Hydrogen tungsten bronze composite photocatalytic material, preparation method and application thereof
Patent Information
- Application Number
- CN202410234109.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-01
- Publication Date
- 2026-08-18
- Estimated Expiration
- 2044-03-01
AI Technical Summary
但氢钨青铜的工业大规模生产受到需富氢气氛中贵金属催化、电化学反应、高温处理(至少500K)等的限制
[0022] Compared to existing technologies, the photocatalytic composite material H for treating antibiotic wastewater described in this invention... x WO3/CQDs have the following advantages:
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Figure CN118105969B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of material synthesis, and particularly relates to a hydrogen tungsten bronze composite photocatalytic material, a preparation method thereof, and an application thereof. Background Art
[0002] With the development of science and technology, some new pollutants are difficult to degrade after entering the natural environment, turning into persistent pollutants and accumulating in the atmosphere, water bodies, and soil, posing serious hazards to the ecological environment and human health. In recent years, antibiotic pollutants widely used, such as penicillin and tetracycline, have received extensive attention due to their interference with the ecological balance and the induction of "super bacteria". Developing efficient treatment technologies for these pollutants and converting them into harmless products is an urgent need for ecological protection and environmental governance.
[0003] As an efficient, safe, and environmentally friendly purification technology, when the absorbed light energy exceeds the bandgap width, electrons on the valence band of the catalyst jump to the excited state, forming electron / hole pairs to participate in the redox process, thereby degrading organic matter. Currently, the photocatalytic technology based on semiconductor materials has developed rapidly and shows good application prospects in solving energy crisis and environmental pollution problems. However, the vast majority of photocatalysts still need to exhibit their catalytic activity under ultraviolet light, have only a small absorption in the visible light region, and have difficulty in utilizing the near-infrared light region with a larger wavelength. And the proportion of visible and infrared light in the solar spectrum accounts for up to 50% of the total energy. How to effectively utilize this part of the energy is still an important topic.
[0004] Tungsten bronze is a WO3 crystal doped with A atoms, that is, cations enter the channels of WO3 to reduce part of the W 6+ to generate non-stoichiometric A x WO3(0 < x < 1) containing mixed-valence tungsten ions. It has excellent photoelectrochemical properties. The study of the local surface plasmon resonance effect reveals that tungsten bronze has strong light absorption ability in the visible to near-infrared region. When the A atom is H + , the tungsten bronze is hydrogen tungsten bronze. The positive holes formed by the insertion of H + ions into the WO3 lattice can play a role in conduction, increasing the Fermi level and the electron density at the charge carriers, and thus having broad application prospects in the fields of photocatalysis, solid oxide fuel cells, organic photovoltaic cells, energy storage, etc. However, the industrial large-scale production of hydrogen tungsten bronze is restricted by the need for noble metal catalysis, electrochemical reactions, high-temperature treatment (at least 500K) in a hydrogen-rich atmosphere, etc. Considering the high cost of hydrogen production and its flammability and explosiveness in use, it is urgent to use other hydrogen-containing substances to replace hydrogen to improve the environmental friendliness of the hydrogen tungsten bronze synthesis process and reduce costs. Summary of the Invention
[0005] In view of this, the present invention aims to propose a method for preparing and applying a hydrogen-tungsten bronze composite photocatalytic material to overcome the shortcomings of the prior art. This hydrogen-tungsten bronze composite photocatalytic material is used for the treatment of recalcitrant antibiotic wastewater. During the ball milling process, the polymer is mechanically induced to decompose and generate hydrogen. Under the hydrogen overflow effect, hydrogen reacts chemically with the tungsten oxide matrix to generate hydrogen-tungsten bronze. Simultaneously, the photocatalytic material is obtained by in-situ composite with carbon quantum dots generated from polymer decomposition.
[0006] A hydrogen tungsten bronze composite photocatalytic material is a composite material of hydrogen tungsten bronze and carbon quantum dots, which is prepared in situ by one-step composite of tungsten trioxide (WO3) and polypropylene (PP) using mechanical ball milling; the mass ratio of tungsten trioxide to polypropylene is 32:1 to 64:1.
[0007] Preferably, the polypropylene is polypropylene microspheres or polypropylene powder; wherein the particle size of the polypropylene microspheres is 2-5 mm, and the particle size of the polypropylene powder is 20-100 μm.
[0008] This invention also provides a method for preparing the hydrogen-tungsten bronze composite photocatalytic material as described above, comprising the following steps:
[0009] 1) Mix tungsten trioxide and polypropylene evenly and place them in a ball mill;
[0010] 2) Add the ball milling media to the mixture obtained in step 1). The ball milling media is zirconia (ZrO2) balls with a diameter of 1 to 10 mm.
[0011] 3) After vacuuming the mixture obtained in step 2) for 5 to 10 minutes, the ball mill is run at a speed of 300 to 500 rpm to grind the mixture for 1 to 5 hours, changing the rotation direction once every 30 minutes, and stopping the grinding for 2 to 5 minutes in between.
[0012] Preferably, in step 2), the mass ratio of the added ZrO2 balls to the total amount of raw materials is 20:1 to 200:1; more preferably, 40:1 to 100:1.
[0013] Preferably, in step 2), the diameter of the zirconia spheres is divided into three types, namely 3, 5 and 10 mm, and the mass ratio of the zirconia spheres of each diameter is (1-5):(4-6):(2-4).
[0014] Preferably, in step 3), the ball mill is run at a speed of 350 to 450 rpm to grind the mixed material for 2.5 to 3.5 hours.
[0015] This invention also provides the application of the hydrogen-tungsten-bronze composite photocatalytic material described above in the treatment of antibiotic-contaminated water.
[0016] This invention also provides the application of the hydrogen-tungsten bronze composite photocatalytic material prepared by the preparation method described above in the treatment of antibiotic-contaminated water.
[0017] Preferably, the antibiotic is tetracycline hydrochloride (TC);
[0018] Preferably, the concentration range of antibiotics in the wastewater is 1–20 mg / L, and the pH is 3–11.
[0019] Carbon quantum dots (CQDs) are quasi-spherical carbon nanomaterials with dimensions smaller than 10 nm. They not only possess strong photoluminescence properties, but also, upon light absorption, their excited-state electrons can transfer between semiconductor materials, promoting the generation and separation of more electron / hole pairs and enhancing the activity of the reaction system. Furthermore, CQDs can regulate the bandgap of composite catalysts, expanding the light absorption range. In existing technologies, water-soluble CQDs are generally synthesized first using hydrothermal or solvothermal methods, and then their surface functional groups are combined with other catalysts to enhance reaction activity.
[0020] This invention uses WO3 as a matrix and PP, a polymer material, as both the carbon source for synthesizing CQDs and the hydrogen source for reducing WO3. The photocatalyst H is directly generated during ball milling through mechanical action. x The preparation of WO3 and its combination with in-situ generated co-catalysts CQDs not only solves the problems of high cost and low yield in the chemical preparation of tungsten bronze materials, but also simplifies the catalyst composite process, resulting in novel and highly efficient composite photocatalytic materials.
[0021] This invention aims to synthesize a composite catalytic material by simultaneously combining WO3 with hydrogen atoms and CQDs, seeking a broad-spectrum photocatalytic solution that does not use precious metals.
[0022] Compared to existing technologies, the photocatalytic composite material H for treating antibiotic wastewater described in this invention... x WO3 / CQDs have the following advantages:
[0023] 1) This invention uses a hydrocarbon polymer as a hydrogen donor, directly inducing the decomposition of PP through mechanical action to generate hydrogen, which then flows into the WO3 lattice to obtain H. x WO3 provides a green, economical, simple, and efficient method for obtaining hydrogen tungsten bronze photocatalytic materials.
[0024] 2) Under mechanochemical decomposition, the polymer can simultaneously depolymerize to generate carbon products CQDs. The generated CQDs and H x In-situ composites of WO3 can serve as co-catalysts, promoting electron-hole recombination under photoexcitation through electron transfer between the two, thereby enhancing the photocatalytic degradation performance of antibiotic pollutants. The resulting composite catalyst is a high-performance photocatalytic treatment material.
[0025] 3) This invention efficiently utilizes polymer materials to obtain high-performance composite photocatalytic materials through a simple and low-consumption one-step mechanical synthesis method. These materials absorb in the near-infrared region and maintain excellent antibiotic wastewater treatment performance even in natural light environments. This broadens the effective utilization range of sunlight and has broad application prospects in the low-consumption treatment of wastewater in industries such as chemical and pharmaceutical. Attached Figure Description
[0026] Figure 1 The images show the XRD patterns of different catalytic materials in the examples. WO3 / PP-milled is the composite photocatalytic material obtained in Example 2; PP-milled is ball-milled polypropylene; WO3-milled is ball-milled tungsten oxide; and WO3 is unmilled tungsten oxide.
[0027] Figure 2 This is a comparison chart of the effects of different catalytic materials on TC removal in the examples.
[0028] Figure 3 The light absorption performance of different catalytic materials is shown in the examples.
[0029] Figure 4 In this example, the composite catalytic material demonstrates its TC degradation performance under natural light.
[0030] Figure 5 In the example, different pH values affect H. x Comparison of WO3 / CQDs photocatalytic degradation of TC. Detailed Implementation
[0031] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.
[0032] The present invention will be described in detail below with reference to the embodiments.
[0033] A method for preparing a photocatalytic composite material for treating antibiotic wastewater includes the following steps:
[0034] High-energy ball milling was performed using WO3 and PP. A certain mass of high-purity WO3 was weighed and added to PP in a specific mass ratio, then placed in a zirconia ball mill. The milling media consisted of 500g of zirconia balls with diameters of 3, 5, and 10 mm, in a mass ratio of 2:5:3. After evacuating the mixture for 10 minutes, the ball mill was run at 400 rpm. The composite material was milled for 3 hours, with the rotation direction changed every 30 minutes and a 5-minute rest period in between. After milling, the resulting composite material was collected and stored in a dry, oxygen-free glass bottle for later use.
[0035] Example 1:
[0036] 5g of WO3 was added to the ball mill, the particle size of the PP powder was 60μm, the mass ratio of WO3 to PP was 32:1, the mixed material was vacuumed for 10 minutes, and then the ball mill was run at 400rpm for 3 hours.
[0037] Example 2:
[0038] 5g of WO3 was added to the ball mill, the particle size of the PP powder was 60μm, the mass ratio of WO3 to PP was 48:1, the mixed material was vacuumed for 10 minutes, and then the ball mill was run at 400rpm for 3 hours.
[0039] The XRD pattern of the obtained photocatalytic composite material is as follows: Figure 1 As shown.
[0040] Example 3:
[0041] 5g of WO3 was added to the ball mill, the particle size of the PP powder was 60μm, the mass ratio of WO3 to PP was 64:1, the mixed material was vacuumed for 10 minutes, and then the ball mill was run at 400rpm for 3 hours.
[0042] Example 4:
[0043] 5g of WO3 was added to the ball mill, the particle size of the PP powder was 60μm, the mass ratio of WO3 to PP was 48:1, the mixed material was not vacuumed, the ball mill was run at 400rpm, and the grinding was carried out for 3 hours.
[0044] Example 5:
[0045] 5g of WO3 was added to the ball mill, the diameter of the PP microspheres was 4mm, the mass ratio of WO3 to PP was 48:1, the mixed materials were vacuumed for 10 minutes, and the ball mill was run at 400rpm for 3 hours.
[0046] Example 6:
[0047] 10g of WO3 was added to the ball mill, the particle size of the PP powder was 60μm, the mass ratio of WO3 to PP was 48:1, the mixture was evacuated for 10 minutes, and then the ball mill was run at 400rpm for 3 hours.
[0048] Comparative example:
[0049] WO3 was not mixed with PP and was ball-milled separately. After vacuuming WO3 and PP for 10 minutes, the ball mill was run at 400 rpm for 3 hours.
[0050] from Figure 1 The XRD pattern of the WO3 / PP-milled material prepared in Example 2 shows that the absorption peak intensity of WO3 decreased after high-energy ball milling, and the absorption peak at 25°–30° basically disappeared. The splitting of the absorption peak also disappeared, indicating that mechanical action transformed the WO3 crystal from a monoclinic phase to a triclinic phase. The characteristic peaks at 26.4°, 36.2°, and 53.3° in the material prepared by ball milling a mixture of PP and WO3 prove that its main component is H. 0.53 WO3. The ball-milled PP system showed significant characteristic peaks, such as the (002) crystal plane of graphitized carbon, at 23.8°, indicating a good crystallization state. Ultraviolet irradiation of its dialysis products produced... Figure 1 The fluorescence emission phenomenon shown in the inset indicates that PP decomposed under mechanical action to generate CQDs with photoluminescence effects. However, the carbon characteristic peak did not appear in the composite ball-milled material, which is due to the relatively small proportion and uniform distribution of CQDs. Characterization results prove that PP underwent cracking during mechanical ball milling, and the generated hydrogen overflow entered the WO3 lattice, causing W... 6+ Partially reduced to form H x WO3, where the value of x is 0.53, generates H x WO3 recombines with CQDs in situ.
[0051] The TC removal performance of the prepared photocatalytic composite material is as follows:
[0052] Photocatalytic degradation experiment of antibiotic TC: Weigh 25 mg of the prepared catalyst material and add it to 50 mL of 20 mg / L TC solution. Place the mixed solution in a dark environment and react for 20 minutes to reach the adsorption equilibrium of TC. Then, use a 300 W Xe lamp with a wavelength of 200-1100 nm as the light source for irradiation. Take 1.5 mL of sample at regular intervals, filter it through a 0.22 μm microporous membrane, and detect the TC concentration using liquid chromatography.
[0053] The experimental results of treating TC with different types of photocatalytic materials are attached. Figure 2As shown. The total amount of catalytic material used in the reaction was 25 mg, and the catalytic composite material used was prepared in Example 2.
[0054] Experimental results showed that, under the conditions of 25 mg catalyst and 20 mg / L TC concentration, compared with the blank TC solution system, neither unmilled WO3 nor ball-milled PP showed significant adsorption and degradation effects; the TC adsorption rate of WO3 after ball milling was 13%, and the total removal rate was 19%; the H obtained after ball milling x The WO3 / CQDs composite catalytic system exhibits a TC adsorption rate of 24% in the dark, while the total removal rate reaches 50% after 1 hour of reaction under Xe lamp irradiation.
[0055] The above experimental results show that simple ball milling can improve the adsorption performance of WO3 for TC to some extent by changing the crystal form, but the improvement in photocatalytic oxidation is not significant. However, the H2O obtained by mechanically ball milling both WO3 and PP is significantly better. x WO3 / CQDs composite catalytic materials exhibit significantly stronger photocatalytic activity.
[0056] The TC removal efficiencies of the catalytic composite materials prepared in Examples 1-6 after 1 hour of Xe lamp irradiation were 26%, 50%, 25%, 17%, 14%, and 28%, respectively.
[0057] The TC removal efficiencies of the catalytic composite materials prepared in Examples 1-6 after 2 hours of Xe lamp irradiation were 30%, 55%, 28%, 22%, 20%, and 32%, respectively.
[0058] The light absorption properties of several prepared catalysts were investigated experimentally. For example... Figure 3 As shown (WO3 / PP-milled prepared in Example 2), both ball-milled WO3 and PP exhibit characteristic absorption peaks in the ultraviolet region. Compared to ball-milled PP, ball-milled WO3 shows stronger absorption in the visible light region, corresponding to its enhanced photocatalytic activity. Meanwhile, in H... x A broad absorption band centered around 800 nm was observed in the near-infrared region of the WO3 / CQDs system, exhibiting strong absorption. The enhanced near-infrared light absorption of the surface composite catalytic material explains the significant improvement in the degradation ability of TC antibiotics.
[0059] Long-term reaction experiments were conducted on the materials prepared in Examples 1-3 under natural light. 25 mg of the prepared catalyst was added to 50 mL of a 20 mg / L TC solution. The results are as follows: Figure 4 As shown. After 2 hours of photocatalysis, the Xe lamp light source was turned off. At this time, the TC removal rates in Examples 1-3 were 30%, 55%, and 28%, respectively. The system was placed under natural light for 46 hours of continuous reaction (including day and night).
[0060] H prepared in Example 2 x The WO3 / CQDs system exhibited the highest total TC removal rate, reaching 84%. The composite materials prepared in Examples 1 and 3 also showed further degradation under natural light, with TC removal rates increasing to 40% and 45% respectively over the same time period. This demonstrates that the H2O composite with CQDs... x WO3 materials have excellent utilization of the spectrum of sunlight and can effectively degrade the antibiotic TC under natural light.
[0061] Studies have found that pH changes affect H x The photocatalytic degradation of TC by WO3 / CQDs has little effect (see appendix) Figure 5 Using the material prepared in Example 2, with a TC concentration of 20 mg / L, a rotation speed of 220 r / min, a temperature of 25°C, and Xe lamp irradiation, the TC removal rate did not change significantly within the pH range of 3–11, remaining between 44% and 50%. Overall, the mechanically prepared photocatalytic composite material maintained good degradation performance within the strongly acidic to strongly alkaline range.
[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a hydrogen-tungsten-bronze composite photocatalytic material, characterized in that: The hydrogen-tungsten bronze composite photocatalyst is a composite material of hydrogen-tungsten bronze and carbon quantum dots, which is prepared in situ in a one-step composite process of tungsten trioxide and polypropylene using a mechanical ball milling method. The preparation includes the following steps: 1) Mix tungsten trioxide and polypropylene evenly and place them in a ball mill; the mass ratio of tungsten trioxide to polypropylene is 32:1~64:1; 2) Add the ball milling media to the mixture obtained in step 1). The ball milling media is zirconia balls with a diameter of 1~10 mm. The mass ratio of the added zirconia balls to the total amount of raw materials is 20:1~200:
1. The diameter of the zirconia balls is divided into three types, namely 3, 5 and 10 mm, and the mass ratio of each diameter of zirconia balls is (1~5):(4~6):(2~4). 3) After vacuuming the mixture obtained in step 2) for 5 to 10 minutes, the ball mill is run at a speed of 300 to 500 rpm to grind the mixture for 1 to 5 hours, changing the rotation direction once every 30 minutes, and stopping the grinding for 2 to 5 minutes in between.
2. The preparation method of the hydrogen-tungsten bronze composite photocatalytic material according to claim 1, characterized in that: Polypropylene is in the form of polypropylene microspheres or polypropylene powder; wherein the particle size of the polypropylene microspheres is 2~5 mm, and the particle size of the polypropylene powder is 20~100 mm. μ m.
3. The preparation method of the hydrogen-tungsten-bronze composite photocatalytic material according to claim 1, characterized in that: In step 2), the mass ratio of the added zirconia balls to the total amount of raw materials is 40:1 to 100:
1.
4. The preparation method of the hydrogen-tungsten-bronze composite photocatalytic material according to claim 1, characterized in that: In step 3), the ball mill runs at a speed of 350~450 rpm and grinds the mixed material for 2.5~3.5 hours.
5. The application of the hydrogen-tungsten bronze composite photocatalytic material prepared by the preparation method according to any one of claims 1 to 4 in the treatment of antibiotic-contaminated water.
6. The application according to claim 5, characterized in that: The antibiotic is tetracycline hydrochloride.
7. The application according to claim 5, characterized in that: The concentration range of antibiotics in wastewater is 1~20 mg / L, and the pH range is 3~11.