A method for reducing the phytotoxicity of pfas by modulating their nanomorphology

Abstract

This invention discloses a method for reducing the phytotoxicity of PFAS by regulating its nanomorphology, belonging to the field of environmental pollutant speciation regulation and risk control technology. The method includes: extracting dissolved organic matter (DOM) from soil or compost products, preparing a DOM solution, and treating PFAS-contaminated media with the DOM solution. The initial form of PFAS in the contaminated media includes molecular form. DOM acts as an interface template and reaction medium, inducing the molecular PFAS to form nanoclusters, thereby reducing the toxic effects of PFAS on plants in the contaminated area. This invention transforms molecular PFAS into a nanocluster form with significantly different physical size and surface properties. This form can be effectively blocked on the plant root surface, significantly reducing translocation into the plant, thus mitigating the phytotoxicity of PFAS from its morphological source. This invention has greater environmental compatibility and potential cost advantages, and has good application prospects.

Description

Technical Field

[0001] This invention belongs to the field of environmental pollutant speciation regulation and risk control technology, specifically involving a method for reducing the phytotoxicity of PFAS nanoforms by regulating the soluble organic matter DOM. Background Technology

[0002] Per- and polyfluoroalkyl compounds (PFAS) are a class of man-made chemicals with excellent chemical stability, hydrophobicity, oleophobicity, and surface activity. They are extremely difficult to degrade and have bioaccumulation properties. Studies have shown that long-term exposure to certain PFAS may interfere with the endocrine system, affect the immune system, and is associated with an increased risk of some cancers. Therefore, they are considered new pollutants of concern.

[0003] Currently, the mainstream technical approach to PFAS environmental risk management is mainly based on the traditional understanding of PFAS as a "molecularly dispersed state," meaning that PFAS exist in the environment as single molecules or ions, migrate, and are absorbed by organisms. Existing technologies based on this understanding primarily focus on adsorption and immobilization techniques. These utilize highly efficient adsorbents such as activated carbon, resins, and modified mineral materials to remove and immobilize dissolved PFAS molecules from the aqueous phase or soil through physical adsorption or chemical action, thereby blocking their migration pathways. The core of this technology is to enhance the affinity and adsorption capacity of materials for PFAS molecules. However, current PFAS environmental risk management technologies have certain limitations, fundamentally due to insufficient understanding of the microscopic morphological evolution mechanisms of PFAS at key environmental interfaces.

[0004] In addition, other technical approaches for PFAS pollution remediation have been developed in the industry. For example, Chinese patent document CN121289234A discloses an in-situ soil remediation method based on electro-chemical-biological synergy. The steps include: electrochemical targeted enrichment: at least one anode and one cathode are placed at the PFAS-contaminated soil, and a pulsed DC electric field is applied to the anode and cathode to drive the migration and enrichment of anionic PFAS in the soil towards the anode area; thermal-chemical synergistic deep oxidation: in the anode area, the anode soil temperature is heated, and composite peroxides and chemical activators are continuously injected to oxidize and degrade the perfluorinated compounds enriched at the anode; microbial polishing and ecological restoration: the electric field is stopped, the anode area is post-treated, and microbial agents and nutrients are added to the anode area to biodegrade the residual perfluorinated compounds or their degradation intermediates. However, this method consumes a lot of energy, the oxidative degradation may produce harmful intermediates, the in-situ remediation may be affected by soil heterogeneity, and the multi-step synergistic operation is complex and difficult to implement in actual sites. Chinese patent document CN120903639A discloses an ultrafiltration separation method for water containing fluorinated alkyl compounds. The steps include: mixing the water containing fluorinated alkyl compounds with a cationic surfactant solution, stirring, and allowing it to stand to form a composite solution containing the complex; and separating the composite solution through an ultrafiltration membrane to obtain permeate. This invention utilizes cationic surfactants to induce pollutants to self-assemble into complexes with larger particle sizes, enabling them to be effectively retained by the ultrafiltration membrane with larger pore sizes. However, the self-assembly process may release bioavailable molecular PFAS due to changes in environmental conditions (such as pH and ionic strength).

[0005] In summary, current PFAS environmental risk management technologies are limited by the traditional "molecular dispersion" paradigm and have failed to develop innovative technical routes that can achieve efficient and long-lasting toxicity mitigation by actively regulating the nano-morphology of pollutants based on a deep understanding of interfacial micro-processes. Summary of the Invention

[0006] To address the problems of unstable and unsustainable risk control effects of PFAS in existing technologies, and the inability to effectively reduce the biotoxicity of PFAS, this invention provides a method for reducing the phytotoxicity of PFAS by regulating its nanomorphology.

[0007] The specific technical solution adopted is as follows: A method for reducing the phytotoxicity of PFAS by modulating its nanomorphology includes: Dissolved organic matter (DOM) is extracted from soil or compost products to prepare DOM solution. The DOM solution is then used to treat PFAS-contaminated media. PFAS in PFAS-contaminated media exists in molecular form (PFAS in PFAS-contaminated media is usually assumed to exist in dissolved molecular form). DOM acts as an interface template and reaction medium, inducing the formation of nanoclusters from molecular PFAS, thereby reducing the toxic effects of PFAS on plants in the contaminated area.

[0008] In existing PFAS risk management strategies, adsorption and fixation technologies only passively remove or regulate the concentration of "molecularly dispersed" PFAS. Their design is entirely based on simple adsorption and distribution principles. This invention aims to break through this traditional paradigm and address the problem of incomplete and inadequate mechanisms of action caused by the failure to recognize and utilize the key process of "PFAS-soluble organic matter (DOM) interface self-assembly to form nanoclusters." This invention introduces and regulates the key factor of DOM, transforming traditionally harmful molecular PFAS into a nanocluster morphology with drastically different physical size and surface properties. This morphology can be effectively blocked at the plant root surface, significantly reducing translocation into the plant, thereby mitigating the phytotoxicity of PFAS from its morphological source.

[0009] Furthermore, existing PFAS risk management strategies only focus on reducing PFAS concentrations and cannot achieve a fundamental change in PFAS speciation, facing the dilemma of desorption risk and fluctuating effects. The method of this invention, through the formation of nanoclusters, overcomes the problems of incomplete and unstable blocking effects, providing a new approach that can actively regulate PFAS speciation, thereby directly and effectively reducing its absorption by plants and its phytotoxicity.

[0010] Preferably, the soil is rich in organic matter, including but not limited to paddy soil and peat soil, to ensure that it has rich aromaticity, aliphatic properties and a variety of functional groups.

[0011] Preferably, the DOM extraction method includes: taking a soil sample or compost product sample, mixing it with water (sample to water mass ratio of 1:2), shaking it at room temperature under inert gas protection for 72 hours (500 rpm), centrifuging the resulting suspension, and filtering it through a 0.22 μm filter membrane to obtain a DOM solution with a total organic carbon content of 1-200 mg-C / L. This concentration range provides sufficient interaction sites while avoiding excessive alteration of the physicochemical properties of the medium.

[0012] The extracted DOM is used directly without desalting to preserve its natural ion-associated state, which is beneficial to the stability of the nanoclusters.

[0013] Furthermore, the total organic carbon content of the DOM solution is 10-50 mg-C / L.

[0014] Specifically, the PFAS contamination medium includes at least one of the following: nonionic PFAS (such as N-methylperfluorooctane sulfonamide), anionic PFAS (such as perfluorooctane sulfonamide acetic acid), cationic PFAS (such as perfluorooctane ammonium salt), and zwitterionic PFAS (such as perfluorooctane betaine). The method of this invention is effective for PFAS of various polarities and has good applicability. For charged PFAS, the induction effect can be enhanced by matching functional groups with opposite charges on the DOM surface.

[0015] Specifically, the PFAS contamination medium is PFAS-contaminated soil or PFAS-contaminated water. In PFAS-contaminated water, the concentration of PFAS is 0.01 µg / L-1 mg / L, more specifically 0.1 µg / L-10 µg / L; in PFAS-contaminated soil, the concentration of PFAS is 1 µg / kg-1000 µg / kg, more specifically 10 µg / kg-100 µg / kg. The DOM solution of this invention can be directly used in the cultivation environment of hydroponic plants contaminated with PFAS. For soil contamination, the DOM solution can be injected or mixed into PFAS-contaminated soil as a conditioner, allowing it to react with in-situ PFAS in the soil pore water to form nanoclusters, thereby inhibiting its toxicity to soil-colonized plants.

[0016] Furthermore, a DOM coating can be prepared on the surface of a carrier using a DOM solution, and the carrier with the DOM coating can be used to treat PFAS contaminated media. The carrier includes, but is not limited to, mica sheets.

[0017] Preferably, when treating PFAS-contaminated media with DOM solution, the mixing and contact time of DOM and PFAS is ≥1 hour, preferably 12-72 hours, to ensure sufficient interaction and reach equilibrium.

[0018] Preferably, when treating PFAS-contaminated media with DOM solution, the pH of the mixed system is 5.0-9.0. For cationic PFAS, slightly alkaline conditions (e.g., pH 7.0-8.0) are further preferred to enhance electrostatic attraction with deprotonated DOM functional groups (e.g., carboxyl groups); for other types of PFAS, neutral to weakly acidic conditions (e.g., pH 5.0-7.0) are generally better.

[0019] Preferably, when treating PFAS-contaminated media with DOM solution, an electrolyte is also added to the mixed system to adjust the ionic strength. The electrolyte includes monovalent, divalent, or trivalent cation salts. The concentration of the electrolyte in the mixed system is 1-100 mM, more preferably 10-100 mM. Higher ionic strength helps compress the electric double layer and promotes nanocluster formation. Divalent or trivalent cations (such as Ca2+) 2+ Fe 3+The introduction of ) can significantly enhance the interaction between PFAS and DOM through a cation bridging mechanism.

[0020] Preferably, when using DOM solution to treat PFAS contaminated media, gentle stirring or shaking is used to ensure homogenization, but avoids violent shearing that could damage the formed nanoclusters.

[0021] By employing the aforementioned optimized conditions, particularly by controlling pH, ionic strength, and cation type, the interaction strength between PFAS and DOM can be actively intervened, thereby directionally inducing the formation of nanoclusters with higher abundance, smaller size, and greater stability. Experiments show that nanoclusters formed under these optimized conditions exhibit a more significant physical barrier effect on the plant root surface and a better mitigation effect on plant toxicity (manifested as decreased biomass and root length inhibition), especially for highly toxic PFAS.

[0022] Specifically, the toxic effects of PFAS on plants in contaminated areas include biomass reduction and root length inhibition; plants in contaminated areas include, but are not limited to, rice, wheat, and corn.

[0023] This invention also provides the application of the method described above for reducing the phytotoxicity of PFAS by regulating its nanomorphology in the agricultural field.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The method of the present invention realizes a paradigm shift in the environmental behavior of PFAS from “passive reduction” to “active morphology regulation”: Existing technologies are limited to adsorption or masking of molecular PFAS. The present invention proposes and realizes the active induction of molecular PFAS to assemble into stable nanoclusters by designing and controlling the interface characteristics of soluble organic matter DOM. This effect is directly verified by in-situ atomic force microscopy (AFM) imaging technology. This phenomenon does not occur in simple molecular solutions or at interfaces lacking DOM. The present invention discovers the key morphological evolution process of PFAS.

[0025] (2) The present invention can significantly and stably reduce the toxicity of PFAS by regulating the nanomorphology of PFAS. It has good universality. Taking rice as an example, compared with molecular PFAS, the PFAS nanoclusters formed by the method of the present invention significantly alleviate the toxicity of rice, and the phenotype and growth indicators of rice are significantly improved.

[0026] (3) This invention fundamentally alters the bioavailability pathway of PFAS by regulating its nanomorphology, achieving a stable detoxification effect by "blocking it outside the root." This invention not only reduces the apparent toxicity of PFAS but also fundamentally blocks its main pathway into plants by changing its physical morphology. In addition, the method of this invention is based on converting PFAS into a more thermodynamically stable and less kinetically mobile nano-aggregate state. Compared with adsorption or complexation techniques that rely on dynamic equilibrium, this morphological conversion is less susceptible to fluctuations in environmental conditions (such as pH and ionic strength), thus providing a more durable and stable risk control effect.

[0027] (4) This invention provides a new green remediation strategy for PFAS polluted media that is environmentally friendly and has great potential. It uses naturally occurring DOM or similar organic matter as a regulating medium. Compared with existing technologies that require the addition of large amounts of engineering materials (such as activated carbon and resin) or chemical agents (surfactants), this invention has greater environmental compatibility and potential cost advantages. Essentially, it is a strategy that uses natural processes to enhance the self-purification capacity of the environment and has good application prospects. Attached Figure Description

[0028] Figure 1 These are the characterization results of PFAS forming nanoclusters at the DOM interface in Example 1. A is a schematic diagram of the experimental setup for in-situ, real-time, fluid-environment AFM observation; B is a control image of the DOM-coated mica surface without PFAS; CF are typical AFM morphologies of nanoclusters dynamically formed at the DOM interface by non-ionic NonPFAS, anionic AnPFAS, cationic CatPFAS, and zwitterPFAS, respectively; GH are quantitative statistical analysis graphs of the number and height of the above nanoclusters; and I represents the characterization results of the significant negative correlation between the number and height of nanoclusters.

[0029] Figure 2 This is an in-situ atomic force microscopy (AFM) observation of non-ionic NonPFAS, anionic AnPFAS, cationic CatPFAS, and zwitterPFAS in Example 1, showing that they did not form nanoclusters at the mica interface without DOM coating.

[0030] Figure 3This is the characterization result of the quantification of molecular interactions between PFAS and DOM functional groups using dynamic force spectroscopy (DFS) in Example 2. A is a schematic diagram of the experimental design for force spectroscopy measurements using PFAS-functionalized AFM probes; B and C are typical force-distance and force-time curves obtained from test A, respectively; D is a comparison diagram of the adhesion force mapping between PFAS and real DOM deposited on mica and hematite surfaces; E is a direct measurement of the interactions between different PFAS and representative DOM functional groups (-CH3, -Ph, -OH, -COO) using single-molecule force spectroscopy. - , -NH3 + The binding force between them.

[0031] Figure 4 This is an in-situ atomic force microscopy (AFM) observation result of the formation of nanoclusters by the full interaction of PFAS and DOM in the plant culture medium in Example 3.

[0032] Figure 5 This is a schematic diagram illustrating the evaluation results of the effect of PFAS nanoclusters on reducing the toxicity of rice plants in Example 3. A shows comparative photographs of the growth phenotypes of rice seedlings under different exposure treatments; B and C represent quantitative analyses of plant biomass and root length, respectively; D shows a statistical analysis of the toxicity mitigation efficiency of molecular PFAS and its corresponding nanoclusters, with * indicating p < 0.05; E shows the distribution ratio of PFAS in plant tissues and on the root surface, revealing the role of nanoclusters in promoting root surface retention. Detailed Implementation

[0033] To make the objectives, features, and advantages of this invention more apparent and understandable, a detailed description is provided below through specific embodiments. Many specific details are set forth in the following description to provide a thorough understanding of the invention. However, the invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below. Technical features in various embodiments of the invention can be combined appropriately without mutual conflict.

[0034] Unless otherwise specified, the operating methods in the following examples are generally performed under conventional conditions or as recommended by the manufacturer. Contents not described in detail in this specification are prior art known to those skilled in the art. Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0035] Example 1: Characterization of DOM-induced formation of nanoclusters from various PFAS DOM extraction: Soil samples were collected from paddy soil in Hangzhou, China, and mixed with ultrapure water at a mass ratio of 1:2. The mixture was shaken at 500 rpm for 72 hours at room temperature under nitrogen protection. The suspension was then centrifuged at 4000 rpm for 30 minutes and filtered through a 0.22 μm polyethersulfone membrane to obtain a DOM stock solution with a total organic carbon (TOC) content of 200 mg-C / L (based on carbon content), which was stored at 4°C in the dark.

[0036] Preparation of DOM functionalized surface: Freshly cleaved mica sheets (V-1 grade, (001) crystal face) were heated at 120 °C for 2 hours to enhance the formation of surface silanol groups. They were then immersed in a 1 mM acetic acid solution containing 1% (v / v) 3-aminopropyltriethoxysilane (APTES) for 30 minutes for silanization. The DOM stock solution was diluted to 20 mg-C / L and pre-activated for 1 hour with 0.5 mg / mL 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDAC) in 50 mM borate buffer at pH 5.8. Finally, the silanized mica was immersed in the activated DOM solution for 12 hours to covalently fix the DOM via amide bonds, forming a stable DOM coating surface.

[0037] PFAS solutions: Four representative PFAS were selected: nonionic (NonPFAS, N-methylperfluorooctane sulfonamide), anionic (AnPFAS, perfluorooctane sulfonamide acetic acid), cationic (CatPFAS, perfluorooctane ammonium salt), and zwitterionic (ZwitterPFAS, perfluorooctane betaine). Working solutions of PFAS with a concentration of 1 µg / L were prepared using ultrapure water. The background electrolyte was 10 mM NaCl, and the pH was adjusted to 6.0 using HCl or NaOH.

[0038] In-situ AFM observation: placing DOM-functionalized mica in an AFM fluid pool ( Figure 1 A). First, a background solution (pH 6, 10 mM NaCl) is introduced for baseline scanning to confirm that the surface is smooth and free of impurities. Figure 1 (B in the text). Then, using a high-precision injection pump, the PFAS solution was continuously infused over the substrate surface at a constant flow rate of 20 mL / h.

[0039] Real-time imaging: In-situ imaging was performed using a Bruker MultiMode 8 atomic force microscope with a ScanAsyst-Fluid+ probe (elastic constant k = 0.7 N / m, tip radius ≈ 2 nm) in a fluid environment. The imaging was conducted at a depth of 2 × 2 μm. 2 The scanning area was scanned at a scanning rate of 2 Hz to capture dynamic changes at the interface in real time. Each PFAS sample was tested three times independently.

[0040] Results and Analysis: like Figure 1 As shown in the CF, approximately 20 minutes after the introduction of PFAS, all four types of PFAS formed clearly visible nanoscale cluster structures on the DOM-coated surface, while such structures were not observed on bare mica surfaces without DOM. Figure 2 This directly proves that the formation of nanoclusters is a specific result of the interaction between PFAS and DOM interfaces, and that soluble organic matter DOM can induce PFAS of different polarities to self-assemble at the interface to form nanoclusters.

[0041] Quantitative analysis showed that ( Figure 1 In the GH (growth density) analysis, the number of nanoclusters follows the order ZwitterPFAS > CatPFAS > AnPFAS > NonPFAS, while the average height of a single nanocluster shows the opposite order. Further statistical analysis reveals a very strong negative linear correlation between the number and height of nanoclusters (R = -0.983, P = 0.017). Figure 1 As shown in Figure I. This pattern indicates that the interaction strength between PFAS and DOM determines the density of nucleation sites, which in turn regulates the morphology of the final nanoclusters: the stronger the interaction, the more numerous and smaller nanoclusters tend to form.

[0042] Example 2: Quantification of the molecular mechanism of interaction between PFAS and DOM functional groups Preparation of PFAS functionalized probes: Gold-coated NPG-10 probes were used. First, the probes were washed sequentially with acetone, ethanol, and ultrapure water. Then, they were immersed in a 0.2 mM solution of N,N-dimethylformamide (DMF) containing the heterobifunctional crosslinking agent LC-SPDP for 40 minutes to form a self-assembled monolayer. Finally, the modified probes were immersed in a 0.1 µM solution of the target PFAS for 12 hours, allowing the PFAS molecules to be covalently fixed to the probe tip via amide bonds. Figure 3 (A in the middle).

[0043] Model functional surface preparation: To simulate the key functional groups of DOM, pretreated mica was reacted with different silane reagents (butyltriethoxysilane, phenyltriethoxysilane, hydroxymethyltriethoxysilane, 3-aminopropyltriethoxysilane, [(3-triethoxysilyl)propyl]succinic anhydride) to prepare surfaces with terminal groups of -CH3 (hydrophobic), -Ph (aromatic), -OH (hydroxyl), and -NH3. + (Amino, positively charged), -COO - (Carboxyl group, negatively charged) model surface.

[0044] Dynamic force spectroscopy measurements: Single-molecule force spectroscopy measurements were performed on the DOM-coated surface or the functional surfaces of various models using PFAS functionalized probes in a background solution (pH 6, 10 mM NaCl). Force-distance curves were acquired at different locations on each surface, and the probe's elastic constant was calibrated using the thermal fluctuation method to ensure the accuracy of force measurements. A typical force-distance curve is shown below. Figure 3 As shown in BC, the sudden drop in force that occurs during probe retraction corresponds to the breaking of a single molecular bond.

[0045] Results and Analysis: The measured specific binding forces were on the order of pN, confirming that PFAS and DOM are primarily bound through non-covalent interactions. Specific force spectral data ( Figure 3 E) in the text shows: For nonionic PFAS, significant binding forces can be detected with -CH3, -Ph, and -OH surfaces, corresponding to hydrophobic interactions, π-π / π-F interactions, and hydrogen bonds, respectively.

[0046] For charged PFAS (AnPFAS, CatPFAS), and surfaces with opposite charges (-NH3) + or -COO - It exhibits the strongest binding force, confirming that electrostatic attraction is the main driving force.

[0047] zwitterionic PFAS exhibit strong interactions with a variety of surfaces.

[0048] Figure 3 D in the figure is a comparison of the adhesion mapping between PFAS and real DOM deposited on the surface of mica and hematite, which intuitively shows the stronger binding between PFAS and DOM.

[0049] Based on the morphological observation of Example 1, it can be concluded that PFAS interacts with complementary functional groups on DOM with varying degrees of strength (electrostatic > hydrogen bonding > aromatic interaction > hydrophobic interaction) through its specific molecular structure. The strength and nature of this interaction directly regulate the nucleation density and final size of the nanoclusters, thereby verifying the technical principle of the present invention of "regulating morphology by regulating interactions".

[0050] Example 3: Validation of the phytotoxicity mitigation effect of PFAS nanoclusters Preparation of nanocluster precursor solutions: The four PFAS (NonPFAS, AnPFAS, CatPFAS, ZwitterPFAS) were prepared into stock solutions with methanol, and then diluted with sterile Hogland nutrient solution (containing a large amount of electrolyte ions) (methanol volume fraction < 0.1%). This PFAS solution was mixed with the DOM stock solution from Example 1 to achieve a final DOM concentration of 20 mg-C / L and a final PFAS concentration of 1 mg / L. The mixture was placed in a polypropylene bottle and shaken at 100 rpm for 72 hours at room temperature in the dark to ensure sufficient interaction between PFAS and DOM to form nanoclusters. The pH of all four mixtures was 5.8. Nanocluster formation was confirmed by AFM sampling (as in Example 1). Figure 4 ).

[0051] Plant culture and exposure: Uniform rice (Oryza sativa L.) seeds were selected, disinfected, and germinated. Healthy seedlings were pre-cultured and then transferred to a hydroponic system. Ten treatment groups were set up: (1) blank control; (2-5) molecular PFAS (four types of NonPFAS, AnPFAS, CatPFAS, ZwitterPFAS), all at a concentration of 1 mg / L; (6) DOM control only, at a concentration of 20 mg-C / L; (7-10) PFAS nanocluster precursor solution (prepared in the above steps). Multiple replicates were set up for each group.

[0052] Exposure and Sampling: Seedlings were exposed to the growing chamber for 15 days, with the treatment solution replaced every 48 hours to maintain a stable concentration. After exposure, plants were collected. The roots were gently rinsed with methanol to collect PFAS adsorbed on the root surface. The plant tissues were then freeze-dried, weighed, and ground. The PFAS absorbed by the plant were extracted using solvent extraction.

[0053] Results and Analysis: Phenotypic and growth indicators: such as Figure 5 As shown in AC, rice seedlings exposed to molecular PFAS exhibited significant leaf yellowing and growth inhibition, with biomass and root length significantly lower than the control group. In contrast, seedlings exposed to the corresponding PFAS nanoclusters showed significantly reduced growth inhibition, and their indicators were closer to those of the control group.

[0054] Quantification of toxicity mitigation efficiency: Calculations showed that the mitigation efficiencies of nanocluster treatment on the toxicity of four PFAS plants were approximately 5.20% for NonPFAS, approximately 10.76% for AnPFAS, approximately 13.86% for CatPFAS, and approximately 23.58% for ZwitterPFAS. Figure 5(D in the text). The mitigation efficiency is positively correlated with the inherent toxicity of molecular PFAS, proving that this method is equally effective for highly toxic pollutants, and the effect is even more significant.

[0055] PFAS distribution path changes: such as Figure 5 As shown in Figure E, in the nanocluster treatment group, the retention rate of PFAS on the root surface significantly increased, while the proportion of PFAS transported and accumulated into the aboveground plant tissues significantly decreased. This directly demonstrates the mechanism of action of the present invention: DOM-induced PFAS nanoclusters, due to their large physical size, are mainly blocked on the root surface and have difficulty entering the plant through cell channels, thus achieving the effect of "blocking" to "reducing toxicity".

[0056] In summary, the above embodiments fully demonstrate that the technical solution provided by the present invention can effectively induce PFAS to form nanoclusters, and by regulating this morphology, significantly reduce the plant absorption and toxicity of PFAS, thus achieving the intended purpose of the invention.

[0057] The embodiments described above provide a detailed explanation of the technical solutions of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, or similar substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for reducing the phytotoxicity of PFAS by regulating its nanomorphology, characterized in that, include: Dissolved organic matter (DOM) is extracted from soil or compost products to prepare DOM solution. DOM solution is then used to treat PFAS-contaminated media. PFAS exists in the PFAS-contaminated media in molecular form. DOM acts as an interface template and reaction medium, inducing the formation of nanoclusters of molecular PFAS, thereby reducing the toxic effects of PFAS on plants in the contaminated area.

2. The method for reducing phytotoxicity of PFAS by regulating its nanostructure according to claim 1, characterized in that, The DOM extraction method includes: taking soil samples or compost product samples, adding water and mixing, shaking at room temperature under inert gas protection, centrifuging the resulting suspension, filtering through a membrane, and obtaining a DOM solution with a total organic carbon content of 1-200 mg-C / L.

3. The method for reducing phytotoxicity of PFAS by regulating its nanostructure according to claim 1, characterized in that, PFAS contamination media include at least one of nonionic PFAS, anionic PFAS, cationic PFAS, and zwitterionic PFAS.

4. The method for reducing phytotoxicity of PFAS by regulating its nanostructure according to claim 1, characterized in that, The PFAS contamination medium is PFAS-contaminated soil or PFAS-contaminated water; in PFAS-contaminated water, the concentration of PFAS is 0.01 µg / L-1 mg / L; in PFAS-contaminated soil, the concentration of PFAS is 1 µg / kg-1000 µg / kg.

5. The method for reducing phytotoxicity of PFAS by regulating its nanostructure according to claim 1, characterized in that, A DOM coating is prepared on the surface of a carrier using a DOM solution, and the carrier with the DOM coating is used to treat PFAS contaminated media. The carrier includes mica sheets.

6. The method for reducing phytotoxicity of PFAS by regulating its nanostructure according to claim 1, characterized in that, When using DOM solution to treat PFAS-contaminated media, the mixing and contact time of DOM and PFAS should be ≥1 hour.

7. The method for reducing phytotoxicity of PFAS by regulating its nanostructure according to claim 1, characterized in that, When using DOM solution to treat PFAS-contaminated media, the pH of the mixed system should be 5.0-9.

0.

8. The method for reducing phytotoxicity of PFAS by regulating its nanostructure according to claim 1, characterized in that, When using DOM solution to treat PFAS contaminated media, an electrolyte is also added to the mixed system to adjust the ionic strength; the electrolyte includes monovalent cation salts, divalent cation salts, or trivalent cation salts.

9. The method for reducing phytotoxicity of PFAS by regulating its nanomorphology according to claim 1, characterized in that, The toxic effects of PFAS on plants in contaminated areas include reduced biomass or inhibited root length; plants in contaminated areas include rice, wheat, or corn.

10. The application of the method for reducing the phytotoxicity of PFAS by regulating its nanomorphology according to any one of claims 1-9 in the agricultural field.

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