Primary aminated polyamide adsorbent as well as preparation method and application thereof

Abstract

The invention relates to a primary aminated polyamide adsorbent as well as a preparation method and application thereof. The adsorbent has a hydrophobic aromatic skeleton and a chain-length-adjustable primary amine group at the same time, that is, the adsorbent contains a hydrophobic benzene ring and an amino group which is easy to protonate; in the preparation process, benzene tetracarboxylic dianhydride and 1, 3, 5-tri (4-aminophenyl) benzene are used as raw materials, a polyimide covalent organic polymer is prepared under the microwave heating condition by adopting a polyimide dehydration condensation reaction, and then the polyimide covalent organic polymer is prepared under the condition of no metal or catalyst. Carrying out ring-opening reaction on the porous polyimide polymer and alkyl diamine molecules with different chain lengths to obtain the primary aminated polyamide adsorbent PA-X. The adsorbent obtained by the invention can synergistically adsorb and remove PFAS through the electrostatic interaction of protonated primary amine or amide groups and the hydrophobic interaction of benzene ring elements, and meanwhile, the adsorbent is washed and regenerated through a sodium chloride methanol solution, so that the cyclic utilization of the adsorbent is realized.

Description

Technical Field

[0001] The invention belongs to the field of environmental materials, and in particular relates to a primary aminated polyamide adsorbent and a preparation method and application thereof. Background Art

[0002] Per- and polyfluoroalkyl substances (PFAS) are a class of persistent organic micropollutants that pose potential risks to human health due to their ecological persistence, bioaccumulation, mutagenicity, reproductive toxicity, and developmental toxicity. Perfluorooctane sulfonic acid (PFOS), one of the most common water-soluble perfluorinated compounds, is commonly used in waterproofing products and the chrome plating industry, and electroplating plant wastewater often contains high concentrations of PFOS. Adsorption technology has advantages in removing water-soluble pollutants due to its simplicity, convenience, and lack of secondary pollution. Covalent organic polymers (COPs) are polymer materials constructed from organic compounds based on lightweight elements (carbon, nitrogen, oxygen, and hydrogen) linked by covalent bonds. They offer advantages such as structural design, high specific surface area, good stability, and ease of preparation, showing potential applications in adsorption and separation. The micro- and nanopores in COPs not only facilitate the transport of guest species such as small molecules and ions, but also allow for the modification of their pore surfaces with various functional groups. Although these materials have been used to remove PFAS from water, they still face one or more challenges, including slow adsorption kinetics, low adsorption capacity, insufficient selectivity, difficulty in regeneration, and poor stability. Therefore, the development of new adsorbents that can achieve rapid, efficient, and reversible adsorption and removal of PFAS from water is of great significance.

[0003] The patent "An Aminated Covalent Organic Polymer Adsorbent, Preparation Method, and Application thereof" (Patent No. ZL202210639812.5) utilizes a Friedel-Crafts acylation reaction to connect a pterygium compound with aromatic tetracarboxylic dianhydride to prepare a carboxylated covalent organic polymer (COP-COOH). This is then modified post-synthetically with a polyamine compound to yield an aminated covalent organic polymer (COP-NH2). Because the adsorbent's synthesis requires the addition of an anhydrous metal salt (AlCl3) catalyst and multiple additional organic base catalysts, it suffers from its reliance on metal and organic base catalysts.

[0004] Therefore, it is extremely important to develop new synthetic routes and prepare new primary aminated polyamide adsorbents with fast PFAS adsorption rate, large adsorption capacity and good recyclability. Summary of the Invention

[0005] The present invention addresses the shortcomings of current technologies by providing a primary aminated polyamide adsorbent, its preparation method, and application. This adsorbent possesses both a hydrophobic aromatic skeleton and primary amine groups with adjustable chain lengths, namely, a hydrophobic benzene ring and an easily protonated amine group. In its preparation, pyromellitic dianhydride and 1,3,5-tris(4-aminophenyl)benzene are used as raw materials. First, a polyimide covalent organic polymer (PI-COF-2) is prepared by a polyimide dehydration condensation reaction under microwave heating. Then, the porous polyimide polymer undergoes a ring-opening reaction with alkyldiamine molecules of varying chain lengths (ethylenediamine, 1,4-butanediamine, or 1,6-hexanediamine) without the need for metals or catalysts, yielding the primary aminated polyamide adsorbent PA-X. The adsorbent can remove PFOS through the synergistic adsorption of protonated primary amine or amide groups and the hydrophobic interaction of the benzene ring moiety. The adsorbent can be regenerated by washing with a sodium chloride methanol solution, enabling its recycling.

[0006] The technical solution of the present invention is:

[0007] A series of primary aminated polyamide adsorbents, using a stable PI-COF-2 as the parent framework, are synthesized into PA-X (X = EA, DA, or HA) through a ring-opening reaction with ethylenediamine (EA), 1,4-butanediamine (DA), or 1,6-hexanediamine (HA) molecules under mild conditions. The structural formula of the adsorbent is one of the following three:

[0008]

[0009] The preparation method of the primary aminated polyamide adsorbent comprises the following steps:

[0010] (1) Preparation of PI-COF-2: An acid anhydride compound, an amino aromatic compound, and a catalyst are added to a first organic solvent; the reaction is carried out at 180-200°C by microwave heating for 2-3 hours, followed by cooling to room temperature and filtering; the reaction is then washed and dried under vacuum to obtain a polyimide covalent organic polymer PI-COF-2;

[0011] Wherein, the molar ratio of the acid anhydride compound to the amino aromatic compound is 3:2;

[0012] Add 0.05-0.20 mmol of anhydride compound per 1 ml of the first organic solvent;

[0013] The catalyst is isoquinoline; the volume ratio of the organic solvent to the catalyst is 20:1-2;

[0014] (2) Preparation of PA-X: Add a second organic solvent and a polyamine to the PI-COF-2 obtained in step (1); stir and react at 60° C. for 0.5 to 3 hours by microwave heating, filter, wash, and vacuum dry to obtain a primary aminated polyamide adsorbent PA-X;

[0015] Wherein, the mass ratio is, PI-COF-2:polyamine=1:4-10;

[0016] Add 10-12 mg of PI-COF-2 per 1 ml of the second organic solvent;

[0017] In step (1), the acid anhydride is 1,2,4,5-pyromellitic dianhydride;

[0018] In step (1), the amino aromatic compound is 1,3,5-tris(4-aminophenyl)benzene;

[0019] In step (1), the first organic solvent is mesitylene and 1-methyl-2-pyrrolidone, and the volume ratio of the two is 1:1;

[0020] In step (2), the second organic solvent is tetrahydrofuran;

[0021] In step (2), the polyamine is ethylenediamine, 1,4-butanediamine or 1,6-hexanediamine;

[0022] In step (2), the reaction time is 0.5 to 1 hour for ethylenediamine, 1 to 2 hours for 1,4-butanediamine, and 2 to 3 hours for 1,6-hexanediamine;

[0023] The application of the primary aminated polyamide adsorbent is used for the adsorption of water-soluble PFAS;

[0024] Specifically comprising the following steps: adding a primary aminated polyamide adsorbent to an aqueous solution containing water-soluble PFAS at a pH value of 3 to 10, and performing adsorption under shaking at room temperature for 3 to 4 hours to complete adsorption;

[0025] The concentration of PFOS or F-53B in the aqueous solution is 10 to 500 mg L -1 ; Add 0.2-2 mg of adsorbent to every 1 ml of solution;

[0026] The aqueous solution of PFOS or F-53B also contains chloride ions or sulfate ions, with concentrations of 0 to 5 mmol L -1 ;

[0027] The water-soluble PFAS is specifically PFOS or F-53B.

[0028] The essential features of the present invention are:

[0029] Currently, the aminated COFs adsorbents used in the literature for adsorbing water-soluble per- and polyfluorinated alkyl sulfonic acid pollutants face difficulties in preparation. The development of a simple and efficient method to prepare primary amine polymers could provide new materials for the adsorption and removal of water-soluble perfluorinated pollutants. Polyimide covalent organic frameworks (PI-COFs) are a class of porous polymers whose polyimide rings can spontaneously react with small alkylamine molecules under certain conditions to form structurally tunable primary aminated polyamide adsorbents. This synthetic method offers the advantages of simple reaction, mild reaction conditions, and ease of scale-up.

[0030] The beneficial effects of the present invention are:

[0031] (1) The primary aminated polyamide (PA-X) adsorbent provided by the present invention has good thermal stability.

[0032] (2) The preparation method of the PA-X adsorbent provided by the present invention is simple and the organic amine functional groups are controllable.

[0033] (3) The PA-EA provided by the present invention is easily protonated in an acidic solution. The protonated PA-EA synergistically adsorbs PFOS or F-53B through electrostatic and hydrophobic interactions.

[0034] (4) The PA-EA provided by the present invention has a high saturated adsorption capacity of 2.84 mmol g for PFOS -1 , far exceeding COP-NH2 (1.40mmol g -1 ) and the benchmark material granular activated carbon GAC (0.78mmol g -1 ) and anion exchange resin IRA-900 (0.73 mmol g -1 ) adsorption capacity under optimized conditions.

[0035] (5) The initial adsorption rate (v0) of PA-EA for PFOS is 0.47 mmol g -1 min -1 , much higher than COP-NH2 (0.10mmol g -1 min -1 ) and granular activated carbon GAC (0.33×10 -3 mmol g -1 min -1 ) and IRA-900 (2.83×10 -3 mmol g -1 min -1 ) of the initial adsorption rate.

[0036] (6) PA-EA that adsorbs PFOS can reversibly desorb PFOS anions through chloride ion exchange to achieve regeneration.

[0037] (7) PA-EA can be reused for PFOS removal after treatment, and after five consecutive adsorption and desorption cycles, the PFOS removal efficiency still reaches over 95%. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 SEM images of PI-COF-2 and PA-X in Examples 1 to 3.

[0039] Figure 2 FT-IR spectra of PMDA, TAPB and PI-COF-2 in Example 1.

[0040] Figure 3 FT-IR spectra of Examples 1 to 3.

[0041] Figure 4 The solid state of PI-COF-2, PA-EA, PA-DA and PA-HA in Examples 1 to 3 13 C NMR spectrum.

[0042] Figure 5 Thermogravimetric diagrams of PI-COF-2, PA-EA, PA-DA and PA-HA in Examples 1 to 3.

[0043] Figure 6 These are the nitrogen adsorption curves of PI-COF-2, PA-EA, and PA-DA in Examples 1 to 3.

[0044] Figure 7 This is the adsorption isotherm of PFOS in water by PI-COF-2 in Example 4.

[0045] Figure 8 This is the adsorption isotherm of PFOS in water by PA-EA in Example 4.

[0046] Figure 9 This is the adsorption isotherm of PFOS in water by PA-DA in Example 4.

[0047] Figure 10 The adsorption kinetics of PFOS in water by PI-COF-2, PA-EA and PA-DA in Example 5.

[0048] Figure 11 This is the adsorption isotherm of PA-EA on F-53B in water in Example 6.

[0049] Figure 12 This is a diagram showing the effect of different pH values ​​on the adsorption efficiency of PFOS by PI-COF-2 and PA-EA in Example 7.

[0050] Figure 13 This is a diagram showing the effect of different interfering anions on the adsorption efficiency of PFOS by PA-EA in Example 8.

[0051] Figure 14 This is the result of the cyclic adsorption of PFOS by PA-EA in Example 9. DETAILED DESCRIPTION

[0052] Example 1: Preparation of primary amine functionalized polyamide (PA) adsorption material

[0053] Pelmetatetracarboxylic dianhydride (32.7 mg, 0.15 mmol) and 1,3,5-tris(4-aminophenyl)benzene (35.1 mg, 0.10 mmol) were dissolved in a mixed solution of mesitylene (0.50 mL), 1-methyl-2-pyrrolidone (0.50 mL) and isoquinoline (0.05 mL). The mixture was heated (190 ° C.) in a microwave tube for 3 hours, cooled to room temperature, and the precipitate was collected by filtration, washed with tetrahydrofuran, and soaked in tetrahydrofuran (20.0 mL) for 8 hours. PI-COF-2 was obtained by vacuum drying at 80 ° C. for 12 hours. The reaction structure is as follows.

[0054]

[0055] PI-COF-2 (120 mg), tetrahydrofuran (10 mL), and ethylenediamine (EA, 520 mg) were added to a microwave tube and microwaved at 60°C for 1 hour to synthesize the primary aminated polyamide adsorbent PA-X (X = EA, DA, HA). The product was then filtered, washed with CH3OH, and dried under vacuum at 60°C for 12 hours to obtain PA-X.

[0056] Example 2:

[0057] The other steps were the same as those in Example 1, except that ethylenediamine was replaced by DA (760 mg) instead of EA, and the reaction time was changed from 1 hour to 2 hours.

[0058] Example 3:

[0059] The other steps were the same as those in Example 1, except that EA was used instead of HA (1001 mg) and the reaction time was changed from 1 hour to 3 hours.

[0060] The reaction formulas in Examples 1-3 are as follows.

[0061]

[0062] Figure 1It shows that PA-EA, PA-DA and PA-HA obtained after modification of PI-COF-2 and primary amine all have spherical morphology with diameters of 0.5-2.0 μm.

[0063] Figure 2 In the FT-IR spectrum of PI-COF-2, the peaks at 1722 and 1778 cm -1 The strong peak at 1765 and 1859 cm-1 is attributed to the characteristic absorption peak of C=O on the five-membered ring of imide, indicating that imide reaction has occurred. -1 The characteristic peak of the stretching vibration of the anhydride between the two groups disappears, and the peak of 1,3,5-tris(4-aminophenyl)benzene (TAPB) at 3348 cm -1 The disappearance of the amino peak at , indicates that the dehydration condensation reaction of pyromellitic dianhydride and the amino aromatic compound is completed.

[0064] Figure 3 Compared with the FT-IR spectra of PI-COF-2, PA-EA, PA-DA and PA-HA showed the best results at 1650 and 1542 cm -1 The characteristic absorption peak of amide C=O appears at 1722cm -1 The imide C=O peak at 1361 cm -1 The characteristic peak of CNC at the connection node basically disappeared, indicating that the imide group reacted with the fatty primary amine to form an amide bond, confirming the structure of PA-EA, PA-DA and PA-HA adsorbents.

[0065] Figure 4 PA-EA and PI-COF-2 13 C solid NMR spectra, a methylene peak appeared at a chemical shift of 49.4; PA-DA and PI-COF-2 13 C solid NMR spectra, multiple methylene peaks appeared at chemical shifts of 48.0 and 33.8; PA-HA and PI-COF-2 13 Compared with the C solid NMR spectrum, multiple methylene peaks appeared at chemical shifts of 48.0 and 34.9, which further confirmed the structures of PA-EA, PA-DA and PA-HA adsorbents.

[0066] Figure 5 It shows that the thermal stability of PI-COF-2 in nitrogen atmosphere reaches 550℃, and the thermal stability of PA-EA, PA-DA and PA-HA reaches 150℃, after which the amide alkyl chain decomposes, reaching a slow degradation platform between 250℃ and 400℃, and then gradually decomposes.

[0067] Figure 6It shows that the BET specific surface area of ​​PI-COF-2 reaches 722 m 2 g -1 , while the BET specific surface areas of PA-EA and PA-DA are only 6 and 7 m 2 g -1 , indicating that the introduction of flexible primary amine alkyl chains significantly reduced the specific surface area of ​​the polyamide adsorbent.

[0068] Example 4:

[0069] The PA-X prepared in Examples 1 to 3 was used to remove PFOS from water by adsorption. The adsorption isotherm experiment was as follows: 6 mg of the adsorbent was added to 30 mL of a 100-500 mg L-1 PBS solution with a pH of 3.0. -1 The PFOS solution was placed in a closed system in a polymer centrifuge tube. After oscillation and adsorption for 4 hours at room temperature, a certain amount of the solution was filtered through a water filter membrane. The filtrate was measured by high performance liquid chromatography and conductivity detection to determine the concentration after adsorption, and the adsorption amount was calculated. The adsorption amount was calculated using the following formula:

[0070]

[0071] Among them, q t is the adsorption amount (mmol g -1 ); c0 and c t The concentrations of PFOS before and after adsorption (mmol L -1 ); V is the volume of the solution (L); m is the mass of the adsorbent (g).

[0072] In addition, the adsorption isotherm data were fitted using the Langmuir model, and the model equation is as follows:

[0073]

[0074] Among them, q t is the adsorption amount at time t (mmol g -1 );q m is the maximum saturated adsorption capacity (mmol g -1 );c e is the equilibrium concentration (mmol g -1 ); t is time (min); K L is the Langmuir constant.

[0075] like Figure 7 , Figure 8 and Figure 9 As shown in the figure, the maximum adsorption capacity of PI-COF-2, PA-EA, and PA-DA for PFOS is 1.12 mmol g -1 、2.84mmol g-1 、0.81mmol g -1 , which indicates that PA-X exhibits enhanced PFOS adsorption capacity.

[0076] Example 5:

[0077] The PA-X prepared in Examples 1 to 3 was used to remove PFOS from water by adsorption. The adsorption kinetics experiment was as follows: 15 mg of the adsorbent was added to 30 mL of a 250 mg L-1 flask with a pH of 3.0. -1 A PFOS solution was placed in a closed system in a polymer centrifuge tube. After adsorption at room temperature for a certain period of time, a certain amount of the solution was filtered through a water filter membrane. The filtrate was measured by high performance liquid chromatography and a conductivity detector to determine the adsorption concentration, and the adsorption amount was calculated. The adsorption amount was calculated using formula (1) in Example 4.

[0078] In addition, the adsorption kinetics data were fitted using a pseudo-second-order kinetic model. The model equation is as follows:

[0079]

[0080] Among them, q t is the adsorption amount at time t (mmol g -1 );q e is the equilibrium adsorption capacity (mmol g -1 ); t is time (min); v0 is the initial adsorption rate (mmol g -1 min -1 ).

[0081] from Figure 10 The adsorption kinetics curves show that the adsorption of PFOS by the adsorbent reaches adsorption equilibrium within two hours. The initial adsorption rates (v0) of PI-COF-2, PA-EA and PA-DA for PFOS are 0.29 mmol g -1 min -1 、0.47mmol g -1 min -1 and 0.07 mmol g -1 min -1 .

[0082] Example 6:

[0083] The PA-EA prepared in Example 1 was used to remove F-53B by adsorption in water. The adsorption isotherm experiment was conducted as follows: 6 mg of the adsorbent was added to 30 mL of a 100-500 mg L-1 flask with a pH of 3.0. -1The adsorption was carried out in a closed system with a vortex-shocked F-53B solution at room temperature for 3 hours. A certain amount of the solution was filtered through a water filter membrane. The filtrate was measured by high performance liquid chromatography and a conductivity detector to determine the concentration of adsorbed F-53B. The adsorption amount was calculated using formula (1) in Example 4.

[0084] right Figure 11 The Langmuir simulation of the adsorption isotherm in the results showed that the maximum adsorption capacity of PA-EA for F-53B was 3.23 mmol g -1 , which is greater than the adsorption amount of PFOS, which may be due to the stronger hydrophobicity of F-53B than PFOS. These results indicate that PA-EA has great application prospects in removing perfluorinated pollutants such as PFOS or F-53B.

[0085] Example 7:

[0086] The effect of pH on the adsorption efficiency of PFOS in water was studied using the adsorbents PI-COF-2 and PA-EA in Example 1. Specifically, 15 mg of the adsorbent was added to 30 mL of 250 mg L-1000 PBS with pH values ​​of 3, 5, 7, 9, and 11. -1 The adsorption was carried out in a closed system with shaking at room temperature for 4 hours. A certain amount of the solution was filtered through a water filter membrane, and the filtrate was measured by high performance liquid chromatography and conductivity detection to determine the adsorbed PFOS concentration. The adsorption amount was calculated using formula (1) in Example 4.

[0087] Figure 12 The results showed that as the pH value decreased, the adsorption capacity of PFOS by PI-COF-2 increased, while the adsorption capacity of PFOS by PA-EA increased significantly. The adsorption rate was the highest at pH 3.0, reaching 2.0 mmol g -1 This indicates that the primary amine and amide groups of PA-EA are protonated under acidic conditions, and can efficiently adsorb anionic PFOS pollutants through ionic interactions and hydrophobic interactions.

[0088] Example 8:

[0089] The adsorbent PA-EA in Example 1 was used to study the effect of interfering anions on the efficiency of adsorption and removal of PFOS in water. Specifically, 15 mg of adsorbent PA-EA was added to 30 mL of 250 mg L-100 solution with a pH of 3.0. -1 PFOS and interfering ions (1, 3, 5 mmol L -1 Cl - or 1, 3, or 5 mmol L -1 SO4 2-) in an aqueous solution in a closed system, with shaking adsorption at room temperature for 4 hours. A certain amount of the solution was filtered through an aqueous filter membrane, and the filtrate was measured for the adsorbed PFOS concentration using high-performance liquid chromatography and a conductivity detector. The adsorbed amount was calculated using formula (1) in Example 4, and the adsorption removal efficiency was calculated.

[0090] Figure 13 As shown, at 5 mmol L -1 Cl - or SO4 2- Under the influence of interfering ions, the removal rates of PFOS decreased from 98.1% to 92.8% and 83.2%, respectively, indicating that PA-EA has good anti-interference ability in the adsorption and removal of PFOS.

[0091] Example 9: Regeneration and removal of PFOS from water using adsorbent PA-EA

[0092] The PA-EA prepared in Example 1 was used for the cyclic test of adsorption and removal of PFOS in water. Specifically, 60 mg of PA-EA was added to 30 mL of 250 mg of L-1 PBS containing 250 mg of PFOS at a pH of 3.0. -1 The system was sealed and shaken at room temperature for 4 hours, followed by centrifugation. A certain amount of the supernatant was filtered through a water filter membrane. The filtrate was measured for the adsorbed PFOS concentration using high-performance liquid chromatography and a conductivity detector. The adsorption amount was calculated using formula (1) in Example 4, and the adsorption removal efficiency was calculated. At the same time, PA-EA adsorbed with PFOS was collected and added to 30 mL of regeneration solvent (30 / 70 v / v, 0.1 M NaCl / methanol). Ultrasonication was performed for 30 minutes, followed by shaking at room temperature for 30 minutes to desorb PFOS. The PA-EA was then filtered and collected for reuse.

[0093] Figure 14 It was shown that after five adsorption-desorption cycles, the adsorption efficiency of PA-EA for PFOS remained above 95% of the initial level, indicating the excellent regeneration performance of the adsorbent.

[0094] Matters not covered by the present invention are known technologies.

Claims

1. A primary aminated polyamide adsorbent, characterized in that the structural formula of the adsorbent is one of the following three:

2. The method for preparing the primary aminated polyamide adsorbent according to claim 1, wherein: The steps include: (1) Preparation of PI-COF-2: An acid anhydride compound, an amino aromatic compound, and a catalyst are added to a first organic solvent; the reaction is carried out at 180-200°C by microwave heating for 2-3 hours, followed by cooling to room temperature and filtering; the reaction is then washed and dried under vacuum to obtain a polyimide covalent organic polymer PI-COF-2; Wherein, the molar ratio of the acid anhydride compound to the amino aromatic compound is 3:2; Add 0.05-0.20 mmol of anhydride compound per 1 ml of the first organic solvent; The catalyst is isoquinoline; the volume ratio of the organic solvent to the catalyst is 20:1-2; (2) Preparation of PA-X: adding a second organic solvent and a polyamine to the PI-COF-2 obtained in step (1); heating by microwave and stirring for 0.5 to 3 hours, filtering, washing, and vacuum drying to obtain a primary aminated polyamide adsorbent PA-X; Wherein, the mass ratio is, PI-COF-2:polyamine=1:4-10; 10-12 mg of PI-COF-2 was added per 1 ml of the second organic solvent.

3. The method for preparing the primary aminated polyamide adsorbent according to claim 2, wherein: In step (1), the acid anhydride is 1,2,4,5-pyromellitic dianhydride; The amino aromatic compound described in step (1) is 1,3,5-tris(4-aminophenyl)benzene; The first organic solvent in step (1) is mesitylene and 1-methyl-2-pyrrolidone, and the volume ratio of the two is 1:1; The second organic solvent in step (2) is tetrahydrofuran; The polyamine described in step (2) is ethylenediamine, 1,4-butanediamine or 1,6-hexanediamine.

4. The method for preparing the primary aminated polyamide adsorbent according to claim 2, wherein: The reaction time in step (2) is 0.5 to 1 hour for ethylenediamine, 1 to 2 hours for 1,4-butanediamine, and 2 to 3 hours for 1,6-hexanediamine.

5. The use of the primary aminated polyamide adsorbent according to claim 1, characterized in that: Used for the adsorption of water-soluble PFAS.

6. The use according to claim 5, characterized in that The method comprises the following steps: adding a primary aminated polyamide adsorbent to an aqueous solution containing water-soluble PFAS under a pH value of 3 to 10, and performing adsorption under shaking at room temperature for 3 to 4 hours to complete adsorption; The concentration of PFOS or F-53B in the aqueous solution is 10 to 500 mg L -1 ; Add 0.2 to 2 mg of adsorbent to every 1 ml of solution.

7. The use according to claim 6, characterized in that The aqueous solution of the water-soluble PFAS also contains chloride ions or sulfate ions with a concentration of 0 to 5 mmol L -1 .

8. The use according to claim 6, characterized in that The water-soluble PFAS is specifically PFOS or F-53B.

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