Composite amine-based resin for removing pfas in drinking water, and preparation method and application thereof

Abstract

The present application belongs to the technical field of environmental functional materials, and discloses a composite amine-based resin for removing PFAS in drinking water and a preparation method and application thereof. The method first prepares a macroporous white ball matrix through primary suspension polymerization, and then forms a macroporous-gel composite white ball through secondary suspension polymerization, thereby constructing a rigid skeleton structure with a certain specific surface area, unblocked mass transfer channel and certain crosslinking degree. The structure enables PFAS molecules to quickly reach the adsorption sites, ensures physical strength, improves safety and prolongs service life. At the same time, a composite amine reagent composed of long-chain alkyl tertiary amine and strong alkaline short-chain amine is used to form two kinds of quaternary ammonium anion exchange sites, thereby enhancing the selectivity to anionic perfluorinated compounds and reducing the interference of other substances in water. The obtained composite amine-based resin has high selectivity, high adsorption capacity and rapid adsorption capacity for PFAS, and can efficiently remove PFOS, PFOA and other PFAS pollutants in drinking water.

Description

Technical Field

[0001] This invention belongs to the field of environmental functional materials technology, and relates to a composite amine resin for removing PFAS from drinking water, its preparation method and application. Background Technology

[0002] Per- and polyfluoroalkyl substances (PFAS) are a class of approximately 5,000 man-made chemical compounds with extremely high carbon-fluorine bond energies in their molecular structure, giving them exceptional thermal stability and chemical inertness. This property has led to their widespread use in textile coatings, fire-fighting foams, and non-stick cookware. Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are among the most commonly detected typical substances in the environment. Due to their structural stability, PFAS are difficult to degrade, can persist in the environment for extended periods, and possess biotoxicity. Their toxicity can be amplified through the food chain, drawing widespread global attention. PFOS and PFOA are listed in the Stockholm Convention and are being phased out as persistent organic pollutants.

[0003] PFAS exhibits extremely high chemical stability, and various types of these substances have been detected in municipal water bodies, drinking water treatment plant effluents, and water sources in multiple locations. Traditional biochemical methods achieve a removal rate of less than 20%, and advanced oxidation processes struggle to effectively break carbon-fluorine bonds. Adsorption is currently the most feasible solution, but commercially available adsorbents have significant drawbacks: powdered activated carbon has weak adsorption capacity for short-chain PFAS, such as perfluorobutanoic acid (PFBA) and perfluorobutane sulfonate (PFBS), and is highly susceptible to competitive adsorption by natural organic matter in the water, resulting in low adsorption capacity and frequent replacement. While conventional anion exchange resins can adsorb PFAS through electrostatic adsorption, they suffer from poor selectivity, susceptibility to competition from inorganic anions, poor mechanical strength leading to breakage, and difficulty in balancing adsorption capacity and kinetic performance. Furthermore, relying solely on electrostatic interactions fails to fully utilize hydrophobic-fluoride-repellent interactions, limiting adsorption efficiency. Therefore, developing a dedicated PFAS adsorption material with high strength, high capacity, high selectivity, and long lifespan is a critical technical challenge that urgently needs to be addressed in this field. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a composite amine resin for removing PFAS from drinking water, its preparation method, and its application, thereby solving the technical problem that the adsorbent materials in the prior art cannot simultaneously achieve the desired strength, adsorption capacity, selectivity, and lifespan.

[0005] This invention is achieved through the following technical solution: A method for preparing a composite amine resin for removing PFAS from drinking water includes the following steps: S1: The first oil phase is added to the first aqueous phase, and a suspension polymerization reaction is carried out in stages with increasing temperature. After the reaction is completed, a macroporous white sphere matrix is ​​obtained. The porogen is extracted by steam and the macroporous white sphere matrix is ​​dried. The dried macroporous white sphere matrix is ​​added to an appropriate amount of saline solution, and the second oil phase is slowly added dropwise. After the dried macroporous white sphere matrix has fully swollen and absorbed the monomer, the second aqueous phase is added, and a second suspension polymerization reaction is carried out in stages with increasing temperature to obtain macroporous-gel composite white spheres. The first oil phase includes monomers, porogens, and initiators. The second oil phase includes monomers and initiators. The monomers in both the first and second oil phases are composed of styrene and divinylbenzene. S2: Mix the macroporous-gel composite white spheres with a chloromethylating agent, add a catalyst, and heat the reaction to obtain macroporous-gel composite chlorospheres; S3: Mix the macroporous-gel composite chlorine spheres with a polar aprotic solvent, first add a long-chain alkyl tertiary amine, then add a strongly basic short-chain amine, react and wash to obtain the composite amine resin for removing PFAS from drinking water.

[0006] Preferably, both the first aqueous phase and the second aqueous phase include a dispersant, an aqueous phase polymerization inhibitor, and saline solution; the ratio of the dispersant, the aqueous phase polymerization inhibitor, and the saline solution in the first aqueous phase and the second aqueous phase is (0.05~0.50)g:(0.0005~0.0010)g:100mL; and the NaCl content in the saline solution is 20%~24%.

[0007] Preferably, the mass ratio of monomer to porogen in the first oil phase is 100:(40~70).

[0008] Preferably, the mass ratio of initiator to monomer in both the first and second oil phases is (1~2):100.

[0009] Preferably, the primary suspension polymerization reaction specifically comprises: heating to 75-80℃ and holding for 2-4 hours, heating to 85-90℃ and holding for 2-4 hours, heating to 95-98℃ and holding for 4-6 hours; the secondary suspension polymerization reaction specifically comprises: heating to 70-75℃ and holding for 2-4 hours, heating to 80-85℃ and holding for 2-4 hours, heating to 90-95℃ and holding for 6-8 hours; Preferably, the ratio of the macroporous-gel composite white spheres to the chloromethylation reagent is 1 g:(4~8) mL.

[0010] Preferably, step S2 specifically involves: mixing macroporous-gel composite white spheres with a chloromethylation reagent, adding a catalyst, heating to 40-43°C, maintaining the temperature for 16-24 hours, separating the solid and liquid phases, and washing to obtain macroporous-gel composite chlorospheres.

[0011] Preferably, the long-chain alkyl tertiary amine is at least one selected from octyl dimethyl tertiary amine, decyl dimethyl tertiary amine, dodecyl dimethyl tertiary amine, tetradecyl dimethyl tertiary amine, hexadecyl dimethyl tertiary amine, octadecyl dimethyl tertiary amine, and docosyl dimethyl tertiary amine; the strongly basic short-chain amine is at least one selected from trimethylamine, triethylamine, tripropylamine, triisopropylamine, and tributylamine.

[0012] A composite amine resin for removing PFAS from drinking water is prepared by the above-described preparation method for the composite amine resin for removing PFAS from drinking water; the particle size of the composite amine resin is 0.5~1.25 mm.

[0013] The above-mentioned composite amine resin for removing PFAS from drinking water is used in the removal of perfluorinated compounds from drinking water.

[0014] Compared with the prior art, the present invention has the following beneficial technical effects: This invention discloses a method for preparing a composite amine resin for removing PFAS from drinking water. The method employs a two-step suspension polymerization: first, a macroporous white sphere matrix is ​​prepared, followed by a secondary polymerization to prepare macroporous-gel composite white spheres. This constructs a rigid framework with a large specific surface area and efficient mass transfer. This structure allows PFAS molecules to quickly reach the adsorption sites while maintaining the physical strength of the resin, reducing column pressure, improving equipment safety, and extending service life. Furthermore, this method uses a composite amination reagent composed of long-chain alkyl tertiary amines and short-chain tertiary amines to perform an amination reaction, generating two types of quaternary ammonium anion exchange sites. High-density positively charged groups and long-chain hydrophobic alkyl groups are simultaneously introduced. The short-chain ammonium anion exchange sites are mostly distributed in the inner layer of the resin particles, enhancing the selectivity for anionic perfluorinated compounds through electrostatic and hydrophobic-fluoride interactions. The long-chain and short-chain ammonium anion exchange sites synergistically interact with the hydrophobic chains and hydrophilic head groups of PFAS, reducing competitive interference from other substances in the water. The prepared macroporous-gel composite amine resin has a unique structure and function, exhibiting high selectivity, large capacity, and fast adsorption of PFAS. It can efficiently remove perfluorinated and polyfluoroalkyl pollutants such as PFOS and PFOA from drinking water, providing an effective solution to the problem of PFAS removal in drinking water.

[0015] Furthermore, both the first and second aqueous phases include a dispersant, an aqueous phase polymerization inhibitor, and saline solution. In both the first and second aqueous phases, the ratio of the dispersant, aqueous phase polymerization inhibitor, and saline solution is (0.05~0.50)g:(0.0005~0.0010)g:100mL. The saline solution contains 20%~24% NaCl. By limiting the composition of the first and second aqueous phases and the ratio of the dispersant, aqueous phase polymerization inhibitor, and saline solution, and specifying that the saline solution contains 20%~24% NaCl, the surface tension of the aqueous phase can be effectively reduced, allowing the oil phase monomers to be more stably dispersed into uniformly sized droplets. This prevents droplets from coalescing and agglomerating during polymerization, improves the particle regularity and batch stability of the white sphere matrix, ensures appropriate system density and osmotic pressure, reduces monomer water-soluble loss, and ensures smooth suspension polymerization.

[0016] Furthermore, the mass ratio of monomer to porogen in the first oil phase is 100:(40~70). By controlling the mass ratio of monomer to porogen in the first oil phase to 100:(40~70), sufficient and stable permanent pores can be formed in the macroporous white sphere matrix prepared by one-time suspension polymerization, optimizing the resin pore structure and specific surface area, ensuring that the monomer can fully penetrate into the interior of the white sphere matrix to participate in the crosslinking reaction during the second polymerization, and providing a reliable structural basis for constructing a macroporous-gel composite structure.

[0017] Furthermore, the mass ratio of initiator to monomer in both the first and second oil phases is (1~2):100. By controlling the mass ratio of initiator to monomer in both the first and second oil phases to (1~2):100, the polymerization reaction can be guaranteed to be initiated and carried out normally at a stable rate. This avoids incomplete reaction and high monomer residue due to insufficient initiator dosage, and also prevents problems such as explosive polymerization, sticking to the reactor, and abnormal particle morphology due to excessive initiator dosage, thereby improving reaction safety and resin quality uniformity.

[0018] Furthermore, the primary suspension polymerization reaction specifically involves: heating to 75-80℃ and holding for 2-4 hours, heating to 85-90℃ and holding for 2-4 hours, and heating to 95-98℃ and holding for 4-6 hours; the secondary suspension polymerization reaction specifically involves: heating to 70-75℃ and holding for 2-4 hours, heating to 80-85℃ and holding for 2-4 hours, and heating to 90-95℃ and holding for 6-8 hours. By employing segmented heating and precise holding process parameters for the primary and secondary suspension polymerizations, the resin skeleton can be gradually cross-linked and the pore structure can be formed in an orderly manner. The primary polymerization constructs a high-strength macroporous matrix, and the secondary polymerization forms a gel layer on the matrix. The macroporous structure ensures smooth mass transfer, and the gel structure provides sufficient adsorption sites, enabling the resin to simultaneously possess excellent mechanical strength, adsorption capacity, and rapid adsorption kinetics.

[0019] Furthermore, the ratio of the macroporous-gel composite white spheres to the chloromethylation reagent is 1g:(4~8)mL. By controlling the ratio of the macroporous-gel composite white spheres to the chloromethylation reagent to 1g:(4~8)mL, the chloromethylation reaction can be fully carried out, so that the chlorine content of the resin meets the design requirements, providing sufficient reaction sites for the subsequent amination reaction, ensuring that the final resin exchange capacity meets the standard, and avoiding excessive reagents that would lead to waste of raw materials, increased costs, and increased post-processing burden.

[0020] Further, step S2 specifically involves mixing macroporous-gel composite white spheres with a chloromethylation reagent, adding a catalyst, heating to 40-43°C, holding at that temperature for 16-24 hours, separating the solid and liquid phases, and washing to obtain macroporous-gel composite chlorospheres. By limiting the chloromethylation reaction temperature to 40-43°C and the holding time to 16-24 hours, sufficient and uniform chloromethylation modification can be achieved under mild conditions. This avoids excessively high reaction temperatures or long reaction times that could lead to resin skeleton degradation and increased side reactions, as well as prevents insufficient reaction resulting in low chlorine content, thus ensuring the stable quality of the resin functionalization precursor.

[0021] Furthermore, the long-chain alkyl tertiary amine is at least one of octyl dimethyl tertiary amine, decyl dimethyl tertiary amine, dodecyl dimethyl tertiary amine, tetradecyl dimethyl tertiary amine, hexadecyl dimethyl tertiary amine, octadecyl dimethyl tertiary amine, and docosyl dimethyl tertiary amine; the strongly basic short-chain amine is at least one of trimethylamine, triethylamine, tripropylamine, triisopropylamine, and tributylamine. By selecting specific long-chain alkyl tertiary amines and strongly basic short-chain amines as amination reagents, two quaternary ammonium anion exchange sites can be formed simultaneously on the resin. The long-chain alkyl provides strong hydrophobic-fluoride-repellent effects to enhance the selectivity for PFAS, while the short-chain amine provides high-density strongly basic sites to enhance electrostatic adsorption and adsorption rate. The synergistic effect of the two significantly reduces the interference of inorganic anions and natural organic matter in the water, enabling the resin to have both high selectivity, high adsorption capacity, and rapid removal ability for PFAS. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of the strong base anion exchange resin with complex amine groups prepared in this invention. Detailed Implementation

[0024] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0025] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0026] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0027] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0028] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0029] This invention provides a method for preparing a composite amine resin for removing PFAS from drinking water, comprising the following steps: S1: The first oil phase is added to the first aqueous phase, and a suspension polymerization reaction is carried out in stages with increasing temperature. After the reaction is completed, a macroporous white sphere matrix is ​​obtained. The pore-forming agent is extracted by steam and the macroporous white sphere matrix is ​​dried. The dried macroporous white sphere matrix is ​​added to an appropriate amount of saline solution, and the second oil phase is slowly added dropwise. After the dried macroporous white sphere matrix has fully swollen and absorbed the monomer, the second aqueous phase is added, and a second suspension polymerization reaction is carried out in stages with increasing temperature to obtain macroporous-gel composite white spheres. The first oil phase includes monomers, pore-forming agents, and initiators; the second oil phase includes monomers and initiators; both the first and second aqueous phases include dispersants, aqueous polymerization inhibitors, and brine. The primary suspension polymerization reaction is as follows: heating to 75-80℃ and holding for 2-4 hours, heating to 85-90℃ and holding for 2-4 hours, heating to 95-98℃ and holding for 4-6 hours; the secondary suspension polymerization reaction is as follows: heating to 70-75℃ and holding for 2-4 hours, heating to 80-85℃ and holding for 2-4 hours, heating to 90-95℃ and holding for 6-8 hours. The dispersant is at least one of gelatin, sodium carboxymethyl cellulose, polyvinyl alcohol, starch, and methyl cellulose; The aqueous polymerization inhibitor is methylene blue; Preferably, in the first aqueous phase and the second aqueous phase, the ratio of the dispersant, the aqueous phase inhibitor, and the brine is (0.05~0.50)g:(0.0005~0.0010)g:100mL; The monomer is composed of styrene and divinylbenzene; the mass ratio of monomer to porogen in the first oil phase is 100:(40~70). The mass ratio of initiator to monomer in both the first and second oil phases is (1~2):100.

[0030] The porogen is at least one of tetramethylbenzene, isododecane, and toluene.

[0031] The initiator is benzoyl peroxide or azobisisobutyronitrile.

[0032] Preferably, step S1 above specifically involves: adding the dispersant and aqueous phase inhibitor to brine with a density of d = 1.15~1.18 g / mL (NaCl content = 20%~24%), heating and stirring to prepare a first aqueous phase; mixing the monomer, porogen, and initiator to prepare a first oil phase; adding the first oil phase to the first aqueous phase and allowing it to stand until the first oil phase and the first aqueous phase completely separate; adjusting the stirring speed to adjust the particle size of the oil phase; then performing a segmented heat preservation operation to complete one suspension polymerization reaction; and finally, extracting water vapor after the reaction. The pore-forming agent was recovered, washed with water, and sieved to obtain a macroporous white sphere matrix with a particle size of 0.3~1.0 mm, which was then dried for later use. Then, a second aqueous phase was prepared by using a dispersant, an aqueous phase inhibitor, and brine. The dried macroporous white sphere matrix was added to an appropriate amount of brine. The monomer and initiator were prepared to form a second oil phase, which was then slowly dripped into the brine containing the macroporous white sphere matrix. After the macroporous white sphere matrix had fully swollen and absorbed the monomer, the prepared second aqueous phase was added, and a secondary suspension polymerization reaction was carried out by staged heating. After the reaction was completed, the macroporous-gel composite white spheres were obtained by washing.

[0033] S2: Mix macroporous-gel composite white spheres with chloromethylation reagent, add catalyst, and heat to react to obtain macroporous-gel composite chlorospheres; The ratio of macroporous-gel composite white spheres to chloromethylation reagent is 1 g:(4~8) mL.

[0034] The chloromethylating agent is chloromethyl ether; The catalyst is aluminum chloride (AlCl3), zinc chloride, or ferric chloride, with aluminum chloride being preferred.

[0035] Macroporous-gel composite white spheres were mixed with chloromethylation reagent, and then a catalyst was added. The mixture was heated to 40-43°C and kept at that temperature for 16-24 hours. After solid-liquid separation and washing, macroporous-gel composite chlorospheres were obtained.

[0036] S3: Preparation of macroporous-gel composite amine resin: The macroporous-gel composite chloride spheres are mixed with a polar aprotic solvent, and then long-chain alkyl tertiary amines and strong-base short-chain amines are added sequentially. Here, the long-chain alkyl tertiary amines and strong-base short-chain amines constitute a composite amination reagent. After reaction and washing, a strong-base anion exchange resin with composite amine groups is obtained, namely the macroporous-gel composite amine resin, which is also a composite amine resin for removing PFAS from drinking water in this invention.

[0037] A schematic diagram of the structure of the strong base anion exchange resin with complex amine groups is shown below. Figure 1 As shown in the figure, R=C n H 2n+1 (n=8~22), R1=C m H 2m+1 (m=1~4).

[0038] The long-chain alkyl tertiary amine is at least one selected from octyl dimethyl tertiary amine, decyl dimethyl tertiary amine, dodecyl dimethyl tertiary amine, tetradecyl dimethyl tertiary amine, hexadecyl dimethyl tertiary amine, octadecyl dimethyl tertiary amine, and docosyl dimethyl tertiary amine. The strongly basic short-chain amine is at least one of trimethylamine, triethylamine, tripropylamine, triisopropylamine, and tributylamine.

[0039] The polar aprotic solvent is at least one of methyl acetal, N,N-dimethylformamide, dimethyl sulfoxide, acetone, and tetrahydrofuran.

[0040] The obtained macroporous-gel composite amine resin has a particle size of 0.5~1.25 mm.

[0041] In addition, the present invention also discloses a composite amino resin for removing PFAS from drinking water prepared by the above method. The composite amino resin contains two kinds of amino functional groups, and the short-chain ammonium anion exchange sites are mainly concentrated in the inner layer of the resin particles, while the long-chain quaternary ammonium anion exchange sites are mainly distributed in the outer layer of the resin particles. The combination of the two can provide sufficient anion active sites and electrostatic adsorption capacity.

[0042] Meanwhile, this invention also discloses the application of the aforementioned composite amine resin in the removal of perfluorinated compounds from drinking water. The resin with composite amine functional groups is used for the deep removal of perfluorinated compounds from drinking water. Adsorption column application experiments have shown that the composite amine resin can reduce at least one of the perfluorinated compounds in tap water, including perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), and other perfluorocarboxylic acids and perfluorosulfonic acids, from an inlet concentration of 220 ng / L to below the national drinking water hygiene standard.

[0043] This invention optimizes the monomer-porogen ratio to prepare a resin with suitable specific surface area, unobstructed mass transfer channels, and a moderately cross-linked rigid framework. This ensures that PFAS molecules quickly reach adsorption sites while improving the resin's physical strength, extending its service life, reducing column pressure, and enhancing equipment operational safety. By employing long-chain tertiary amines such as octyl dimethyl tertiary amine, decyl dimethyl tertiary amine, dodecyl dimethyl tertiary amine, tetradecyl dimethyl tertiary amine, hexadecyl dimethyl tertiary amine, octadecyl dimethyl tertiary amine, and docosyl dimethyl tertiary amine, and comonodimethyl dimethyl amine, and short-chain amines such as trimethylamine, triethylamine, tripropylamine, triisopropylamine, and tributylamine, two types of quaternary ammonium anion exchange sites are introduced into the resin structure. This simultaneously achieves high-density loading of quaternary ammonium groups and long-chain hydrophobic alkyl groups, enhancing the resin's positive charge and improving selectivity for anionic perfluorinated compounds through electrostatic interactions and hydrophobic-fluoride synergistic effects. The outer layer of the resin particles mainly contains long-chain quaternary ammonium groups, which significantly reduces the interference of inorganic anions in water and ensures selectivity for PFAS. The short-chain quaternary ammonium groups are mainly distributed in the inner layer of the resin particles, working synergistically with the small amount of long-chain quaternary ammonium groups in the inner layer to ensure the adsorption capacity of PFAS. Through electrostatic interaction and hydrophobic-fluoride interaction, both selectivity and adsorption capacity are achieved.

[0044] The composite amine resin provided by this invention can efficiently remove PFAS (including PFOS, PFOA, etc.) from drinking water. By rationally controlling the pore structure, cross-linking framework and composite amine functional groups, the synergistic effect of electrostatic attraction, hydrogen bonding, multiple active sites and steric hindrance is achieved, giving the resin high selectivity for PFAS, high adsorption capacity, fast adsorption rate and excellent mechanical strength, effectively solving the problem of difficult removal of perfluorinated compounds in drinking water.

[0045] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0046] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0047] Example 1 A method for preparing a macroporous-gel composite amino resin includes the following steps: (1) Preparation of macroporous-gel composite white spheres: In a 1L three-necked flask, 2g of gelatin, 1g of sodium carboxymethyl cellulose, and 6mL of 0.1% methylene blue aqueous solution were dissolved in 600mL of brine (d=1.15g / mL) and stirred until homogeneous to obtain the first aqueous phase. 9.1g of divinylbenzene, 134.3g of styrene, 57.4g of toluene, and 1.43g of benzoyl peroxide were mixed and stirred until homogeneous to obtain the first oil phase. The homogeneous first oil phase was added to the first aqueous phase, and stirring was started to control the oil droplet size at approximately 0.3mm. The reaction was carried out in stages with increasing temperature: 75℃ for 3h, 85℃ for 3h, and 95℃ for 6h. After the reaction, the mixture was filtered and washed, and the pore-forming agent inside the white spheres was extracted by steam purging. The mixture was then dried at 100℃ to obtain the macroporous white sphere matrix.

[0048] In a three-necked flask, 100g of macroporous white sphere matrix and 200mL of brine (d=1.15g / mL) were mixed, stirred, and heated to 45℃ for later use. 9.1g of divinylbenzene, 134.3g of styrene, and 1.43g of benzoyl peroxide were mixed and stirred until homogeneous to obtain a second oil phase. The second oil phase was slowly added dropwise to the three-necked flask to allow the macroporous white sphere matrix to fully swell and absorb the oil phase. In another three-necked flask, 2g of gelatin, 1g of sodium carboxymethyl cellulose, and 6mL of 0.1% methylene blue aqueous solution were dissolved in 400mL of brine (d=1.15g / mL) and stirred until homogeneous to obtain a second aqueous phase. The second aqueous phase was added to the white sphere flask that had fully swelled and absorbed the oil phase. The reaction was carried out in stages: 70℃ for 3h, 80℃ for 3h, and 90℃ for 6h. After the reaction was completed, the flask was washed and dried to obtain macroporous-gel composite white spheres.

[0049] (2) Preparation of macroporous-gel composite chlorine spheres: Take 100g of macroporous-gel composite white spheres, add 400mL of chloromethyl ether, add 20g of anhydrous aluminum chloride in batches, heat to 40℃ and react for 16h; after the reaction is completed, wash with methyl acetal to obtain macroporous-gel composite chlorine spheres.

[0050] (3) Preparation of macroporous-gel composite amine resin: Take 100g of macroporous-gel composite chlorine spheres, add 550mL of methyl acetal, first add 51.4g of octyl dimethyl tertiary amine dropwise, heat to 40℃ and stir for 8h, then add 11g of triethylamine dropwise and continue the reaction for 8h. After the reaction is completed, wash with methyl acetal, then wash with a large amount of pure water until near neutral, and sieve to obtain macroporous-gel composite amine resin with a particle size of 0.5mm~1.25mm.

[0051] Example 2 A method for preparing a macroporous-gel composite amino resin includes the following steps: (1) Preparation of macroporous-gel composite white spheres: In a 1L three-necked flask, 0.75g gelatin, 0.75g sodium carboxymethyl cellulose, and 5mL of 0.1% methylene blue aqueous solution were dissolved in 600mL of brine (d=1.16g / mL) and stirred until homogeneous to obtain the first aqueous phase. 9.1g divinylbenzene, 134.3g styrene, 71.7g toluene, and 1.72g benzoyl peroxide were mixed and stirred until homogeneous to obtain the first oil phase. The homogeneous first oil phase was added to the aqueous phase, and stirring was started to control the oil droplet size at approximately 0.3mm. The reaction was carried out in stages with increasing temperature: 78℃ for 4 h, 88℃ for 4 h, and 98℃ for 6 h. After the reaction was completed, the mixture was filtered and washed, and the pore-forming agent inside the white spheres was extracted by steam purging. The mixture was then dried at 100℃ to obtain the macroporous white sphere matrix.

[0052] In a three-necked flask, 100g of macroporous white sphere matrix and 200mL of brine (d=1.16g / mL) were mixed, stirred, and heated to 45℃ for later use. 9.1g of divinylbenzene, 134.3g of styrene, and 1.72g of benzoyl peroxide were mixed and stirred until homogeneous to obtain a second oil phase. The second oil phase was slowly added dropwise to the three-necked flask to allow the macroporous white sphere matrix to fully swell and absorb the oil phase. In another three-necked flask, 0.75g of gelatin, 0.75g of sodium carboxymethyl cellulose, and 5mL of 0.1% methylene blue aqueous solution were dissolved in 400mL of brine (d=1.16g / mL) and stirred until homogeneous to obtain a second aqueous phase. The second aqueous phase was added to the white sphere flask that had fully swelled and absorbed the oil phase. The reaction was carried out in stages at 72℃ for 3h, 82℃ for 3h, and 92℃ for 6h. After the reaction was completed, the flask was washed and dried to obtain macroporous-gel composite white spheres.

[0053] (2) Preparation of macroporous-gel composite chlorine spheres: Take 100g of macroporous-gel composite white spheres, add 500mL of chloromethyl ether, add 20g of anhydrous aluminum chloride in batches, heat to 42℃ and react for 16h; after the reaction is completed, wash with N,N-dimethylformamide to obtain macroporous-gel composite chlorine spheres.

[0054] (3) Preparation of macroporous-gel composite amino resin: Take 100g of macroporous-gel composite chlorine beads, add 550mL of N,N-dimethylformamide, first add 59.3g of decyl dimethyl tertiary amine, heat to 80℃ and stir for 8h, then add 15.3g of tripropylamine and continue the reaction for 8h. After the reaction is completed, wash with N,N-dimethylformamide, then wash with a large amount of pure water until near neutral, and sieve to obtain macroporous-gel composite amino resin with a particle size of 0.5mm~1.25mm.

[0055] Example 3 A method for preparing a macroporous-gel composite amino resin includes the following steps: (1) Preparation of macroporous-gel composite white spheres: 0.3g polyvinyl alcohol, 0.3g sodium carboxymethyl cellulose and 4mL 0.1% methylene blue aqueous solution were dissolved in 600mL salt water (d=1.17g / mL) and stirred evenly to obtain the first aqueous phase. 9.1g divinylbenzene, 134.3g styrene, 78.9g tetramethylbenzene and 2.15g benzoyl peroxide were mixed and stirred evenly to obtain the first oil phase. The mixed first oil phase was added to the aqueous phase, and stirring was turned on to control the oil droplet size to about 0.3mm. The reaction was carried out in stages: 80℃ for 3h, 90℃ for 3h, and 97℃ for 8h. After the reaction was completed, the mixture was filtered and washed, and the pore-forming agent inside the white spheres was extracted by purging with steam. The mixture was dried at 100℃ to obtain the macroporous white sphere matrix.

[0056] In a three-necked flask, 100g of macroporous white sphere matrix and 200mL of brine (d=1.17g / mL) were mixed, stirred, and heated to 45℃ for later use. 9.1g of divinylbenzene, 134.3g of styrene, and 2.15g of benzoyl peroxide were mixed and stirred until homogeneous to obtain a second oil phase. This second oil phase was slowly added dropwise to the three-necked flask to allow the macroporous white sphere matrix to fully swell and absorb the oil phase. In another three-necked flask, 0.3g of polyvinyl alcohol, 0.3g of sodium carboxymethyl cellulose, and 4mL of 0.1% methylene blue aqueous solution were dissolved in 400mL of brine (d=1.17g / mL) and stirred until homogeneous to obtain a second aqueous phase. This second aqueous phase was added to the white sphere flask that had fully swelled and absorbed the oil phase. The reaction was carried out in stages: 70℃ for 3h, 85℃ for 3h, and 93℃ for 6h. After the reaction was completed, the flask was washed and dried to obtain macroporous-gel composite white spheres.

[0057] (2) Preparation of macroporous-gel composite chlorine spheres: Take 100g of macroporous-gel composite white spheres, add 600mL of chloromethyl ether, add 20g of anhydrous aluminum chloride in batches, heat to 43℃ and react for 18h; after the reaction is completed, wash with acetone to obtain macroporous-gel composite chlorine spheres.

[0058] (3) Preparation of macroporous-gel composite amine resin: Take 100g of macroporous-gel composite chlorine beads, add 550mL of acetone, first add 68.1g of dodecyl dimethyl tertiary amine, heat to 50℃ and stir for 8h, then add 30.5g of triisopropylamine and continue the reaction for 8h. After the reaction is completed, wash with acetone, then wash with a large amount of pure water until near neutral, and sieve to obtain macroporous-gel composite amine resin with a particle size of 0.5mm~1.25mm.

[0059] Example 4 A method for preparing a macroporous-gel composite amino resin includes the following steps: (1) Preparation of macroporous-gel composite white spheres: In a 1L three-necked flask, 0.15g gelatin, 0.15g sodium carboxymethyl cellulose and 3 mL of 0.1% methylene blue aqueous solution were dissolved in 600 mL of saline solution (d=1.18g / mL) and stirred evenly to obtain the first aqueous phase. 9.1g divinylbenzene, 134.3g styrene, 86g tetramethylbenzene and 2.86g perazobisisobutyronitrile were mixed and stirred evenly to obtain the first oil phase. The mixed first oil phase was added to the aqueous phase, and stirring was turned on to control the oil droplet size to about 0.3mm. The reaction was carried out in stages: 75℃ for 3h, 86℃ for 3h, and 95℃ for 8h. After the reaction was completed, the mixture was filtered and washed, and the pore-forming agent inside the white spheres was extracted by steam purging. The mixture was dried at 100℃ to obtain the macroporous white sphere matrix.

[0060] In a three-necked flask, 100 g of macroporous white sphere matrix was mixed with 200 mL of brine (d = 1.18 g / mL), stirred, and heated to 45 °C for later use. 9.1 g of divinylbenzene, 134.3 g of styrene, and 2.86 g of benzoyl peroxide were mixed and stirred until homogeneous to obtain a second oil phase. This second oil phase was slowly added dropwise to the three-necked flask to allow the macroporous white sphere matrix to fully swell and absorb the oil phase. In another three-necked flask, 0.15 g of gelatin, 0.15 g of sodium carboxymethyl cellulose, and 6 mL of 0.1% methylene blue aqueous solution were dissolved in 400 mL of brine (d = 1.18 g / mL) and stirred until homogeneous to obtain a second aqueous phase. This second aqueous phase was added to the white sphere flask that had fully swelled and absorbed the oil phase. The reaction was carried out in stages at 72 °C for 4 h, 82 °C for 4 h, and 95 °C for 8 h. After the reaction was completed, the flask was washed and dried to obtain macroporous-gel composite white spheres.

[0061] (2) Preparation of macroporous-gel composite chlorine spheres: Take 100g of macroporous-gel composite white spheres, add 700mL of chloromethyl ether, add 20g of anhydrous aluminum chloride in batches, heat to 41℃ and react for 20h; after the reaction is completed, wash with acetone to obtain macroporous-gel composite chlorine spheres.

[0062] (3) Preparation of macroporous-gel composite amine resin: Take 100g of macroporous-gel composite chlorine beads, add 550mL of acetone, first add 60.1g of tetradecyl dimethyl tertiary amine, heat to 50℃ and stir for 8h, then add 34.6g of tributylamine and continue the reaction for 8h. After the reaction is completed, wash with acetone, then wash with a large amount of pure water until near neutral, and sieve to obtain macroporous-gel composite amine resin with a particle size of 0.5mm~1.25mm.

[0063] Example 5 A method for preparing a macroporous-gel composite amino resin includes the following steps: (1) Preparation of macroporous-gel composite white spheres: In a 1L three-necked flask, 0.6g polyvinyl alcohol, 0.6g sodium carboxymethyl cellulose and 6 mL of 0.1% methylene blue aqueous solution were dissolved in 600 mL of brine (d=1.18g / mL) and stirred evenly to obtain the first aqueous phase. 9.1g divinylbenzene, 134.3g styrene, 100.4g isododecane and 1.43g azobisisobutyronitrile were mixed and stirred evenly to obtain the first oil phase. The mixed first oil phase was added to the aqueous phase, and stirring was turned on to control the oil droplet size to about 0.3mm. The reaction was carried out in stages: 80℃ for 3h, 90℃ for 3h, and 98℃ for 8h. After the reaction was completed, the mixture was filtered and washed, and the pore-forming agent inside the white spheres was extracted by steam purging. The mixture was dried at 100℃ to obtain the macroporous white sphere matrix.

[0064] In a three-necked flask, 100g of macroporous white sphere matrix and 200mL of brine (d=1.18g / mL) were mixed, stirred, and heated to 45℃ for later use. 9.1g of divinylbenzene, 134.3g of styrene, and 1.43g of azobisisobutyronitrile were mixed and stirred until homogeneous to obtain a second oil phase. The second oil phase was slowly added dropwise to the three-necked flask to allow the macroporous white sphere matrix to fully swell and absorb the oil phase. In another three-necked flask, 0.6g of polyvinyl alcohol, 0.6g of sodium carboxymethyl cellulose, and 6mL of 0.1% methylene blue aqueous solution were dissolved in 400mL of brine (d=1.18g / mL) and stirred until homogeneous to obtain a second aqueous phase. The second aqueous phase was added to the white sphere flask that had fully swelled and absorbed the oil phase. The reaction was carried out in stages at 75℃ for 4h, 85℃ for 4h, and 95℃ for 8h. After the reaction was completed, the flask was washed and dried to obtain macroporous-gel composite white spheres.

[0065] (2) Preparation of macroporous-gel composite chlorine spheres: Take 100g of macroporous-gel composite white spheres, add 800mL of chloromethyl ether, add 20g of anhydrous aluminum chloride in batches, heat to 43℃ and react for 24h; after the reaction is completed, wash with tetrahydrofuran to obtain macroporous-gel composite chlorine spheres.

[0066] (3) Preparation of macroporous-gel composite amine resin: Take 100g of macroporous-gel composite chlorine beads, add 550mL of tetrahydrofuran, first add 75.6g of hexadecyl dimethyl tertiary amine, heat to 60℃ and stir for 8h, then add 26.8g of triisopropylamine and continue the reaction for 8h. After the reaction is completed, wash with tetrahydrofuran, then wash with a large amount of pure water until near neutral, and sieve to obtain macroporous-gel composite amine resin with a particle size of 0.5mm~1.25mm.

[0067] Comparative Example 1 A method for preparing a macroporous composite amine resin includes the following steps: (1) Preparation of macroporous white sphere matrix: In a 1L three-necked flask, 2g of polyvinyl alcohol, 1g of sodium carboxymethyl cellulose and 6mL of 0.1% methylene blue aqueous solution were dissolved in 600mL of brine (d=1.15g / mL) and stirred evenly to obtain an aqueous phase. 14.14g of divinylbenzene, 134.3g of styrene, 100.4g of toluene and 1.48g of benzoyl peroxide were mixed and stirred evenly to obtain an oil phase. The mixed oil phase was added to the aqueous phase, and stirring was turned on to control the oil droplet size to about 0.3mm. The reaction was carried out in stages: 75℃ for 3h, 85℃ for 3h, and 95℃ for 8h. After the reaction was completed, the mixture was filtered and washed, and the pore-forming agent inside the white spheres was extracted by purging with steam. The mixture was dried at 100℃ to obtain the macroporous white sphere matrix.

[0068] (2) Preparation of macroporous chlorine spheres: Take 100g of macroporous white sphere matrix, add 400mL of chloromethyl ether, add 20g of anhydrous aluminum chloride in batches, heat to 41℃ and react for 18h; after the reaction is completed, wash with methyl acetal to obtain macroporous chlorine spheres.

[0069] (3) Preparation of macroporous composite amine resin: Take 100g of macroporous chlorine spheres, add 550mL of methyl acetal, first add 72.2g of tetradecyl dimethyl tertiary amine dropwise, heat to 40℃ and stir for 8h, then add 18.1g of triethylamine dropwise and continue the reaction for 8h. After the reaction is completed, wash with methyl acetal, then wash with a large amount of pure water until near neutral, and sieve to obtain macroporous composite amine resin with a particle size of 0.5mm~1.25mm.

[0070] Comparative Example 2 A method for preparing a macroporous amine resin includes the following steps: (1) Preparation of macroporous white sphere matrix: In a 1L three-necked flask, 0.75g gelatin, 0.75g sodium carboxymethyl cellulose and 5mL of 0.1% methylene blue aqueous solution were dissolved in 600mL of brine (d=1.18g / mL) and stirred evenly to obtain an aqueous phase. 14.14g divinylbenzene, 134.3g styrene, 74.2g tetramethylbenzene and 1.78g benzoyl peroxide were mixed and stirred evenly to obtain an oil phase. The mixed oil phase was added to the aqueous phase, and stirring was turned on to control the oil droplet size to about 0.3mm. The reaction was carried out in stages: 78℃ for 3h, 88℃ for 3h, and 98℃ for 8h. After the reaction was completed, the mixture was filtered and washed, and the pore-forming agent inside the white spheres was extracted by purging with steam. The mixture was dried at 100℃ to obtain the macroporous white sphere matrix.

[0071] (2) Preparation of macroporous chlorine spheres: Take 100g of macroporous white sphere matrix, add 600mL of chloromethyl ether, add 20g of anhydrous aluminum chloride in batches, heat to 43℃ and react for 16h; after the reaction is completed, wash with N,N-dimethylformamide to obtain macroporous chlorine spheres.

[0072] (3) Preparation of macroporous amine resin: Take 100g of macroporous chlorine balls, add 550mL of N,N-dimethylformamide, add 84.9g of decyl dimethyl tertiary amine dropwise, heat to 80℃ and stir for 16h. After the reaction is completed, wash with N,N-dimethylformamide, and then wash with a large amount of pure water until it is nearly neutral. The macroporous amine resin with a particle size of 0.5mm~1.25mm is obtained by sieving.

[0073] Comparative Example 3 A method for preparing a macroporous amine resin includes the following steps: (1) Preparation of macroporous white sphere matrix: In a 1L three-necked flask, 0.3g polyvinyl alcohol, 0.3g sodium carboxymethyl cellulose and 4mL of 0.1% methylene blue aqueous solution were dissolved in 600mL of brine (d=1.17g / mL) and stirred evenly to obtain an aqueous phase. 9.1g divinylbenzene, 134.3g styrene, 78.9g toluene and 2.15g azobisisobutyronitrile were mixed and stirred evenly to obtain an oil phase. The mixed oil phase was added to the aqueous phase, and stirring was started to control the oil droplet size to about 0.3mm. The reaction was carried out in stages: 80℃ for 3h, 90℃ for 3h, and 96℃ for 8h. After the reaction was completed, the mixture was filtered and washed, and the pore-forming agent inside the white spheres was extracted by purging with steam. The mixture was dried at 100℃ to obtain the macroporous white sphere matrix.

[0074] (2) Preparation of macroporous chlorine balls: The operation steps are the same as those in Comparative Example 2, and will not be repeated.

[0075] (3) Preparation of macroporous amine resin: Except for the amination reagent of 53.7g tripropylamine, the other operations are the same as those in comparative example 2, and will not be repeated here.

[0076] Comparative Example 4 A method for preparing a gel-type composite amino resin includes the following steps: (1) Preparation of gel white spheres: In a 1L three-necked flask, 0.15g gelatin, 0.15g sodium carboxymethyl cellulose and 3mL of 0.1% methylene blue aqueous solution were dissolved in 600mL of saline solution (d=1.16g / mL) and stirred evenly to obtain an aqueous phase. 14.14g divinylbenzene, 134.3g styrene and 2.67g benzoyl peroxide were mixed and stirred evenly to obtain an oil phase. The mixed oil phase was added to the aqueous phase, and stirring was turned on to control the oil droplet size to about 0.3mm. The reaction was carried out in stages: 75℃ for 4h, 85℃ for 4h, and 95℃ for 6h. After the reaction was completed, the mixture was filtered and washed, and dried at 100℃ to obtain gel white spheres.

[0077] (2) Preparation of chlorine balls: Take 100g of gel white balls, add 800mL of chloromethyl ether, add 20g of anhydrous aluminum chloride in batches, heat to 43℃ and react for 16h; after the reaction is completed, wash with N,N dimethylformamide to obtain gel chlorine balls.

[0078] (3) Preparation of gel-type composite amine resin: Take 100g of gel chlorine balls, add 550mL of N,N-dimethylformamide, first add 47.6g of octyl dimethyl tertiary amine, heat to 80℃ and stir for 8h, then add 43.3g of triisopropylamine and continue the reaction for 8h. After the reaction is completed, wash with N,N-dimethylformamide, then wash with a large amount of pure water until near neutral, and sieve to obtain gel-type composite amine resin with a particle size of 0.5mm~1.25mm.

[0079] Comparative Example 5 A method for preparing a gel-type amine resin includes the following steps: (1) Preparation of gel white spheres: In a 1L three-necked flask, 0.6g of gelatin, 0.6g of sodium carboxymethyl cellulose and 6mL of 0.1% methylene blue aqueous solution were dissolved in 600mL of saline solution (d=1.17g / mL) and stirred evenly to obtain an aqueous phase. 14.14g of divinylbenzene, 134.3g of styrene and 2.97g of azobisisobutyronitrile were mixed and stirred evenly to obtain an oil phase. The mixed oil phase was added to the aqueous phase, and stirring was turned on to control the oil droplet size to about 0.3mm. The reaction was carried out in stages: 73℃ for 4h, 84℃ for 4h, and 93℃ for 6h. After the reaction was completed, the mixture was filtered and washed, and dried at 100℃ to obtain gel white spheres.

[0080] (2) Preparation of chlorine balls: The operation steps are the same as those in Comparative Example 4, and will not be repeated.

[0081] (3) Preparation of gel-type amine resin: Take 100g of gel chlorine balls, add 550mL of acetone, add 55.7g of tributylamine, heat to 50℃ and stir for 16h. After the reaction is completed, wash with acetone and then wash with a large amount of pure water until it is nearly neutral. The gel amine resin with a particle size of 0.5mm~1.25mm is obtained by sieving.

[0082] Comparative Example 6 A method for preparing a gel-type amine resin includes the following steps: (1) Preparation of gel white spheres: The operation steps are the same as those in Comparative Example 4, and will not be repeated.

[0083] (2) Preparation of chlorine balls: The operation steps are the same as those in Comparative Example 4, and will not be repeated.

[0084] (3) Preparation of gel-type amine resin: Take 100g of gel chlorine balls, add 550mL of methyl acetal, add 156.8g of hexadecyl dimethyl tertiary amine, heat to 40℃ and stir for 16h. After the reaction is completed, wash with methyl acetal and then wash with a large amount of pure water until it is nearly neutral. The gel-type amine resin with a particle size of 0.5mm~1.25mm is obtained by sieving.

[0085] The differences between Examples 1-5 and Comparative Examples 1-6 are summarized here: the main differences lie in the preparation of white spheres, the use of amination reagents, and the type of resin structure. Specifically: 1. Preparation of white balls Examples 1-5: Preparation of macroporous-gel composite white spheres using a two-step method. The first step involves preparing a macroporous white sphere matrix by reacting monomers, porogens, and initiators in a specific ratio in an aqueous phase composed of brine, dispersant, and polymerization inhibitor. After controlling the particle size, the matrix undergoes heating, reaction, cooling, washing, porogen recovery, sieving, and drying to obtain a dry macroporous white sphere matrix. The second step involves adding the dried macroporous white sphere matrix stepwise to a newly prepared second aqueous phase, followed by a second oil phase without porogens. After sufficient swelling and absorption, a heating and holding process is performed to obtain macroporous-gel composite white spheres.

[0086] Comparative Examples 1-3: Macroporous white spheres were prepared by a one-step method, in which the oil phase was directly added to the aqueous phase for reaction. After controlling the particle size, the macroporous white spheres were obtained by heating, reaction, cooling, washing and drying. Subsequently, chlorination and amination reactions were carried out based on these dried macroporous white spheres.

[0087] Comparative Examples 4-6: Gel white spheres were prepared using the same one-step method, but without adding a porogen to the oil phase. The oil phase was added to the aqueous phase for reaction. After controlling the particle size, the gel white spheres were obtained by heating, reacting, cooling, washing, and drying. Chlorination and amination reactions were then carried out based on these gel white spheres.

[0088] 2. Use of amination reagents Examples 1-5: Two amination reagents were used in combination: long-chain alkylamines such as octyl dimethyl tertiary amine, decyl dimethyl tertiary amine, dodecyl dimethyl tertiary amine, tetradecyl dimethyl tertiary amine, hexadecyl dimethyl tertiary amine, octadecyl dimethyl tertiary amine, and docosyl dimethyl tertiary amine, and short-chain amines such as trimethylamine, triethylamine, tripropylamine, triisopropylamine, and tributylamine. Amination reactions introduced a complex amine functional group, forming two quaternary ammonium anion exchange sites. Simultaneously, high-density positively charged groups and long-chain hydrophobic alkyl groups were introduced. Electrostatic interactions and hydrophobic-fluoride interactions enhanced the selectivity for anionic perfluorinated compounds. Furthermore, the long-chain and short-chain ammonium anion exchange sites synergistically interacted with the hydrophobic and hydrophilic ends of the PFAS chains, reducing competitive interference from other substances in the water. The amount of complex amine added varied in different examples.

[0089] Comparative Example 1: Two amination reagents, a short-chain amine and a long-chain alkyl tertiary amine, were used.

[0090] Comparative Example 2: Only long-chain alkyl tertiary amines were used as amination reagents.

[0091] Comparative Example 3: Only short-chain amines were used as amination reagents.

[0092] Comparative Example 4: Two amination reagents were used: a short-chain amine and a long-chain alkyl tertiary amine.

[0093] Comparative Example 5: Only short-chain amines were used as amination reagents.

[0094] Comparative Example 6: Only long-chain alkyl tertiary amines were used as amination reagents.

[0095] 3. Resin structure type Examples 1-5: Macroporous-gel composite amine resins were prepared, which have the characteristics of both macroporous and gel structures. They have a certain specific surface area and unobstructed mass transfer channels, as well as a rigid skeleton structure with a certain degree of crosslinking.

[0096] Comparative Examples 1-3: Macroporous amine resins were prepared, which have only macroporous structures and good physical strength and certain mass transfer properties.

[0097] Comparative Examples 4-6: Gel-type amine resins were prepared, which only had a gel structure, relatively small specific surface area, and relatively narrow mass transfer channels.

[0098] The following describes the performance tests conducted on the resins of Examples 1-5 and Comparative Examples 1-6 as follows: Application experiments on the adsorption and removal of perfluorinated compounds were conducted on 11 resins, including Examples 1, 2, 3, 4, 5, Comparative Examples 1, 2, 3, 4, 5, and 6. Simulated wastewater preparation: 220 ng / L each of four perfluorinated compounds, PFOS, PFOA, perfluorobutyric acid (PFBA), and perfluorobutanesulfonic acid (PFBS), were added to tap water. The contents of calcium and magnesium in the tap water were measured to be approximately 100 mg / L, sodium ion content 30 mg / L, sulfate content 80 mg / L, chloride ion content 50 mg / L, and fulvic acid and humic acid totaling 0.1 mg / L. This was done to simulate the actual tap water environment as closely as possible and to reflect the removal effect of the resin in the actual water body.

[0099] Resin column chromatography experiment: Take 5 mL of each of the above 11 resins and place them in a chromatography column with an inner diameter of 1.5 cm. Use a peristaltic pump to control the water sample to pass through the resin column at a uniform flow rate of 50 BV / h. After continuous operation for 50 h, a total of 2500 BV of sample has passed through the column. Spot the 2500 BV sample and use liquid chromatography-tandem mass spectrometry to determine the concentration of perfluorinated substances in the sample. The results are shown in Tables 1 and 2 below: Table 1. Comparison of PFAS removal efficiency of resins prepared in each embodiment and comparative example in simulated wastewater.

[0100] Table 2. Adsorption and removal rates (%) of PFAS by the resins prepared in each example and comparative example in simulated wastewater.

[0101] Table 1 shows that the resins prepared in Examples 1-5 and Comparative Examples 1-6 exhibit significant differences in adsorption performance. The resins in the Examples show superior removal rates after 50 hours of operation. For example, regarding PFOS, the Examples show higher adsorption capacity and removal rates after 50 hours, indicating that the preparation method used in the Examples of this invention (macroporous-gel composite structure and the introduction of complex amine functional groups, etc.) effectively enhances the resin's adsorption capacity for perfluorinated compounds. Furthermore, the removal rate data after 50 hours reflects the resin's stability over a longer period. The resins in the Examples maintain a high removal rate after 50 hours of operation, demonstrating good stability and durability, and the ability to continuously and effectively remove perfluorinated compounds from drinking water over a longer period.

[0102] The above results demonstrate that the macroporous-gel composite amine resin synthesized in this invention achieves a complete removal effect of perfluoroalkyl compounds from drinking water that meets the drinking water hygiene standards. This proves that the resin of this invention has good adsorption performance for both short-chain and long-chain perfluoro compounds, and also illustrates the application prospects of this resin in drinking water treatment engineering.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a composite amine resin for removing PFAS from drinking water, characterized in that, Includes the following steps: S1: The first oil phase is added to the first aqueous phase, and a suspension polymerization reaction is carried out in stages with increasing temperature. After the reaction is completed, a macroporous white sphere matrix is ​​obtained. The porogen is extracted by steam and the macroporous white sphere matrix is ​​dried. The dried macroporous white sphere matrix is ​​added to an appropriate amount of saline solution, and the second oil phase is slowly added dropwise. After the dried macroporous white sphere matrix has fully swollen and absorbed the monomer, the second aqueous phase is added, and a second suspension polymerization reaction is carried out in stages with increasing temperature to obtain macroporous-gel composite white spheres. The first oil phase includes monomers, porogens, and initiators. The second oil phase includes monomers and initiators. The monomers in both the first and second oil phases are composed of styrene and divinylbenzene. S2: Mix the macroporous-gel composite white spheres with a chloromethylating agent, add a catalyst, and heat the reaction to obtain macroporous-gel composite chlorospheres; S3: Mix the macroporous-gel composite chlorine spheres with a polar aprotic solvent, first add a long-chain alkyl tertiary amine, then add a strongly basic short-chain amine, react and wash to obtain the composite amine resin for removing PFAS from drinking water.

2. The method for preparing a composite amine resin for removing PFAS from drinking water according to claim 1, characterized in that, Both the first and second aqueous phases include a dispersant, an aqueous phase polymerization inhibitor, and saline solution; in both the first and second aqueous phases, the ratio of the dispersant, the aqueous phase polymerization inhibitor, and the saline solution is (0.05~0.50)g:(0.0005~0.0010)g:100mL; the saline solution contains 20%~24% NaCl.

3. The method for preparing a composite amine resin for removing PFAS from drinking water according to claim 1, characterized in that, The mass ratio of monomer to porogen in the first oil phase is 100:(40~70).

4. The method for preparing a composite amine resin for removing PFAS from drinking water according to claim 1, characterized in that, The mass ratio of initiator to monomer in both the first and second oil phases is (1~2):

100.

5. The method for preparing a composite amine resin for removing PFAS from drinking water according to claim 1, characterized in that, The primary suspension polymerization reaction specifically involves: heating to 75-80℃ and holding for 2-4 hours, heating to 85-90℃ and holding for 2-4 hours, and heating to 95-98℃ and holding for 4-6 hours; the secondary suspension polymerization reaction specifically involves: heating to 70-75℃ and holding for 2-4 hours, heating to 80-85℃ and holding for 2-4 hours, and heating to 90-95℃ and holding for 6-8 hours.

6. The method for preparing a composite amine resin for removing PFAS from drinking water according to claim 1, characterized in that, The ratio of macroporous-gel composite white spheres to chloromethylation reagent is 1 g:(4~8) mL.

7. The method for preparing a composite amine resin for removing PFAS from drinking water according to claim 1, characterized in that, Step S2 specifically involves mixing macroporous-gel composite white spheres with a chloromethylation reagent, adding a catalyst, heating to 40-43°C, maintaining the temperature for 16-24 hours, separating the solid and liquid phases, and washing to obtain macroporous-gel composite chlorospheres.

8. The method for preparing a composite amine resin for removing PFAS from drinking water according to claim 1, characterized in that, The long-chain alkyl tertiary amine is at least one of octyl dimethyl tertiary amine, decyl dimethyl tertiary amine, dodecyl dimethyl tertiary amine, tetradecyl dimethyl tertiary amine, hexadecyl dimethyl tertiary amine, octadecyl dimethyl tertiary amine, and docosyl dimethyl tertiary amine; the strongly basic short-chain amine is at least one of trimethylamine, triethylamine, tripropylamine, triisopropylamine, and tributylamine.

9. A composite amine resin for removing PFAS from drinking water, characterized in that, The composite amine resin for removing PFAS from drinking water is prepared by any one of claims 1 to 8; the particle size of the composite amine resin is 0.5 to 1.25 mm.

10. The application of the composite amine resin for removing PFAS from drinking water as described in claim 9 in the removal of perfluorinated compounds from drinking water.

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