Nano-scale bismuth-based glass fiber composite photocatalytic material and preparation method thereof

Abstract

The present invention relates to a nano-scale bismuth-based glass fiber composite photocatalytic material and a preparation method thereof, the preparation method comprising the following steps: pretreatment: adding a modifier to chopped glass fiber, reacting the chopped glass fiber with the modifier to obtain a modified glass fiber; the modifier is a silane coupling agent KH-550, an aminosilane coupling agent, an epoxysilane coupling agent, or a methacrylate coupling agent; synthesis: dissolving Bi(NO3)3·5H2O and Na2WO4,5H2O in deionized water to obtain a mixed solution, impregnating the modified glass fiber with the mixed solution, and then transferring the mixed solution to a reactor for a thermochemical reaction. After the reaction is completed, the obtained white precipitate is centrifuged and washed to obtain a glass fiber composite photocatalytic material. The present invention has the advantages of optimizing material dispersibility and active site exposure, improving catalytic efficiency and stability, and enhancing application adaptability in complex media.

Description

Technical Field

[0001] The present invention relates to the field of photocatalysis, and in particular to a nano-level bismuth-based glass fiber composite photocatalytic material and a preparation method thereof. Background Art

[0002] In recent years, with the rapid development of industrialization and urbanization, environmental problems have increased year by year. Human consumption and livestock farms have caused a large amount of organic matter in surface water to exceed the standard. The organic matter that cannot be completely metabolized remains in the water environment, causing serious biological toxicity. Pollutants such as dyes, antibiotics, and pesticides remaining in water bodies can damage liver and kidney function, reduce immune function, and endanger human health. Traditional water treatment processes have been used to remove many common pollutants in water, but organic pollutants are highly toxic, such as organic dyes and antibiotics that exist in water bodies at the microscopic scale and cannot be completely removed by the above processes. In order to reduce the environmental burden and avoid harm to human health, there is an urgent need to develop a more effective and sustainable method to eliminate organic pollution.

[0003] Photocatalytic technology is a pollutant treatment process that uses visible and ultraviolet light combined with low-dose photocatalysts to mineralize toxic and harmful organic pollutants into harmless small molecules. Many photocatalytic materials, such as ZnO, SnO2, and TiO2, have been widely studied for environmental remediation due to their excellent photochemical stability, high photocatalytic activity, and low cost. However, due to their wide band gap, photocatalytic reactions can only be carried out under ultraviolet (UV) excitation, resulting in low solar energy conversion efficiency. Sunlight only contains 5% UV light, 43%-46% visible light, and 49%-52% near-infrared (NIR) light. Therefore, it is necessary to develop photocatalytic materials that can respond to visible light and effectively utilize near-infrared light for environmental photocatalysis. Compared with other treatment processes, photocatalytic technology uses renewable light energy and has the advantages of low energy consumption and low cost.

[0004] In recent years, double-helix photocatalysts, particularly bismuth-based nanocomposites, have become a hot topic of research in both scientific research and industry due to their exceptional photocatalytic performance and unique physicochemical properties. As novel photocatalysts, bismuth-based nanocomposites offer significant advantages over traditional materials. These materials not only exhibit excellent electrical, optical, magnetic, photocatalytic, and thermal properties, but also show significant potential for applications in sensing and environmental remediation. Their suitable band structure enables bismuth-based materials to efficiently absorb visible light, making them widely considered ideal candidates for photocatalytic applications. Bismuth-based photocatalysts such as Bi2O3, Bi2S3, BiFeO3, Bi2MoO6, Bi2WO6, and BiOX (X = Cl, Br, I) exhibit exceptional activity in the degradation of organic pollutants and environmental remediation due to their narrow band gap structure and excellent light absorption capacity. However, despite their multiple performance advantages, they still face challenges, such as the stability of their photocatalytic efficiency and performance degradation after long-term use. Furthermore, the complexity and cost of their preparation processes limit their widespread adoption in industrial applications.

[0005] Existing photocatalytic materials have the following disadvantages:

[0006] 1. Light energy absorption and utilization defects: Photocatalytic materials generally have a high absorption capacity for specific parts of the spectrum (such as ultraviolet light). However, the proportion of ultraviolet light in sunlight is relatively low, and in practical applications, the absorption and conversion efficiency of photocatalytic materials is often limited. This leads to low light energy utilization in actual operation. Even after long-term exposure to light sources, the efficiency of photocatalytic reactions may not be high. In addition, photocatalytic materials may be interfered with by other light sources, such as visible light or infrared light, further reducing their light energy utilization efficiency.

[0007] 2. Insufficient Reactive Sites: The number of reactive sites in a photocatalytic material significantly impacts reaction efficiency. However, existing photocatalytic materials may have fewer or unevenly distributed reactive sites, which limits the rate and effectiveness of the photocatalytic reaction. In practice, even increasing the amount of photocatalytic material may not significantly improve reaction efficiency because the number of reactive sites remains essentially unchanged.

[0008] 3. Insufficient stability and durability: The structure and properties of photocatalytic materials may change during prolonged exposure to light or during catalytic reactions, leading to reduced stability and durability. For example, some photocatalytic materials may experience photocorrosion or changes in their lattice structure under light, thereby reducing their catalytic activity. Furthermore, catalyst loss and poisoning may also affect the stability and durability of the material. Furthermore, most photocatalytic materials currently are nanopowder materials, which, in addition to their lack of durability, also have application drawbacks such as difficulty in recycling and repeated use. Summary of the Invention

[0009] The main purpose of the present invention is to provide a nano-scale bismuth-based glass fiber composite photocatalytic material with improved catalytic efficiency and stability and a preparation method thereof.

[0010] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0011] A method for preparing a nano-scale bismuth-based glass fiber composite photocatalytic material comprises the following steps:

[0012] (1) Pretreatment: adding a modifier to the chopped glass fibers to react with the modifier to obtain modified glass fibers;

[0013] The modifier is silane coupling agent KH-550, aminosilane coupling agent, epoxysilane coupling agent or methacrylate coupling agent;

[0014] (2) Synthesis: 9.5 g of Bi(NO3)3·5H2O and 3.95 g of Na2WO4·5H2O were dissolved in 100-500 mL of deionized water to obtain a mixed solution. The modified glass fiber was impregnated with the mixed solution and then transferred to a reactor for thermochemical reaction. After the reaction was completed, the obtained white precipitate was centrifuged and washed to obtain a Bi2WO6-based chopped glass fiber composite photocatalytic material.

[0015] The chopped glass fibers are subjected to extraction and cleaning treatment before being added to the modifier. After the modifier is added to the chopped glass fibers, the fibers are stirred at 70-90° C. at a stirring speed of 200-400 rpm / min for 4-6 hours, and then the chopped glass fibers are filtered out. The chopped glass fibers are placed in a vacuum drying oven, dried for 2-4 hours at a vacuum degree of 0.07-0.09 MPa and 85-105° C., and then heated at 90-150° C. for modification for 10 minutes to 1 hour.

[0016] The mass ratio of Bi(NO3)3·5H2O and Na2WO4·5H2O is 9.5:3.95;

[0017] The concentration of the mixed solution is 0.02-0.1 mol / L.

[0018] Furthermore, 5 g to 15 g of the modified glass fiber is soaked in every 100 mL of the mixed solution.

[0019] The modified glass fiber is impregnated for 1-5 hours.

[0020] Furthermore, Bi(NO3)3·5H2O and Na2WO4·5H2O were dissolved in deionized water and stirred at a stirring speed of 200-400 rpm / min for 1-2 h.

[0021] The reaction temperature in the reactor is 100-200° C., and the reaction time is 3-15 hours.

[0022] The white precipitate is centrifuged 3-5 times, the speed of the centrifugation is 2000-3500 rpm / min, and the time of the centrifugation is 3-5 minutes;

[0023] The washing comprises washing with distilled water and ethanol 3 to 5 times respectively.

[0024] Furthermore, the washed product is dried in a hot air oven at 50-70° C. for 6-12 hours to obtain a Bi 2 WO 6 -based chopped glass fiber composite photocatalytic material.

[0025] The present invention also provides a nano-level bismuth-based glass fiber composite photocatalytic material, which is prepared according to the preparation method.

[0026] By means of the above technical solution, the present invention has at least the following advantages:

[0027] 1. Optimizing material dispersibility and active site exposure: The present invention addresses the significant shortcoming of easy recombination of photogenerated electrons and holes in the photocatalytic process of bismuth-based semiconductors. The present invention produces nanoparticles in the generation of bismuth tungstate. The catalyst is prepared into nanoscale particles and then combined with a strong fiber carrier. This method can reduce the band gap energy of the catalyst material, absorb sunlight in a wider wavelength range, and shorten the migration distance of photogenerated carriers from the catalyst body to the surface, which can effectively inhibit the recombination of photogenerated electrons and holes.

[0028] 2. Improved catalytic efficiency and stability: The nano-scale bismuth-based oxygen-containing salts in the Bi2WO6-based short-cut glass fiber composite photocatalytic material of the present invention have a wider solar light absorption range and high photocatalytic activity, which can effectively improve the absorption and utilization capacity of ultraviolet and visible light; the short-cut glass fiber carrier has good biocompatibility, stability and non-toxicity, etc., which can further enhance the reflection and absorption of ultraviolet and visible light, while increasing the mechanical strength, thereby expanding the subsequent application forms.

[0029] 3. Enhanced adaptability in complex media: Surface modification of chopped glass fibers by introducing hydrophobic organic groups can alter the surface properties of photocatalytic materials, improving their compatibility and dispersibility in organic systems. This improvement enables bismuth-based photocatalysts to better adapt to complex environmental conditions, such as in organic wastewater treatment and air purification, thereby expanding their practical applications and effectiveness.

[0030] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a photocatalytic degradation curve diagram of each embodiment provided by the embodiments of the present invention;

[0032] Figure 2 is a scanning electron microscope image of Example 1 provided in an embodiment of the present invention;

[0033] Figure 3 This is a scanning electron microscope image of Example 6 provided in the examples of the present invention. DETAILED DESCRIPTION

[0034] To further illustrate the technical means and effects employed by the present invention to achieve its intended objectives, the following detailed description of the specific embodiments, structures, features, and effects of the present invention is provided in conjunction with the accompanying drawings and preferred embodiments. In the following description, different references to "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0035] Example 1:

[0036] (1) Pretreatment: Add γ-methacryloxypropyltrimethoxysilane, i.e., silane coupling agent KH570, to the extracted and cleaned chopped glass fibers, stir at 80°C and 300 rpm / min for 5 h, filter out the chopped glass fibers, place the chopped glass fibers in a vacuum drying oven, and dry them at 95°C for 3 h under the conditions of vacuum degree of 0.08 MPa and 30 min. After the water is evaporated, heat at 120°C for 30 min to allow the chopped glass fibers to fully react with the modifier, and obtain the modified glass fibers.

[0037] (2) Synthesis: A Bi2WO6-based chopped glass fiber composite material was prepared by a hydrothermal method. 9.5 g of Bi(NO3)3·5H2O and 3.95 g of Na2WO4,5H2O were dissolved in 250 mL of deionized water and stirred continuously at a stirring speed of 300 rpm / min for 1.5 h to form a white mixed solution with a concentration of 0.04 mol / L. Subsequently, 100 mL of the mixed solution was impregnated with 10 g of modified glass fiber for 3 h. The impregnated mixture was transferred to a polytetrafluoroethylene-lined stainless steel autoclave and maintained at 180°C for 12 h to obtain a white precipitate. The white precipitate was centrifuged five times, each time at a speed of 3000 rpm / min for 3 min, and washed with distilled water and ethanol five times each. Finally, the obtained product was dried in a hot air oven at 60°C for 10 h to obtain a Bi2WO6-based chopped glass fiber composite photocatalytic material.

[0038] Example 2:

[0039] (1) Pretreatment: Add epoxy silane coupling agent to the chopped glass fibers after extraction and cleaning, stir at 70°C at a stirring speed of 200 rpm / min for 6 hours, filter out the chopped glass fibers, place the chopped glass fibers in a vacuum drying oven, and dry them at a vacuum degree of 0.07 MPa and 85°C for 4 hours. After the water is evaporated, heat at 90°C for 1 hour to allow the chopped glass fibers to fully react with the modifier, and obtain the modified glass fibers;

[0040] (2) Synthesis: A Bi2WO6-based short-cut glass fiber composite material was prepared by a hydrothermal method. 9.5 g of Bi(NO3)3·5H2O and 3.95 g of Na2WO4,5H2O were dissolved in 100 mL of deionized water and stirred continuously at a stirring speed of 200 rpm / min for 2 h to form a white mixed solution with a concentration of 0.1 mol / L. Subsequently, 10 g of modified glass fiber was infiltrated with 100 mL of the mixed solution for 5 h. The infiltrated mixture was transferred to a polytetrafluoroethylene-lined stainless steel autoclave and maintained at 100°C for 15 h to obtain a white precipitate. The white precipitate was centrifuged four times, each time at a speed of 2000 rpm / min for 5 min, and washed with distilled water and ethanol three times each. Finally, the obtained product was dried in a hot air oven at 70°C for 6 h to obtain a Bi2WO6-based short-cut glass fiber composite photocatalytic material.

[0041] Example 3:

[0042] (1) Pretreatment: Add methacrylate coupling agent to the chopped glass fibers after extraction and cleaning, stir at 90°C at a stirring speed of 400 rpm / min for 4 hours, filter out the chopped glass fibers, place the chopped glass fibers in a vacuum drying oven, and dry them at a vacuum degree of 0.09 MPa and 105°C for 2 hours. After the water is evaporated, heat at 150°C for 10 minutes to allow the chopped glass fibers to fully react with the modifier, and then discharge the modified glass fibers;

[0043] (2) Synthesis: A Bi2WO6-based short-cut glass fiber composite material was prepared by a hydrothermal method. 9.5 g of Bi(NO3)3·5H2O and 3.95 g of Na2WO4,5H2O were dissolved in 500 mL of deionized water and stirred at 400 rpm / min for 1 h to form a white mixed solution with a concentration of 0.02 mol / L. Subsequently, 100 mL of the mixed solution was impregnated into 5 g of modified glass fiber for 1 h. The impregnated mixture was transferred to a polytetrafluoroethylene-lined stainless steel autoclave and maintained at 200°C for 3 h to obtain a white precipitate. The white precipitate was centrifuged three times, each time at 3500 rpm / min for 4 min, and washed four times with distilled water and ethanol. Finally, the obtained product was dried in a hot air oven at 50°C for 12 h to obtain a Bi2WO6-based short-cut glass fiber composite photocatalytic material.

[0044] Example 4:

[0045] The preparation method of this embodiment is basically the same as that of Example 1, except that:

[0046] The reaction time of the impregnated mixture in the autoclave is 6 h.

[0047] Example 5:

[0048] The preparation method of this embodiment is basically the same as that of Example 1, except that:

[0049] The impregnated mixture was reacted in a high-pressure reactor at a temperature of 150°C.

[0050] Example 6:

[0051] The preparation method of this embodiment is basically the same as that of Example 1, except that:

[0052] The time for the chopped glass fiber to fully react with the modifier is 1 h;

[0053] 9.5 g Bi(NO3)3·5H2O and 3.95 g Na2WO4, 5H2O were dissolved in 500 mL deionized water.

[0054] Example 7:

[0055] The preparation method of this embodiment is basically the same as that of Example 1, except that:

[0056] 9.5 g Bi(NO3)3·5H2O and 3.95 g Na2WO4, 5H2O were dissolved in 500 mL deionized water.

[0057] Example 8:

[0058] The preparation method of this embodiment is basically the same as that of Example 1, except that:

[0059] The modifier is silane coupling agent KH-550.

[0060] The photocatalytic performance of the Bi2WO6-based chopped glass fiber composite photocatalytic materials prepared in each embodiment was comprehensively evaluated according to the following testing methods:

[0061] To evaluate the degradation efficiency of the photocatalytic materials, the following experiment was conducted: First, eight 50 mL portions of a 100 mg / L methylene blue solution were prepared and mixed with 50 mg of the photocatalytic materials from Examples 1 to 8. The mixtures were then dispersed using ultrasonic dispersion for 30 minutes to ensure uniform distribution of the photocatalytic materials throughout the solution.

[0062] Next, the dispersed solution is placed in a photoreactor, the light source is turned off, and a dark adsorption process of 30 min is carried out to reach adsorption-desorption equilibrium. After the dark adsorption is completed, the light source is turned on, and samples are taken at the time points of 2 min, 5 min, 10 min, 20 min, 30 min and 40 min. After each sampling, a quencher is used to terminate the reaction to ensure that the reaction does not proceed during the sampling process. Subsequently, the solution after sampling is transferred to a liquid chromatograph and tested for pollutant concentration to measure the residual concentration of methylene blue at each time point. The concentration data obtained by the liquid chromatograph are used to calculate the degradation rate at different time points, and a photocatalytic degradation curve is drawn to compare the photocatalytic efficiency of each embodiment.

[0063] The experimental results are as follows Figure 1 As shown, Figure 1 The horizontal axis Time is the time in minutes, and the vertical axis C / C0 is the ratio of the reactant concentrations. Figure 1It can be seen that the optimal composite photocatalytic material prepared by the present invention has an excellent photocatalytic effect. The composite material used in Example 1 achieved a photocatalytic degradation rate of more than 95% in the experiment, showing excellent performance. Compared with Example 8, Example 1 adopted a different surface modifier, among which γ-methacryloxypropyltrimethoxysilane has a better effect on stimulating the surface activity of glass fibers. Examples 2 and 3 were compared with Example 1 in terms of multiple factors. The most prominent factors were the type of glass fiber modifier and modification time, and the difference in Bi2WO6 loading (related to the growth concentration). The Bi2WO6 loading was related to the concentration of the mixed solution and the amount of glass fiber impregnated with a certain amount of mixed solution after modification. The data showed that Example 1 had the best photocatalytic effect, among which the appropriate type of modifier and modification time were the most important for the process of in-situ loading of nanoparticles on glass fibers, followed by the difference in the impact of the loading amount, which also accounted for a large proportion. However, under different conditions, better catalytic performance could be obtained under the conditions of the interaction of various factors.

[0064] In order to further explore the factors that affect the photocatalytic effect, comparative tests were conducted on reaction temperature, reaction time, modification time and reactant concentration in Examples 4 to 8. The results showed that changes in reaction time and reaction temperature had a significant impact on the progress of the photocatalytic reaction, slowing down the reaction speed and causing the final degradation rate to drop by about 10-50%. Among them, in Examples 4 and 5, the reaction concentration was reduced during the preparation of the reactants, such as Figure 2 As shown, this is the SEM image of Example 1. Figure 3 As shown, this is the SEM image of Example 6. The precursor concentrations of Example 1 and Example 6 are different. Comparing the two SEM images, the results show that the loading rate of the nanocatalytic material on the surface of the final glass fiber is correspondingly reduced, which in turn affects its photocatalytic performance, which is worse than that of Example 1.

[0065] It can be seen that the loading amount of nanocatalytic materials on the glass fiber surface has an important influence on the final photocatalytic performance. The appropriate selection of surface modifiers and the optimization of reaction conditions are crucial for the preparation of efficient composite photocatalytic materials.

[0066] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the present profession can make slight changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a nano-scale bismuth-based glass fiber composite photocatalytic material, characterized by: The following steps are involved: (1) Pretreatment: adding a modifier to the chopped glass fibers to react with the modifier to obtain modified glass fibers; The modifier is silane coupling agent KH-550, aminosilane coupling agent, epoxysilane coupling agent or methacrylate coupling agent; (2) Synthesis: Bi(NO3)3·5H2O and Na2WO4·5H2O were dissolved in deionized water to obtain a mixed solution, which was then used to impregnate the modified glass fiber. The modified glass fiber was then transferred to a reactor for a thermochemical reaction. After the reaction was completed, the obtained white precipitate was centrifuged and washed to obtain a Bi2WO6-based chopped glass fiber composite photocatalytic material. The reaction temperature in the reactor is 100-200° C., and the reaction time is 3-15 hours.

2. The preparation method according to claim 1, characterized in that The chopped glass fibers are subjected to extraction and cleaning treatment before being added to the modifier. After the modifier is added to the chopped glass fibers, the fibers are stirred at 70-90° C. at a stirring speed of 200-400 rpm for 4-6 hours, and then the chopped glass fibers are filtered out. The chopped glass fibers are placed in a vacuum drying oven, dried for 2-4 hours at a vacuum degree of 0.07-0.09 MPa and 85-105° C., and then heated at 90-150° C. for modification for 10 minutes to 1 hour.

3. The preparation method according to claim 1, characterized in that The mass ratio of Bi(NO3)3·5H2O and Na2WO4·5H2O is 9.5:3.95; The concentration of the mixed solution is 0.02-0.1 mol / L.

4. The preparation method according to claim 3, characterized in that Every 100 mL of the mixed solution is used to soak 5 g to 10 g of the modified glass fiber.

5. The preparation method according to claim 4, characterized in that The modified glass fiber is impregnated for 1-5 hours.

6. The preparation method according to claim 5, characterized in that Dissolve Bi(NO3)3·5H2O and Na2WO4·5H2O in deionized water and stir at a stirring speed of 200-400 rpm for 1-2 hours.

7. The preparation method according to any one of claims 1 to 6, characterized in that The white precipitate is centrifuged 3-5 times, the speed of the centrifugation is 2000-3500 rpm, and the time of the centrifugation is 3-5 minutes; The washing is performed by washing with distilled water and ethanol 3 to 5 times respectively.

8. The preparation method according to claim 7, characterized in that The washed product is dried in a hot air oven at 50-70° C. for 6-12 hours to obtain a Bi 2 WO 6 -based chopped glass fiber composite photocatalytic material.

9. A nano-scale bismuth-based glass fiber composite photocatalytic material, characterized by: It is prepared according to the preparation method according to any one of claims 1 to 8.

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