polyfluoroalkyl compounds remain in the environment in various forms with a wide range of physicochemical properties, and existing adsorbents do not have sufficient collection performance, and there was a problem that accurate quantitative measurement could not be performed.

[0011] Therefore, the applicant has proceeded with the study using activated carbon as a trapping material for PFAS, and has found that it enables the trapping of PFAS and greatly contributes to accurate quantitative measurement.

Prior Art Documents

Patent Documents

[0012]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0013] The present invention has been made in view of the above points, and particularly provides an activated carbon adsorbent for PFAS capable of collecting PFAS in an air sample and a filter body using the same.

Means for Solving the Problems

[0014] That is, the first invention is composed of an activated carbon adsorbent having a BET specific surface area of 900 m 2 / g or more, The average pore diameter is 1.64 to 1.89 nm. and relates to an activated carbon adsorbent for PFAS in an air sample for adsorbing PFAS in the air sample, wherein the volume difference (V mic ) between the sum (V met ) of the micropore volumes of 1 nm or less defined by the following formula (i) of the activated carbon adsorbent and the sum (V s ) of the mesopore volumes of 2 to 60 nm or less is 0.45 cm 3 / g or more.

[0015]

Number

[0016] The second invention is the activated carbon adsorbent in the first invention, wherein the The aforementionedSum of micropore volumes (V mic ) is 0.35 cm 3 / g or more, relating to activated carbon for adsorbing perfluoroalkyl and polyfluoroalkyl compounds in an air sample.

[0017] According to a third invention, in the first or second invention, the The aforementioned sum of mesopore volumes (V met ) is 0.02 cm 3 / g or more, relating to activated carbon for adsorbing perfluoroalkyl and polyfluoroalkyl compounds in an air sample.

[0018] The 4 invention relates to activated carbon for adsorbing perfluoroalkyl and polyfluoroalkyl compounds in an air sample, wherein the amount of surface oxide of the activated carbon adsorbent is 0.10 meq / g or more in any one of the first to 3 inventions.

[0019] The 5 invention relates to activated carbon for adsorbing perfluoroalkyl and polyfluoroalkyl compounds in an air sample, wherein the activated carbon adsorbent is fibrous activated carbon in any one of the first to 4 inventions.

[0020] The 6 invention relates to a filter body for adsorbing perfluoroalkyl and polyfluoroalkyl compounds in an air sample, which is characterized by holding the adsorbent activated carbon according to any one of the first to 5 inventions.

Advantages of the Invention

[0021] According to the activated carbon for adsorbing perfluoroalkyl and polyfluoroalkyl compounds in an air sample according to the first invention, it consists of an activated carbon adsorbent with a BET specific surface area of 900 m 2 / g or more, and The average pore diameter is 1.64 to 1.89 nm. the volume difference (V mic ) between the sum of micropore volumes (V met ) of 1 nm or less defined by the above formula (i) of the activated carbon adsorbent and the sum of mesopore volumes (V s ) of 2 to 60 nm or less is 0.45 cm 3 / gAs described above, this activated carbon for adsorbing per and polyfluoroalkyl compounds in atmospheric samples can efficiently capture these compounds, which have previously been difficult to quantitatively measure.

[0022] According to the second invention, which describes the activated carbon adsorbent for per and polyfluoroalkyl compounds in an atmospheric sample, in the first invention, the activated carbon adsorbent is The aforementioned Sum of micropore volumes (V mic ) is 0.35cm 3 Because the concentration is greater than / g, per- and polyfluoroalkyl compounds can be efficiently collected.

[0023] According to the third invention, which involves the adsorption of per and polyfluoroalkyl compounds in an atmospheric sample by activated carbon, in the first or second invention, the activated carbon adsorbent is The aforementioned Sum of mesopore volumes (V met ) is 0.02cm 3 Because the concentration is greater than / g, per- and polyfluoroalkyl compounds can be efficiently collected.

[0024] The 4 According to the activated carbon for adsorption of per and polyfluoroalkyl compounds in atmospheric samples according to the invention, the first to 3 In any of the inventions, since the surface oxide content of the activated carbon adsorbent is 0.10 meq / g or more, it possesses not only adsorption performance through the pores of the activated carbon but also chemical adsorption capacity, thereby further improving the adsorption performance of per and polyfluoroalkyl compounds.

[0025] The 5 According to the activated carbon for adsorption of per and polyfluoroalkyl compounds in atmospheric samples according to the invention, the first to 4 In any of the inventions, since the activated carbon adsorbent is fibrous activated carbon, the contact efficiency with per and polyfluoroalkyl compounds is increased, and the adsorption performance can be improved.

[0026] The 6According to the per- and polyfluoroalkyl compound adsorption filter body in an atmospheric sample according to the invention, the first to 5 Since it holds an adsorbent activated carbon according to any of the inventions, it can enhance the collection efficiency of per and polyfluoroalkyl compounds while providing good handling properties. [Modes for carrying out the invention]

[0027] The activated carbon used for adsorbing perfluoroalkyl compounds in atmospheric samples according to 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, such as phenolic resin-based, acrylic resin-based, cellulose-based, and coal pitch-based materials. The fiber length and cross-sectional diameter are as appropriate.

[0028] Raw materials for granular activated carbon include wood (waste wood, thinned wood, sawdust), coffee grounds, rice husks, coconut shells, tree bark, and fruit kernels. These naturally derived materials develop pores more easily through carbonization and activation. Furthermore, because they are a secondary use of waste, they can be procured at low cost. Other materials that can be used include tires, petroleum pitch, calcined products derived from synthetic resins such as urethane resin and phenolic resin, and even coal.

[0029] The activated carbon raw material is heated and carbonized in the temperature range of 200°C to 600°C as needed to form micropores. Subsequently, the activated carbon raw material is exposed to steam and carbon dioxide in the temperature range of 600°C to 1200°C to be activated. As a result, activated carbon with various types of pores is produced. In addition, zinc chloride activation is also performed during the activation process.

[0030] The physical properties of the activated carbon thus produced determine its adsorption performance for the substance to be adsorbed. The adsorption performance of activated carbon that adsorbs per- and polyfluoroalkyl compounds, which are the target substances of the present invention, is determined by the specific surface area, which is an indicator of the amount of pores formed in the activated carbon. In this specification, the specific surface area of ​​each prototype example was measured by the BET method (Brunauer, Emmett, and Teller method).

[0031] Activated carbon is also defined by the pore size of its micropores. In the case of adsorbents like activated carbon, micropores, mesopores, and macropores are all present. The adsorption targets and performance of activated carbon change depending on which range of pores is more developed. The activated carbon desired in this invention is one that can effectively adsorb molecules of per- and polyfluoroalkyl compounds in a desorbable manner.

[0032] Furthermore, acidic functional groups are present on the surface of activated carbon. The acidic functional groups that increase due to surface oxidation of activated carbon are mainly hydrophilic groups such as carboxyl groups and phenolic hydroxyl groups. The acidic functional groups on the surface of activated carbon affect its collection capacity. The amount of these acidic functional groups can be determined as the amount of surface oxides. When the amount of surface oxides of activated carbon increases, the hydrophilicity of the activated carbon surface increases, and it is thought that the collection performance of fluorotelomer alcohols, which have hydrophilic groups, among per and polyfluoroalkyl compounds, improves.

[0033] Methods for increasing the surface oxide content of activated carbon include the following: One method involves promoting the oxidation of surface residues through a reheating process, thereby increasing the amount of acidic functional groups. This is known as oxidation in an air or oxygen atmosphere. Alternatively, air at a temperature of 25-40°C and humidity of 60-90% is introduced simultaneously under an air atmosphere. The activated carbon is then heated at 150-900°C for 1-10 hours to obtain activated carbon with an increased amount of surface oxides. It is believed that heating with humid air oxidizes hydrocarbon groups such as alkyl groups present on the surface of the activated carbon, or introduces hydroxyl groups of water to the surface, thereby increasing the amount of acidic functional groups.

[0034] Another method involves oxidizing the surface of activated carbon with an oxidizing agent to increase the amount of surface oxides. Examples of oxidizing agents include hypochlorous acid and hydrogen peroxide. By immersing activated carbon in a solution containing these oxidizing agents and then drying it, activated carbon with an increased amount of surface oxides can be obtained. The amount of acidic functional groups on the surface of the activated carbon can be measured as the amount of surface oxides, as shown in the prototype examples described below.

[0035] The adsorption performance of activated carbon that can desorb per- and polyfluoroalkyl compounds in atmospheric samples is derived from the examples described below, with a specific surface area of ​​900 m². 2 This effect is achieved by setting the concentration to 1 / g or higher. The adsorption performance of the compound is ensured by the formation of a certain number of pores in the activated carbon.

[0036] Furthermore, it was found that the pore distribution formed on the activated carbon also contributes to the adsorption of per- and polyfluoroalkyl compounds in atmospheric samples. In this specification, micropores refer to pores with a pore diameter of 1 nm or less, and as can be derived from the examples described later, the pore volume (V) of the micropores mic The total of ) is 0.35 cm 3 When the concentration is set to 1 / g or higher, the adsorption performance of per- and polyfluoroalkyl compounds in atmospheric samples is improved. In this specification, the micropore volume of 1 nm or less in each prototype example is measured by the MP method (Micropore method). It is thought that when a certain number of micropores are formed, the compounds are more easily captured in the pores.

[0037] Furthermore, in this specification, a mesopore refers to a pore with a pore diameter in the range of 2 to 60 nm, and as can be derived from the examples described later, the pore volume (V) of the mesopore. met The total of ) is 0.02 cm 3 When the concentration is set to 1 / g or higher, the adsorption performance of per- and polyfluoroalkyl compounds in atmospheric samples is improved. In this specification, the mesopore volume in the range of 2 to 60 nm for each prototype example was measured by the DH method (Dollimore-Heal method). Because the measurement was performed by the DH method, the measurement target was pores of 2.43 to 59.72 nm. It is thought that when mesopores are formed to a certain extent or higher, the compound can easily penetrate into the micropores.

[0038] In addition, the difference between the pore volume of micropores and the pore volume of mesopores is also thought to contribute to the efficient adsorption of per- and polyfluoroalkyl compounds. As can be derived from the examples described later, the sum of the micropore volumes (V mic ) and the sum of the mesopore volumes (V met) Volume difference (V s By setting the ratio to 0.45 or higher, per- and polyfluoroalkyl compounds in atmospheric samples can be efficiently adsorbed and desorbed. By using activated carbon with well-developed micropores in addition to not overdeveloping mesopores, the adsorption performance of per- and polyfluoroalkyl compounds is improved, and the compounds can be smoothly desorbed during subsequent extraction operations, thereby enabling accurate quantitative measurements.

[0039] Next, by setting the surface oxide content to 0.10 meq / g or higher, the hydrophilicity of the activated carbon surface is increased, enabling efficient adsorption of per- and polyfluoroalkyl compounds in the atmospheric sample. [Examples]

[0040] [Activated carbon adsorbent used] The inventors used the following raw materials to create activated carbon for adsorption of per and polyfluoroalkyl compounds. • Fibrous activated carbon Futamura Chemical Co., Ltd.: Fibrous activated carbon "CF" (average fiber diameter: 15 μm) Hereafter, this will be referred to as C1. Futamura Chemical Co., Ltd.: Fibrous activated carbon "FE3010" (average fiber diameter: 15 μm) Hereafter, this will be referred to as C2. Futamura Chemical Co., Ltd.: Fibrous activated carbon "FE3012" (average fiber diameter: 15 μm) Hereafter, this will be referred to as C3. Futamura Chemical Co., Ltd.: Fibrous activated carbon "FE3013" (average fiber diameter: 15 μm) Hereafter, this will be referred to as C4. Futamura Chemical Co., Ltd.: Fibrous activated carbon "FE3015" (average fiber diameter: 15 μm) Hereafter, this will be referred to as C5. Futamura Chemical Co., Ltd.: Fibrous activated carbon "FE3018" (average fiber diameter: 15 μm) Hereafter, this will be referred to as C6. ·Granular activated carbon Futamura Chemical Co., Ltd.: Coconut shell activated carbon "CW480SZ" (average particle size: 250 μm) Hereafter, this will be referred to as C7. Futamura Chemical Co., Ltd.: Phenolic resin activated carbon "QW250" (average particle size: 250 μm) Hereafter, this will be referred to as C8.

[0041] [Investigation of the collection performance of per- and polyfluoroalkyl compounds in atmospheric samples 1] The inventors conducted experiment 1 on the collection of per- and polyfluoroalkyl compounds in atmospheric samples using the following prototype examples 1 to 5.

[0042] [Preparation of prototype examples] <Prototype Example 1> For prototype example 1, we used "CF" (C1), a fibrous activated carbon produced by carbonizing phenol resin fibers, which are the same raw material as FE3010, at 600°C.

[0043] <Prototype Example 2> Futamura Chemical's fibrous activated carbon "FE3015" (C5) was used as the activated carbon for prototype example 2.

[0044] <Prototype Example 3> Teng of Futamura Chemical's fibrous activated carbon "FE3010" (C2) was immersed in 500 ml of a 6% hydrogen peroxide solution, left to stand for 150 hours, then removed and dried to produce the activated carbon for Prototype Example 3.

[0045] <Prototype Example 4> Teng of Futamura Chemical's fibrous activated carbon "FE3015" (C5) was immersed in 500 ml of a 6% hydrogen peroxide solution, left to stand for 70 hours, then removed and dried to produce the activated carbon for Prototype Example 4.

[0046] <Prototype Example 5> Teng of Futamura Chemical's fibrous activated carbon "FE3018" (C6) was immersed in 500 ml of a 6% hydrogen peroxide solution, left to stand for 50 hours, then removed and dried to produce the activated carbon for Prototype Example 5.

[0047] [Measurement of activated carbon 1] [Surface oxide amount] The amount of surface oxide (meq / g) was determined by applying Boehm's method: each example of adsorbent activated carbon was shaken in a 0.05 N sodium hydroxide aqueous solution, filtered, and the filtrate was neutralized by titration with 0.05 N hydrochloric acid, at which point the amount of sodium hydroxide was recorded.

[0048] [BET specific surface area] Specific surface area (m 2 The specific surface area ( / g) was determined by measuring the nitrogen adsorption isotherm at 77K using the BELSORP-miniII automatic specific surface area / pore distribution analyzer manufactured by Microtrac-Bell Co., Ltd., and then using the BET method (BET specific surface area).

[0049] [Average pore diameter] The average pore diameter (nm) is calculated assuming the pore shape is cylindrical, and the pore volume (cm³) is calculated as follows: 3 ( / g) and specific surface area (m²) 2 The value of / g) was used to obtain the result from formula (iv).

[0050]

number

[0051] The physical properties of the activated carbon for prototypes 1-5 are shown in Table 1. From top to bottom in Table 1 are: surface oxide content (meq / g), BET specific surface area (m²). 2 These are the values ​​(per g), average pore diameter (nm), and average fiber diameter (μm).

[0052] [Table 1]

[0053] [Measurement of collection efficiency of perfluoroalkyl compounds in atmospheric samples 1] As per- and polyfluoroalkyl compounds, fluorotelomer alcohols (hereinafter referred to as "FTOHs") and ethyl perfluorooctanesulfamide (IUPAC name: N-ethyl-1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluorooctane-1-sulfamide) (hereinafter referred to as "N-EtFOSA") were used for evaluation. FTOHs are substances represented by the chemical formula (ii) above, and their names differ depending on the number of carbon atoms. For example, C8F 17 In the case of CH2CH2OH, it is named 8:2FTOH (IUPAC name: 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluoro-1-decanol). N-EtFOSA is a substance represented by the following chemical formula (v).

[0054]

number

[0055] Each standard substance was diluted to 100 ppb with methanol, and 100 μl of each solution was added to flexible polyurethane foam (PUF), which was then set in the first stage. Next, 1.2 g of the prototype adsorbent activated carbon was filled into a 45 mm diameter case in the second stage, and air at 22-24°C was blown through the PUF in the first stage and the fibrous activated carbon in the second stage at a rate of 20 l / min for 48 hours.

[0056] After aeration, the prototype activated carbon adsorbent was thoroughly contacted and stirred with 15 ml of a mixed solvent mainly composed of dichloromethane and ethyl acetate, then centrifuged to separate the solid and liquid, and the extract was collected.

[0057] The extract was quantitatively measured using GC-MS / MS (Waters QuatrimicroGC) in MRM mode to confirm its collection performance.

[0058] Table 2 shows the recovery rate (%) of fluoritelomeric alcohol (FTOH) for each target substance in the activated carbon of prototype examples 1 to 5. The target substances are 4:2FTOH (IUPAC name: 3,3,4,4,5,5,6,6,6-nonafluoro-1-hexanol), 6:2FTOH (IUPAC name: 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanol), 8:2FTOH, 10:2FTOH (IUPAC name: 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-henicosafluoro-1-dodecanol), and N-EtFOSA.

[0059] [Table 2]

[0060] In the table, "ND" indicates that the value is below the limit of quantification. Note that in some cases, recovery rates exceeding 150% were observed due to co-elution, where the same mass number affects the same fragment.

[0061] [Investigation of the collection performance of per- and polyfluoroalkyl compounds in atmospheric samples, Part 2] Next, the inventors re-examined the optimal transition and collision energy of the GC-MS / MS MRM mode using prototype examples 6-21 below, and conducted collection experiments 2 of per- and polyfluoroalkyl compounds in atmospheric samples under more precise analytical conditions.

[0062] [Preparation of prototype examples] <Prototype Example 6> 10g of Futamura Chemical's fibrous activated carbon "CF" (C1) was used as the activated carbon for prototype example 6.

[0063] <Prototype Example 7> Ten g of Futamura Chemical's fibrous activated carbon "CF" (C1) was immersed in 500 ml of a 4.2% hydrogen peroxide solution, left to stand for 220 hours, then removed and dried to obtain the activated carbon for Prototype Example 7.

[0064] <Prototype Example 8> 10g of Futamura Chemical's fibrous activated carbon "FE3010" (C2) was used as the activated carbon for prototype example 8.

[0065] <Prototype Example 9> 10g of Futamura Chemical's fibrous activated carbon "FE3010" (C2) was immersed in 500ml of a 4.2% hydrogen peroxide solution, left to stand for 150 hours, then removed and dried to obtain the activated carbon for prototype example 9.

[0066] <Prototype Example 10> 10g of Futamura Chemical's fibrous activated carbon "FE3012" (C3) was used as the activated carbon for prototype example 10.

[0067] <Prototype Example 11> 10g of Futamura Chemical's fibrous activated carbon "FE3012" (C3) was immersed in 500ml of a 4.2% hydrogen peroxide solution, left to stand for 100 hours, then removed and dried to obtain the activated carbon for prototype example 11.

[0068] <Prototype Example 12> 10g of Futamura Chemical's fibrous activated carbon "FE3013" (C4) was immersed in 500ml of a 1.5% hydrogen peroxide solution, left to stand for 70 hours, then removed and dried to obtain the activated carbon for prototype example 12.

[0069] <Prototype Example 13> 10g of Futamura Chemical's fibrous activated carbon "FE3015" (C5) was used as the activated carbon for prototype example 13.

[0070] <Prototype Example 14> 10g of Futamura Chemical's fibrous activated carbon "FE3015" (C5) was immersed in 500ml of a 1.5% hydrogen peroxide solution, left to stand for 40 hours, then removed and dried to obtain the activated carbon for prototype example 14.

[0071] <Prototype Example 15> 10g of Futamura Chemical's fibrous activated carbon "FE3015" (C5) was immersed in 500ml of a 4.2% hydrogen peroxide solution, left to stand for 70 hours, then removed and dried to obtain the activated carbon for prototype example 15.

[0072] <Prototype Example 16> Ten g of Futamura Chemical's fibrous activated carbon "FE3015" (C5) was immersed in 500 ml of a 14.0% hydrogen peroxide solution, left to stand for 350 hours, then removed and dried to obtain the activated carbon for prototype example 16.

[0073] <Prototype Example 17> 10g of Futamura Chemical's fibrous activated carbon "FE3015" (C5) was immersed in 500ml of an 18.9% hydrogen peroxide solution, left to stand for 480 hours, then removed and dried to obtain the activated carbon for prototype example 17.

[0074] <Prototype Example 18> 10g of Futamura Chemical's fibrous activated carbon "FE3018" (C6) was used as the activated carbon for prototype example 18.

[0075] <Prototype Example 19> 10g of Futamura Chemical's fibrous activated carbon "FE3018" (C6) was immersed in 500ml of a 4.2% hydrogen peroxide solution, left to stand for 50 hours, then removed and dried to obtain the activated carbon for prototype example 19.

[0076] <Prototype Example 20> Teng of Futamura Chemical's coconut shell activated carbon "CW480SZ" (C7) was immersed in 500 ml of a 4.2% hydrogen peroxide solution, left to stand for 70 hours, then removed and dried to obtain the activated carbon for prototype example 20.

[0077] <Prototype Example 21> 10g of Futamura Chemical's phenol resin activated carbon "QW250" (C8) was immersed in 500ml of a 4.2% hydrogen peroxide solution, left to stand for 70 hours, then removed and dried to obtain the activated carbon for prototype example 21.

[0078] [Measurement of activated carbon 2] The surface oxide, specific surface area, and average pore diameter of prototype examples 6-21 were determined in the same manner as described in "Measurement of Activated Carbon 1" above.

[0079] [Micropore volume] Pore ​​volume was measured by nitrogen adsorption using an automated specific surface area / pore distribution analyzer ("BELSORP-miniII", manufactured by Microtrac-Bel Co., Ltd.). The sum of the micropore volumes (V) of prototypes 6-21 with pore diameters of 1 nm or less. mic )(cm 3 The dV / dD values ​​in the range of pore diameter less than 1 nm were determined by analyzing the t-plot of nitrogen gas adsorption isotherms using the MP method.

[0080] [Mesopore volume] The dV / dD values ​​for pore diameters in the range of 2 to 60 nm were analyzed using the DH method from nitrogen gas adsorption isotherms. Note that the diameter range for pore diameters of 2 to 60 nm in the analysis software is 2.43 to 59.72 nm. From these analysis results, the sum of the mesopore volumes (V) for prototype examples 6 to 21 in the range of pore diameters of 2 to 60 nm was calculated. met )(cm 3 We calculated / g).

[0081] [Volume difference] Volume difference (V) of prototype examples 6-21 s ) is the sum of the micropore volumes (V mic )(cm 3 (V) met )(cm 3 This is the value obtained by subtracting ( / g), and was calculated from equation (i) above.

[0082] The physical properties of the activated carbon for prototype examples 6-21 are shown in Tables 3 and 4. From top to bottom in Table 3 are: surface oxide content (meq / g), BET specific surface area (m²). 2 ( / g), average pore diameter (nm), micropore volume (V mic )(cm 3 ( / g), mesopore volume (V met )(cm 3 / g), volume difference (V s )(cm 3 It is / g).

[0083] [Table 3]

[0084] [Table 4]

[0085] [Table 5]

[0086] [Measurement of collection efficiency of perfluoroalkyl compounds in atmospheric samples 2] As per- and polyfluoroalkyl compounds, FTOHs were used to evaluate prototypes 6-21, similar to the collection experiment 1 described above.

[0087] Each standard substance was diluted with methanol to 100 ng / ml (100 ppb), and 100 μl of each was added to flexible polyurethane foam (PUF) and set in the first stage. Next, the prototype activated carbon was filled into a 47 mmφ case in the second stage so that the thickness when filled was approximately 2 mm, and air at 22-24°C was blown through the PUF in the first stage and the fibrous activated carbon in the second stage at a rate of 20 l / min for 48 hours.

[0088] After aeration, the activated carbon from the prototype was transferred to a PP centrifuge tube (15 ml capacity), and 10 ml of a mixed solvent mainly composed of dichloromethane and ethyl acetate was added. The centrifuge tube was shaken at 225 rpm for 10 minutes, and the extract was collected. This extract collection process was repeated twice, and a total of 30 ml of extract was collected.

[0089] The collected extract was concentrated to 1 ml using a nitrogen-blown concentration device, and then quantitatively measured in MRM mode using a GC-MS / MS ("GCMS-TQ8050", manufactured by Shimadzu Corporation) to confirm its collection performance.

[0090] Tables 6-8 show the recovery rate (%) of fluorotelomer alcohols (FTOHs) for each target substance in the activated carbon of prototype examples 6-21. The target substances are 4:2FTOH (IUPAC name: 3,3,4,4,5,5,6,6,6-nonafluoro-1-hexanol), 6:2FTOH (IUPAC name: 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanol), 8:2FTOH, and 10:2FTOH (IUPAC name: 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-henicosafluoro-1-dodecanol).

[0091] [Table 6]

[0092] [Table 7]

[0093] [Table 8]

[0094] In the table, "ND" indicates that the value is below the limit of quantification. Compared to collection experiment 1, the variability in the mass spectrometry measurements was reduced for each value.

[0095] [Results and Discussion] In prototype examples 6-9, the recovery rate for all FTOH was below the limit of quantification, indicating insufficient adsorption of the target substance. It is presumed that the adsorption performance was not achieved because the pores or specific surface area necessary for the adsorption of the target substance were not present.

[0096] Prototypes 10-21 were recoverable for all FTOH. The BET specific surface area was 900 m². 2It was shown that adsorption of the target substance is possible when the amount is greater than / g. It is inferred that the specific surface area parameter of the activated carbon has a certain effect on the adsorption performance of each FTOH. In particular, prototype examples 10-19, which are fibrous activated carbon, showed good results with recovery rates of 50% or more for all FTOH. From the viewpoint of contact efficiency between the target substance and activated carbon, it is thought that fibrous activated carbon allows for more efficient adsorption of FTOH.

[0097] Furthermore, it was shown that activated carbon with well-developed micropores and mesopores exhibits higher adsorption performance for all types of FTOH. In prototypes 6 and 7, neither micropores nor mesopores were well-developed, and it is thought that no FTOH was adsorbed. In prototypes 8 and 9, while micropores were well-developed, mesopores were not. As a result, there were fewer mesopores on the entrance side of the activated carbon pores, and it is thought that FTOH molecules were not smoothly introduced into the micropores, leading to no adsorption.

[0098] In prototypes 10-21, both the micropore and mesopore volumes were large, suggesting that both types of pores were well-developed. This likely allowed FTOH molecules to be smoothly introduced into the activated carbon pores, resulting in excellent adsorption performance. Prototypes 12-19 showed particularly excellent FTOH recovery performance. All of prototypes 12-19 are characterized by large micropore volumes and well-developed mesopores, although the mesopore volumes are not as large. After adsorbing FTOH molecules into the micropores, they are easily detached from the pores during the extraction process, which is likely why they showed particularly good recovery rates.

[0099] In contrast, prototypes 20 and 21 have large pore volumes for both micropores and mesopores, indicating that they are activated carbons with complexly developed pores ranging from large to small. It is presumed that FTOH molecules adsorbed within these complexly developed pores are less easily removed during the extraction process, resulting in a slightly lower FTOH recovery rate compared to prototypes 12-19. Considering these results, the sum of the pore volumes of the micropores of the activated carbon (V mic ), sum of pore volumes of mesopores (Vmet ) and the difference between them, which is the volume difference (V s It is understood that this affects the recovery rate of FTOH.

[0100] Furthermore, in addition to the pore conditions of the activated carbon, we investigated whether improving the amount of surface oxides would enhance the affinity with hydrophilic FTOH and thus improve the adsorption performance of FTOH. Comparing prototype examples 14-17, which had an increased amount of surface oxides, with prototype example 13 using the same activated carbon raw material, prototype examples 14-17 showed better adsorption performance. Similarly, in prototype example 19, which had a higher amount of surface oxides, showed better adsorption performance than prototype example 18. Therefore, it is understood that increasing the amount of surface oxides in activated carbon can further improve the adsorption performance of FTOH. [Industrial applicability]

[0101] The per- and polyfluoroalkyl compound adsorption activated carbon of the present invention can adsorb per- and polyfluoroalkyl compounds in atmospheric samples, thereby enabling quantitative measurement of these compounds, which was not possible with existing adsorption materials. This allows for effective quantitative evaluation of persistent organic pollutants.

Claims

1. BET specific surface area is 900 m ２ It consists of activated carbon adsorbent material with a concentration of 1 / g or more, The average pore diameter is 1.64–1.89 nm. The sum of the micropore volumes of the activated carbon adsorbent with a micropore volume of 1 nm or less as defined in the following formula (i) (V ｍｉｃ ) and the sum of the mesopore volumes from 2 to 60 nm (V ｍｅｔ ) Volume difference (V ｓ ) is 0.45 cm ３ / g or more For adsorption of per and polyfluoroalkyl compounds in atmospheric samples Activated carbon for adsorption of per- and polyfluoroalkyl compounds in atmospheric samples. [Math 1]

2. The sum of the micropore volumes of the activated carbon adsorbent (V ｍｉｃ ) is 0.35 cm ３ The activated carbon for adsorbing per and polyfluoroalkyl compounds in an atmospheric sample according to claim 1, wherein the amount is 1 / g or more.

3. The sum (V ｍｅｔ ) of the mesopore volumes of the activated carbon adsorbent is 0.02 cm ３ / g or more, and the activated carbon for adsorbing perfluoroalkyl and polyfluoroalkyl compounds in an air sample according to claim 1 or 2.

4. The activated carbon for adsorbing per and polyfluoroalkyl compounds in an atmospheric sample according to any one of claims 1 to 3, wherein the surface oxide content of the activated carbon adsorbent is 0.10 meq / g or more.

5. The activated carbon for adsorbing per and polyfluoroalkyl compounds in an atmospheric sample according to any one of claims 1 to 4, wherein the activated carbon adsorbent is fibrous activated carbon.

6. An adsorption filter body for per and polyfluoroalkyl compounds in an atmospheric sample, characterized by holding the adsorption activated carbon described in any one of claims 1 to 5.

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