PMMA-based photocatalytic composite fiber material as well as preparation method and application thereof

Abstract

The invention discloses a PMMA (polymethyl methacrylate)-based photocatalytic composite fiber material as well as a preparation method and application thereof, and the preparation method comprises the following steps: uniformly mixing polymethyl methacrylate, a pore-foaming agent and a solvent to obtain a mixed solution I; uniformly mixing polyaniline and nano metal oxide with the mixed solution I to obtain a spinning solution II; spinning the spinning solution II through a centrifugal spinning machine to obtain composite fibers; the composite fiber is sequentially immersed in an AgNO3 solution and a NaCl solution, an in-situ coprecipitation reaction is carried out, after the reaction is finished, cleaning is carried out, and then the photocatalytic composite fiber is obtained through freeze drying; the photocatalytic composite fiber is subjected to illumination treatment under an ultraviolet lamp, and the PMMA-based photocatalytic composite fiber material is obtained. The photocatalytic performance and the mass transfer efficiency of the material are synergistically improved, the light response range of the photocatalyst can be widened, the quantum efficiency can be improved, and the material can be endowed with 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 much attention in the field of environmental governance due to its green and sustainable characteristics. However, traditional powdered photocatalysts (such as TiO 2 In the prior art, although the use of polymer matrix to fix photocatalytic components can improve the recyclability of materials, it generally faces the following challenges: ① the dense polymer matrix hinders the diffusion of pollutant molecules, resulting in low utilization of active sites; ② the interface compatibility of multiphase components is poor, and the transmission path of photogenerated electrons is discontinuous; ③ the dependence on ultraviolet light is strong, and the visible light response is insufficient.

[0003] Recent studies have shown that the mass transfer efficiency can be effectively improved by constructing a porous fiber structure. Among them, polymethyl methacrylate (PMMA) has become an ideal carrier material due to its excellent light transmittance (>85%), chemical stability and processability. However, existing PMMA-based composite fibers have problems such as uncontrollable porosity and uneven loading of photocatalytic components, which affect the photocatalytic performance and restrict 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: A method for preparing a PMMA-based photocatalytic composite fiber material comprises the following steps: (1) uniformly mixing polymethyl methacrylate, a porogen and a solvent to obtain a mixed solution I; (2) uniformly mixing the polyaniline and the nano-metal oxide with the mixed solution I to obtain a spinning solution II; (3) spinning the spinning solution II through a centrifugal spinning machine to obtain MOx / PANI / PMMA composite fibers; (4) Immerse MOx / PANI / PMMA composite fibers in AgNO 3 solution and NaCl solution, to carry out in-situ coprecipitation reaction to load silver chloride nanoparticles on the surface and inside of the composite fiber, and after the reaction is completed, the composite fiber is washed and then freeze-dried to obtain a photocatalytic composite fiber; (5) The photocatalytic composite fiber is subjected to light treatment under ultraviolet light to obtain PMMA-based Ag@AgCl / MOx / PANI photocatalytic composite fiber.

[0006] 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.

[0007] 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.

[0008] As a further improvement, the nano metal oxide in step (2) is ZrO 2 , Sb 2 O 3 、NbO、Fe 3 O 4 , ZnO or at least one of the above.

[0009] As a further improvement, the rotation speed of the centrifugal spinning machine in step (3) is 500-5000 r / min, and the spinneret hole size of the spinning head of the centrifugal spinning machine is 0.1-0.5 mm.

[0010] As a further improvement, during the spinning process in step (3), the temperature of the fiber solidification treatment is 40-80°C and the humidity is ≤60RH%.

[0011] As a further improvement, the AgNO 3 The concentration of the solution is 0.03-0.25 mol / L, and the concentration of the NaCl solution is 0.03-0.25 mol / L.

[0012] The present invention also provides a PMMA-based photocatalytic composite fiber material, which is prepared by the preparation method.

[0013] The invention also provides an application of the PMMA-based photocatalytic composite fiber material in degrading organic pollutants.

[0014] 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.

[0015] The present invention innovatively introduces porogens, combines centrifugal spinning of oriented fibers with in-situ co-precipitation precision loading technology, synergistically constructs a porous structure, composites conductive polyaniline (PANI), nano-metal oxides (MOx) and polymethyl methacrylate, and further synthesizes Ag@AgCl nanoparticle photocatalysts in situ to prepare PMMA-based Ag@AgCl / MOx / PANI multi-element photocatalytic composite fiber materials. The synergistic improvement of the photocatalytic performance and mass transfer efficiency of the material is achieved, which can not only broaden the light response range of the photocatalyst and improve the quantum efficiency, but also give the material good biocompatibility and degradability. The 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 environmental governance and other fields.

[0016] Compared with the existing powder photocatalyst preparation technology, the present invention has the following beneficial effects: (1) Multi-dimensional structural synergistic mechanism: The continuous fiber network constructed based on centrifugal spinning technology realizes the three-dimensional orderly distribution of photocatalytic components in the polymethyl methacrylate matrix. The uniformity control of fiber diameter enables the material to obtain a controllable through-channel structure, and its pore characteristics break through the mass transfer resistance 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, synergistic with the surface plasmon resonance excitation of Ag@AgCl nanoparticles, and establishes an efficient carrier transmission channel from the bulk to the surface, significantly improving the visible light capture and energy conversion efficiency.

[0017] (2) Breakthrough in engineering preparation technology: The innovatively developed in-situ co-precipitation-centrifugal spinning coupling process precisely controls the fiber forming process through the dynamic shear field of the centrifugal spinning process, achieving gradient loading of nano-photocatalysts from the surface to the inside of the polymer matrix. This process breaks through the dependence of traditional electrospinning on high voltage environment, and can complete the directional assembly of fiber structures under mild conditions, greatly reducing the complexity of production equipment and energy consumption costs. The precise matching mechanism of spinning parameters and solution rheological properties provides an industrial implementation path for customized regulation of performance indicators such as material pore size distribution and mechanical strength.

[0018] (3) Innovation of green material system: Biocompatible polymethyl methacrylate is used as a flexible carrier, combined with environmentally friendly solvents and degradable additives to build 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 in a closed loop of matrix resin and precious metal components through thermal cracking, truly practicing the concept of sustainable development.

[0019] The composite fiber material of the present invention successfully solves common problems such as shielding of active sites of traditional photocatalysts 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

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0021] Figure 1 This is the photocatalytic degradation result of the Ag@AgCl / MOx / PANI / PMMA photocatalytic composite fiber prepared in Example 1.

[0022] Figure 2 This is the surface image of the Ag@AgCl / MOx / PANI / PMMA photocatalytic composite fiber prepared in Example 1.

[0023] Figure 3 This is a microscopic image of the Ag@AgCl / MOx / PANI / PMMA photocatalytic composite fiber prepared in Example 1. DETAILED DESCRIPTION

[0024] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0025] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional 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.

[0026] 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.

[0027] The present invention dissolves PMMA and mixes it with PANI and nano-metal oxides, and obtains MOx / PANI / PMMA composite fibers through centrifugal spinning; then Ag@AgCl nanoparticles are uniformly loaded on the surface and inside of the fibers by an in-situ coprecipitation method, and finally Ag@AgCl / MOx / PANI / PMMA composite fibers are obtained.

[0028] In some specific embodiments, the method for preparing the PMMA-based photocatalytic composite fiber material of the present invention comprises the following steps: (1) Polymethyl methacrylate (PMMA), a porogen and a solvent are uniformly mixed to obtain a mixed solution I.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] (2) Polyaniline (PANI) and nano-metal oxide (Nano-MOx) are uniformly mixed with the mixed solution I to obtain a spinning solution II.

[0034] In some embodiments, the mixed solution I is first mixed with polyaniline (PANI), stirred and dissolved for 45-90 minutes, and then the obtained solution is mixed with nano metal oxide (Nano-MOx), stirred for 60-120 minutes, and then the obtained mixed solution is allowed to stand for 1-3 hours to defoam, so as to obtain spinning solution II.

[0035] 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.

[0036] In some embodiments, the nano metal oxide is ZrO 2 , Sb 2 O 3 、NbO、Fe 3 O 4 The nano metal oxide is a metal oxide powder with an average particle size of 20-50nm.

[0037] In some embodiments, the polyaniline is a conductive polyaniline powder having an average particle size of 20-50 nm.

[0038] (3) The spinning solution II is spun through a centrifugal spinning machine to obtain MOx / PANI / PMMA composite fibers.

[0039] 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 size of the spinneret of the centrifugal spinning machine spinning head is 0.1-0.5 mm, so that the diameter of the fiber is 11.6-45.9 μm.

[0040] In some embodiments, during the spinning process, the conditions for the fiber solidification treatment meet the following conditions: the atmosphere is air atmosphere, the temperature is 40-80° C., and the humidity is ≤60RH%. If the humidity is too high, the volatilization of the solvent during the fiber forming process will be delayed, resulting in the densification of the fiber structure and the reduction of porosity, which reduces the exposure of the photocatalytic active sites and hinders the mass transfer efficiency of the reactants.

[0041] (4) The composite fibers are sequentially immersed in AgNO 3 In the solution and NaCl solution, an in-situ coprecipitation reaction is carried out 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.

[0042] In some embodiments, the composite fiber is first immersed in AgNO 3 The obtained product is immersed in a NaCl solution for a contact reaction time of 10-30 minutes.

[0043] In some embodiments, AgNO 3 The contact of the solution is carried out in the presence of ultrasound, and the ultrasound frequency is 20-60KHz, so that the surface and the interior of the composite fiber are uniformly contacted with AgNO 3 Solution.

[0044] In some embodiments, the AgNO 3 The concentration of the 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 AgNO 3 The concentration of the solution is 0.03-0.15 mol / L, and the concentration of the NaCl solution is 0.03-0.15 mol / L. 3 Too high concentration or NaCl concentration will reduce the photocatalytic activity and stability.

[0045] In some embodiments, after the reaction is completed, the obtained composite fiber is washed and freeze-dried in sequence, the washing solvent is deionized water, the freeze-drying temperature is minus 55°C to minus 35°C, and the freeze-drying time is 6-12 hours. Compared with other drying methods, freeze-drying can keep the fiber structure intact.

[0046] (5) The dried photocatalytic composite fiber is irradiated under ultraviolet light to obtain PMMA-based Ag@AgCl / MOx / PANI photocatalytic composite fiber.

[0047] In some embodiments, the light treatment time is 30-90 minutes. After being irradiated by ultraviolet light, silver chloride will generate a more stable Ag and AgCl composite structure.

[0048] In the present invention, PANI promotes the transport and separation of photogenerated carriers by enhancing conductivity, and nano-metal oxides serve as photosensitizers to broaden the spectral response range and as carriers of Ag@AgCl to improve its dispersion stability. Ag@AgCl, metal oxides and polyaniline work synergistically after contacting each other in the fiber, significantly enhancing the photocatalytic performance. The prepared material combines the high toughness and chemical stability of the PMMA matrix with the visible light response characteristics of the composite system, and effectively improves the degradation efficiency of organic pollutants through the construction of a multi-component heterogeneous structure.

[0049] The present invention adopts polymethyl methacrylate as the substrate, and coordinates conductive polymer polyaniline, nano-metal oxide and silver chloride (Ag@AgCl) as organic and inorganic fillers, which can significantly expand the spectral response range of the composite fiber, increase the utilization of visible light by the composite fiber, and reduce the recombination of photogenerated electron pairs and hole pairs, thereby accelerating the degradation of pollutants in the water body; at the same time, the fiber body form is conducive to separation and recovery during use, and through AgNO 3 The synergistic effect of Ag@AgCl with good antibacterial activity can be obtained.

[0050] Example 1 Polymethyl methacrylate (1 / 7 of the total mass of mixed solution I) and glycerol as a porogen (0.02 / 7 ​​of the total mass) were mixed with N,N-dimethylformamide solvent in proportion, stirred at 25°C for 4 hours at a stirring speed of 250rpm to obtain a uniform mixed solution I. Subsequently, the mixed solution I was mixed and stirred with polyaniline for 60 minutes, and then nano zirconium oxide powder was added, stirred for 90 minutes and allowed to stand for 3 hours to obtain spinning solution II, in which 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 rotation speed of 5000r / min and a spinneret of 0.1mm. The fiber curing temperature was 80°C and the humidity was 60RH% to obtain ZrO / PANI / PMMA composite fibers. Afterwards, the composite fibers were successively immersed in 0.10mol / L AgNO 3 The in-situ coprecipitation reaction was carried out in the solution and 0.1 mol / L NaCl solution for 2 hours and 10 minutes, respectively. 3 The contact of the solution was carried out under 35KHz ultrasound. After the reaction was completed, the composite fiber was thoroughly washed with deionized water and freeze-dried at minus 55°C for 6 hours. Finally, the dried composite fiber was irradiated under ultraviolet light for 60 minutes to obtain the final photocatalytic composite fiber. The degradation of organic pollutants by the prepared photocatalytic composite fiber is shown in Table 1.

[0051] Figure 2 This is the surface image 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.

[0052] Example 2 Polymethyl methacrylate (1 / 13 of the total mass of mixed solution I) and ethylene glycol as a porogen (0.1 / 13 of the total mass) were mixed with tetrahydrofuran solvent in proportion, stirred at 800 rpm for 6 hours at 10°C to obtain a uniform mixed solution I. Subsequently, the mixed solution I was mixed and stirred with polyaniline for 45 minutes, and then nano-iron tetroxide powder was added, stirred for 120 minutes and allowed to stand for 1 hour to obtain spinning solution II, in which 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 with a rotation speed of 500 r / min and a spinneret hole of 0.5 mm. The fiber curing temperature was 40°C and the humidity was 30 RH% to obtain Fe 3 O 4 / PANI / PMMA composite fibers. Then, the composite fibers were immersed in 0.03 mol / L AgNO 3 The in-situ coprecipitation reaction was carried out in the solution and 0.03 mol / L NaCl solution for 1 hour and 30 minutes, respectively. 3 The contact of the solution was carried out under 20KHz ultrasound. After the reaction was completed, the composite fiber was thoroughly washed with deionized water and freeze-dried at minus 35°C for 12 hours. Finally, the dried composite fiber was irradiated under ultraviolet light for 30 minutes to obtain the final photocatalytic composite fiber. The degradation of organic pollutants by the prepared photocatalytic composite fiber is shown in Table 1.

[0053] Example 3 Polymethyl methacrylate (accounting for 1 / 11 of the total mass of mixed solution I) and pentaerythritol as a porogen (accounting for 0.05 / 11 of the total mass) were mixed with tetrahydrofuran solvent in proportion, stirred at 20°C for 5 hours at a stirring speed of 600 rpm to obtain a uniform mixed solution I. Subsequently, the mixed solution I was mixed and stirred with polyaniline for 75 minutes, and then nano zinc oxide powder was added, stirred for 100 minutes and allowed to stand for 2.5 hours to obtain spinning solution II, in which the mass ratio of PMMA, polyaniline and nano metal oxide was 1:0.004:0.004. Spinning solution II was spun using a centrifugal spinning machine with a rotation speed of 3000 r / min and a spinneret hole of 0.2 mm. The fiber curing temperature was 50°C and the humidity was 45 RH% to obtain ZnO / PANI / PMMA composite fibers. Afterwards, the composite fibers were successively immersed in 0.15 mol / L AgNO 3 The in-situ coprecipitation reaction was carried out in the solution and 0.15 mol / L NaCl solution for 1.5 hours and 20 minutes, respectively. 3 The contact of the solution was carried out under 40KHz ultrasound. After the reaction was completed, the composite fiber was thoroughly washed with deionized water and freeze-dried at -50°C for 9 hours. Finally, the dried composite fiber was irradiated under ultraviolet light for 60 minutes to obtain the final photocatalytic composite fiber. The degradation of organic pollutants by the prepared photocatalytic composite fiber is shown in Table 1.

[0054] Example 4 Polymethyl methacrylate (1 / 9 of the total mass of mixed solution I) and propylene glycol as a porogen (0.08 / 9 of the total mass) were mixed with ethyl acetate solvent in proportion, stirred at 400 rpm at 15°C for 4.5 hours to obtain a uniform mixed solution I. Subsequently, the mixed solution I was mixed and stirred with polyaniline for 90 minutes, and then nano niobium pentoxide powder was added, stirred for 80 minutes and allowed to stand for 1.5 hours to obtain spinning solution II, in which 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 with a rotation speed of 4000 r / min and a spinneret hole of 0.4 mm. The fiber curing temperature was 65°C and the humidity was 55RH%, and Nb 2 O 5 / PANI / PMMA composite fibers. Then, the composite fibers were immersed in 0.25 mol / L AgNO 3 The in-situ coprecipitation reaction was carried out in the solution and 0.25 mol / L NaCl solution for 2.0 hours and 15 minutes, respectively. 3 The contact of the solution was carried out under 50KHz ultrasound. After the reaction was completed, the composite fiber was thoroughly washed with deionized water and freeze-dried at -45°C for 10 hours. Finally, the dried composite fiber was irradiated under ultraviolet light for 90 minutes to obtain the final photocatalytic composite fiber. The degradation of organic pollutants by the prepared photocatalytic composite fiber is shown in Table 1.

[0055] Example 5 Polymethyl methacrylate (accounting for 1 / 8 of the total mass of mixed solution I), diethylene glycol as a porogen (accounting for 0.03 / 8 of the total mass) and dioxane solvent were mixed in proportion, stirred at 700 rpm at 25°C for 3.5 hours to obtain a uniform mixed solution I. Subsequently, the mixed solution I was mixed and stirred with polyaniline for 100 minutes, and then nano antimony trioxide powder was added, stirred for 70 minutes and allowed to stand for 2.0 hours to obtain spinning solution II, in which 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 with a rotation speed of 2000 r / min and a spinneret hole of 0.3 mm. The fiber curing temperature was 75°C and the humidity was 25RH%, and Sb 2 O 3 / PANI / PMMA composite fibers. Then, the composite fibers were immersed in 0.1 mol / L AgNO 3 The in-situ coprecipitation reaction was carried out in the solution and 0.1 mol / L NaCl solution for 1.0 hour and 25 minutes, respectively. 3The contact of the solution was carried out under 50KHz ultrasound. After the reaction was completed, the composite fiber was thoroughly washed with deionized water and freeze-dried at minus 55°C for 8 hours. Finally, the dried composite fiber was irradiated under ultraviolet light for 75 minutes to obtain the final photocatalytic composite fiber. The degradation of organic pollutants by the prepared photocatalytic composite fiber is shown in Table 1.

[0056] Comparative Example 1 Polymethyl methacrylate (1 / 7 of the total mass of mixed solution I) and glycerol as a porogen (0.02 / 7 ​​of the total mass) were mixed with N,N-dimethylformamide solvent in proportion, stirred at 25°C for 4 hours at a stirring speed of 250rpm to obtain a uniform mixed solution I. Subsequently, the mixed solution I was mixed and stirred with polyaniline for 60 minutes, and then nano zirconium oxide powder was added, stirred for 90 minutes and allowed to stand for 3 hours to obtain spinning solution II, in which 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 rotation speed of 5000r / min and a spinneret hole of 0.1mm. The fiber curing temperature was 80°C and the humidity was 80RH% to obtain ZrO / PANI / PMMA composite fibers. Afterwards, the composite fibers were successively immersed in 0.40mol / L AgNO 3 The in-situ coprecipitation reaction was carried out in the solution and 0.4 mol / L NaCl solution for 2 hours and 10 minutes, respectively. 3 The contact of the solution was carried out under 35KHz ultrasound. After the reaction was completed, the composite fiber was thoroughly washed with deionized water and freeze-dried at minus 55°C for 6 hours. Finally, the dried composite fiber was irradiated under ultraviolet light for 60 minutes to obtain the final photocatalytic composite fiber. The degradation of organic pollutants by the prepared photocatalytic composite fiber is shown in Table 1.

[0057] Comparative Example 2 Polymethyl methacrylate (1 / 7 of the total mass) was mixed with N,N-dimethylformamide solvent in proportion, stirred at 25°C for 4 hours at a stirring speed of 250 rpm to obtain a uniform mixed solution I. Subsequently, the mixed solution I was mixed and stirred with polyaniline for 60 minutes, and then nano zirconium oxide powder was added, stirred for 90 minutes and allowed to stand for 3 hours to obtain spinning solution II, in which 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 rotation speed of 5000 r / min and a spinneret hole of 0.1 mm. The fiber curing temperature was 80°C and the humidity was 60 RH% to obtain ZrO / PANI / PMMA composite fibers. Afterwards, the composite fibers were immersed in 0.10 mol / L AgNO3 The in-situ coprecipitation reaction was carried out in the solution and 0.1 mol / L NaCl solution for 2 hours and 10 minutes, respectively. 3 The contact of the solution was carried out under 35KHz ultrasound. After the reaction was completed, the composite fiber was thoroughly washed with deionized water and freeze-dried at minus 55°C for 6 hours. Finally, the dried composite fiber was irradiated under ultraviolet light for 60 minutes to obtain the final photocatalytic composite fiber. The degradation of organic pollutants by the prepared photocatalytic composite fiber is shown in Table 1.

[0058] Comparative Example 3 Polymethyl methacrylate (1 / 7 of the total mass) and glycerol as a porogen (0.02 / 7 ​​of the total mass) were mixed with N,N-dimethylformamide solvent in proportion, stirred at 25°C for 4 hours at a stirring speed of 250 rpm to obtain a uniform mixed solution I. Subsequently, the mixed solution I was mixed and stirred with nano zirconium oxide for 90 minutes and then allowed to stand for 3 hours to obtain a spinning solution II, in which the mass ratio of PMMA to nano metal oxide was 1:0.003. A centrifugal spinning machine with a rotation speed of 5000 r / min and a spinneret of 0.1 mm was used to spin the spinning solution II. The fiber curing temperature was 80°C and the humidity was 60 RH% to obtain ZrO / PMMA composite fibers. Afterwards, the composite fibers were immersed in 0.10 mol / L AgNO 3 The in-situ coprecipitation reaction was carried out in the solution and 0.1 mol / L NaCl solution for 2 hours and 10 minutes, respectively. 3 The contact of the solution was carried out under 35KHz ultrasound. After the reaction was completed, the composite fiber was thoroughly washed with deionized water and freeze-dried at minus 55°C for 6 hours. Finally, the dried composite fiber was irradiated under ultraviolet light for 60 minutes to obtain the final photocatalytic composite fiber. The degradation of organic pollutants by the prepared photocatalytic composite fiber is shown in Table 1.

[0059] The photocatalytic composite fiber materials prepared in Examples 1-5 and Comparative Examples 1-3 were tested for performance, and the testing method was as follows: At room temperature, using a 500W xenon lamp as a 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), and the solution was kept uniform by magnetic stirring. 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 lasted 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.

[0060] Table 1. Degradation rates of different pollutants catalytically degraded by photocatalytic composite fiber materials prepared in Examples and Comparative Examples (degradation rate / %=(1-C / C 0 )×100%, C is the concentration, C 0 is the initial concentration)

[0061] In Comparative Example 1, the high humidity environment was used to delay 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 the photocatalytic active sites and hindered the mass transfer efficiency of the reactants; Excessive concentration Under the action of ultrasound, AgCl particles with uneven sizes are rapidly nucleated, and their surface plasmon resonance effect is weakened and the recombination of photogenerated carriers is intensified. At the same time, the increase in NaCl concentration leads to excessive Competitive coordination with the amino groups of polyaniline weakens the bonding strength between AgCl and the fiber matrix and induces lattice distortion, further reducing the photocatalytic activity and stability.

[0062] In Comparative Example 2, no porogen was added, the pore structure of the prepared fiber was not rich, the catalyst activity in the bulk phase was not stimulated, and the organic pollutants could only be degraded by the surface catalyst, but the fiber diameter was small and the effect was limited. In addition, no porogen was added, the fiber pore structure was not rich, and the adsorption capacity of organic pollutants was weakened, so the degradation effect of organic pollutants became worse.

[0063] In comparative example 3, the fiber without polyaniline (PANI) has 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 and reduce 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 (~2.8 eV) of PANI 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.

[0064] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Therefore, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the content of the technical solution 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; (2) uniformly mixing the polyaniline and the nano-metal oxide with the mixed solution I to obtain a spinning solution II; (3) spinning the spinning solution II through a centrifugal spinning machine to obtain MOx / PANI / PMMA composite fibers; (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. (5) The photocatalytic composite fiber is subjected to light treatment under ultraviolet light to obtain PMMA-based Ag@AgCl / MOx / PANI photocatalytic composite fiber.

2. The preparation method according to claim 1, characterized in that: 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.

3. The preparation method according to claim 1, characterized in that: The mass ratio of the polymethyl methacrylate, polyaniline and nano-metal oxide is 1:0.001-0.008:0.001-0.

008.

4. The preparation method according to claim 1, characterized in that: The nano metal oxide in step (2) is at least one of ZrO2, Sb2O3, NbO, Fe3O4, and ZnO.

5. The preparation method according to any one of claims 1 to 4, characterized in that The rotation speed of the centrifugal spinning machine in step (3) is 500-5000 r / min, and the spinneret hole size of the spinning head of the centrifugal spinning machine is 0.1-0.5 mm.

6. The preparation method according to any one of claims 1 to 4, 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%.

7. The preparation method according to any one of claims 1 to 4, characterized in that In step (4), 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.

8. A PMMA-based photocatalytic composite fiber material, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the PMMA-based photocatalytic composite fiber material according to claim 8 in degrading organic pollutants.

10. The use according to claim 9, 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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