TW202112676A - Active carbon for adsorbing perfluoroalkyl and polyfluoroalkyl compounds in water sample - Google Patents

Abstract

To provide: an active carbon for adsorbing perfluoroalkyl and polyfluoroalkyl compounds in a water sample, said active carbon having a high collection rate of water-sample-borne perfluoroalkyl and polyfluoroalkyl compounds; and a filter body using the active carbon. The present active carbon for adsorbing perfluoroalkyl and polyfluoroalkyl compounds in a water sample comprises an active carbon adsorbent wherein: the BET specific surface area is 800 m2/g or greater or the surface oxide content is 0.20 meq/g or less, or the BET specific surface area is 800 m2/g or greater and the surface oxide content is 0.50 meq/g or less; and the sum (Vmic) of 1 nm-or-less micropore volumes thereof is 0.30 cm3/g or greater. Said active carbon is for adsorbing perfluoroalkyl and polyfluoroalkyl compounds in a water sample such that it is possible to desorb said compounds.

Description

Activated carbon for adsorbing perfluorinated and polyfluorinated alkyl compounds in water samples

The present invention relates to an activated carbon capable of trapping perfluoro and polyfluoroalkyl compounds contained in water samples to adsorb perfluoro and polyfluoroalkyl compounds.

Perfluoro and polyfluoroalkyl compounds are fluorine-substituted aliphatic compounds with high thermal stability, high chemical stability, and high surface modification activity. Perfluoro and polyfluoroalkyl compounds utilize the aforementioned properties and are widely used in industrial and chemical applications such as surface treatment agents, packaging materials, and liquid fire extinguishing agents.

Some perfluorinated and polyfluorinated alkyl compounds are extremely stable chemical substances, and after being released into the environment, they are not easily decomposed under natural conditions. Therefore, in recent years, perfluorinated and polyfluoroalkyl compounds are widely known as persistent organic pollutants (POPs). Among them, perfluorooctane sulfonic acid (PFOS) (IUPAC name: 1,1,2,2,3,3) ,4,4,5,5,6,6,7,7,8,8,8-Heptafluorooctane-1-sulfonic acid) has been in the Stockholm Convention on Persistent Organic Pollutants since 2010 ( In the POPs Convention), its manufacture or use is regulated.

In addition, the perfluoroalkyl compound is a substance having a fully fluorinated linear alkyl group and represented by the chemical formula (i). For example, perfluorooctane sulfonic acid (PFOS) or perfluorooctanoic acid (PFOA) (IUPAC name: 2,2,3,3,4,4,5,5, 6,6,7,7, 8,8,8- Pentafluorooctanoic acid) and so on.

[Number 1]

The polyfluoroalkyl compound refers to a substance in which a part of the hydrogen of the alkyl group is replaced by fluorine, and is represented by the chemical formula (ii). For example, there are fluorine short-chain polymer alcohols and the like.

[Number 2]

As mentioned above, because perfluorinated and polyfluoroalkyl compounds will continue to remain in nature (water, soil, and air), some people have studied and established quantitative testing methods for perfluorinated and polyfluoroalkyl compounds. The research subject of the quantitative test method is to develop a collection material with high adsorption and desorption properties of perfluoro and polyfluoroalkyl compounds. It collects perfluoro and polyfluoroalkyl compounds by contacting water or air as a sample containing trace amounts of perfluorinated and polyfluoroalkyl compounds with the collecting material, and the extraction step makes the adsorbed on the collecting material The compound is separated into the extract and concentrated. After concentration, it can be quantitatively determined by LC-MS/MS or GC-MS/MS, etc., and the concentration of perfluoro and polyfluoroalkyl compounds contained in the sample can be determined.

As an existing collection material, for example, an organic fluorine-based compound adsorbent composed of a cyclodextrin polymer has been proposed (Patent Document 1). This adsorbent is specially modified to only adsorb the compound but cannot desorb it, so it is not suitable as a trapping material for quantitative determination. In addition, the cyclodextrin polymer is in the form of powder or fine particles, has poor handling properties, has high resistance when passing liquid or gas, and has problems such as the risk of fine powder flowing out to the secondary side.

Furthermore, perfluoro and polyfluoroalkyl compounds often remain in the environment in various forms with a wide range of physicochemical properties, and existing adsorbents do not have sufficient trapping performance, and there is a problem that quantitative determination cannot be accurately performed.

Therefore, the applicant in this case conducted research using activated carbon as a trap for perfluoro and polyfluoroalkyl compounds, and found that it can trap perfluoro and polyfluoroalkyl compounds and is extremely helpful for accurate quantitative determination. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] JP 2012-101159 A

[The problem to be solved by the invention]

The present invention was completed in view of the foregoing matters, and in particular provides an activated carbon capable of detachably trapping perfluoro and polyfluoroalkyl compounds in water samples to adsorb perfluoro and polyfluoroalkyl compounds in water samples And the filter body that uses it. [Means to solve the problem]

That is, the first invention relates to an activated carbon for adsorbing perfluoro and polyfluoroalkyl compounds in a water sample, which is used to detachably adsorb perfluoro and polyfluoroalkyl compounds in a water sample, wherein , The BET specific surface area of the activated carbon adsorbent is 800 m ² /g or more or the amount of surface oxide is 0.20 meq/g or less.

The second invention relates to an activated carbon for adsorbing perfluoro and polyfluoroalkyl compounds in a water sample, which is used to detachably adsorb perfluoro and polyfluoroalkyl compounds in a water sample, wherein the activated carbon The BET specific surface area of the adsorbent is 800 m ² /g or more, and the amount of surface oxide is 0.50 meq/g or less.

The third invention relates to the perfluorinated content in the adsorbed water sample in which _{the sum (V mic} ) of the micropore volume of 1 nm or less of the activated carbon adsorbent in the first or second invention is 0.30 cm ^{3 /g or more in the first or second invention.} Activated carbon for fluoroalkyl compounds.

The fourth invention relates to activated carbon of perfluoro and polyfluoroalkyl compounds in a water sample in which the aforementioned activated carbon adsorbent is fibrous activated carbon in any one of the first to third inventions.

The fifth invention relates to a filter for adsorbing perfluoro and polyfluoroalkyl compounds in a water sample, which is characterized by retaining the adsorbed activated carbon as in any one of the first to fourth inventions. [Effects of Invention]

According to the first invention, the activated carbon for adsorbing perfluoro and polyfluoroalkyl compounds in a water sample has a BET specific surface area of 800 m ² /g or more or a surface oxide content of 0.20 meq/g or less because of the activated carbon adsorbent It is used to detachably adsorb the perfluorinated and polyfluoroalkyl compounds in the water sample, and the activated carbon for the adsorption of perfluorinated and polyfluoroalkyl compounds, so it can detachably capture the compounds that have not been easy to quantitatively measure so far.

According to the second invention, the activated carbon for adsorbing perfluoro and polyfluoroalkyl compounds in a water sample has a BET specific surface area of 800 m ² /g or more, and a surface oxide content of 0.50 meq/g or less. It is used to detachably adsorb the perfluorinated and polyfluoroalkyl compounds in the water sample. The activated carbon for the adsorption of perfluorinated and polyfluoroalkyl compounds can be more effectively and detachably captured, which has not been easily quantitatively measured so far. Compound.

According to the third invention, the activated carbon for adsorbing the perfluoro and polyfluoroalkyl compounds in the water sample is the sum of the pore volume of the aforementioned activated carbon adsorbent with a pore volume of less than 1 nm (V _mic ) is 0.30 cm ³ /g or more, and can effectively and detachably trap perfluoro and polyfluoroalkyl compounds.

According to the fourth invention, the activated carbon for adsorbing perfluoro and polyfluoroalkyl compounds in a water sample is in any one of the first to third inventions, and the aforementioned activated carbon adsorbent is fibrous activated carbon. It can improve the contact efficiency with perfluoro and polyfluoroalkyl compounds, and can improve the adsorption performance.

According to the fifth invention, the filter for adsorbing perfluorinated and polyfluoroalkyl compounds in a water sample is formed by maintaining the adsorbed activated carbon of any one of the first to fourth inventions, so it can increase the perfluorinated and polyfluorinated compounds. The collection efficiency of fluoroalkyl compounds, and has good handling and handling.

[The form of implementing the invention]

The activated carbon of the perfluoro and polyfluoroalkyl compounds in the adsorbed water sample of the present invention is composed of fibrous activated carbon or granular activated carbon. The fibrous activated carbon is an activated carbon obtained by carbonizing and activating suitable fibers, and examples thereof include phenol resins, acrylic resins, celluloses, coal tar pitches, and the like. Fiber length or cross-sectional diameter is suitable.

As raw materials for granular activated carbon, there are raw materials such as wood (waste wood, thinned wood, sawdust), coffee bean filter residue, rice husk, coconut husk, bark, and fruit. These natural-derived raw materials are easy to be carbonized and activated to perfect the pores; in addition, because they are recycled waste, they can be supplied inexpensively. In addition, there are fired products derived from synthetic resins such as tires, petroleum pitch, urethane resins, and phenol resins; even coal, etc. can also be used as raw materials.

The activated carbon raw material is heated and carbonized in a temperature range of 200°C to 600°C as required to form fine pores. Next, the activated carbon raw material is exposed to water vapor and carbon dioxide in a temperature range of 600°C to 1200°C for activation treatment. As a result, activated carbon with well-formed various pores is formed. In addition, during activation, there are other zinc chloride activations. In addition, washing is performed successively.

The adsorption performance of the adsorbed substance is determined by the physical properties of the activated carbon thus formed. The adsorption performance of the activated carbon of the perfluoro and polyfluoroalkyl compounds that adsorb the target adsorbed substance of the present invention is specified by the specific surface area, which is an index indicating the amount of pores formed in the activated carbon. In addition, in this specification, the specific surface area of each prototype is measured according to the BET method (Brunauer, Emmett, and Teller method).

The adsorption performance of activated carbon is also determined by the acidic functional groups present on the surface of activated carbon. The acidic functional groups increased 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 will affect the trapping ability. The amount of these acidic functional groups can be grasped by the amount of surface oxides.

In water, the larger the amount of surface oxides of activated carbon, it is speculated that the water molecules strongly adsorbed on the surface functional groups due to hydrogen bonding and the resulting water molecule clusters are more likely to block the pores and hinder the target adsorbed substance from moving towards The physical access path of the adsorption point (micropore). Therefore, it is determined that the smaller the amount of surface oxides of activated carbon, the more the adsorption performance of the target adsorbed substance can be improved.

As a method for reducing the surface oxides of activated carbon, well-known methods such as heat treatment in an inert gas atmosphere can be used, which can reduce acidic functional groups such as phenolic hydroxyl groups or carboxyl groups on the surface of activated carbon.

In addition, activated carbon is also regulated by the pore diameter of the pores. In the case of an adsorbent such as activated carbon, there are any pores of micropores, mesopores, and macropores. Among them, the adsorption object and performance of activated carbon may change as the pores of any range are more perfected and formed. The activated carbon desired in the present invention can effectively adsorb molecules of perfluoro and polyfluoroalkyl compounds in a releasable manner.

The adsorption performance of activated carbon that can detachably adsorb the perfluoro and polyfluoroalkyl compounds in the water sample is as derived from the following examples, by making the specific surface area 800 m ² /g or more or the amount of surface oxides 0.20 meq/g or less to exert adsorption performance. Our research concluded that due to the acidic functional groups on the surface of activated carbon, the water molecules adsorbed by hydrogen bonding and the resulting water molecule clusters will block the pores. Therefore, when the amount of surface oxides is small, the ratio Activated carbon with a small surface area and a small amount of pores can still adsorb more than a certain amount of the compound. Conversely, even when the amount of surface oxides is large and the adsorption of the compound in the pores is hindered, as long as the activated carbon has a large specific surface area and a large amount of pores, the compound can be adsorbed in a certain amount or more.

In addition, as long as the specific surface area is above a predetermined value and the amount of surface oxides is below the predetermined value, the perfluoro and polyfluoroalkyl compounds in the water sample can be adsorbed more effectively and releasably. As shown in the following examples, by setting the BET specific surface area of the activated carbon adsorbent to be 800 m ² /g or more, and the amount of surface oxides to be 0.50 meq/g or less, the perfluorinated and polyfluorinated levels in the water sample can be further increased. Adsorption performance of alkyl compounds. [Example]

[Activated carbon adsorption material used] The inventors of the present application used the following raw materials in order to prepare activated carbon for adsorbing perfluoro and polyfluoroalkyl compounds. • Fibrous activated carbon Made by FUTAMURA CHEMICAL Co., Ltd.: Fibrous activated carbon "CF" (average fiber diameter: 15μm) {The following table is marked as C1} Made by FUTAMURA CHEMICAL Co., Ltd.: Fibrous activated carbon "FE3010" (average fiber diameter: 15μm) {The following table is marked as C2} Made by FUTAMURA CHEMICAL Co., Ltd.: Fibrous activated carbon "FE3012" (average fiber diameter: 15μm) {The following table is marked as C3} Made by FUTAMURA CHEMICAL Co., Ltd.: Fibrous activated carbon "FE3013" (average fiber diameter: 15μm) {The following table is marked as C4} Made by FUTAMURA CHEMICAL Co., Ltd.: Fibrous activated carbon "FE3015" (average fiber diameter: 15μm) {The following table is marked as C5} Made by FUTAMURA CHEMICAL Co., Ltd.: Fibrous activated carbon "FE3018" (average fiber diameter: 15μm) {The following table is marked as C6} • Granular activated carbon Made by FUTAMURA CHEMICAL Co., Ltd.: Coconut shell activated carbon "CW480SZ" (average particle size: 250μm) {The following table is marked as C7}

[Discussion on the capture performance of perfluoro and polyfluoroalkyl compounds in water samples 1] The inventors of the present case used the following trial example 1 to carry out the capture experiment 1 of perfluoro and polyfluoroalkyl compounds in a water sample.

[Preparation of trial example] ＜Prototype 1＞ 10 g of fibrous activated carbon "FE3015" (C5) manufactured by FUTAMURA CHEMICAL was immersed in 500 ml of a 6% hydrogen peroxide solution, and after standing for 70 hours, it was taken out and dried to prepare the activated carbon of Prototype Example 1.

[Determination of activated carbon 1] [Surface oxide amount] The amount of surface oxide (meq/g) is based on Boehm's method. The adsorbed activated carbon of each case is shaken in a 0.05N sodium hydroxide aqueous solution and then filtered. The filtrate is neutralized and titrated with 0.05N hydrochloric acid. The amount of sodium.

[BET specific surface area] The specific surface area (m ² /g) is obtained by measuring the nitrogen adsorption isotherm at 77K using the automatic specific surface area/pore distribution measuring device "BELSORP-miniII" manufactured by MicrotracBEL Co., Ltd., and obtained by the BET method (BET specific surface area).

[Average pore diameter] The average pore diameter (nm) assumes that the shape of the pore is cylindrical, and the value of the pore volume (cm ³ /g) and specific surface area (m ² /g) is calculated by the formula ( iii) Obtained.

[Number 3]

The physical properties of the activated carbon in the trial example 1 are shown in Table 1. From the top of Table 1, the amount of surface oxides (meq/g), the BET specific surface area (m ² /g), the average pore diameter (nm), and the average fiber diameter (μm) are listed in order.

[Measurement of the collection efficiency of perfluoro and polyfluoroalkyl compounds in water samples 1] As perfluoro and polyfluoroalkyl compounds, fluorine short-chain polymer alcohols (hereinafter referred to as "FTOHs") are used here. to evaluate. FTOHs are substances represented by the above chemical formula (ii), and the names of the substances vary with the number of carbons. For example, when it is C ₈ F ₁₇ CH ₂ CH ₂ OH, the system 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).

The standard reagents for each FTOH of the object were added to ultrapure water to prepare a test solution of 0.5 ng/ml (0.5 ppb).

0.2g of the fibrous activated carbon of Prototype Example 1 was filled in a 20ml syringe, and the test solution was introduced into 20ml of the above test solution at a rate of 1 drop/second. After 30 seconds of ventilation and dehydration, the adsorbed activated carbon in the syringe was fully contacted and stirred with a mixed solvent mainly composed of 15 ml of dichloromethane and ethyl acetate, and then solid-liquid separation was performed by centrifugal separation and the extract was collected.

This extract was quantitatively measured in the MRM mode by GC-MS/MS (QuatrimicroGC manufactured by Waters) to confirm the collection performance.

Table 2 shows the recovery rate (%) of FTOHs for each target substance for the activated carbon of Prototype Example 1. The target substances are 4:2FTOH, 6:2FTOH, 8:2FTOH, and 10:2FTOH.

[Discussion on the capture performance of perfluoro and polyfluoroalkyl compounds in water samples 2] Secondly, the inventors of this case used PFOA (C ₈ HF ₁₅ O ₂ ) and PFOS (C ₈ HF ₁₇ O ₃ S) as the whole For the fluorine and polyfluoroalkyl compounds, the trapping experiment 2 was performed and evaluated for the following trial examples 2-13.

[Preparation of trial example] ＜Prototype 2＞ 10 g of fibrous activated carbon "CF" (C1) manufactured by FUTAMURA CHEMICAL was used as the activated carbon of Prototype Example 2.

＜Prototype 3＞ 10 g of fibrous activated carbon "CF" (C1) manufactured by FUTAMURA CHEMICAL was immersed in 500 ml of a 4.2% hydrogen peroxide concentration solution, and after standing for 220 hours, it was taken out and dried to prepare the activated carbon of Trial Example 3.

＜Prototype 4＞ 10 g of fibrous activated carbon "FE3010" (C2) manufactured by FUTAMURA CHEMICAL was used as the activated carbon of Trial Example 4.

<Prototype example 5> 10 g of fibrous activated carbon "FE310" (C2) manufactured by FUTAMURA CHEMICAL was immersed in 500 ml of a 4.2% hydrogen peroxide solution, and after standing for 150 hours, the activated carbon was taken out and dried to prepare the activated carbon of Prototype Example 5.

<Prototype example 6> 10 g of fibrous activated carbon "FE3012" (C3) manufactured by FUTAMURA CHEMICAL was used as the activated carbon of Trial Example 6.

<Prototype Example 7> 10 g of fibrous activated carbon "FE3012" (C3) manufactured by FUTAMURA CHEMICAL was immersed in 500 ml of a 4.2% hydrogen peroxide concentration solution. After standing for 100 hours, it was taken out and dried to prepare the activated carbon of Prototype 7.

＜Prototype 8＞ 10 g of fibrous activated carbon "FE3013" (C4) manufactured by FUTAMURA CHEMICAL was immersed in 500 ml of a 1.5% hydrogen peroxide concentration solution, and after standing for 70 hours, it was taken out and dried to prepare the activated carbon of Prototype 8.

<Prototype example 9> 10 g of fibrous activated carbon "FE3015" (C5) manufactured by FUTAMURA CHEMICAL was used as the activated carbon of Trial Example 9.

＜Prototype 10＞ 10 g of fibrous activated carbon "FE3015" (C5) manufactured by FUTAMURA CHEMICAL was immersed in 500 ml of a 1.5% hydrogen peroxide concentration solution. After standing for 40 hours, the activated carbon was taken out and dried to prepare the activated carbon of Prototype 10.

＜Prototype example 11＞ 10 g of fibrous activated carbon "FE3015" (C) manufactured by FUTAMURA CHEMICAL was immersed in 500 ml of a 4.2% hydrogen peroxide concentration solution, and after standing for 70 hours, it was taken out and dried to prepare the activated carbon of Prototype Example 11.

＜Prototype 12＞ 10 g of fibrous activated carbon "FE3015" (C5) manufactured by FUTAMURA CHEMICAL was immersed in 500 ml of a 14.0% hydrogen peroxide solution, and after standing for 350 hours, the activated carbon was taken out and dried to prepare the activated carbon of Prototype Example 12.

<Prototype example 13> 10 g of fibrous activated carbon "FE3015" (C5) manufactured by FUTAMURA CHEMICAL was immersed in 500 ml of a 18.9% hydrogen peroxide concentration solution. After standing for 480 hours, the activated carbon was taken out and dried to prepare the activated carbon of Prototype Example 13.

<Prototype example 14> 10 g of fibrous activated carbon "FE3018" (C6) manufactured by FUTAMURA CHEMICAL was used as the activated carbon of Prototype Example 14.

＜Prototype 15＞ 10 g of fibrous activated carbon "FE3018" (C6) manufactured by FUTAMURA CHEMICAL was immersed in 500 ml of a 4.2% hydrogen peroxide concentration solution, and after standing for 50 hours, it was taken out and dried to prepare the activated carbon of Prototype 15.

<Prototype example 16> 10 g of fibrous activated carbon "FE3018" (C6) manufactured by FUTAMURA CHEMICAL was immersed in 500 ml of a 14.0% hydrogen peroxide solution, and after standing for 350 hours, the activated carbon was taken out and dried to prepare the activated carbon of Prototype 16.

<Prototype example 17> 10 g of fibrous activated carbon "FE3018" (C6) manufactured by FUTAMURA CHEMICAL was immersed in 500 ml of a 18.9% hydrogen peroxide concentration solution. After standing for 480 hours, the activated carbon was taken out and dried to prepare the activated carbon of Prototype Example 17.

＜Prototype 18＞ 10g of coconut shell activated carbon "CW480SZ" (C7) manufactured by FUTAMURA CHEMICAL was used as the activated carbon of trial example 18.

[Determination of activated carbon 2] The surface oxides, specific surface area, and average pore diameter of Prototype Examples 2 to 18 were obtained in the same manner as in the above-mentioned "Measurement of Activated Carbon 1".

[Micropore volume] The pore volume was measured by nitrogen adsorption using an automatic specific surface area/pore distribution measuring device ("BELSORP-miniII", manufactured by MicrotracBEL Co., Ltd.). _{The sum of the pore volume (V mic} ) (cm ³ /g) of the pore volume in the range of the pore diameter of 1 nm or less in the trial examples 2 to 18 is the dV/dD value of the pore diameter in the range of 1 nm or less by nitrogen The t-plot of the adsorption isotherm is obtained by analysis based on the MP method.

[Mesopore volume] The dV/dD value of the pore diameter in the range of 2-60 nm is analyzed by the DH method based on the adsorption isotherm of nitrogen gas. In addition, the pore diameter of the analytical software ranges from 2 to 60 nm in diameter from 2.43 to 59.72 nm. _{From the analysis results, the sum (V met} ) (cm ³ /g) of the mesopore volume of the pore volume in the range of pore diameter 2 to 60 nm in Prototype Examples 6-21 was obtained.

The physical properties of the activated carbons of trial production examples 2-18 are shown in Tables 3-5. From the top of Table 3, the amount of surface oxide (meq/g), BET specific surface area (m ² /g), average pore diameter (nm), micropore volume (V _mic ) (cm ³ /g), medium Pore volume (V _met ) (cm ³ /g).

[Determination of the collection efficiency of perfluoro and polyfluoroalkyl compounds in water samples 2] Perfluoro and polyfluoroalkyl compounds are evaluated using PFOA and PFOS.

The standard reagents of PFOA and PFOS of the target substance were added to ultrapure water, and the solution concentration of PFOA and PFOS was adjusted to 10 ng/ml (10ppb) to prepare a test solution.

0.2g of the above-mentioned test sample carbon was filled in a 20ml syringe, and 20ml of the test solution was introduced into the test solution at a rate of 1 drop/second. After the liquid is passed, the water in the activated carbon of the test sample in the syringe is removed by centrifugal separation. After that, 14 ml of methanol solution adjusted to an ammonia concentration of 0.01% was used to pass it into the dehydrated trial sample at a rate of 1 drop/second, and the extract was taken.

After concentrating the collected extract to 1 ml with a nitrogen blowing and concentrating device, the extract was quantitatively measured in MRM mode using LC-MS/MS ("LCMS-8030", manufactured by Shimadzu Corporation) to confirm the capture performance.

Tables 6 to 8 show the recovery rate (%) of each target substance for Prototype Examples 2 to 18. The target substances are PFOA and PFOS.

[Results and Investigation] In Trial Examples 3 and 5, both PFOA and PFOS have a low recovery rate, and the target substance cannot be sufficiently adsorbed. It is inferred that because the specific surface area is small and the amount of surface oxides is large, the pores for adsorbing the target substance are insufficient, and the adsorption performance cannot be exhibited.

In contrast, Trial Example 2 with a small specific surface area can sufficiently adsorb the target substance. It is believed that this is because the amount of surface oxides is small, and water molecules are adsorbed to the functional groups on the surface of activated carbon by hydrogen bonding, or the clogging of the pores caused by the resulting water molecule clusters is not easy to occur, and it is fully present. Even if the specific surface area is small, it can still adsorb the pores of the target substance. Therefore, it has been determined that the adsorption performance of activated carbon can be exerted well.

The trial samples 12, 13, 16, and 17 with a large amount of surface oxide also show that the target substance can be adsorbed. It is believed that this is because even though the amount of surface oxides is large and the clogging of pores caused by water molecules or clusters occurs, the large specific surface area still has sufficient pores for adsorbing the target substance. Therefore, it is determined that the adsorption performance of activated carbon can be exerted, and the adsorption performance of perfluoro and polyfluoroalkyl compounds can be shown. From these facts, it can be seen that the specific surface area is greater than the fixed value or the surface oxide amount is less than the fixed value, which is the condition to ensure the adsorption performance of the perfluoro and polyfluoroalkyl compounds in the water sample.

Observing the results of trial examples 9-13 and 14-17 that use the same activated carbon to change the amount of surface oxides, it can be understood that in the trial examples where the amount of surface oxides increased by the oxidation treatment, the oxidation treatment or non-oxidation treatment Oxidation treatment tends to be inferior to the trial case where the amount of surface oxides is less than the adsorption performance. Therefore, as mentioned above, with regard to the adsorption performance of perfluoro and polyfluoroalkyl compounds in water samples, it can be seen that the amount of surface oxides should be smaller.

If the comparative surface oxide amount is the same in the trial examples 2, 6, 9, and 14, it shows that if the specific surface area is more than a fixed value, the adsorption of the perfluoro and polyfluoroalkyl compounds in the water sample is good. Especially when the amount of surface oxides is small, as long as the BET specific surface area is 800 m ² /g or more, sufficient adsorption performance can be exerted; when the amount of surface oxides is large, the one with larger specific surface area will show better adsorption performance. The tendency.

If activated carbon with a large specific surface area and a small amount of surface oxides is used, it is shown that the adsorption performance can be further improved for both PFOA and PFOS. It is known that the permeable specific surface area is greater than a predetermined value and the amount of surface oxides is less than a predetermined value, which can further improve the adsorption performance of the perfluoro and polyfluoroalkyl compounds in the water sample and show a good recovery rate. In addition, from the viewpoint of the contact efficiency between the target substance and the activated carbon, it has been determined that if the fibrous activated carbon is used, the perfluoro and polyfluoroalkyl compounds can be adsorbed more effectively.

Furthermore, if the activated carbon that satisfies the above-mentioned conditions and completes the formation of the micropores is used, it can be inferred that the adsorption performance for the perfluoro and polyfluoroalkyl compounds in the water sample can be further improved. In addition, if the mesopores are perfectly formed, it is inferred that the molecules of the target substance can be smoothly introduced into the pores of the activated carbon to exhibit excellent adsorption performance. In addition, after studying and judging that the molecules of the target substance are adsorbed in the micropores, it is easy to smoothly detach them out of the pores during the extraction operation, and a good recovery rate is achieved. [Industrial availability]

The activated carbon for adsorbing the perfluoro and polyfluoroalkyl compounds in the water sample of the present invention can detachably adsorb the perfluoro and polyfluoroalkyl compounds in the water sample, and it can be used as a collection material that cannot be achieved. Quantitative determination of the compound. As a result, quantitative assessment of persistent organic pollutants can be effectively carried out.

Claims (5)

An activated carbon that adsorbs perfluoro and polyfluoroalkyl compounds in a water sample is used to detachably adsorb perfluoro and polyfluoroalkyl compounds in a water sample. Among them, the BET specific surface area of the activated carbon adsorbent It is 800 m ² /g or more or the amount of surface oxide is 0.20 meq/g or less. An activated carbon that adsorbs perfluoro and polyfluoroalkyl compounds in a water sample is used to detachably adsorb perfluoro and polyfluoroalkyl compounds in a water sample. Among them, the BET specific surface area of the activated carbon adsorbent It is 800 m ² /g or more, and the amount of surface oxide is 0.50 meq/g or less. For example, the activated carbon for adsorbing perfluoro and polyfluoroalkyl compounds in the water sample of claim 1 or 2, wherein the sum of the pore volume (V _mic ) of the ^{aforementioned activated carbon adsorbent below 1 nm is 0.30 cm 3} /g or more . The activated carbon for adsorbing perfluoro and polyfluoroalkyl compounds in a water sample according to any one of claims 1 to 3, wherein the aforementioned activated carbon adsorbent is fibrous activated carbon. A filter for adsorbing perfluorinated and polyfluoroalkyl compounds in a water sample, characterized by maintaining the adsorbed activated carbon according to any one of claims 1 to 4.