A composite fiber membrane for PFAS detection, degradation and material harmless treatment and an integrated application method thereof

Abstract

The present application belongs to the field of environmental functional materials and water pollution treatment technology, and specifically relates to a composite fiber membrane for PFAS detection, degradation and harmless treatment of materials and an integrated application method thereof. The composite fiber membrane is a porous fiber network structure prepared by electrospinning from a polymer matrix, a semiconductor light functional material and a functional recognition additive. The functional recognition additive selectively captures PFAS and regulates the luminescent properties of the semiconductor material to produce a fluorescent response under excitation light, realizing quantitative detection of PFAS; under visible light irradiation, the semiconductor material generates hydroxyl radicals to degrade the adsorbed PFAS; after use, the fiber membrane is completely biodegraded under the action of lipase, and the leakage amount of heavy metal ions is lower than the standard limit value of drinking water. The present application integrates fluorescent detection, visible light catalytic degradation and harmless treatment of materials into one, and provides an efficient and low-cost innovative solution for in-situ treatment and green management of the whole life cycle of PFAS in water.

Description

Technical Field

[0001] This invention belongs to the field of environmental functional materials and water pollution control technology, specifically relating to a composite fiber membrane for PFAS detection, degradation and material harmless treatment and its integrated application method. Background Technology

[0002] Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic organic compounds with unique chemical and physical properties. Due to their excellent stability, water and oil repellency, they are widely used in many fields, such as the manufacture of waterproof textiles, coatings, and fire-fighting foams. Common PFAS include perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). However, with in-depth research, the potential hazards of PFAS to the environment and human health have become increasingly apparent. They are difficult to degrade naturally in the environment, and their long-distance migration capabilities allow them to spread widely and persist in media such as water, air, and soil for extended periods. They are biotoxic and can be transmitted through the food chain, thus posing a serious threat to ecosystems and human health. In recent years, PFAS pollution has attracted widespread global attention, especially in aquatic environments, where the detection and degradation technologies of PFAS have become a research hotspot. The detection of PFAS requires very low detection limits (typically as low as ng / L). Currently, traditional solid-phase extraction-liquid chromatography / tandem mass spectrometry techniques can detect trace levels of PFCs, but these methods are time-consuming and costly.

[0003] In comparison, fluorescence analysis offers advantages such as low cost, ease of operation, fast response, and high sensitivity, leading to the use of various fluorescent probes for PFAS detection. However, most of these probes exhibit fluorescence quenching responses, making their signals susceptible to interference from water pH, temperature, and coexisting ions, and they cannot remove pollutants after detection. On the other hand, PFAS removal technologies primarily include activated carbon adsorption, ion exchange resins, and advanced oxidation / reduction processes. Adsorption methods only transfer pollutants from the aqueous phase to the solid phase; after adsorption saturation, the material requires secondary treatment, posing a risk of pollutant re-release. While photocatalytic degradation can completely mineralize PFAS, existing photocatalysts, such as metal oxide materials (TiO2, etc.), perovskite oxide materials (LiNiO3, etc.), and organometallic framework materials, rely on high-temperature sintering processes and noble metal doping (such as Y). 3+PFAS, existing in rigid bulk or powder form, typically require high-energy ultraviolet light excitation and exhibit low degradation efficiency for trace amounts, failing to integrate with fluorescence sensing or flexible material design. The development of treatment technologies plays a crucial role in PFAS pollution control, with adsorption-degradation methods combining the advantages of adsorption and degradation technologies. By combining adsorbents with catalytic degradation materials, the two work synergistically to achieve efficient enrichment and removal of pollutants. Although some studies have attempted to use supramolecular materials such as cyclodextrins for the inclusion adsorption of PFAS, or to employ semiconductor materials for photocatalytic degradation, most technologies focus on a single function and cannot achieve integrated "detection-adsorption-degradation" operations on a single material platform. Sensitive detection of PFAS can better qualitatively and quantitatively identify trace pollutants and further guide and monitor the photocatalytic degradation process; however, materials possessing both sensitive detection and high-performance photocatalytic activity are still rarely reported, and their design and development remain challenging.

[0004] Metal halide perovskite materials possess high extinction coefficients, high photoluminescence quantum yields, narrow full width at half maximum (FWHM), and tunable emission wavelengths, offering significant advantages in fluorescence analysis and photocatalysis. In particular, precise control of the band gap structure through component engineering allows for matching its redox potential with that of the reaction substrate, enabling more efficient utilization of solar energy during photocatalytic degradation. However, due to their ionic crystal properties, perovskites are prone to structural damage upon contact with water, leading to harmful lead leakage and limiting their practical applications. Traditional perovskite materials also exhibit high particle aggregation and low specific surface area, restricting their catalytic activity. Therefore, preparing perovskite materials that combine water stability and excellent optical properties is crucial. Utilizing cyclodextrin host-guest inclusion complex technology and surface functional group chemical modification technology, the band gap structure of perovskite materials can be tuned, improving their stability, specific surface area, and interaction with PFAS. This enables sensitive detection, efficient adsorption, and catalytic degradation of PFAS in water, providing new solutions for environmental protection and pollution control. In existing technologies, researchers have improved the stability of perovskites through hydrophobic polymer encapsulation or cyclodextrin host-guest inclusion. However, related patent applications (such as CN114541041A, CN120273106A, and CN122168274A) focus on improving the luminescent properties and stability of perovskite materials. Their applications are limited to optical displays in static environments and have not been extended to the field of pollutant detection and treatment. Furthermore, the polymers used are non-degradable, posing a risk of microplastic pollution. To date, there are no reports of using perovskite-based composite materials to simultaneously achieve fluorescence detection and photocatalytic degradation of PFAS, and there is a lack of integrated technical solutions that combine flexibility, portability, biodegradability, and in-situ remediation. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a composite fiber membrane for PFAS detection, degradation, and material decontamination, along with its integrated application method. Semiconductor photofunctional materials and functional recognition additives are composited into a biodegradable polymer matrix using electrospinning technology. The selective affinity of the functional recognition additives for PFAS enables rapid enrichment and fluorescence response, while the reactive oxygen species generated by the semiconductor material under visible light irradiation degrade the PFAS. This integrated material not only solves the problems of single function, demanding conditions, and poor portability in existing technologies, but also avoids secondary pollution through the introduction of a biodegradable matrix, providing a novel solution for the rapid on-site detection and efficient in-situ treatment of persistent organic pollutants in water.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of this invention provides a composite fiber membrane for the detection, degradation, and detoxification of perfluorinated and polyfluoroalkyl compounds, wherein the composite fiber membrane has a porous fiber network structure and comprises the following components: Polymer matrix: The skeletal structure used to form fibrous membranes; Semiconductor optical functional materials: dispersed inside or on the surface of the polymer matrix, which can simultaneously generate photoluminescence signals and photocatalytic active species under excitation light irradiation; Functional identification additives: These additives chemically interact with the surface of the semiconductor optical functional material, selectively capturing perfluorinated and polyfluoroalkyl compound molecules and modulating the luminescent properties of the semiconductor optical functional material.

[0007] Furthermore, the composite fiber membrane was prepared by electrospinning, and the resulting fiber diameter was 50 nm to 10 μm.

[0008] Further, the polymer matrix is ​​at least one of polycaprolactone (PCL), polylactic acid (PLA), polyglycolic acid (PGA), polyhydroxyalkanoate (PHA), polypropylene carbonate (PPC), polybutylene succinate (PBS), polystyrene (PS), acrylonitrile-butadiene-styrene copolymer (ABS), polyethylene (PE), polypropylene (PP), polyamide (PA), polyoxymethylene (POM), high-temperature nylon, and polyphenylene sulfide (PPS).

[0009] Furthermore, the semiconductor optical functional material is an inorganic perovskite material with the general formula ABX3, where A is Cs. + Rb + At least one of them; B is Pb 2+ Cu 2+ Ag + In 3+ Sn 2+At least one of them; X is Cl - , Br - I - At least one of them.

[0010] Furthermore, the functional recognition additive is a macrocyclic molecule with cationic or polar functional groups, including but not limited to cyclodextrin, crown ether, calixarene, columnar aromatics or cucurbituril, which can capture PFAS through electrostatic interactions, hydrogen bonds or host-guest inclusion interactions.

[0011] Furthermore, the functional identification additive is at least one of cationic cyclodextrin, quaternized cyclodextrin, and aminolated cyclodextrin; the cyclodextrin is at least one of α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, and cyclodextrin derivatives; and the cyclodextrin derivative is at least one of (2-hydroxy-3-N,N,N-trimethylamino)propyl-β-cyclodextrin chloride, 2-hydroxypropyl-β-cyclodextrin, and iodobutyl ether-β-cyclodextrin.

[0012] A second aspect of the present invention provides a method for preparing the above-mentioned composite fiber membrane, comprising the following steps: Step X1: Dissolve the precursor of the semiconductor optical functional material and the polymer matrix in an organic solvent to obtain the spinning solution; Step X2: Add functional identification additives to the spinning solution, mix, and obtain the spinning working solution; Step X3: Spin the spinning working solution by electrospinning and dry it to obtain the final product.

[0013] Furthermore, the electrospinning process parameters are as follows: voltage 8~30 kV, receiving distance 8~20 cm, roller speed 150~1000 rpm, spinning solution delivery rate 0.1~10 mL / h, temperature 25~60 ℃, and relative humidity 30%~80%.

[0014] A third aspect of the present invention provides an integrated method for detecting, degrading, and rendering harmless PFAS in water using the aforementioned composite fiber membrane, comprising the following steps: Step Y1, Detection Step: Place the composite fiber membrane in water containing PFAS. Utilize the selective affinity of functional recognition additives for PFAS to enrich PFAS on the surface and in the internal pores of the fiber membrane. During or after adsorption, irradiate the composite fiber membrane with an excitation light source and record the change in photoluminescence intensity of the fiber membrane. Determine the concentration of PFAS in the water based on the degree of fluorescence enhancement or quenching. Step Y2, Degradation Step: After or simultaneously with the detection step, the composite fiber membrane is irradiated with a light source containing visible light to excite the semiconductor photofunctional material to generate reactive oxygen species such as hydroxyl radicals or superoxide radicals, which degrade the PFAS adsorbed on the composite fiber membrane into fluoride ions and short-chain carboxylic acids. Step Y3, Biodegradation Step: The composite fiber membrane that has completed the detection and degradation tasks is placed in a buffer solution containing lipase or esterase and incubated under mild conditions (30~40 ℃, pH 7.0~8.0) with shaking to completely degrade the polymer matrix in the composite fiber membrane. At the same time, the leakage of heavy metal ions is controlled below the drinking water standard limit through the chelating effect of functional recognition additives, so as to achieve the harmless disposal of materials.

[0015] Furthermore, the PFAS is at least one of perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluoroheptanoic acid (PFHpA), perfluorohexanoic acid (PFHxA), perfluorovalerate (PFPeA), and perfluorobutyric acid (PFBA).

[0016] Furthermore, the PFAS is perfluorooctanoic acid (PFOA).

[0017] Furthermore, in step Y1, a linear quasi-curve is established between the detected photoluminescence intensity change and the PFAS concentration to achieve quantitative detection of PFAS.

[0018] Further, in step Y2, the light source includes ultraviolet light, sunlight, or a simulated sunlight LED light source, preferably sunlight or a simulated sunlight LED light source, with a light intensity of 50-200 mW / cm². 2 .

[0019] In the integrated method described in this invention, the three steps of detection, degradation and biodegradation are completed continuously on the same fiber membrane without the need to replace materials, thus realizing a complete closed loop of "detection-degradation-harmless disposal".

[0020] A fourth aspect of the present invention provides an application of the above-described composite fiber membrane as a fluorescent test strip for the rapid detection of perfluorinated and polyfluoroalkyl compounds.

[0021] Furthermore, the fluorescent test paper is made from the composite fiber membrane by cutting or punching to obtain the required size.

[0022] The fifth aspect of this invention provides an application of the composite fiber membrane described above in wastewater treatment involving the photocatalytic degradation of PFAS.

[0023] Compared with the prior art, the beneficial effects of the present invention are: (1) This invention integrates the three functions of PFAS—fluorescence detection, selective adsorption, and visible light photocatalytic degradation—into the same flexible fiber membrane material for the first time, achieving "multi-purpose membrane" and simplifying the water treatment process.

[0024] (2) The change in the fluorescence detection signal of the present invention can both quantitatively indicate the PFAS concentration and reflect the degradation progress in real time, forming a closed loop of "detection → degradation → effect feedback". The two functions are linked, and photocatalytic degradation is directly triggered after detection without the need to change materials or add reagents, thus achieving "in-situ treatment".

[0025] (3) The present invention can drive photocatalytic degradation using visible light (including natural sunlight), avoiding the use of ultraviolet light sources or high temperature and high pressure, with low energy consumption, and is suitable for emergency treatment in remote areas or in the field.

[0026] (4) The present invention prepares a composite fiber membrane through a one-step electrospinning technology. It has the characteristics of being flexible, lightweight, cuttable and rollable. It can be integrated into portable devices such as handheld detectors and wearable sensors, which facilitates rapid on-site deployment and improves the convenience of application.

[0027] (5) The present invention uses biodegradable polymer as matrix, which can be completely degraded by lipase or microorganisms after use, thus avoiding microplastic pollution; at the same time, the lead ion concentration after material degradation is lower than the drinking water standard limit, thus realizing the whole chain of environmental friendliness from use to disposal.

[0028] (6) For natural water bodies polluted by PFAS, fiber membranes can be directly placed and detected and degraded by sunlight. After use, the material can be degraded by biological enzymes, eliminating the need to build fixed treatment facilities, significantly reducing treatment costs and preventing secondary pollution. Attached Figure Description

[0029] Figure 1 This is a scanning electron microscope image of the composite fiber membrane prepared in Example 1 of the present invention.

[0030] Figure 2 This is a water contact angle test diagram of the composite fiber membrane prepared in Example 1 of the present invention.

[0031] Figure 3 This is a comparison of the fluorescence spectra of the composite fiber membrane before and after cyclodextrin modification in Example 1 of the present invention.

[0032] Figure 4 The images show the fluorescence spectra and photographs of the composite fiber membrane prepared in Example 1 of this invention before and after water immersion.

[0033] Figure 5 The photoluminescence spectra of the composite fiber membrane with different contents of functional identification additives in Example 1 of the present invention are shown.

[0034] Figure 6 This is a photograph of the composite fiber membrane in lipase solution during biodegradation in Example 1 of the present invention.

[0035] Figure 7 The fluorescence spectra of the composite fiber membrane fluorescent test paper at different PFOA concentrations in Example 2 of the present invention are shown.

[0036] Figure 8 This is a fitted curve showing the linear relationship between the fluorescence intensity ratio and the PFOA concentration in Example 2 of the present invention.

[0037] Figure 9 The results of the selective and anti-interference experiments of the composite fiber membrane for PFOA detection in Example 2 of the present invention are shown.

[0038] Figure 10 This is the adsorption-desorption equilibrium curve of PFOA on the composite fiber membrane in Example 3 of the present invention.

[0039] Figure 11 The photocatalytic degradation kinetics curves of PFOA under visible light / ultraviolet irradiation are shown for composite fiber membranes with different contents of functional identification additives in Example 3 of the present invention.

[0040] Figure 12 This is the electron paramagnetic resonance spectrum of the photocatalytic degradation process of the composite fiber membrane in Example 3 of the present invention.

[0041] Figure 13 This is a schematic diagram of the integrated closed-loop application of the composite fiber membrane for PFAS in Embodiment 4 of the present invention, which involves "detection-degradation-material harmless treatment".

[0042] Figure 14 This is a schematic diagram of the integrated method of the present invention for detecting, degrading and rendering harmless to PFAS in water using a composite fiber membrane. Detailed Implementation

[0043] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0044] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.

[0045] Example 1: Preparation and performance characterization of a composite fiber membrane for integrated PFAS detection and degradation The specific preparation method of the composite fiber membrane is as follows: (1) The precursor of the semiconductor optical functional material (taking a 1:1 molar ratio of CsBr and PbBr2 as an example) was dissolved in N,N-dimethylformamide (DMF) to prepare a 0.1 mol / L solution. Separately, the biodegradable polymer polycaprolactone (PCL) was dissolved in a DMF / dichloromethane (DCM) mixed solvent (volume ratio 1:4) to prepare a 20 wt% polymer solution. The semiconductor precursor solution and the polymer solution were mixed at a volume ratio of 1:10 and stirred for 2 hours to obtain the spinning solution.

[0046] (2) Add functional identification additives to the above spinning solution. Taking quaternary ammonium cyclodextrin ((2-hydroxy-3-N,N,N-trimethylamino)propyl-β-cyclodextrin chloride, abbreviated as C-βCD) as an example, the amount is 1% of the polymer mass. Continue stirring for 1 hour to obtain the spinning working solution.

[0047] (3) Using electrospinning technology, the spinning working solution was injected into a 5 mL syringe equipped with a 21G stainless steel needle, a voltage of 18 kV was applied, the receiving distance was 15 cm, the liquid supply rate was 1.0 mL / h, the ambient temperature was 25 °C, and the relative humidity was 55%. The fiber membrane was collected on aluminum foil. After spinning for 2 hours, the fiber membrane was naturally dried at 40 °C for 12 hours to obtain a composite fiber membrane.

[0048] Scanning electron microscope images of the microstructure of the composite fiber membrane are shown below. Figure 1 As shown, the fiber diameter is uniform and orderly arranged, with an average diameter of 0.91±0.12 μm, indicating the stability of the spinning process under suitable parameters.

[0049] Functional identification additives (cyclodextrins) possess a unique host-guest inclusion structure. Their internal hydrophobic cavities and external hydrophilic surfaces can form stable inclusion complexes with various substances, effectively encapsulating semiconductor nanocrystals in fibers and reducing their direct contact with water molecules. During electrospinning, cyclodextrins also bind tightly to the fiber matrix through cross-linking, forming a stable network structure, thereby optimizing fiber morphology and reducing surface defects. The uniform fiber structure significantly improves the overall stability of the fiber membrane, especially in aqueous environments. Figure 2 As shown, the hydrophobicity of the fiber membrane is significantly improved after modification with cyclodextrin.

[0050] Furthermore, the host-guest interaction between functional recognition additives and semiconductor optical functional materials can suppress halide segregation and phase separation, reducing material degradation in aqueous environments. For example... Figure 3 , Figure 4 As shown, the modified composite fiber membrane exhibits significantly enhanced fluorescence intensity and maintains stable luminescence for a longer period of time, even in an aqueous environment.

[0051] By adjusting the content of functional recognition additives (C-βCD concentration 0~0.03 mol / L) in the spinning solution, a wide range of continuous control over the band structure of composite fiber membrane materials can be achieved. For example... Figure 5 As shown, with the increase of C-βCD addition, its free chloride ions undergo halide ion exchange reactions with the semiconductor material, and the fluorescence emission peak continuously blue-shifts from 515 nm to 430 nm. This wide-range (green to blue-violet) tunable characteristic allows the same material platform to be optimized for different water quality conditions and PFAS pollution levels: in fluorescence detection, the emission wavelength can be flexibly selected to avoid background fluorescence interference from humic substances, significantly improving the detection signal-to-noise ratio; in photocatalytic degradation, the band gap broadening enhances the oxidation ability of photogenerated holes, which is conducive to the generation of hydroxyl radicals, thereby improving the cleavage efficiency of PFAS carbon-fluorine bonds and achieving a synergistic improvement in detection sensitivity and catalytic activity.

[0052] The polymer matrix (PCL) used in this embodiment possesses excellent biocompatibility and biodegradability, enabling the composite fiber membrane to be completely degraded by bioenzymes, avoiding microplastic pollution caused by traditional plastics. Simultaneously, the chelating effect of the functional recognition additives effectively inhibits the leakage of heavy metal ions, further enhancing the material's environmental friendliness. The biodegradation experiment of the fiber membrane is as follows... Figure 6 As shown: A 0.05 mg / mL lipase solution (dissolved in PBS buffer) was prepared, and the cut composite fiber membrane (5 cm × 5 cm) was immersed in it and placed in a 37 °C constant-temperature shaker (120 rpm). After 5 hours, the fiber membrane was completely degraded. After degradation, the solution was filtered, and the lead ion concentration was measured three times in parallel. The result was 2.5 μg / L, which meets the US Environmental Protection Agency's drinking water limit, confirming the low environmental risk and high biocompatibility of the material of this invention.

[0053] Example 2: Quantitative detection of PFOA using perovskite fluorescent test strips The perovskite@cyclodextrin (CPB@C-βCD) composite fiber membrane exhibits blue fluorescence, high stability and high luminescence efficiency in aquatic environments, and can be used to develop portable fluorescence sensors for real-time detection of pollutants in water.

[0054] The specific fabrication method of the portable fluorescence sensor is as follows: (1) The composite fiber membrane prepared in Example 1 was cut into strips of 1 cm × 4 cm to serve as portable fluorescent test strips. A handheld ultraviolet lamp (excitation wavelength 365 nm) was used as the excitation source, and the initial fluorescence intensity of the test strip (denoted as I0) was recorded using a portable fiber optic spectrometer. All tests were performed at room temperature with a relative humidity of 50%–70%.

[0055] (2) Using perfluorooctanoic acid (PFOA) as a representative PFAS pollutant, standard solutions with concentrations of 0, 20, 50, 100, 200, and 500 μg / L were prepared using deionized water. 100 μL of each concentration of standard solution was dropped onto the surface of test paper. Rapid fluorescence enhancement was observed within seconds under UV excitation. After standing for 1 minute, the fluorescence intensity (denoted as I) was measured under the same excitation conditions. Each concentration was measured in triplicate, and the average value was taken.

[0056] (3) A linear regression equation was constructed using the ratio of fluorescence intensity to initial intensity (I / I0) measured by PFOA standards at different concentrations and the concentration of PFOA.

[0057] like Figure 7 , Figure 8 As shown, when PFOA standards of different concentrations were dropped onto the fiber membrane, the fluorescence intensity gradually increased with the increase of PFOA concentration (0-500 ppb, ug / L), and there was a good linear relationship between fluorescence intensity and PFOA concentration, with a correlation coefficient R. 2 The limit of detection (LOD) was >0.98 and the limit of detection (LOD) was 13.2 μg / L. These results indicate that the fiber membrane fluorescent test paper exhibits high sensitivity and a wide linear range for PFOA detection, enabling rapid and sensitive detection of low concentrations of PFOA in water.

[0058] The complex matrix composition of real water samples places high demands on the selectivity and anti-interference ability of detection methods. To systematically evaluate the selectivity of the composite fiber membrane of this invention for PFAS detection, the coexistence of inorganic ions (K+, K+, K+) was investigated. + Na + Ca 2 + Mg 2+ Cl – HCO3 – SO4 2– The concentrations were all 1×10 –4 mol / L), common organic solvents (methanol, ethanol, isopropanol, ethyl acetate, acetonitrile, 1% by volume), and PFAS structural analogs (perfluorooctane sulfonic acid (PFOS) and perfluorohexanoic acid (PFHxA), both at a concentration of 1×10⁻⁶). –6 The effect of (mol / L) on the detection signal. The results show that ( Figure 9The composite fiber membrane of this invention exhibits significant specific recognition ability for PFOA, with negligible interference from coexisting inorganic ions and organic solvents on the fluorescence signal (relative deviation <5%). It also shows certain fluorescence responses to PFOS and PFHxA, with the response intensity order being PFOA > PFOS > PFHxA. Mechanistic analysis indicates that the hydrophobic cavity (approximately 0.78 nm in diameter) of the functional recognition additive (cyclodextrin) provides optimal size matching for the perfluoroalkyl chain of PFOA, allowing it to efficiently embed within the cavity and enhancing passivation of surface defects in semiconductor optical functional materials, thereby generating a stronger fluorescence enhancement signal. Due to the large steric hindrance of the sulfonic acid groups, the carbon chain of PFOS enters the cavity more efficiently, weakening the passivation effect. PFHxA, with its shorter carbon chain, has lower affinity for cyclodextrin, resulting in weaker inclusion. Even when multiple interfering ions coexist, the fiber membrane's response intensity to PFOA remains at 86.8% of the blank control, indicating high detection sensitivity even in complex matrices. Furthermore, common organic solvents have little effect on the fluorescence intensity of the material, demonstrating that the fiber membrane of this invention has good structural stability.

[0059] In summary, the composite fiber membrane of this invention achieves a highly selective fluorescence response to PFOA by means of the host-guest inclusion effect and electrostatic attraction between the functional recognition additive and PFAS, and has the potential for stable detection in complex aquatic environments (such as industrial wastewater and tap water).

[0060] Example 3: Photocatalytic degradation performance of composite fiber membranes on PFAS The perovskite@cyclodextrin (CPB@C-βCD) composite fiber membrane exhibits high efficiency and stability in the photocatalytic degradation of PFAS-type organic pollutants and can be applied to the degradation of pollutants in aquatic environments.

[0061] The specific operating method is as follows: (1) The composite fiber membrane prepared in Example 1 was used to make circular sheets with a diameter of 0.5 cm as photocatalytic material. A PFOA aqueous solution with a concentration of 500 μg / L was prepared to simulate industrial wastewater with moderate pollution levels, using perfluorooctanoic acid (PFOA) as the target pollutant. 30 mL of PFOA solution and 1 mg of composite fiber membrane disc were added to the photocatalytic reactor (50 mL quartz tube). The reaction temperature was controlled at 25 °C using a water-cooling platform. The pH of the solution was adjusted to 2.5 with formic acid (which is beneficial for the generation of hydroxyl radicals and the degradation reaction). The reaction system was continuously stirred for 90 minutes under light-protected conditions to allow the fiber membrane and PFOA to reach adsorption-desorption equilibrium, thus eliminating the contribution of simple adsorption to the removal rate.

[0062] (2) Use white LED lights (wavelength range 400~760 nm, light intensity 100 mW / cm²).2 A simulated AM 1.5G sunlight was used as the visible light source; an 80 W, air-cooled ultraviolet lamp with a main wavelength of 365 nm was used as a control light source. Timing began after the light source was turned on, and 2 mL samples were taken at regular intervals. After passing through a 0.22 μm filter, the samples were diluted with methanol and analyzed. The residual concentration of PFOA was determined using high-performance liquid chromatography-mass spectrometry (LC-MS). Three parallel samples were set up for each experiment, and the average value was taken.

[0063] like Figure 10 As shown, after 90 minutes of light-shielded adsorption, the PFOA concentration decreased by approximately 15%, indicating that the fiber membrane has a good adsorption and enrichment capacity for PFOA, thereby enhancing the subsequent photocatalytic degradation efficiency. This is attributed to the composite fiber membrane of this invention having a porous nanofiber structure and a large specific surface area, which is beneficial for the rapid mass transfer of pollutants. In addition, the strong adsorption capacity of the functional recognition additive (cyclodextrin) can effectively increase the contact sites between PFOA and the catalytic surface, strengthen interfacial interactions, and promote photocatalytic degradation.

[0064] Catalyst-free controlled experiments showed that PFOA was relatively stable under both UV and visible light irradiation, with a self-degradation rate of less than 5%. Figure 11 As shown in Figure a, when the composite fiber membrane (CPB@C-βCD) prepared with a functional recognition additive (C-βCD) content of 0.01 mol / L is used as a catalyst, the degradation efficiency reaches 90.8% after 13 hours of visible light irradiation, and near-complete degradation occurs after 45 hours. However, the fiber membrane prepared with an additive content of 0.03 mol / L shows a degradation efficiency of only 71.3% after 13 hours under visible light. This is because although more additives provide more adsorption sites, excessive chloride ion doping leads to excessive broadening of the semiconductor band gap, reducing visible light absorption efficiency and thus inhibiting photocatalytic activity. This further verifies the importance of appropriate additives in balancing adsorption and catalytic activity. Figure 11 As shown in b, a similar degradation trend was observed under ultraviolet light irradiation as a comparative experiment (the degradation rate reached 94.2% after 13 hours of ultraviolet light), slightly higher than that of the visible light group. Considering that visible light (especially natural sunlight) requires no additional energy consumption, has lower equipment costs, and is safer for operators, the degradation performance of the composite fiber membrane of this invention under visible light can meet the actual water treatment needs, and has greater application advantages and promotion value.

[0065] Under illumination, perovskite materials absorb light energy and generate photogenerated electrons and holes. These photogenerated charge carriers can react with water molecules or dissolved oxygen to produce highly oxidizing reactive oxygen species, such as hydroxyl radicals (·OH). Hydroxyl radicals can efficiently degrade PFOA molecules. To verify the degradation mechanism of this system, electron paramagnetic resonance (EPR) was used for radical capture experiments. Figure 12As shown, a characteristic quartet (intensity ratio 1:2:2:1) belonging to DMPO-·OH was clearly detected after ultraviolet light irradiation. Simultaneously, the characteristic peak of DMPO-·CR (perfluoroalkyl radical) increased with increasing reaction time, confirming the radical-triggered degradation mechanism. These results indicate that the hydroxyl radicals generated by the semiconductor photofunctional material under light irradiation are the main active species for cleaving the carbon-fluorine bonds of PFAS, providing mechanistic support for the material's practical water treatment applications.

[0066] Example 4: Composite fiber membrane used in the integrated closed-loop application of PFAS "detection-degradation-material harmless treatment" To fully demonstrate the multifunctional integrated advantages of the composite fiber membrane of this invention, this embodiment, based on Embodiments 1, 2, and 3, connects three functions—fluorescence detection, photocatalytic degradation, and post-use material biodegradation—onto a single material platform, showcasing a complete closed-loop process from pollutant identification and removal to the harmless disposal of the material. All operational steps are based on the experimental conditions and data verified in the aforementioned embodiments, without introducing any new experimental variables.

[0067] The specific operating method is as follows: (1) Take the composite fiber membrane prepared in Example 1 and make it into a circular sheet with a diameter of 0.5 cm using a punch for subsequent tandem experiments. All materials are stored in a desiccator in the dark before use.

[0068] (2) A circular fiber membrane was placed in a quartz reactor. A 365 nm handheld UV lamp was used as the excitation source. The initial fluorescence intensity I0 of the fiber membrane was recorded using a portable fiber optic spectrometer. 30 mL of an aqueous solution containing 500 μg / L perfluorooctanoic acid (PFOA) was added (the pH was adjusted to 2.5 with formic acid). The sample to be tested was then placed under the same conditions to measure the fluorescence intensity I. According to the standard curve established in Example 2 (I / I0 showed a good linear relationship with the PFOA concentration, R...), 2 >0.98 (detection limit 13.2 μg / L), confirming the concentration of PFOA in the water sample. The detection response time is less than 1 minute.

[0069] (3) After the detection is completed, the fiber membrane is not removed; the same reaction system is directly subjected to photocatalytic degradation. A simulated sunlight LED light source (wavelength range 400~760 nm, light intensity 100 mW / cm²) is used. 2 The reaction was carried out under irradiation, with the reaction temperature controlled at 25 °C using a water-cooling platform and continuous stirring. Based on the experimental results of Example 3, the degradation efficiency of PFOA reached 90.8% after 13 hours of irradiation. After degradation, the fiber membrane was irradiated with ultraviolet light again, and its fluorescence intensity had basically recovered to the initial level, indicating that PFOA was effectively removed and the material could be reused or enter the degradation treatment stage.

[0070] (3) The fiber membrane that has completed the detection and degradation tasks was removed and treated according to the biodegradation method in Example 1: a 0.05 mg / mL lipase solution (dissolved in PBS buffer, pH 7.4) was prepared, and the fiber membrane was immersed in it and placed in a constant temperature shaker at 37 °C at 120 rpm. According to the results of Example 1, the fiber membrane was completely degraded after 5 hours. The degraded solution was filtered, and the lead ion concentration was determined by inductively coupled plasma mass spectrometry (ICP-MS). The average value of three parallel measurements was 2.5 μg / L, which meets the lead content limit for drinking water stipulated by the US Environmental Protection Agency.

[0071] like Figure 13 As shown, this embodiment fully demonstrates the continuous realization of the three core functions of the composite fiber membrane of the present invention on the same material platform. The closed-loop process of "detection → degradation → harmless disposal" verifies that the present invention is significantly superior to the prior art in terms of functional integration, ease of operation, and environmental friendliness, providing a complete technical solution for the rapid on-site detection and in-situ green treatment of persistent organic pollutants in water.

[0072] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A composite fiber membrane for the detection, degradation, and harmless treatment of perfluorinated and polyfluoroalkyl compounds, characterized in that, The composite fiber membrane has a porous fiber network structure and contains the following components: Polymer matrix: The skeletal structure used to form fibrous membranes; Semiconductor optical functional materials: dispersed inside or on the surface of the polymer matrix, which can simultaneously generate photoluminescence signals and photocatalytic active species under excitation light irradiation; Functional identification additives: These additives chemically interact with the surface of the semiconductor optical functional material, selectively capturing perfluorinated and polyfluoroalkyl compound molecules and modulating the luminescent properties of the semiconductor optical functional material.

2. The composite fiber membrane for the detection, degradation, and harmless treatment of perfluorinated and polyfluoroalkyl compounds according to claim 1, characterized in that, The polymer matrix is ​​at least one of polycaprolactone, polylactic acid, polyglycolic acid, polyhydroxyalkanoate, polypropylene carbonate, polybutylene succinate, polystyrene, acrylonitrile-butadiene-styrene copolymer, polyethylene, polypropylene, polyamide, polyoxymethylene, high-temperature nylon, and polyphenylene sulfide.

3. The composite fiber membrane for the detection, degradation, and harmless treatment of perfluorinated and polyfluoroalkyl compounds according to claim 1, characterized in that, The semiconductor optical functional material is an inorganic perovskite material with the general formula ABX3, where A is Cs. + Rb + At least one of them; B is Pb 2+ Cu 2+ Ag + In 3+ Sn 2+ At least one of them; X is Cl - , Br - I - At least one of them.

4. The composite fiber membrane for the detection, degradation, and harmless treatment of perfluorinated and polyfluoroalkyl compounds according to claim 1, characterized in that, The functional recognition additive is a macrocyclic molecule with cationic or polar functional groups, and the macrocyclic molecule is at least one of cyclodextrin, crown ether, calixarene, columnar aromatics, and cucurbituril. The functional recognition additive captures perfluorinated and polyfluoroalkyl compounds through electrostatic interaction, hydrogen bonding, or host-guest inclusion.

5. A method for preparing a composite fiber membrane as described in any one of claims 1 to 4, characterized in that, Includes the following steps: Step X1: Dissolve the precursor of the semiconductor optical functional material and the polymer matrix in an organic solvent to obtain the spinning solution; Step X2: Add functional identification additives to the spinning solution, mix, and obtain the spinning working solution; Step X3: Spin the spinning working solution by electrospinning and dry it to obtain the final product.

6. The preparation method according to claim 5, characterized in that, The electrospinning process parameters are as follows: voltage 8~30 kV, receiving distance 8~20 cm, roller speed 150~1000 rpm, spinning solution delivery rate 0.1~10 mL / h, temperature 25~60 ℃, and relative humidity 30%~80%.

7. An integrated method for detecting, degrading, and rendering harmless the composite fiber membrane described in any one of claims 1 to 4 to water PFAS, characterized in that, Includes the following steps: Step Y1, Detection Step: Place the composite fiber membrane in a water body containing PFAS to enrich PFAS on the fiber membrane; irradiate the composite fiber membrane with an excitation light source and determine the concentration of PFAS in the water body based on the change in fluorescence intensity; Step Y2, Degradation Step: After or simultaneously with the detection step, the composite fiber membrane is irradiated with a light source containing visible light to excite the semiconductor photofunctional material to generate reactive oxygen species, thereby degrading the adsorbed PFAS. Step Y3, Biodegradation Step: The composite fiber membrane that has completed the detection and degradation tasks is placed in a buffer solution containing lipase or esterase to completely degrade the polymer matrix. At the same time, the leakage of heavy metal ions is controlled by the chelating effect of functional recognition additives.

8. The integrated method according to claim 7, characterized in that, The PFAS is at least one of perfluorooctanoic acid, perfluorooctane sulfonic acid, perfluoroheptanoic acid, perfluorohexanoic acid, perfluorovalerate, and perfluorobutyric acid.

9. The application of a composite fiber membrane as described in any one of claims 1 to 4 as a fluorescent test strip for rapid detection of perfluorinated and polyfluoroalkyl compounds.

10. The application of a composite fiber membrane as described in any one of claims 1 to 4 in wastewater treatment involving the photocatalytic degradation of PFAS.

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