A polymer fiber membrane with selective catalytic self-degradation function and its preparation method and application

Abstract

The present invention relates to the technical field of degradable polymer fibers, and more particularly to a polymer fiber membrane with selective catalytic self-degradation function and its preparation method and application, comprising the following steps: dissolving a dispersant in deionized water, adding a nano-photocatalyst to obtain a photocatalyst dispersion liquid; dissolving an aluminum salt in deionized water to obtain an aluminum salt solution; slowly adding the aluminum salt solution dropwise to the photocatalyst dispersion liquid, stirring and aging to obtain a core-shell photocatalyst; dissolving a polymer to obtain a polymer solution, adding a core-shell photocatalyst, stirring evenly at 20-40°C to obtain a polymer spinning solution; spinning the polymer spinning solution using a centrifugal electrostatic spinning method, and drying to obtain a polymer fiber membrane. The present invention adopts the above steps, prepares a shell by controlling the synthesis conditions of Al2O3, obtains a core-shell photocatalyst with pH selectivity, adds it to the polymer fiber membrane, to prepare a self-degradable polymer fiber membrane.

Description

Technical Field

[0001] The present invention relates to the technical field of degradable polymer fibers, in particular to a polymer fiber membrane with selective catalytic self-degradation function, and a preparation method and application thereof. Background Art

[0002] In recent years, microplastic pollution has become one of the most serious environmental issues globally. Fibers account for the largest proportion of microplastics, making addressing waste fiber pollution a pressing issue. Biodegradable materials have long been considered an alternative to traditional non-biodegradable materials and one of the most effective solutions to plastic pollution.

[0003] Biodegradable materials are still the most widely used degradable materials on the market. However, their degradation conditions are demanding, and their degradation performance is affected by numerous environmental factors, such as the type and distribution of microorganisms, humidity, and pH. Furthermore, the degradation time required is very long, requiring at least several months. Therefore, degradable materials with simple degradation conditions, fast degradation rates, and no impact on normal use are more attractive for alleviating the problem of plastic pollution.

[0004] Photodegradable materials have simple degradation conditions, with sunlight as their primary energy source. These conditions are mild and widely applicable to various environments. They are categorized into two types: synthetic and additive. Synthetic photodegradable materials require a more complex production process, often requiring complex metal complexes as catalysts. In contrast, additive photodegradable materials are simple to prepare; simply adding a photosensitizer with photocatalytic activity to the polymer imbues the material with photodegradability.

[0005] Additive photodegradable materials have a faster degradation rate. Patent CN201510801124.4 reports that adding a photodegradant to PE can impart photodegradation properties to PE, allowing the material to fully degrade in a short period of time under light. Patent CN01128331.9 mentions that adding the photosensitizer ferric citrate to PP resin can degrade the PP resin material into powder within 75 days. However, the biggest problem with additive photodegradable materials is the difficulty in simultaneously achieving stability during use and rapid degradation after becoming waste. Therefore, it is extremely important to develop photodegradable materials that have good stability under normal use environments and good degradability under specific conditions. Summary of the Invention

[0006] The purpose of the present invention is to provide a polymer fiber membrane with selective catalytic self-degradation function, its preparation method and application, by controlling the synthesis conditions of Al2O3 to prepare the shell, obtain a core-shell photocatalyst with pH selectivity, and add it to the polymer fiber membrane to prepare a polymer fiber membrane with self-degradation function.

[0007] To achieve the above object, the present invention provides a method for preparing a polymer fiber membrane with selective catalytic self-degradation function, comprising the following steps:

[0008] S1. Dissolve the dispersant in deionized water, add the nano-photocatalyst, and mix by ultrasonication and magnetic stirring to obtain a photocatalyst dispersion.

[0009] S2. dissolving aluminum salt in deionized water to obtain an aluminum salt solution;

[0010] S3. Under magnetic stirring, slowly dropwise add the aluminum salt solution obtained in S2 to the photocatalyst dispersion in S1 to obtain a mixed system, adjust the pH of the mixed system to 5-12, stir and age, wash and dry to obtain a core-shell photocatalyst;

[0011] S4, dissolving the polymer to obtain a polymer solution, adding the core-shell photocatalyst obtained in S3, and stirring at 20-40° C. to obtain a polymer spinning solution;

[0012] S5. Spinning the polymer spinning solution in S4 by using a centrifugal-electrospinning method, and drying the solution to obtain a polymer fiber membrane.

[0013] Preferably, in S1, the dispersant is (NaPO3)6, and the nano-photocatalyst includes one or more of WO3, CdS, BiVO4, TiO2, SrTiO3, ZnO, and CuO.

[0014] Preferably, in S2, the aluminum salt is NaAlO2.

[0015] Preferably, in S3, the mass of the aluminum salt is 0.5-5.0% of the total mass of the mixed system, the mass of the dispersant is 0.01-0.05% of the total mass of the mixed system, the stirring temperature is 20-80°C, the aging time is 24-48h, and the drying temperature is 60-180°C.

[0016] Preferably, in S4, the polymer is one or more of polymer chips and polymer powder;

[0017] The polymer includes one or more of polyethylene terephthalate (PET), polyacrylonitrile (PAN), polyethylene (PE), polypropylene (PP), polycarbonate (PC), polyvinyl chloride (PVC), polystyrene (PS), and polyamide (PA).

[0018] Preferably, in S4, the concentration of the polymer solution is 5-15 wt %, and the dissolution temperature of the polymer is 20-40°C.

[0019] Preferably, in S4, the amount of the core-shell photocatalyst added to the polymer spinning solution is 0.5-5 wt%.

[0020] Preferably, in S5, the spinning parameters of the centrifugal-electrospinning method include: a spinning needle of one of 25G, 27G and 30G, a spinning speed of 3500 r / min, a voltage of 10 kV, and a collection distance of 10 cm.

[0021] The polymer fiber membrane prepared by the above-mentioned preparation method of the polymer fiber membrane with selective catalytic self-degradation function.

[0022] The above-mentioned application of the polymer fiber membrane with selective catalytic self-degradation function is used in the preparation of clothing, carpets, curtains and toys.

[0023] The mechanism of the present invention is:

[0024] Under neutral, alkaline and weakly acidic conditions, the Al2O3 on the surface of the core-shell photocatalyst has good stability, can shield light, protect the internal nano-photocatalyst particles from being excited, and enable the polymer fiber membrane to be used normally. Under the condition of pH 3, the outer shell Al2O3 of the core-shell photocatalyst dissolves and falls off, exposing the internal nano-photocatalyst particles, which produce ·OH and ·O2 after being exposed to light. - 、 1 O2 and other free radicals, thereby oxidizing the nearby polymer chains to achieve the purpose of self-degradation.

[0025] Therefore, the present invention adopts the above-mentioned polymer fiber membrane with selective catalytic self-degradation function and its preparation method and application, and its beneficial effects are:

[0026] 1. The present invention controls the synthesis conditions of Al2O3 to prepare a shell to obtain a core-shell photocatalyst with pH selectivity, which is added to polymer fibers to prepare a photodegradable polymer fiber membrane with environmental selectivity;

[0027] 2. The polymer fiber membrane prepared in the present invention has pH selectivity and can be fully degraded after being irradiated by sunlight. The intermediate products produced during the degradation process are non-toxic to the environment, which can ensure normal storage and use under conventional conditions. When the polymer fiber membrane becomes waste, it can also be rapidly photodegraded under specific conditions, achieving both usability and degradability.

[0028] 3. The content of the core-shell photocatalyst added to the polymer fiber membrane in the present invention is relatively low, which can improve the tensile strength of the polymer fiber membrane, with only a small decrease in the elongation at break, and has little effect on the mechanical properties of the polymer fiber membrane.

[0029] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is the SEM image of the original TiO2 and the core-shell photocatalyst TiO2@Al2O3 in Example 1 of the present invention;

[0031] Figure 2 is a schematic diagram of the polymer fiber membrane TiO2@Al2O3 / PA6 in Example 1 of the present invention;

[0032] Figure 3 is a graph showing the photodegradation performance of the polymer fiber membrane under different pH conditions in Example 1 of the present invention;

[0033] Figure 4 This is a combined graph showing the change in the actual morphology of the polymer fiber membrane as a function of illumination time when the pH value of the polymer fiber membrane in Example 1 of the present invention is 3;

[0034] Figure 5 is a graph showing mass loss of the polymer fiber membrane in Example 2 of the present invention after irradiation for 100 hours under different pH conditions;

[0035] Figure 6 3 are SEM images of the polymer fiber membrane before and after irradiation in Example 3 of the present invention. DETAILED DESCRIPTION

[0036] The present invention is further described below with reference to the accompanying drawings and examples. Unless otherwise defined, technical or scientific terms used herein shall have the same meanings as those commonly understood by persons of ordinary skill in the art to which the present invention pertains. The above-mentioned features or features described in the specific examples of the present invention may be combined in any manner. These specific examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention.

[0037] Example 1

[0038] S1. Dissolve 4 mg of dispersant (NaPO3)6 in 10 mL of deionized water, add 1 g of nano-photocatalyst TiO2, ultrasonicate for 10 min until uniform, and then magnetically stir for 1.5 h to obtain a photocatalyst dispersion.

[0039] S2. Dissolve 156 mg of aluminum salt NaAlO2 in 2 mL of deionized water to obtain an aluminum salt solution.

[0040] S3, under magnetic stirring at 30℃, slowly add the aluminum salt solution obtained in S2 to the photocatalyst dispersion in S1 to obtain a mixed system, add dilute sulfuric acid in parallel to adjust the pH of the mixed system to 7, stir at 30℃ for 1.5h, and then age for 40h, wash with deionized water to remove excess aluminum salt, and dry at 150℃ for 24h to obtain core-shell photocatalyst TiO2@Al2O3, such as Figure 1 As shown, Figure 1(a) is the SEM image of the original TiO2, showing that the edge of the nano-photocatalyst TiO2 particles is clear and the diameter is about 25nm. Figure 1 (b) is the SEM image of the core-shell photocatalyst TiO2@Al2O3. It can be seen that a layer of Al2O3 film is obviously formed on the surface of the nanophotocatalyst. The nanophotocatalyst particles are core-shell in shape, and the diameter increases to about 40nm, which is enough to show that this method has successfully prepared the core-shell catalyst TiO2@Al2O3.

[0041] S4. Dissolve 1.75 g of polyamide 6 (PA6) in 10 mL of hexafluoroisopropanol (HFIP) under stirring at 35° C. for 12 h to obtain a polymer solution, add 44.4 mg of the core-shell photocatalyst obtained in S3 (the core-shell catalyst accounts for 2.5 wt% of the total mass (core-shell catalyst + polymer)), and stir at 35° C. for 24 h to obtain a polymer spinning solution.

[0042] S5, the polymer spinning solution in S4 was spun using a centrifugal-electrospinning method, with the spinning parameters including: a 27G spinning needle, a spinning speed of 3500 r / min, a voltage of 10 kV, and a collection distance of 10 cm. The excess solvent was removed by drying at 60°C for 12 h to obtain a polymer fiber membrane TiO2@Al2O3 / PA6, such as Figure 2 shown.

[0043] Example 2

[0044] S1. Dissolve 4 mg of dispersant (NaPO3)6 in 10 mL of deionized water, add 1 g of nano-photocatalyst TiO2, ultrasonicate for 10 min until uniform, and then magnetically stir for 1.5 h to obtain a photocatalyst dispersion.

[0045] S2. Dissolve 78 mg of aluminum salt NaAlO2 in 2 mL of deionized water to obtain an aluminum salt solution.

[0046] S3. Under magnetic stirring at 50°C, the aluminum salt solution obtained in S2 was slowly added dropwise to the photocatalyst dispersion in S1 to obtain a mixed system. Dilute sulfuric acid was added dropwise in parallel to adjust the pH of the mixed system to 7. The system was stirred at 50°C for 1.5 hours and then aged for 36 hours. The system was washed with deionized water to remove excess aluminum salt and dried at 150°C for 24 hours to obtain a core-shell photocatalyst TiO2@Al2O3.

[0047] S4. Dissolve ethylene terephthalate (PET) in HFIP under stirring at 35° C. for 12 h to obtain a 12 wt% polymer solution, add the core-shell photocatalyst obtained in S3 (the core-shell catalyst accounts for 2.5 wt% of the total mass (core-shell catalyst + polymer)), and stir at 35° C. for 24 h to obtain a polymer spinning solution.

[0048] S5. The polymer spinning solution in S4 was spun using a centrifugal-electrospinning method. The spinning parameters included a 25G spinning needle, a spinning speed of 3500 r / min, a voltage of 10 kV, and a collection distance of 10 cm. The solution was then dried at 60°C for 12 hours to remove excess solvent, thereby obtaining a polymer fiber membrane TiO2@Al2O3 / PET.

[0049] Example 3

[0050] S1. Dissolve 6 mg of dispersant (NaPO3)6 in 10 mL of deionized water, add 1 g of nano-photocatalyst ZnO, ultrasonicate for 10 min until uniform, and then magnetically stir for 1.5 h to obtain a photocatalyst dispersion.

[0051] S2. Dissolve 234 mg of aluminum salt NaAlO2 in 3 mL of deionized water to obtain an aluminum salt solution.

[0052] S3. Under magnetic stirring at 80°C, the aluminum salt solution obtained in S2 was slowly added dropwise to the photocatalyst dispersion in S1 to obtain a mixed system. Dilute sulfuric acid was added dropwise in parallel to adjust the pH of the mixed system to 9. The system was stirred at 80°C for 1.5 hours and then aged for 40 hours. The system was washed with deionized water to remove excess aluminum salt and dried at 150°C for 24 hours to obtain a core-shell photocatalyst ZnO@Al2O3.

[0053] S4. Dissolve polyacrylonitrile (PAN) in 10 mL of N,N-dimethylformamide (DMF) under stirring at 35°C for 12 h to obtain a 10 wt% polymer solution, add the core-shell photocatalyst obtained in S3 (the core-shell catalyst accounts for 5.0 wt% of the total mass (core-shell catalyst + polymer)), and stir at 35°C for 24 h to obtain a polymer spinning solution.

[0054] S5. The polymer spinning solution in S4 was spun using a centrifugal-electrospinning method. The spinning parameters included: a 30G spinning needle, a spinning speed of 3500 r / min, a voltage of 10 kV, and a collection distance of 10 cm. The solution was then dried at 60°C for 12 hours to remove excess solvent, thereby obtaining a polymer fiber membrane ZnO@Al2O3 / PAN.

[0055] Example 4

[0056] S1. Dissolve 4 mg of dispersant (NaPO3)6 in 10 mL of deionized water, add 1 g of nano-photocatalyst CdS, ultrasonicate for 10 min until uniform, and then magnetically stir for 1.5 h to obtain a photocatalyst dispersion.

[0057] S2. Dissolve 200 mg of aluminum salt NaAlO2 in 3 mL of deionized water to obtain an aluminum salt solution.

[0058] S3. Under magnetic stirring at 80°C, the aluminum salt solution obtained in S2 was slowly added dropwise to the photocatalyst dispersion in S1 to obtain a mixed system. Dilute sulfuric acid was added dropwise in parallel to adjust the pH of the mixed system to 11.5. The system was stirred at 80°C for 1.5 hours and then aged for 40 hours. The system was washed with deionized water to remove excess aluminum salt and dried at 150°C for 24 hours to obtain a core-shell photocatalyst CdS@Al2O3.

[0059] S4. Dissolve PAN in DMF at 35°C with stirring for 12 hours to obtain a 10 wt% polymer solution, add the core-shell photocatalyst obtained in S3 (the core-shell catalyst accounts for 5.0 wt% of the total mass (core-shell catalyst + polymer)), and stir at 35°C for 24 hours to obtain a polymer spinning solution.

[0060] S5. The polymer spinning solution in S4 was spun using a centrifugal-electrospinning method. The spinning parameters included: a 30G spinning needle, a spinning speed of 3500 r / min, a voltage of 10 kV, and a collection distance of 10 cm. The solution was then dried at 60°C for 12 hours to remove excess solvent, thereby obtaining a polymer fiber membrane CdS@Al2O3 / PAN.

[0061] Comparative Example 1

[0062] S1. Dissolve 5 mg of dispersant (NaPO3)6 in 10 mL of deionized water, add 1 g of nano-photocatalyst TiO2, ultrasonicate for 10 min until uniform, and then magnetically stir for 1.5 h to obtain a photocatalyst dispersion.

[0063] S2. Dissolve 39 mg of aluminum salt NaAlO2 in 2 mL of deionized water to obtain an aluminum salt solution.

[0064] S3. Under magnetic stirring at 30°C, the aluminum salt solution obtained in S2 was slowly added dropwise to the photocatalyst dispersion in S1 to obtain a mixed system. Dilute sulfuric acid was added dropwise in parallel to adjust the pH of the mixed system to 9. The system was stirred at 80°C for 1.5 hours and then aged for 24 hours. The system was washed with deionized water to remove excess aluminum salt and dried at 100°C for 24 hours to obtain the photocatalyst TiO2@Al2O3.

[0065] S4. Dissolve PA6 in HFIP at 35°C with stirring for 12 h to obtain a 10 wt% polymer solution, add the photocatalyst obtained in S3 (the core-shell catalyst accounts for 2.0 wt% of the total mass (core-shell catalyst + polymer)), and stir at 35°C for 24 h to obtain a polymer spinning solution.

[0066] S5. The polymer spinning solution in S4 was spun using a centrifugal-electrospinning method. The spinning parameters included a 27G spinning needle, a spinning speed of 3500 r / min, a voltage of 10 kV, and a collection distance of 12 cm. The solution was then dried at 60°C for 12 hours to remove excess solvent, thereby obtaining a polymer fiber membrane TiO2@Al2O3 / PA6.

[0067] Comparative Example 2

[0068] S1. Dissolve 5 mg of dispersant (NaPO3)6 in 10 mL of deionized water, add 1 g of nano-photocatalyst TiO2, ultrasonicate for 10 min until uniform, and then magnetically stir for 1.5 h to obtain a photocatalyst dispersion.

[0069] S2. Dissolve 312 mg of aluminum salt NaAlO2 in 4 mL of deionized water to obtain an aluminum salt solution.

[0070] S3. Under magnetic stirring at 80°C, the aluminum salt solution obtained in S2 was slowly added dropwise to the photocatalyst dispersion in S1 to obtain a mixed system. Dilute sulfuric acid was added dropwise in parallel to adjust the pH of the mixed system to 9. The system was stirred at 80°C for 1.5 hours and then aged for 24 hours. The system was washed with deionized water to remove excess aluminum salt and dried at 100°C for 24 hours to obtain the photocatalyst TiO2@Al2O3.

[0071] S4. Dissolve PA6 in HFIP at 35°C with stirring for 12 h to obtain a 10 wt% polymer solution, add the photocatalyst obtained in S3 (the core-shell catalyst accounts for 25 wt% of the total mass (core-shell catalyst + polymer)), and stir at 35°C for 24 h to obtain a polymer spinning solution.

[0072] S5. The polymer spinning solution in S4 was spun using a centrifugal-electrospinning method. The spinning parameters included a 27G spinning needle, a spinning speed of 3500 r / min, a voltage of 10 kV, and a collection distance of 12 cm. The solution was then dried at 60°C for 12 hours to remove excess solvent, thereby obtaining a polymer fiber membrane TiO2@Al2O3 / PA6.

[0073] Comparative Example 3

[0074] S1. Dissolve 4 mg of dispersant (NaPO3)6 in 10 mL of deionized water, add 1 g of nano-photocatalyst WO3, ultrasonicate for 10 min until uniform, and then magnetically stir for 1.5 h to obtain a photocatalyst dispersion.

[0075] S2. Dissolve 200 mg of aluminum salt NaAlO2 in 2.5 mL of deionized water to obtain an aluminum salt solution.

[0076] S3. Under magnetic stirring at 60°C, the aluminum salt solution obtained in S2 was slowly added dropwise to the photocatalyst dispersion in S1 to obtain a mixed system. Dilute sulfuric acid was added dropwise in parallel to adjust the pH of the mixed system to 8. The system was stirred at 60°C for 1.5 hours and then aged for 24 hours. The system was washed with deionized water to remove excess aluminum salt and dried at 80°C for 24 hours to obtain the photocatalyst WO3@Al2O3.

[0077] S4. Dissolve polystyrene (PS) in DMF at 35°C with stirring for 12 h to obtain a 9 wt% polymer solution, add the photocatalyst obtained in S3 (the core-shell catalyst accounts for 1.0 wt% of the total mass (core-shell catalyst + polymer)), and stir at 35°C for 24 h to obtain a polymer spinning solution.

[0078] S5. The polymer spinning solution in S4 was spun using a centrifugal-electrospinning method. The spinning parameters included a 27G spinning needle, a spinning speed of 3500 r / min, a voltage of 10 kV, and a collection distance of 12 cm. The solution was then dried at 60°C for 12 h to remove excess solvent, thereby obtaining a polymer fiber membrane WO3@Al2O3 / PS.

[0079] Test Example 1

[0080] The polymer fiber membranes obtained in Examples 1-4 and Comparative Examples 1-3 were placed in aqueous solutions with pH values ​​of 3, 5, 7, 9, and 11 for simulated light exposure, and the self-degradation of the polymer fiber membranes under acidic, neutral, and alkaline conditions was tested, as shown in Table 1.

[0081] Table 1. Degradation of polymer fiber membranes in Examples 1-4 and Comparative Examples 1-3

[0082]

[0083] It can be seen from Table 1 that the polymer fiber membranes in Examples 1-4 have pH selectivity, self-degrading at a pH of 3, and not degrading under neutral, alkaline and weakly acidic conditions. Figure 3 It can be seen that the polymer fiber membrane in Example 1 can achieve a mass loss of 38% after 120 hours of sunlight irradiation at a pH of 3, and almost no degradation occurs under neutral, alkaline and weakly acidic conditions. Figure 4 It can be seen that Figure 4 (a)-(f) represent the macroscopic morphologies after irradiation for 0 h, 24 h, 48 h, 72 h, 96 h and 120 h, respectively. The polymer fiber membrane in Example 1 gradually degrades with the increase of irradiation time, and only a small amount of powder remains in the end.

[0084] Depend on Figure 5It can be seen that the polymer fiber membrane in Example 2 photodegraded at pH 3, with a mass loss of 11.1% after only 100 h of sunlight irradiation, while being stable under neutral, alkaline and weakly acidic conditions. Figure 6 It can be seen that the polymer fiber membrane in Example 3 ( Figure 6 (a)) in the figure shows a complete fiber morphology. After 150 hours of light exposure, ( Figure 6 In (b), the fibers showed significant fragmentation and numerous cavities on the surface, confirming the self-degradation properties of the polymer fiber membrane matrix. The polymer fiber membrane in Example 4 lost approximately 25% of its mass after 150 hours of simulated light exposure at a pH of 3, while exhibiting no degradation under neutral, alkaline, and weakly acidic conditions.

[0085] The polymer fiber membrane in Comparative Example 1 exhibited weak self-degradation under acidic, neutral, and alkaline conditions, indicating that its degradation was not pH-selective. This is because under these preparation conditions, Al2O3 did not coat TiO2, but existed solely as Al2O3 particles.

[0086] The polymer fiber membrane in Comparative Example 2 was self-degradable under acidic, neutral, and alkaline conditions, and its degradation performance was not pH-selective. This is because under these preparation conditions, Al2O3 did not coat TiO2 and existed solely as Al2O3 particles.

[0087] In Comparative Example 3, the polymer fiber membrane is difficult to self-degrade under acidic, neutral and alkaline conditions, and the degradation performance of the polymer fiber membrane is not pH selective. 3+ It is difficult to adsorb on the surface of the catalyst, so it is difficult to form a coating. The prepared Al2O3 easily forms blocky particles, which have a shielding effect on light.

[0088] Therefore, the present invention adopts the above-mentioned polymer fiber membrane with selective catalytic self-degradation function and its preparation method and application, and prepares the shell by controlling the synthesis conditions of Al2O3 to obtain a core-shell photocatalyst with pH selectivity, which is added to the polymer fiber to prepare a photodegradable polymer fiber membrane with environmental selectivity.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a polymer fiber membrane with selective catalytic self-degradation function, characterized by: The following steps are included: S1. Dissolve the dispersant in deionized water, add the nano-photocatalyst, and mix by ultrasonication and magnetic stirring to obtain a photocatalyst dispersion; In S1, the dispersant is (NaPO3)6, and the nano-photocatalyst includes one or more of WO3, CdS, BiVO4, TiO2, SrTiO3, ZnO, and CuO; S2. dissolving aluminum salt in deionized water to obtain an aluminum salt solution; In S2, the aluminum salt is NaAlO2; S3. Under magnetic stirring, slowly dropwise add the aluminum salt solution obtained in S2 to the photocatalyst dispersion in S1 to obtain a mixed system, adjust the pH of the mixed system to 5-12, stir and age, wash and dry to obtain a core-shell photocatalyst; In S3, the mass of the aluminum salt is 0.5-5.0% of the total mass of the mixed system, the mass of the dispersant is 0.01-0.05% of the total mass of the mixed system, the stirring temperature is 20-80°C, the aging time is 24-48h, and the drying temperature is 60-180°C; S4, dissolving the polymer to obtain a polymer solution, adding the core-shell photocatalyst obtained in S3, and stirring at 20-40° C. to obtain a polymer spinning solution; In S4, the amount of core-shell photocatalyst added to the polymer spinning solution is 0.5-5 wt%; S5. Spinning the polymer spinning solution in S4 by using a centrifugal-electrospinning method, and drying the solution to obtain a polymer fiber membrane.

2. The method for preparing a polymer fiber membrane with selective catalytic self-degradation function according to claim 1, characterized in that: In S4, the polymer is one or more of polymer chips and polymer powder; The polymer includes one or more of polyethylene terephthalate, polyacrylonitrile, polyethylene, polypropylene, polycarbonate, polyvinyl chloride, polystyrene, and polyamide.

3. The method for preparing a polymer fiber membrane with selective catalytic self-degradation function according to claim 1, characterized in that: In S4, the concentration of the polymer solution is 5-15 wt %, and the dissolution temperature of the polymer is 20-40°C.

4. The method for preparing a polymer fiber membrane with selective catalytic self-degradation function according to claim 1, characterized in that: In S5, the spinning parameters of the centrifugal-electrospinning method include: a spinning needle of one of 25G, 27G, and 30G, a spinning speed of 3500 r / min, a voltage of 10 kV, and a collection distance of 10 cm.

5. The polymer fiber membrane prepared according to the method for preparing a polymer fiber membrane with selective catalytic self-degradation function according to any one of claims 1 to 4.

6. The use of a polymer fiber membrane with selective catalytic self-degradation function according to claim 5, characterized in that: Polymer fiber films are used in the preparation of clothing, carpets, curtains and toys.

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