Br-W double defect high-efficiency photocatalytic material V Br+W BiOBr / Bi2WO6 and preparation method and application

Abstract

A Br-W dual-defect high-efficiency photocatalytic material V Br+W -BiOBr / Bi2WO6, its preparation method, and applications: Method 1: Bismuth nitrate pentahydrate is dispersed in ethylene glycol, and hexadecyltrimethylammonium bromide is dispersed in anhydrous ethanol. After mixing and stirring, a mixture 1 is obtained. Mixture 1 is transferred to a Teflon liner and heated at 160℃ for 12 hours. After cooling, it is washed successively with anhydrous ethanol and deionized water to obtain BiOBr. 2: Bismuth nitrate pentahydrate is dissolved in nitric acid solution, and sodium tungstate dihydrate is dissolved in deionized water. After mixing and stirring, a mixture 2 is obtained. BiOBr is sonicated for 15 minutes and dispersed in deionized water to obtain solution F. Mixture 2 and solution F are mixed and sonicated for 15 minutes, then stirred for 2 hours to obtain mixture 3. Mixture 3 is transferred to a Teflon-lined reactor and heated at 160℃ for 20 hours. A white precipitate is obtained, filtered, and washed successively with anhydrous ethanol and deionized water to obtain BiOBr / Bi2WO6. 3: BiOBr / Bi2WO6 is dispersed in sodium hydroxide solution, stirred, filtered, and dried to obtain V. Br+W -BiOBr / Bi2WO6. This invention has good effect on degrading antibiotics in water, and is simple to operate and easy to industrialize.

Description

Technical Field

[0001] This invention belongs to the field of environmental chemical photocatalysis technology, specifically relating to a Br-W dual-defect photocatalytic material V Br+W -BiOBr / Bi2WO6, its preparation methods, and applications. Background Technology

[0002] In recent years, with population growth and the development of large-scale aquaculture technology, antibiotics, as drugs for treating infectious diseases, have been widely used in medicine, animal husbandry, and aquaculture, posing potential harm to the health of various organisms in the environment and human health. Norfloxacin, in particular, has been widely detected in various water bodies both domestically and internationally due to its poor biodegradability and widespread use. Among all treatment technologies, photocatalysis has received widespread attention due to its green, harmless, and highly efficient nature.

[0003] In practical applications of photocatalysis, Bi-based photocatalysts have a relatively wide absorption range for visible light, and their stability can also prevent secondary pollution during the treatment process. In 2016, Li J et al. (Li J, Sun S, Qian C, et al. The role of adsorption in photocatalytic degradation of ibuprofen under visible light irradiation by BiOBr microspheres[J]. Chemical Engineering Journal, 2016) prepared BiOBr microspheres using a hydrothermal method for the photocatalytic degradation of ibuprofen. The study found that BiOBr has strong adsorption performance, but the photocatalytic degradation efficiency is low due to the recombination of photogenerated carriers. He J et al. (He J, Liu Y, Wang M, et al. Ionic liquid-hydrothermal synthesis of Z-scheme BiOBr / Bi2WO6 heterojunction with enhanced photocatalytic activity[J]. Journal of Alloys and Compounds, 2021) reported that the composite BiOBr and Bi2WO6 form a Z-type heterojunction, which can effectively suppress carrier recombination. However, its photocatalytic activity under visible light still does not meet industry standards. Therefore, how to effectively enhance its photocatalytic performance is a key issue in solving the application of semiconductor photocatalysts. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a Br-W dual-defect photocatalytic material VBr+W -BiOBr / Bi2WO6, its preparation method, and applications; the aim is to prepare V that can simultaneously contain Br and W defects. Br+W -BiOBr / Bi2WO6 photocatalytic material is used to treat antibiotic wastewater, thereby effectively enhancing its photocatalytic performance and solving the problem of semiconductor photocatalyst applications.

[0005] To achieve the above objectives, the specific solution of the present invention is as follows:

[0006] A highly efficient Br-W dual-defect photocatalytic material, rich in Br and W defects, with the chemical formula V0 Br+W -BiOBr / Bi2WO6.

[0007] A method for preparing the aforementioned Br-W dual-defect high-efficiency photocatalytic material, using an in-situ solvothermal method, includes the following steps:

[0008] Step 1: Disperse bismuth nitrate pentahydrate in ethylene glycol and stir for 10 min to obtain solution A. Disperse hexadecyltrimethylammonium bromide in anhydrous ethanol and stir for 30 min to obtain solution B. Mix solution A and solution B to obtain mixture one. Transfer mixture one to a stainless steel tank lined with Teflon and keep it at 160℃ for 12 h. After natural cooling, wash three times with anhydrous ethanol and deionized water respectively to obtain BiOBr.

[0009] Step 2: Dissolve bismuth nitrate pentahydrate in nitric acid solution to obtain solution C, and dissolve sodium tungstate dihydrate in deionized water to obtain solution D. Mix solution C and solution D and stir to obtain mixture two. Then, sonicate BiOBr prepared in step 1 for 15 min and disperse it in deionized water to obtain solution F. Mix mixture two and solution F are mixed and sonicated for 15 min and stirred for 2 h to obtain mixture three. Mix mixture three is transferred to a Teflon-lined reactor and heated at 160℃ for 20 h. The obtained white precipitate is filtered and washed three times with anhydrous ethanol and deionized water respectively to obtain BiOBr / Bi2WO6 powder.

[0010] Step 3: Disperse the BiOBr / Bi2WO6 powder obtained in Step 2 in sodium hydroxide solution, stir, filter, wash three times each with anhydrous ethanol and deionized water, and vacuum dry overnight to obtain V. Br+W -BiOBr / Bi2WO6.

[0011] Further, in step 1, the molar volume ratio of bismuth nitrate pentahydrate to ethylene glycol is 1 mmol: 10 ml, the molar volume ratio of hexadecyltrimethylammonium bromide to anhydrous ethanol is 1 mmol: 25 ml, the molar mass ratio of bismuth nitrate pentahydrate to hexadecyltrimethylammonium bromide is 1:1, and the mixing and stirring time of solution A and solution B is 60 min.

[0012] Further, in step 2, the molar volume ratio of bismuth nitrate pentahydrate to nitric acid solution is 1.08–1.48 mmol:10 ml, the volume ratio of HNO3 to H2O in the nitric acid solution is 7:43, the molar volume ratio of sodium tungstate dihydrate to deionized water is 0.54–0.74 mmol:10 ml, the molar mass ratio of bismuth nitrate pentahydrate to sodium tungstate dihydrate is 2:1, and the theoretical molar mass ratio of BiOBr to Bi2WO6 in the BiOBr / Bi2WO6 powder is 1:0.27–0.42.

[0013] Further, the stirring time in step 3 is 1 to 3 hours, the solid-liquid ratio of BiOBr / Bi2WO6 to sodium hydroxide solution is 500 mg: 50 ml, the concentration of sodium hydroxide solution is 0 to 1 mol / L, and the vacuum drying temperature is 70°C.

[0014] The Br-W dual-defect photocatalytic material or the V prepared by the method described above. Br+W - Application of BiOBr / Bi2WO6 photocatalytic material in the degradation of norfloxacin in water.

[0015] The application includes the following steps: preparing the V... Br+W -BiOBr / Bi2WO6 photocatalyst material was added to norfloxacin solution and stirred in the dark for 40 min. The reaction was continued under visible light irradiation, and samples were taken every 20 min to determine the concentration of norfloxacin.

[0016] Furthermore, the V Br+W The solid-liquid ratio of BiOBr / Bi2WO6 photocatalyst material to norfloxacin solution is 0.02-0.05 g: 100 ml. The visible light irradiation is performed using a 300 W xenon lamp, and the photocatalytic reaction is carried out at room temperature and pressure.

[0017] Advantages of the present invention

[0018] The method for preparing the Br-W dual-defect high-efficiency photocatalytic material of the present invention involves alkaline etching to prepare V materials containing both Br and W defects. Br+W -BiOBr / Bi2WO6 photocatalytic material can be used to treat antibiotic wastewater. V Br+W -BiOBr / Bi2WO6 photocatalytic material possesses a nano-flower-like microstructure with a large specific surface area. The synergistic effect of Br and W defects results in excellent degradation performance of norfloxacin under visible light conditions. Furthermore, after drying, the material can be reused and still exhibits good redox properties under visible light irradiation, demonstrating its reusability. Br+WThe use of bismuth nitrate pentahydrate as a visible light photocatalyst material (BiOBr / Bi2WO6) significantly reduces the material's preparation cost due to its lower cost. Furthermore, the resulting V... Br+W -BiOBr / Bi2WO6 material exhibits good processing efficiency. The raw materials used in this invention are common and readily available, the process is simple, and it is easy to achieve industrial production. Attached Figure Description

[0019] Figure 1 V prepared in Example 3 Br+W XRD patterns of BiOBr / Bi2WO6 photocatalyst material and materials prepared in Comparative Examples 1-5.

[0020] Figure 2 V prepared in Example 3 Br+W TEM and EDS images of the BiOBr / Bi2WO6 photocatalyst material.

[0021] Figure 3 V prepared for implementation of column 3 Br+W - SEM-EDS elemental analysis results of BiOBr / Bi2WO6 photocatalytic material and materials prepared in comparison columns 1-5.

[0022] Figure 4 V prepared in Example 3 Br+W - Degradation efficiency of BiOBr / Bi2WO6 photocatalyst material and materials prepared in Comparative Examples 1-5 for the degradation of norfloxacin.

[0023] Figure 5 V prepared in Examples 1-4 Br+W - Degradation efficiency of norfloxacin by BiOBr / Bi2WO6 photocatalytic material.

[0024] Figure 6 For different V values ​​in Examples 7-10 Br+W - Degradation efficiency of norfloxacin by dose-dependent degradation of BiOBr / Bi2WO6 photocatalytic material.

[0025] Figure 7 Examples 11-15 show V at different pH values. Br+W - Degradation efficiency of norfloxacin by BiOBr / Bi2WO6 photocatalytic material. Detailed Implementation

[0026] The present invention will be further explained and described below with reference to the accompanying drawings and specific embodiments. It should be noted that the specific embodiments are not intended to limit the scope of the present invention.

[0027] Example 1

[0028] V provided in Example 1Br+W The preparation method of BiOBr / Bi2WO6 dual-defect high-efficiency photocatalytic material includes the following steps:

[0029] Step 1: BiOBr was prepared by solvothermal method. 2 mmol of bismuth nitrate pentahydrate was dispersed in 20 ml of ethylene glycol and stirred for 10 min to obtain solution A. 2 mmol of hexadecyltrimethylammonium bromide (hereinafter referred to as CTAB) was dispersed in 50 ml of anhydrous ethanol and stirred for 30 min to obtain solution B. Solution A and solution B were mixed and stirred for 60 min to obtain mixture one. Mixture one was transferred to a Teflon-lined stainless steel container and kept at 160℃ for 12 h. After natural cooling, it was washed three times with anhydrous ethanol and three times with deionized water to obtain BiOBr for later use.

[0030] Step 2: Dissolve 1.08 mmol of bismuth nitrate pentahydrate in 10 ml of 2 mol / L nitric acid solution to prepare solution C. Dissolve 0.54 mmol of sodium tungstate dihydrate in 10 ml of deionized water (hereinafter referred to as DI) to prepare solution D. Mix solution C and solution D and stir for 10 min to obtain mixture two. Sonicate the BiOBr prepared in step 1 for 15 min and disperse it in 50 ml of DI to obtain solution F. Mix mixture two and solution F and sonicate for 15 min and stir for 2 h to obtain mixture three. Transfer mixture three to a 100 ml Teflon-lined reactor and heat at 160 °C for 20 h. Filter the obtained white precipitate and wash it three times with anhydrous ethanol and deionized water respectively to obtain BiOBr / Bi2WO6 powder with a theoretical molar mass ratio of 1:0.27.

[0031] Step 3: Weigh 500 mg of the BiOBr / Bi2WO6 powder obtained in Step 2 and disperse it in 50 ml of 0.5 mol / L sodium hydroxide solution. Stir for 1.5 h, filter, wash three times successively with anhydrous ethanol and deionized water, and dry overnight in a vacuum drying oven at 70°C to obtain V. Br+W -BiOBr / Bi2WO6.

[0032] Example 2

[0033] Example 2 provides V Br+W The preparation of BiOBr / Bi2WO6 dual-defect high-efficiency photocatalytic materials includes the following steps:

[0034] Step 1: BiOBr was prepared by solvothermal method. 2 mmol of bismuth nitrate pentahydrate was dispersed in 20 ml of ethylene glycol and stirred for 10 min to obtain solution A. 2 mmol of CTAB was dispersed in 50 ml of anhydrous ethanol and stirred for 30 min to obtain solution B. Solution A and solution B were mixed and stirred for 60 min to obtain mixture one. Mixture one was transferred to a Teflon-lined stainless steel container and kept at 160℃ for 12 h. After natural cooling, it was washed three times with anhydrous ethanol and three times with deionized water to obtain BiOBr for later use.

[0035] Step 2: First, dissolve 1.28 mmol of bismuth nitrate pentahydrate in 10 ml of 2 mol / L nitric acid solution to prepare solution C. Dissolve 0.64 mmol of sodium tungstate dihydrate in 10 ml of DI to prepare solution D. Mix solutions C and D and stir for 10 min to obtain mixture two. Sonicate the BiOBr prepared in step 1 for 15 min and disperse it in 50 ml of DI to obtain solution F. Mix mixture two and solution F and sonicate for 15 min. Stir for 2 h to obtain mixture three. Transfer mixture three to a 100 ml Teflon-lined reactor and heat at 160 °C for 20 h. Filter the obtained white precipitate and wash it three times with anhydrous ethanol and deionized water respectively to obtain BiOBr / Bi2WO6 powder with a theoretical molar mass ratio of 1:0.32.

[0036] Step 3: Weigh 500 mg of the BiOBr / Bi2WO6 obtained in Step 2 and disperse it in 50 ml of 0.5 mol / L sodium hydroxide solution. Stir for 1.5 h, filter, wash three times successively with anhydrous ethanol and deionized water, and dry overnight in a vacuum drying oven at 70°C to obtain V. Br+W -BiOBr / Bi2WO6.

[0037] Example 3

[0038] Example 3 provides V Br+W The preparation method of BiOBr / Bi2WO6 dual-defect high-efficiency photocatalytic material includes the following steps:

[0039] Step 1: BiOBr was prepared by solvothermal method. 2 mmol of bismuth nitrate pentahydrate was dispersed in 20 ml of ethylene glycol and stirred for 10 min to obtain solution A. 2 mmol of CTAB was dispersed in 50 ml of anhydrous ethanol and stirred for 30 min to obtain solution B. Solution A and solution B were mixed and stirred for 60 min to obtain mixture one. Mixture one was transferred to a Teflon-lined stainless steel container and kept at 160℃ for 12 h. After natural cooling, it was washed three times with anhydrous ethanol and deionized water to obtain BiOBr for later use.

[0040] Step 2: Dissolve 1.48 mmol of bismuth nitrate pentahydrate in 10 ml of 2 mol / L nitric acid solution to prepare solution C, and dissolve 0.74 mmol of sodium tungstate dihydrate in 10 ml of DI to prepare solution D. Mix solutions C and D and stir for 10 min to obtain mixture two. Sonicate the BiOBr prepared in step 1 for 15 min and disperse it in 50 ml of DI to obtain solution F. Mix mixture two and solution F are mixed and sonicated for 15 min, and stirred for 2 h to obtain mixture three. Transfer mixture three to a 100 ml Teflon-lined reactor and heat at 160 °C for 20 h. Filter the obtained white precipitate and wash it three times with anhydrous ethanol and deionized water respectively to obtain BiOBr / Bi2WO6 powder with a theoretical molar mass ratio of 1:0.37.

[0041] Step 3: Weigh 500 mg of the BiOBr / Bi2WO6 obtained in Step 2 and disperse it in 50 ml of 0.5 mol / L sodium hydroxide solution. Stir for 1.5 h, filter, wash three times each with anhydrous ethanol and deionized water, and dry overnight in a vacuum drying oven at 70°C to obtain V. Br+W -BiOBr / Bi2WO6.

[0042] X-ray diffraction analysis showed that the prepared photocatalyst material was V. Br+W -BiOBr / Bi2WO6.

[0043] Example 4

[0044] V provided in Example 4 Br+W The preparation method of BiOBr / Bi2WO6 dual-defect high-efficiency photocatalytic material includes the following steps:

[0045] Step 1: BiOBr was prepared by solvothermal method. 2 mmol of bismuth nitrate pentahydrate was dispersed in 20 ml of ethylene glycol and stirred for 10 min to obtain solution A. 2 mmol of CTA was dispersed in 50 ml of anhydrous ethanol and stirred for 30 min to obtain solution B. Solution A and solution B were mixed and stirred for 60 min to obtain mixture one. Mixture one was transferred to a Teflon-lined stainless steel container and kept at 160℃ for 12 h. After natural cooling, it was washed three times with anhydrous ethanol and deionized water to obtain BiOBr for later use.

[0046] Step 2: Dissolve 1.68 mmol of bismuth nitrate pentahydrate in 10 ml of 2 mol / L nitric acid solution to prepare solution C, and dissolve 0.84 mmol of sodium tungstate dihydrate in 10 ml of DI to prepare solution D. Mix solution C and solution D and stir for 10 min to obtain mixture two. Sonicate the BiOBr prepared in step 1 for 15 min and disperse it in 50 ml of DI to obtain solution F. Mix mixture two and solution F and sonicate for 15 min and stir for 2 h to obtain mixture three. Transfer mixture three to a 100 ml Teflon-lined reactor and heat in an oven at 160 °C for 20 h. Filter the obtained white precipitate and wash it three times with anhydrous ethanol and deionized water respectively to obtain BiOBr / Bi2WO6 powder with a theoretical molar mass ratio of 1:0.42.

[0047] Step 3: Weigh 500 mg of the BiOBr / Bi2WO6 obtained in Step 2 and disperse it in 50 ml of 0.5 mol / L sodium hydroxide solution. Stir for 1.5 h, filter, wash the product three times with anhydrous ethanol and deionized water, and dry it overnight in a vacuum drying oven at 70°C to obtain V. Br+W -BiOBr / Bi2WO6.

[0048] Comparative Example 1

[0049] The preparation of Bi₂WO₆ single photocatalyst material in Comparative Example 1 differs from Example 3 in that step 1 is omitted, and in step 3, the 0.5 mol / L sodium hydroxide solution is replaced with DI. Everything else is the same as in Example 3 and will not be repeated here. X-ray diffraction analysis confirmed that the prepared photocatalyst material was Bi₂WO₆.

[0050] Comparative Example 2

[0051] Preparation of W-defect-rich V W -Bi2WO6 single photocatalyst material. The basic difference between Comparative Example 2 and Example 3 is that step 1 is not required. Everything else is the same as in Example 3 and will not be repeated here. X-ray diffraction analysis shows that the prepared photocatalyst material is V... W -Bi2WO6.

[0052] Comparative Example 3

[0053] The preparation of BiOBr single photocatalyst material differs from Example 3 in that bismuth nitrate pentahydrate and sodium tungstate dihydrate are not added in step 2, and the 0.5 mol / L sodium hydroxide solution is replaced with DI in step 3. Other aspects are the same as in Example 3 and will not be repeated here. X-ray diffraction analysis confirmed that the prepared photocatalyst material is BiOBr.

[0054] Comparative Example 4

[0055] Preparation of Br-defective V Br -BiOBr single photocatalyst material. The basic difference between Comparative Example 4 and Example 3 is that bismuth nitrate pentahydrate and sodium tungstate dihydrate are not added in step 2. Everything else is the same as in Example 3 and will not be repeated here. X-ray diffraction analysis showed that the prepared photocatalyst material is V. Br -BiOBr.

[0056] Comparative Example 5

[0057] The BiOBr / Bi2WO6 photocatalytic material was prepared. The main difference between Comparative Example 5 and Example 3 is that in step 3, the 0.5 mol / L sodium hydroxide solution was replaced with DI. Everything else is the same as in Example 3 and will not be repeated here. X-ray diffraction analysis confirmed that the prepared photocatalytic material was BiOBr / Bi2WO6.

[0058] Example 6

[0059] The photocatalytic materials prepared in Examples 1, 2, 3, and 4, and Comparative Examples 1, 2, 3, 4, and 5 were used to degrade norfloxacin, and the steps are as follows:

[0060] 0.03 g of photocatalytic material was added to 100 mL of norfloxacin mixed solution, the concentration of norfloxacin in the solution being 10 mg / L. The solution was stirred in the dark for 40 min to allow norfloxacin to reach adsorption-desorption equilibrium on the surface of the photocatalytic material. Degradation was then carried out under visible light irradiation from a 300 W xenon lamp. The norfloxacin concentration was measured every 20 min. After 160 min of experimentation, the degradation of norfloxacin in each example and comparative example was as follows:

[0061] V in Example 1 Br+W -The degradation efficiency of norfloxacin by the BiOBr / Bi2WO6 photocatalytic material is 91.52%;

[0062] V in Example 2 Br+W -The BiOBr / Bi2WO6 photocatalytic material achieved a degradation efficiency of 93.39% for norfloxacin;

[0063] V in Example 3 Br+W -The BiOBr / Bi2WO6 photocatalytic material can achieve a degradation efficiency of 97.58% for norfloxacin;

[0064] V in Example 4 Br+W -The BiOBr / Bi2WO6 photocatalytic material achieved a degradation efficiency of 95.49% for norfloxacin;

[0065] The degradation efficiency of the Bi2WO6 photocatalyst material in Comparative Example 1 for norfloxacin was 36.08%.

[0066] Comparative Example 2 V W -The degradation efficiency of Bi2WO6 photocatalyst for norfloxacin is 45.70%;

[0067] The degradation efficiency of the BiOBr photocatalyst material in Comparative Example 3 for norfloxacin was 69.11%.

[0068] Comparative Example 4 V Br -BiOBr photocatalytic material showed a degradation efficiency of 84.98% for norfloxacin;

[0069] The BiOBr / Bi2WO6 photocatalyst material in Comparative Example 5 showed a degradation efficiency of 89.03% for norfloxacin.

[0070] like Figure 1 As shown, Figure 1 The V prepared in Example 3 is shown. Br+W - X-ray diffraction image of the BiOBr / Bi2WO6 visible light photocatalyst material. The image shows that the prepared visible light photocatalyst material is a composite of BiOBr and Bi2WO6.

[0071] like Figure 2 As shown, Figure 2 The V prepared in Example 3 is shown. Br+W Transmission electron microscope (TEM) images and EDS images of the BiOBr / Bi2WO6 visible light photocatalyst material, by [source missing]. Figure 2 It can be known that V Br+W -BiOBr / Bi2WO6 particle size in Within the range.

[0072] Figure 3 BiOBr and V were showcased. Br -BiOBr, Bi2WO6, V W -Bi2WO6, BiOBr / Bi2WO6, V Br+W -SEM-EDS elemental analysis results of BiOBr / Bi2WO6 visible light photocatalyst material. The figure shows that after etching, V... W -Bi₂WO₆ contains significantly fewer W atoms and V atoms. Br -Br content in BiOBr is significantly reduced. Similarly, compared to BiOBr / Bi2WO6, V... Br+W -BiOBr / Bi2WO6 has significant Br and W atoms missing, forming a Br-W double-defect photocatalyst.

[0073] Figure 4 BiOBr and V were showcased. Br -BiOBr, Bi2WO6, V W -Bi2WO6, BiOBr / Bi2WO6, VBr+W - Degradation efficiency diagram of norfloxacin degradation by BiOBr / Bi2WO6 visible light photocatalyst material, from Figure 3 It can be seen that both Br and W defects improve the degradation performance of the single material after etching. It is worth noting that V defects after etching... Br -BiOBr exhibits significantly improved degradation performance compared to BiOBr. Furthermore, the V-shaped degradation performance of the heterojunction material after etching is [not specified]. Br+W -BiOBr / Bi2WO6 showed the best degradation effect on norfloxacin and exhibited good visible light photocatalytic performance, indicating that Br defects and W defects have a synergistic effect, which effectively improves the photocatalytic performance of the material.

[0074] V prepared in Examples 1-4 Br+W The degradation efficiency of BiOBr / Bi2WO6 photocatalytic material for norfloxacin, such as Figure 5 As shown.

[0075] Example 7

[0076] V prepared in Example 3 Br+W The method for degrading norfloxacin using BiOBr / Bi2WO6 photocatalytic material is as follows:

[0077] Weigh 0.02g of V obtained in Example 3. Br+W BiOBr / Bi2WO6 photocatalyst material was added to 100 mL of a norfloxacin mixed solution with a concentration of 10 mg / L. The solution was stirred in the dark for 40 min to allow norfloxacin to reach adsorption-desorption equilibrium on the photocatalyst material surface. Degradation was then carried out under visible light irradiation from a 300 W xenon lamp. Samples were taken every 20 min to measure the norfloxacin concentration. After 120 min of irradiation, 0.02 g of V... Br+W -BiOBr / Bi2WO6 photocatalytic degradation can achieve a degradation efficiency of 70.40% for norfloxacin.

[0078] Example 8

[0079] The difference between this embodiment and embodiment 7 is that the V Br+W The dosage of BiOBr / Bi2WO6 photocatalyst material was 0.03 g. Everything else was the same as in Example 7 and will not be repeated here. 0.03 g of V Br+W -BiOBr / Bi2WO6 photocatalytic degradation can achieve a degradation efficiency of 97.58% for norfloxacin.

[0080] Example 9

[0081] The difference between this embodiment and embodiment 7 is that the V Br+WThe dosage of BiOBr / Bi2WO6 photocatalyst material was 0.04 g. Everything else was the same as in Example 7 and will not be repeated here. 0.04 g of V Br+W The photocatalytic degradation efficiency of BiOBr / Bi2WO6 for norfloxacin can reach 98.25%.

[0082] Example 10

[0083] The difference between this embodiment and embodiment 7 is that the V Br+W The dosage of BiOBr / Bi2WO6 photocatalyst material was 0.05 g. Everything else was the same as in Example 7 and will not be repeated here. 0.05 g of V Br+W -BiOBr / Bi2WO6 photocatalytic degradation can achieve a degradation efficiency of 98.74% for norfloxacin.

[0084] The results of Examples 7-10 show that the Br-W dual-defect photocatalyst V prepared in Example 3 is effective. Br+W -BiOBr / Bi2WO6 exhibits good degradation performance for norfloxacin, such as Figure 6 As shown, the degradation performance is directly proportional to the amount of catalyst added. When the amount of catalyst added increases from 0.2 g / L to 0.3 g / L, the degradation performance of the material for norfloxacin is significantly improved, and about 95% degradation performance can be achieved after 60 minutes of light irradiation.

[0085] Example 11

[0086] V prepared in Example 3 Br+W The method for degrading norfloxacin using BiOBr / Bi2WO6 photocatalytic material is as follows:

[0087] 0.03g of V prepared in Example 3 Br+W BiOBr / Bi2WO6 photocatalyst material was added to 100 mL of a norfloxacin mixed solution with a concentration of 10 mg / L. The pH of the norfloxacin solution was adjusted to 3 using HCl and NaOH. The solution was stirred in the dark for 40 min to allow the norfloxacin to reach adsorption-desorption equilibrium on the surface of the photocatalyst material. Degradation was then carried out under visible light irradiation from a 300 W xenon lamp. Samples were taken every 20 min to measure the norfloxacin concentration. After 120 min of irradiation, 0.03 g of V... Br+W -BiOBr / Bi2WO6 photocatalytic degradation can achieve a degradation efficiency of 53.39% for norfloxacin.

[0088] Example 12

[0089] The difference between this embodiment and Example 11 is that the pH of the norfloxacin solution was adjusted to 5 using HCl and NaOH. Everything else is the same as in Example 11 and will not be repeated here. Example 3 prepared VBr+W -BiOBr / Bi2WO6 photocatalytic degradation can achieve a degradation efficiency of 91.65% for norfloxacin.

[0090] Example 13

[0091] The difference between this embodiment and Example 11 is that the pH of the norfloxacin solution was adjusted to 7 using HCl and NaOH. Everything else is the same as in Example 11 and will not be repeated here. Example 3 prepared V Br+W - Photocatalytic degradation by BiOBr / Bi2WO6. The degradation efficiency for norfloxacin can reach 97.58%.

[0092] Example 14

[0093] The difference between this embodiment and Example 11 is that the pH of the norfloxacin solution was adjusted to 9 using HCl and NaOH. Everything else is the same as in Example 11 and will not be repeated here. Example 3 prepared V Br+W -BiOBr / Bi2WO6 photocatalytic degradation can achieve a degradation efficiency of 94.56% for norfloxacin.

[0094] Example 15

[0095] The difference between this embodiment and Example 11 is that the pH of the norfloxacin solution was adjusted to 11 using HCl and NaOH. Everything else is the same as in Example 11 and will not be repeated here. Example 3 prepared V Br+W -BiOBr / Bi2WO6 photocatalytic degradation can achieve a degradation efficiency of 90.39% for norfloxacin.

[0096] like Figure 7 As shown, the results of Examples 11-15 indicate that when the pH of the norfloxacin solution is <7, the Br-W double-defect V prepared in Example 3... Br+W The degradation performance of BiOBr / Bi2WO6 photocatalyst for norfloxacin decreases with decreasing pH, but decreases with increasing pH when pH>7.

Claims

1. A Br-W dual-defect high-efficiency photocatalytic material, characterized in that, Rich in Br and W defects, its chemical formula is V Br+W The preparation method of the Br-W dual-defect high-efficiency photocatalytic material -BiOBr / Bi2WO6 adopts an in-situ solvothermal method, including the following steps: Step 1: Disperse bismuth nitrate pentahydrate in ethylene glycol and stir for 10 min to obtain solution A. Disperse hexadecyltrimethylammonium bromide in anhydrous ethanol and stir for 30 min to obtain solution B. Mix solution A and solution B to obtain mixture one. Transfer mixture one to a stainless steel tank lined with Teflon and keep it at 160℃ for 12 h. After natural cooling, wash three times with anhydrous ethanol and deionized water respectively to obtain BiOBr. Step 2: Dissolve bismuth nitrate pentahydrate in nitric acid solution to obtain solution C, and dissolve sodium tungstate dihydrate in deionized water to obtain solution D. Mix solution C and solution D and stir to obtain mixture two. Then, sonicate BiOBr prepared in step 1 for 15 min and disperse it in deionized water to obtain solution F. Mix mixture two and solution F are mixed and sonicated for 15 min and stirred for 2 h to obtain mixture three. Mix mixture three is transferred to a Teflon-lined reactor and heated at 160℃ for 20 h. The obtained white precipitate is filtered and washed three times with anhydrous ethanol and deionized water respectively to obtain BiOBr / Bi2WO6 powder. Step 3: Disperse the BiOBr / Bi2WO6 powder obtained in Step 2 in sodium hydroxide solution, stir, filter, wash three times each with anhydrous ethanol and deionized water, and vacuum dry overnight to obtain V. Br+W -BiOBr / Bi2WO6.

2. A method for preparing the Br-W dual-defect high-efficiency photocatalytic material according to claim 1, characterized in that, The preparation method employed is an in-situ solvothermal method, comprising the following steps: Step 1: Disperse bismuth nitrate pentahydrate in ethylene glycol and stir for 10 min to obtain solution A. Disperse hexadecyltrimethylammonium bromide in anhydrous ethanol and stir for 30 min to obtain solution B. Mix solution A and solution B to obtain mixture one. Transfer mixture one to a stainless steel tank lined with Teflon and keep it at 160℃ for 12 h. After natural cooling, wash three times with anhydrous ethanol and deionized water respectively to obtain BiOBr. Step 2: Dissolve bismuth nitrate pentahydrate in nitric acid solution to obtain solution C, and dissolve sodium tungstate dihydrate in deionized water to obtain solution D. Mix solution C and solution D and stir to obtain mixture two. Then, sonicate BiOBr prepared in step 1 for 15 min and disperse it in deionized water to obtain solution F. Mix mixture two and solution F are mixed and sonicated for 15 min and stirred for 2 h to obtain mixture three. Mix mixture three is transferred to a Teflon-lined reactor and heated at 160℃ for 20 h. The obtained white precipitate is filtered and washed three times with anhydrous ethanol and deionized water respectively to obtain BiOBr / Bi2WO6 powder. Step 3: Disperse the BiOBr / Bi2WO6 powder obtained in Step 2 in sodium hydroxide solution, stir, filter, wash three times each with anhydrous ethanol and deionized water, and vacuum dry overnight to obtain V. Br+W -BiOBr / Bi2WO6.

3. The preparation method according to claim 2, characterized in that, In step 1, the molar volume ratio of bismuth nitrate pentahydrate to ethylene glycol is 1 mmol: 10 ml, the molar volume ratio of hexadecyltrimethylammonium bromide to anhydrous ethanol is 1 mmol: 25 ml, the molar mass ratio of bismuth nitrate pentahydrate to hexadecyltrimethylammonium bromide is 1:1, and the mixing and stirring time of solution A and solution B is 60 min.

4. The preparation method according to claim 2, characterized in that, In step 2, the molar volume ratio of bismuth nitrate pentahydrate to nitric acid solution is 1.08~1.48 mmol:10 ml, the volume ratio of HNO3 to H2O in the nitric acid solution is 7:43, the molar volume ratio of sodium tungstate dihydrate to deionized water is 0.54~0.74 mmol:10 ml, and the molar ratio of bismuth nitrate pentahydrate to sodium tungstate dihydrate is 2:

1.

5. The preparation method according to claim 2, characterized in that, The stirring time in step 3 is 1-3 hours, the solid-liquid ratio of BiOBr / Bi2WO6 to sodium hydroxide solution is 500 mg: 50 ml, the concentration of sodium hydroxide solution is 0.5-1 mol / L, and the vacuum drying temperature is 70°C.

6. A Br-W dual-defect photocatalytic material as described in claim 1, or a V material prepared by the preparation method according to any one of claims 2 to 5. Br+W - Application of BiOBr / Bi2WO6 photocatalytic material in the degradation of norfloxacin in water.

7. The application according to claim 6, characterized in that, The process includes the following steps: preparing the V... Br+W -BiOBr / Bi2WO6 photocatalyst material was added to norfloxacin solution and stirred in the dark for 40 min. The reaction was continued under visible light irradiation, and samples were taken every 20 min to determine the concentration of norfloxacin.

8. The application according to claim 7, characterized in that, The V Br+W The solid-liquid ratio of BiOBr / Bi2WO6 photocatalyst material to norfloxacin solution is 0.02~0.05g:100ml. The visible light irradiation is performed using a 300W xenon lamp, and the photocatalytic reaction is carried out at room temperature and pressure.

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