A PMMA-based photocatalytic composite fiber material and its preparation method and application

Abstract

The present invention discloses a PMMA-based photocatalytic composite fiber material and its preparation method and application, comprising the following steps: uniformly mixing polymethyl methacrylate, a porogen, and a solvent to obtain a mixed solution I; uniformly mixing polyaniline and a nano-metal oxide with the mixed solution I to obtain a spinning solution II; spinning the spinning solution II using a centrifugal spinning machine to obtain a composite fiber; sequentially immersing the composite fiber in an AgNO3 solution and a NaCl solution to perform an in-situ coprecipitation reaction, washing the composite fiber after the reaction, and then freeze-drying the fiber to obtain a photocatalytic composite fiber; and irradiating the photocatalytic composite fiber under an ultraviolet lamp to obtain a PMMA-based photocatalytic composite fiber material. The present invention achieves a synergistic improvement in the photocatalytic performance and mass transfer efficiency of the material, which not only broadens the light response range of the photocatalyst and improves the quantum efficiency, but also gives the material good biocompatibility and degradability.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental functional materials, and in particular relates to a porous photocatalytic composite fiber material based on polymethyl methacrylate (PMMA), a preparation method thereof, and an application thereof. Background Art

[0002] Photocatalytic technology has attracted significant attention in the field of environmental governance due to its green and sustainable nature. However, traditional powdered photocatalysts (such as TiO2) face bottlenecks such as easy aggregation and deactivation, difficult solid-liquid separation, and high recombination rates of photogenerated carriers. While existing technologies that immobilize photocatalytic components in a polymer matrix can improve material recyclability, they generally face the following challenges: ① The dense polymer matrix hinders the diffusion of pollutant molecules, resulting in low utilization of active sites; ② Poor interfacial compatibility between multiphase components leads to discontinuous transport pathways for photogenerated electrons; and ③ Strong dependence on UV light and insufficient visible light response.

[0003] Recent research has demonstrated that the construction of porous fiber structures can effectively improve mass transfer efficiency. Polymethyl methacrylate (PMMA) is an ideal carrier material due to its excellent light transmittance (>85%), chemical stability, and processability. However, existing PMMA-based composite fibers suffer from uncontrollable porosity and uneven loading of photocatalytic components, which compromise photocatalytic performance and hinder their practical application. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology, provide a PMMA-based photocatalytic composite fiber material and its preparation method and application, and prepare a composite fiber material with excellent photocatalytic performance and stability through a simple, efficient and low-cost method.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0006] A method for preparing a PMMA-based photocatalytic composite fiber material comprises the following steps:

[0007] (1) uniformly mixing polymethyl methacrylate, a porogen, and a solvent to obtain a mixed solution I;

[0008] (2) uniformly mixing the polyaniline and the nano-metal oxide with the mixed solution I to obtain a spinning solution II;

[0009] (3) spinning the spinning solution II through a centrifugal spinning machine to obtain MOx / PANI / PMMA composite fibers;

[0010] (4) The MOx / PANI / PMMA composite fiber was immersed in AgNO3 solution and NaCl solution in turn to carry out in situ coprecipitation reaction to load silver chloride nanoparticles on the surface and inside of the composite fiber. After the reaction was completed, the composite fiber was washed and then freeze-dried to obtain a photocatalytic composite fiber;

[0011] (5) The photocatalytic composite fiber is subjected to light treatment under an ultraviolet lamp to obtain a PMMA-based Ag@AgCl / MOx / PANI photocatalytic composite fiber.

[0012] As a further improvement, the porogen in step (1) is selected from at least one of ethylene glycol, diethylene glycol, glycerol, pentaerythritol, and propylene glycol, and the mass ratio of polymethyl methacrylate to the porogen is 1:0.02-0.1.

[0013] As a further improvement, the mass ratio of the polymethyl methacrylate, polyaniline and nano-metal oxide is 1:0.001-0.008:0.001-0.008.

[0014] As a further improvement, the nano metal oxide in step (2) is at least one of ZrO2, Sb2O3, NbO, Fe3O4, and ZnO.

[0015] As a further improvement, the rotation speed of the centrifugal spinning machine in step (3) is 500-5000 r / min, and the spinneret size of the spinning head of the centrifugal spinning machine is 0.1-0.5 mm.

[0016] As a further improvement, during the spinning process in step (3), the temperature of the fiber curing treatment is 40-80°C and the humidity is ≤60RH%.

[0017] As a further improvement, the concentration of the AgNO3 solution in step (4) is 0.03-0.25 mol / L, and the concentration of the NaCl solution is 0.03-0.25 mol / L.

[0018] The present invention also provides a PMMA-based photocatalytic composite fiber material, which is prepared by the above-mentioned preparation method.

[0019] The present invention also provides an application of the PMMA-based photocatalytic composite fiber material in degrading organic pollutants.

[0020] As a further improvement, the application includes: dispersing the PMMA-based photocatalytic composite fiber material in a solution containing organic pollutants and degrading them under light.

[0021] This invention innovatively introduces a porogen, combining centrifugal spinning of aligned fibers with in-situ co-precipitation precision loading technology to synergistically construct a porous structure. Conductive polyaniline (PANI), nanometal oxides (MOx), and polymethyl methacrylate are then composited, and Ag@AgCl nanoparticle photocatalysts are further synthesized in situ to create a PMMA-based Ag@AgCl / MOx / PANI multi-component photocatalytic composite fiber material. This achieves a synergistic improvement in the material's photocatalytic performance and mass transfer efficiency, broadening the photocatalyst's light response range and improving its quantum efficiency while also imparting good biocompatibility and degradability. This material is suitable for the efficient adsorption and degradation of organic pollutants and is of great significance for promoting the application of photocatalytic technology in areas such as environmental remediation.

[0022] Compared with the existing powder photocatalyst preparation technology, the present invention has the following beneficial effects:

[0023] (1) Multi-dimensional structural synergistic mechanism: A continuous fiber network constructed based on centrifugal spinning technology achieves a three-dimensional ordered distribution of photocatalytic components in a polymethyl methacrylate matrix. The uniformity of fiber diameter enables the material to obtain a controllable through-pore structure. Its pore characteristics break through the mass transfer resistance limitations of traditional fibers and form a rapid diffusion path for pollutant molecules. The molecular-level composite of nano-metal oxides and conductive polyaniline produces an interfacial electronic coupling effect, which synergizes with the surface plasmon resonance excitation of Ag@AgCl nanoparticles to establish an efficient carrier transmission channel from the bulk to the surface, significantly improving the efficiency of visible light capture and energy conversion.

[0024] (2) Breakthrough in engineering preparation technology: The innovative in-situ co-precipitation-centrifugal spinning coupling process precisely controls the fiber formation process through the dynamic shear field during centrifugal spinning, achieving a gradient loading of nanophotocatalysts from the surface to the inside of the polymer matrix. This process breaks through the traditional electrospinning's dependence on high voltage environments and can complete the directional assembly of fiber structures under mild conditions, significantly reducing the complexity of production equipment and energy consumption costs. The precise matching mechanism between spinning parameters and solution rheological properties provides an industrial implementation path for customized control of material performance indicators such as pore size distribution and mechanical strength.

[0025] (3) Innovation in green material systems: Biocompatible polymethyl methacrylate (PMMA) is used as a flexible carrier, combined with environmentally friendly solvents and biodegradable additives to construct a green preparation system for the entire life cycle. The material maintains excellent chemical stability during use, avoiding secondary pollution caused by photocatalyst dissolution. Waste fibers can be recycled through thermal cracking to achieve closed-loop recovery of the matrix resin and precious metal components, truly implementing the concept of sustainable development.

[0026] The composite fiber material of the present invention successfully solves common problems such as shielding of traditional photocatalyst active sites and difficulty in solid-liquid separation through the trinity innovation of "structure-process-performance", providing a technical solution with both theoretical value and industrial feasibility for the development of a new generation of environmental purification materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 This is the photocatalytic degradation result of the Ag@AgCl / MOx / PANI / PMMA photocatalytic composite fiber prepared in Example 1.

[0029] Figure 2 This is the surface appearance of the Ag@AgCl / MOx / PANI / PMMA photocatalytic composite fiber prepared in Example 1.

[0030] Figure 3 This is a microscopic image of the Ag@AgCl / MOx / PANI / PMMA photocatalytic composite fiber prepared in Example 1. DETAILED DESCRIPTION

[0031] To facilitate understanding of the present invention, the present invention will be described in more comprehensive and detailed form below in conjunction with the accompanying drawings and preferred embodiments. However, the protection scope of the present invention is not limited to the following specific embodiments.

[0032] Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0033] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0034] The present invention dissolves PMMA and then blends it with PANI and nano-metal oxides, and prepares MOx / PANI / PMMA composite fibers through centrifugal spinning. Subsequently, Ag@AgCl nanoparticles are uniformly loaded on the surface and inside of the fibers by an in-situ co-precipitation method, and finally Ag@AgCl / MOx / PANI / PMMA composite fibers are obtained.

[0035] In some specific embodiments, the method for preparing the PMMA-based photocatalytic composite fiber material of the present invention comprises the following steps:

[0036] (1) Polymethyl methacrylate (PMMA), a porogen, and a solvent are uniformly mixed to obtain a mixed solution I.

[0037] In some embodiments, the mass ratio of polymethyl methacrylate, porogen, and solvent in the mixed solution I is 1:0.02-0.1:6-12.

[0038] In some embodiments, the porogen is selected from at least one of ethylene glycol, diethylene glycol, glycerol, pentaerythritol, and propylene glycol. More preferably, the porogen is glycerol.

[0039] In some embodiments, the solvent is selected from at least one of N,N-dimethylformamide, N,N-dimethylacetamide, acetone, tetrahydrofuran, chloroform, dichloromethane, dioxane, and ethyl acetate.

[0040] In some embodiments, the mixing is performed under stirring at a speed of 250-800 rpm, a temperature of 10-30° C., and a time of 3-6 h.

[0041] (2) Polyaniline (PANI) and nano-metal oxide (Nano-MOx) are uniformly mixed with the mixed solution I to obtain a spinning solution II.

[0042] In some embodiments, the mixed solution I is first mixed with polyaniline (PANI), stirred and dissolved for 45-90 minutes, and then the resulting solution is mixed with nano-metal oxide (Nano-MOx), stirred for 60-120 minutes, and then the resulting mixed solution is allowed to stand for 1-3 hours to defoam, to obtain spinning solution II.

[0043] In some embodiments, the mass ratio of the PMMA, the polyaniline, and the nano-metal oxide is 1:0.001-0.008:0.001-0.008.

[0044] In some embodiments, the nano-metal oxide is at least one of ZrO2, Sb2O3, NbO, Fe3O4, and ZnO. The nano-metal oxide is a metal oxide powder with an average particle size of 20-50 nm.

[0045] In some embodiments, the polyaniline is a conductive polyaniline powder with an average particle size of 20-50 nm.

[0046] (3) The spinning solution II is spun through a centrifugal spinning machine to obtain MOx / PANI / PMMA composite fibers.

[0047] In some embodiments, the centrifugal spinning machine is a temperature-controlled centrifugal spinning machine. Preferably, the rotation speed of the centrifugal spinning machine is 500-5000 r / min; preferably, the spinneret size of the centrifugal spinning machine is 0.1-0.5 mm, so that the diameter of the fiber is 11.6-45.9 μm.

[0048] In some embodiments, during the spinning process, the fiber solidification treatment conditions meet the following requirements: an air atmosphere, a temperature of 40-80°C, and a humidity of ≤60%RH. Excessively high humidity will delay the volatilization of the solvent during the fiber forming process, resulting in densification of the fiber structure and reduced porosity, reducing the exposure of photocatalytic active sites and hindering the mass transfer efficiency of the reactants.

[0049] (4) The composite fiber is immersed in AgNO3 solution and NaCl solution in sequence to carry out in situ coprecipitation reaction to load silver chloride nanoparticles on the surface and inside of the composite fiber. After the reaction is completed, the composite fiber is washed and then freeze-dried to obtain a photocatalytic composite fiber.

[0050] In some embodiments, the composite fiber is first immersed in an AgNO 3 solution for 1-2 hours, and then the obtained product is immersed in a NaCl solution for 10-30 minutes.

[0051] In some embodiments, the contact with the AgNO 3 solution is performed in the presence of ultrasound with a frequency of 20-60 KHz, so that the surface and interior of the composite fiber are uniformly contacted with the AgNO 3 solution.

[0052] In some embodiments, the concentration of the AgNO3 solution is 0.03-0.25 mol / L, and the concentration of the NaCl solution is 0.03-0.25 mol / L. More preferably, the concentration of the AgNO3 solution is 0.03-0.15 mol / L, and the concentration of the NaCl solution is 0.03-0.15 mol / L. Excessive concentrations of AgNO3 or NaCl can reduce photocatalytic activity and stability.

[0053] In some embodiments, after the reaction, the resulting composite fibers are washed and freeze-dried in sequence. The washing solvent is deionized water, and the freeze-drying temperature is between -55°C and -35°C for 6-12 hours. Compared to other drying methods, freeze-drying can preserve the fiber structure.

[0054] (5) The dried photocatalytic composite fiber was irradiated under ultraviolet light to obtain PMMA-based Ag@AgCl / MOx / PANI photocatalytic composite fiber.

[0055] In some embodiments, the light treatment time is 30-90 minutes. After the silver chloride is irradiated by the ultraviolet light, a more stable Ag and AgCl composite structure is generated.

[0056] In this invention, PANI promotes the transport and separation of photogenerated carriers by enhancing its conductivity. Nanometal oxides act as photosensitizers to broaden the spectral response range and as carriers for Ag@AgCl, improving its dispersion stability. The Ag@AgCl, metal oxides, and polyaniline interact synergistically within the fiber, significantly enhancing photocatalytic performance. The resulting material combines the high toughness and chemical stability of the PMMA matrix with the visible light response characteristics of the composite system, effectively improving the degradation efficiency of organic pollutants through the construction of a multi-component heterogeneous structure.

[0057] The present invention uses polymethyl methacrylate as a substrate and synergistically combines conductive polymer polyaniline, nano-metal oxides and silver chloride (Ag@AgCl) as organic and inorganic fillers. This can significantly expand the spectral response range of the composite fiber, increase the composite fiber's utilization of visible light, reduce the recombination of photogenerated electron-hole pairs, and accelerate the degradation of pollutants in water. At the same time, the use of a fibrous form is conducive to separation and recovery during use, and through the synergistic effect of AgNO3 and NaCl, Ag@AgCl with good antibacterial activity can be obtained.

[0058] Example 1

[0059] Polymethyl methacrylate (PMMA) (1 / 7 by weight) and glycerol (0.02 / 7 by weight) as a porogen were mixed with N,N-dimethylformamide (DNMF) solvent at a stirring rate of 250 rpm at 25°C for 4 hours to obtain a uniform PMMA I. Subsequently, PMMA I was mixed with polyaniline (PANI) and stirred for 60 minutes. Nanozirconia powder was then added, stirred for another 90 minutes, and allowed to stand for 3 hours to obtain spinning solution II. The mass ratio of PMMA, polyaniline, and nano-zirconia was 1:0.003:0.003. Spinning solution II was spun using a centrifugal spinning machine with a 0.1 mm spinneret at 5000 rpm. The fibers were cured at 80°C and maintained at a relative humidity of 60%. The composite fibers were then immersed in a 0.10 mol / L AgNO₃ solution and a 0.1 mol / L NaCl solution for 2 hours and 10 minutes, respectively, for in-situ coprecipitation reactions. The AgNO₃ solution contact was performed under 35 kHz ultrasonic waves. After the reaction, the composite fibers were thoroughly rinsed with deionized water and freeze-dried at -55°C for 6 hours. Finally, the dried composite fibers were irradiated under UV light for 60 minutes to obtain the final photocatalytic composite fibers. The degradation of organic pollutants by the prepared photocatalytic composite fibers is shown in Table 1.

[0060] Figure 2 This is the surface appearance of the Ag@AgCl / MOx / PANI / PMMA photocatalytic composite fiber prepared in Example 1. Figure 3 This is a microscopic image of the Ag@AgCl / MOx / PANI / PMMA photocatalytic composite fiber prepared in Example 1.

[0061] Example 2

[0062] Polymethyl methacrylate (PMMA) (1 / 13 by weight of mixed solution I) and ethylene glycol (0.1 / 13 by weight) as a porogen were mixed with tetrahydrofuran solvent in appropriate proportions and stirred at 800 rpm at 10°C for 6 hours to obtain a uniform mixed solution I. Subsequently, mixed solution I was mixed with polyaniline (PANI) and stirred for 45 minutes. Nano-ferroferric oxide powder was then added, stirred for a further 120 minutes, and allowed to stand for 1 hour to obtain spinning solution II. The mass ratio of PMMA, polyaniline, and nano-metal oxide was 1:0.001:0.001. Spinning solution II was spun using a centrifugal spinning machine equipped with a 0.5 mm spinneret at 500 rpm. The fibers were cured at 40°C and maintained at a relative humidity of 30%. The composite fibers were then immersed in a 0.03 mol / L AgNO₃ solution and a 0.03 mol / L NaCl solution, respectively, for 1 hour and 30 minutes, respectively, for in-situ coprecipitation reactions. The AgNO₃ solution contact was performed under 20 kHz ultrasonic waves. After the reaction, the composite fibers were thoroughly rinsed with deionized water and freeze-dried at -35°C for 12 hours. Finally, the dried composite fibers were irradiated under UV light for 30 minutes to obtain the final photocatalytic composite fibers. The degradation of organic pollutants by the prepared photocatalytic composite fibers is shown in Table 1.

[0063] Example 3

[0064] Polymethyl methacrylate (PMMA) (1 / 11 by weight) and pentaerythritol (0.05 / 11 by weight) as a porogen were mixed with tetrahydrofuran solvent at a stirring rate of 600 rpm at 20°C for 5 hours to obtain a uniform PMMA I. Subsequently, PMMA I was mixed with polyaniline (PANI) and stirred for 75 minutes. Nano-zinc oxide powder was then added, stirred for 100 minutes, and allowed to stand for 2.5 hours to obtain spinning solution II. The mass ratio of PMMA, polyaniline, and nano-zinc oxide was 1:0.004:0.004. Spinning solution II was spun using a centrifugal spinning machine equipped with a 0.2 mm spinneret at a speed of 3000 rpm. The fibers were cured at a temperature of 50°C and a humidity of 45% to obtain ZnO / PANI / PMMA composite fibers. The composite fibers were then immersed in a 0.15 mol / L AgNO₃ solution and a 0.15 mol / L NaCl solution, respectively, for 1.5 hours and 20 minutes of contact time, respectively, to perform an in-situ coprecipitation reaction. The AgNO₃ solution contact was performed under 40 kHz ultrasonic waves. After the reaction, the composite fibers were thoroughly rinsed with deionized water and freeze-dried at -50°C for 9 hours. Finally, the dried composite fibers were irradiated under UV light for 60 minutes to obtain the final photocatalytic composite fibers. The degradation of organic pollutants by the prepared photocatalytic composite fibers is shown in Table 1.

[0065] Example 4

[0066] Polymethyl methacrylate (PMMA) (1 / 9 by weight of mixed solution I) and propylene glycol (0.08 / 9 by weight) as a porogen were mixed with ethyl acetate solvent in appropriate proportions and stirred at 400 rpm at 15°C for 4.5 hours to obtain a uniform mixed solution I. Subsequently, mixed solution I was mixed with polyaniline (PANI) and stirred for 90 minutes. Nano-niobium pentoxide powder was then added, stirred for a further 80 minutes, and allowed to stand for 1.5 hours to obtain spinning solution II. The mass ratio of PMMA, polyaniline, and nano-metal oxide was 1:0.002:0.002. Spinning solution II was spun using a centrifugal spinning machine equipped with a 0.4 mm spinneret at 4000 rpm. The fibers were cured at 65°C and maintained at a relative humidity of 55%. The composite fibers were then immersed in a 0.25 mol / L AgNO₃ solution and a 0.25 mol / L NaCl solution, respectively, for 2 hours and 15 minutes, respectively, for in-situ coprecipitation reactions. The AgNO₃ solution contact was performed under 50 kHz ultrasonic waves. After the reaction, the composite fibers were thoroughly rinsed with deionized water and freeze-dried at -45°C for 10 hours. Finally, the dried composite fibers were irradiated under UV light for 90 minutes to obtain the final photocatalytic composite fibers. The degradation of organic pollutants by the prepared photocatalytic composite fibers is shown in Table 1.

[0067] Example 5

[0068] Polymethyl methacrylate (PMMA) (1 / 8 by weight of mixed solution I) and diethylene glycol (0.03 / 8 by weight) as a porogen were mixed with dioxane solvent in appropriate proportions and stirred at 700 rpm at 25°C for 3.5 hours to obtain a homogeneous mixed solution I. Subsequently, mixed solution I was mixed with polyaniline and stirred for 100 minutes. Nano-antimony trioxide powder was then added, stirred for a further 70 minutes, and allowed to stand for 2.0 hours to obtain spinning solution II. The mass ratio of PMMA, polyaniline, and nano-metal oxide was 1:0.008:0.008. Spinning solution II was spun using a centrifugal spinning machine equipped with a 0.3 mm spinneret at 2000 rpm. The fiber curing temperature was 75°C and the humidity was 25% RH to obtain Sb2O3 / PANI / PMMA composite fibers. The composite fibers were then immersed in a 0.1 mol / L AgNO₃ solution and a 0.1 mol / L NaCl solution for 1.0 hour and 25 minutes, respectively, for in-situ coprecipitation reactions. The AgNO₃ solution contact was performed under 50 kHz ultrasonic waves. After the reaction, the composite fibers were thoroughly rinsed with deionized water and freeze-dried at -55°C for 8 hours. Finally, the dried composite fibers were irradiated under UV light for 75 minutes to obtain the final photocatalytic composite fibers. The degradation of organic pollutants by the prepared photocatalytic composite fibers is shown in Table 1.

[0069] Comparative Example 1

[0070] Polymethyl methacrylate (PMMA) (1 / 7 by weight) and glycerol (0.02 / 7 by weight) as a porogen were mixed with N,N-dimethylformamide (DNMF) solvent at a stirring rate of 250 rpm at 25°C for 4 hours to obtain a uniform DN I. Subsequently, DN I was mixed with polyaniline (PANI) and stirred for 60 minutes. Nanozirconia powder was then added, stirred for another 90 minutes, and allowed to stand for 3 hours to obtain spinning solution II. The mass ratio of PMMA, polyaniline, and nano-metal oxide was 1:0.003:0.003. Spinning solution II was spun using a centrifugal spinning machine with a 0.1 mm spinneret at 5000 rpm. The fibers were cured at 80°C and 80% relative humidity to obtain ZrO / PANI / PMMA composite fibers. The composite fibers were then immersed in a 0.40 mol / L AgNO₃ solution and a 0.4 mol / L NaCl solution for 2 hours and 10 minutes, respectively, for in-situ coprecipitation reactions. The AgNO₃ solution contact was performed under 35 kHz ultrasonic waves. After the reaction, the composite fibers were thoroughly rinsed with deionized water and freeze-dried at -55°C for 6 hours. Finally, the dried composite fibers were irradiated under UV light for 60 minutes to obtain the final photocatalytic composite fibers. The degradation of organic pollutants by the prepared photocatalytic composite fibers is shown in Table 1.

[0071] Comparative Example 2

[0072] Polymethyl methacrylate (PMMA) (1 / 7 by weight) and N,N-dimethylformamide (DNFA) were mixed in appropriate proportions and stirred at 250 rpm for 4 hours at 25°C to produce a homogeneous mixed solution I. Subsequently, mixed solution I was mixed with polyaniline (PANI) and stirred for 60 minutes. Nanozirconia powder was then added, stirred for a further 90 minutes, and allowed to stand for 3 hours to produce spinning solution II. The mass ratio of PMMA, polyaniline, and nanometal oxide was 1:0.003:0.003. Spinning solution II was spun using a centrifugal spinning machine with a 0.1 mm spinneret at 5000 rpm. The fibers were cured at 80°C and maintained at a relative humidity of 60%. The resulting ZrO / PANI / PMMA composite fibers were obtained. The composite fibers were then immersed in a 0.10 mol / L AgNO₃ solution and a 0.1 mol / L NaCl solution for 2 hours and 10 minutes, respectively, for in-situ coprecipitation reactions. The AgNO₃ solution contact was performed under 35 kHz ultrasonic waves. After the reaction, the composite fibers were thoroughly rinsed with deionized water and freeze-dried at -55°C for 6 hours. Finally, the dried composite fibers were irradiated under UV light for 60 minutes to obtain the final photocatalytic composite fibers. The degradation of organic pollutants by the prepared photocatalytic composite fibers is shown in Table 1.

[0073] Comparative Example 3

[0074] Polymethyl methacrylate (PMMA) (1 / 7 by weight) and glycerol (0.02 / 7 by weight) as a porogen were mixed with N,N-dimethylformamide (DNMF) solvent in appropriate proportions and stirred at 250 rpm for 4 hours at 25°C to obtain a homogeneous mixed solution I. Subsequently, mixed solution I was mixed with nano-zirconia (ZrO) for 90 minutes and allowed to stand for 3 hours to obtain spinning solution II, in which the mass ratio of PMMA to nano-zirconia was 1:0.003. Spinning solution II was spun using a centrifugal spinning machine with a 0.1 mm spinneret at 5000 rpm. The fibers were cured at 80°C and 60% relative humidity to obtain ZrO / PMMA composite fibers. The composite fibers were then immersed in a 0.10 mol / L AgNO₃ solution and a 0.1 mol / L NaCl solution for 2 hours and 10 minutes, respectively, for in-situ coprecipitation. The AgNO₃ solution was exposed to 35 kHz ultrasonic waves. After the reaction, the composite fibers were thoroughly rinsed with deionized water and freeze-dried at -55°C for 6 hours. Finally, the dried composite fibers were irradiated under UV light for 60 minutes to obtain the final photocatalytic composite fibers. The degradation of organic pollutants by the prepared photocatalytic composite fibers is shown in Table 1.

[0075] The performance of the photocatalytic composite fiber materials prepared in Examples 1-5 and Comparative Examples 1-3 was tested using the following method:

[0076] At room temperature, using a 500W xenon lamp as the light source, 0.4g of the photocatalytic composite fiber material was evenly dispersed in 150mL of a 10mg / L organic pollutant solution (rhodamine B, malachite green, norfloxacin, or ofloxacin). Magnetic stirring was used to maintain the solution homogeneity. Samples were taken every hour and the absorbance of the solution was measured using a UV-visible spectrophotometer to monitor the degradation process. The reaction was continued for 6 hours. The test results are shown in Table 1. Figure 1 This is the photocatalytic degradation result of the Ag@AgCl / MOx / PANI / PMMA photocatalytic composite fiber prepared in Example 1.

[0077] Table 1. Degradation rates of different pollutants by photocatalytic composite fiber materials prepared in Examples and Comparative Examples (degradation rate / % = (1-C / C0) × 100%, where C is the concentration and C0 is the initial concentration)

[0078]

[0079] In Comparative Example 1, the use of a high humidity environment delayed the volatilization of the solvent during the fiber forming process, resulting in the densification of the fiber structure and the reduction of porosity, which reduced the exposure of photocatalytic active sites and hindered the mass transfer efficiency of the reactants. The excessively high AgNO3 concentration promoted the rapid nucleation of Ag⁺ under the action of ultrasound, forming AgCl particles of uneven size, which weakened the surface plasmon resonance effect and intensified the recombination of photogenerated carriers. At the same time, the increase in NaCl concentration led to the competitive coordination of excess Cl⁻ with the amino groups of polyaniline, weakening the bonding strength of AgCl with the fiber matrix and inducing lattice distortion, further reducing the photocatalytic activity and stability.

[0080] Comparative Example 2, in which no porogen was added, resulted in a weak pore structure for the prepared fibers, which in turn failed to activate the catalyst activity in the bulk phase. Organic pollutant degradation relied solely on surface catalysts, but the fiber diameter was small, limiting the impact. Furthermore, the lack of a porogen reduced the fiber's weak pore structure, weakening its adsorption capacity for organic pollutants and resulting in poor degradation.

[0081] In Comparative Example 3, the fibers without polyaniline (PANI) added have significantly reduced photodegradation performance due to the lack of its multi-level synergistic effect: the π-conjugated skeleton of PANI can construct a continuous electron transmission channel, reducing the recombination rate of photogenerated carriers, while the absence of PANI leads to the obstruction of electron migration; at the same time, the narrow band gap of PANI (~2.8 eV) forms an energy level match with Ag@AgCl, extending the light response range to the visible light region (420-650 nm). When it is not added, the system relies on ultraviolet light and the absorption coefficient is reduced; in addition, PANI regulates the PMMA / porogen phase separation through hydrogen bonds to form a porous structure, and its absence reduces the mass transfer efficiency of pollutants; the -NH- group of PANI also guides the uniform dispersion of Ag@AgCl nanoparticles through chelation. In the absence of PANI, the particles agglomerate, resulting in a reduction in catalytic sites.

[0082] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any form. Therefore, any simple modifications, equivalent variations, and modifications to the above embodiments that do not depart from the technical solution of the present invention and are based on the technical essence of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a PMMA-based photocatalytic composite fiber material, characterized in that: The steps include: (1) uniformly mixing polymethyl methacrylate, a porogen, and a solvent to obtain a mixed solution I; the porogen is selected from at least one of ethylene glycol, diethylene glycol, glycerol, pentaerythritol, and propylene glycol, and the mass ratio of polymethyl methacrylate to the porogen is 1:0.02-0.1; (2) uniformly mixing polyaniline and nano-metal oxide with the mixed solution I to obtain spinning solution II; the mass ratio of the polymethyl methacrylate, polyaniline and nano-metal oxide is 1:0.001-0.008:0.001-0.008; (3) spinning the spinning solution II through a centrifugal spinning machine to obtain MOx / PANI / PMMA composite fibers; (4) immersing the MOx / PANI / PMMA composite fiber in an AgNO3 solution and a NaCl solution in sequence to perform an in-situ coprecipitation reaction to load silver chloride nanoparticles on the surface and inside of the composite fiber. After the reaction is completed, the composite fiber is washed and then freeze-dried to obtain a photocatalytic composite fiber; the concentration of the AgNO3 solution is 0.03-0.25 mol / L, and the concentration of the NaCl solution is 0.03-0.25 mol / L; (5) The photocatalytic composite fiber is subjected to light treatment under an ultraviolet lamp to obtain a PMMA-based Ag@AgCl / MOx / PANI photocatalytic composite fiber.

2. The preparation method according to claim 1, characterized in that The nano metal oxide in step (2) is at least one of ZrO2, Sb2O3, and ZnO.

3. The preparation method according to claim 1 or 2, characterized in that The rotation speed of the centrifugal spinning machine in step (3) is 500-5000 r / min, and the spinneret size of the spinning head of the centrifugal spinning machine is 0.1-0.5 mm.

4. The preparation method according to claim 1 or 2, characterized in that During the spinning process in step (3), the temperature of the fiber curing treatment is 40-80°C and the humidity is ≤60RH%.

5. A PMMA-based photocatalytic composite fiber material, characterized in that: The invention discloses a novel nanostructured ...

6. Use of the PMMA-based photocatalytic composite fiber material according to claim 5 in degrading organic pollutants.

7. The use according to claim 6, characterized in that include: The PMMA-based photocatalytic composite fiber material is dispersed in a solution containing organic pollutants and degraded under light.

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