Preparation method and application of bismuth vanadate photocatalyst with oxygen vacancy

Abstract

The invention discloses a preparation method and application of a bismuth vanadate photocatalyst with oxygen vacancies, and relates to a preparation method and application of a photocatalyst. The invention aims to solve the problems of low efficiency of photocatalytic degradation of sulfamethoxazole by bismuth vanadate and low sunlight utilization efficiency of titanium dioxide in the prior art. The preparation method comprises the following steps: 1, preparing a mixed solution of NaVO3 and CTAB; 2, preparing a bismuth nitrate solution; 3, adjusting the pH value to 6.0; 4, carrying out hydrothermal reaction; and 5, washing and drying. The bismuth vanadate photocatalyst with the oxygen vacancy is used for degrading antibiotics. The bismuth vanadate photocatalyst with oxygen vacancies prepared by the invention is synthesized by a hydrothermal method, the long-rod-shaped bismuth vanadate photocatalyst with proper oxygen vacancies concentration and controllable morphology is obtained by effectively regulating and controlling the preparation conditions of the catalyst, and the catalyst is green, environment-friendly, good in response to visible light and high in sunlight utilization rate; the SMX degradation rate is high, and the optimal degradation rate can reach 93% within 120 min.

Description

Technical Field

[0001] The invention relates to a preparation method and application of a photocatalyst. Background Art

[0002] Antibiotics have been detected in surface water, groundwater, domestic sewage and drinking water in different parts of the world. Antibiotic pollution has become one of the water pollution problems facing all mankind. How to effectively treat antibiotic wastewater has attracted widespread attention from experts and scholars at home and abroad.

[0003] Sulfamethoxazole (SMX) is one of the most widely used sulfonamide antibiotics in the world and is widely used in the treatment of bacterial infections. Due to the extensive use of SMX, its residual problem in the environment has become increasingly serious. Not only is the detection rate and concentration in the environment at the forefront, but the cumulative amount is also increasing. It is reported that the residual amount of SMX in rivers and surface water is high and will exist in the water environment for a long time, which has serious harm to aquatic organisms. Sulfamethoxazole residues have even been detected in drinking water sources, greatly increasing the risk of the spread of drug-resistant bacteria and resistance genes in the environment. According to the list of carcinogens published by the World Health Organization's International Agency for Research on Cancer, SMX is listed in the Class 3 carcinogen list. The residue of SMX in the water environment has become a major hidden danger to the health of humans and other animals and plants. Therefore, the removal of sulfamethoxazole has become a focus of attention.

[0004] At present, in the field of photocatalytic oxidation degradation of antibiotics, titanium dioxide (TiO2) has been well applied to treat various organic pollutants, but the wide band gap (3.2eV) of TiO2 makes it only activated under ultraviolet light (about 5% of sunlight), thus limiting its efficiency in utilizing sunlight. Monoclinic bismuth vanadate (m-BiVO4)-based photocatalyst is a visible light responsive semiconductor with low toxicity and good stability in the visible light range, and its potential in the field of environmental remediation is yet to be explored. However, due to the high recombination and low charge transport characteristics of m-BiVO4 electron-hole pairs, its photocatalytic performance will be reduced. Therefore, improving the photogenerated charge separation efficiency and photocatalytic degradation performance of m-BiVO4 is the research direction and goal. Summary of the invention

[0005] The purpose of the present invention is to solve the problems of low efficiency of existing bismuth vanadate photocatalytic degradation of sulfamethoxazole and low efficiency of titanium dioxide in utilizing sunlight, and to provide a preparation method and application of a bismuth vanadate photocatalyst with oxygen vacancies.

[0006] A method for preparing a bismuth vanadate photocatalyst having oxygen vacancies is specifically completed by the following steps:

[0007] 1. Prepare a mixed solution of NaVO3 and CTAB:

[0008] Sodium metavanadate and hexadecyltrimethylammonium bromide are added to water, heated and stirred for a period of time to obtain a mixed solution of NaVO3 and CTAB;

[0009] 2. Preparation of bismuth nitrate solution:

[0010] Add Bi(NO3)3·5H2O to nitric acid and stir for a while to obtain bismuth nitrate solution;

[0011] 3. Adding the bismuth nitrate solution to the mixed solution of NaVO3 and CTAB, stirring for a period of time, and then adjusting the pH value to 6.0 with a sodium hydroxide solution to obtain a mixed solution with a pH value of 6.0;

[0012] 4. Hydrothermal reaction:

[0013] The mixed solution with a pH value of 6.0 is placed in a stainless steel reactor, and then placed in an oven for hydrothermal reaction to obtain a reaction product;

[0014] 5. Washing and drying:

[0015] The reaction product is centrifugally washed for several times, and then placed in a vacuum drying oven for drying to obtain a bismuth vanadate photocatalyst with oxygen vacancies.

[0016] A bismuth vanadate photocatalyst with oxygen vacancies for the degradation of antibiotics.

[0017] The present invention successfully prepares an m-BiVO4 photocatalyst with high photogenerated charge separation efficiency and high degradation performance with oxygen vacancies, which can efficiently degrade and mineralize SMX; the photocatalyst can be prepared by a simple hydrothermal method, and the oxygen vacancy concentration and micromorphology of the catalyst can be controlled by controlling the concentration of added hexadecyltrimethylammonium bromide (CTAB), thereby optimizing the effect of degrading SMX; through calculation, the catalyst achieves a high SMX degradation rate (93%); the method is simple, short in time, high in yield, and highly repeatable, and is suitable for mass production, which is of great significance for promoting the practical application research of photocatalytic degradation of antibiotics.

[0018] Compared with the prior art, the advantages of the present invention are:

[0019] (1) The bismuth vanadate photocatalyst with oxygen vacancies prepared by the present invention is synthesized by a hydrothermal method. By effectively controlling the preparation conditions of the catalyst, a long rod-shaped bismuth vanadate photocatalyst with a suitable concentration of oxygen vacancies and controllable morphology is obtained. The catalyst is green and environmentally friendly, has a good visible light response, and has a high utilization rate of sunlight;

[0020] (2) The bismuth vanadate photocatalyst with oxygen vacancies prepared by the present invention can achieve a high degradation rate for SMX. Within 120 minutes, the optimal degradation rate can reach 93%;

[0021] (3) The preparation method of the present invention is simple, the process is controllable, the cost is low, and it is easy to mass produce. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The images of the BiVO4 catalysts in Examples 1 to 6 under XRD characterization;

[0023] Figure 2 It is the O1s image of the BiVO4 catalyst in Examples 1 to 6 under XPS characterization;

[0024] Figure 3 The degradation efficiency diagram of SMX by BiVO4 catalyst in Examples 1 to 6 under light for 2 hours;

[0025] Figure 4 is a scanning electron microscope image of the BiVO4 catalyst in Example 5;

[0026] Figure 5 is a scanning electron microscope image of the BiVO4 catalyst in Example 1;

[0027] Figure 6 is a scanning electron microscope image of the BiVO4 catalyst in Example 2;

[0028] Figure 7 is a scanning electron microscope image of the BiVO4 catalyst in Example 3;

[0029] Figure 8 is a scanning electron microscope image of the BiVO4 catalyst in Example 4;

[0030] Fig. 9 This is a scanning electron microscope image of the BiVO4 catalyst in Example 6. DETAILED DESCRIPTION

[0031] Specific implementation method 1: This implementation method is a method for preparing a bismuth vanadate photocatalyst with oxygen vacancies, which is specifically completed according to the following steps:

[0032] 1. Prepare a mixed solution of NaVO3 and CTAB:

[0033] Sodium metavanadate and hexadecyltrimethylammonium bromide are added to water, heated and stirred for a period of time to obtain a mixed solution of NaVO3 and CTAB;

[0034] 2. Preparation of bismuth nitrate solution:

[0035] Add Bi(NO3)3·5H2O to nitric acid and stir for a while to obtain bismuth nitrate solution;

[0036] 3. Adding the bismuth nitrate solution to the mixed solution of NaVO3 and CTAB, stirring for a period of time, and then adjusting the pH value to 6.0 with a sodium hydroxide solution to obtain a mixed solution with a pH value of 6.0;

[0037] 4. Hydrothermal reaction:

[0038] The mixed solution with a pH value of 6.0 is placed in a stainless steel reactor, and then placed in an oven for hydrothermal reaction to obtain a reaction product;

[0039] 5. Washing and drying:

[0040] The reaction product is centrifugally washed for several times, and then placed in a vacuum drying oven for drying to obtain a bismuth vanadate photocatalyst with oxygen vacancies.

[0041] Specific embodiment 2: This embodiment differs from specific embodiment 1 in that: the molar ratio of sodium metavanadate to hexadecyltrimethylammonium bromide described in step 1 is (1mmol-1.5mmol):(0.2mmol-1mmol); the volume ratio of the amount of sodium metavanadate described in step 1 to water is (1mmol-1.5mmol):(30mL-50mL); the temperature of heating and stirring described in step 1 is 40°C-50°C, and the time of heating and stirring is 20min-40min. The other steps are the same as those in specific embodiment 1.

[0042] Specific implementation method 3: This implementation method is different from specific implementation method 1 or 2 in that: the concentration of nitric acid in step 2 is 17 mmol / L to 18 mmol / L; the stirring time in step 2 is 20 min to 40 min; the concentration of bismuth nitrate solution in step 2 is 1 mmol to 1.5 mmol. The other steps are the same as those in specific implementation method 1 or 2.

[0043] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that: the concentration of the sodium hydroxide solution in step 3 is 10 mol / L; the molar ratio of bismuth nitrate to the mixed solution of NaVO3 and CTAB in step 3 is 1 mmol:(0.2 mmol to 1 mmol); the stirring time in step 3 is 20 min to 40 min. The other steps are the same as those in specific embodiments 1 to 3.

[0044] Specific embodiment 5: This embodiment differs from specific embodiments 1 to 4 in that the temperature of the hydrothermal reaction in step 4 is 105° C. and the time of the hydrothermal reaction is 20 h to 24 h. The other steps are the same as those of specific embodiments 1 to 4.

[0045] Specific embodiment 6: The difference between this embodiment and specific embodiments 1 to 5 is that: the rotation speed of each centrifugal washing in step 5 is 100 rpm, and the time is 10 min to 15 min; in step 5, the reaction product is first centrifuged and washed 3 to 5 times with anhydrous ethanol, and then centrifuged and washed 3 to 5 times with deionized water; the vacuum drying temperature in step 5 is 60°C to 70°C, and the vacuum drying time is 10h to 12h. The other steps are the same as those in specific embodiments 1 to 5.

[0046] Specific embodiment seven: This embodiment is a bismuth vanadate photocatalyst with oxygen vacancies for degrading antibiotics.

[0047] Specific embodiment 8: This embodiment differs from specific embodiments 1 to 7 in that the antibiotic is sulfamethoxazole. The other steps are the same as those of specific embodiments 1 to 7.

[0048] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that: a method for using a bismuth vanadate photocatalyst with oxygen vacancies to degrade antibiotics is accomplished by the following steps:

[0049] 1. Add the bismuth vanadate photocatalyst with oxygen vacancies into the antibiotic solution and stir for a period of time in the dark;

[0050] 2. Degrading for a period of time under the conditions of irradiation with a 150W xenon lamp, with the surface of the solution 10cm away from the light source and a light intensity of 132.5kLux, to obtain a solution after the antibiotics have been removed. The other steps are the same as those in the first to eighth embodiments.

[0051] Specific embodiment 10: This embodiment differs from specific embodiments 1 to 9 in that: the mass ratio of the bismuth vanadate photocatalyst with oxygen vacancies described in step 1 to the volume ratio of the antibiotic solution is 5 mg:100 mL; the time of light-proof stirring described in step 1 is 0.5 h to 1 h; the concentration of the antibiotic solution described in step 1 is 5 mg / L; the degradation time described in step 2 is 100 min to 120 min. The other steps are the same as specific embodiments 1 to 9.

[0052] The following examples are used to verify the beneficial effects of the present invention:

[0053] Example 1: A method for preparing a bismuth vanadate photocatalyst having oxygen vacancies is completed by the following steps:

[0054] 1. Preparation of NaVO3 solution:

[0055] Add 0.192 g of sodium metavanadate into 30 mL of water and stir at 45 °C for 30 min to obtain a NaVO3 solution;

[0056] 2. Preparation of bismuth nitrate solution:

[0057] Add 0.52 g Bi(NO3)3·5H2O to 15 mL nitric acid and stir for 30 min to obtain bismuth nitrate solution:

[0058] The concentration of nitric acid described in step 2 is 17.8 mmol;

[0059] 3. Add the bismuth nitrate solution to the NaVO3 solution, stir for 30 minutes, and then adjust the pH value to 6.0 with a sodium hydroxide solution to obtain a mixed solution with a pH value of 6.0;

[0060] The concentration of the sodium hydroxide solution described in step 3 is 10 mol / L;

[0061] 4. Hydrothermal reaction:

[0062] The mixed solution with a pH value of 6.0 is placed in a stainless steel reactor, and then placed in an oven for hydrothermal reaction to obtain a reaction product;

[0063] The temperature of the hydrothermal reaction in step 4 is 105° C., and the time of the hydrothermal reaction is 24 h;

[0064] 5. Washing and drying:

[0065] The reaction product was centrifugally washed 5 times with anhydrous ethanol, then centrifugally washed 5 times with deionized water, and then placed in a vacuum drying oven for drying to obtain a yellow bismuth vanadate photocatalyst (BiVO4 catalyst) with oxygen vacancies;

[0066] In step 5, the speed of each centrifugal washing is 100 rpm and the time is 10 min;

[0067] The vacuum drying temperature in step 5 is 60° C., and the vacuum drying time is 12 h.

[0068] Example 2: A method for preparing a bismuth vanadate photocatalyst having oxygen vacancies is specifically completed by the following steps:

[0069] 1. Prepare a mixed solution of NaVO3 and CTAB:

[0070] 0.192 g of sodium metavanadate and 0.116 g of hexadecyltrimethylammonium bromide were added to 30 mL of water and stirred at 45 °C for 30 min to obtain a mixed solution of NaVO3 and CTAB;

[0071] 2. Preparation of bismuth nitrate solution:

[0072] Add 0.52gBi(NO3)3·5H2O to 15mL nitric acid and stir for 30min to obtain bismuth nitrate solution:

[0073] The concentration of nitric acid described in step 2 is 17.8mmol / L;

[0074] 3. adding the bismuth nitrate solution to the mixed solution of NaVO3 and CTAB, stirring for 30 minutes, and then adjusting the pH value to 6.0 with a sodium hydroxide solution to obtain a mixed solution with a pH value of 6.0;

[0075] The concentration of the sodium hydroxide solution described in step 3 is 10 mol / L;

[0076] 4. Hydrothermal reaction:

[0077] The mixed solution with a pH value of 6.0 is placed in a stainless steel reactor, and then placed in an oven for hydrothermal reaction to obtain a reaction product;

[0078] The temperature of the hydrothermal reaction in step 4 is 105° C., and the time of the hydrothermal reaction is 24 h;

[0079] 5. Washing and drying:

[0080] The reaction product was centrifugally washed 5 times with anhydrous ethanol, then centrifugally washed 5 times with deionized water, and then placed in a vacuum drying oven for drying to obtain a yellow bismuth vanadate photocatalyst (BiVO4 catalyst) with oxygen vacancies;

[0081] In step 5, the speed of each centrifugal washing is 100 rpm and the time is 10 min;

[0082] The vacuum drying temperature in step 5 is 60° C., and the vacuum drying time is 12 h.

[0083] Example 3: A method for preparing a bismuth vanadate photocatalyst having oxygen vacancies is specifically completed by the following steps:

[0084] 1. Prepare a mixed solution of NaVO3 and CTAB:

[0085] 0.192 g of sodium metavanadate and 0.154 g of hexadecyltrimethylammonium bromide were added to 30 mL of water and stirred at 45 °C for 30 min to obtain a mixed solution of NaVO3 and CTAB;

[0086] 2. Preparation of bismuth nitrate solution:

[0087] Add 0.52 g Bi(NO3)3·5H2O to 15 mL nitric acid and stir for 30 min to obtain bismuth nitrate solution:

[0088] The concentration of nitric acid described in step 2 is 17.8mmol / L;

[0089] 3. adding the bismuth nitrate solution to the mixed solution of NaVO3 and CTAB, stirring for 30 minutes, and then adjusting the pH value to 6.0 with a sodium hydroxide solution to obtain a mixed solution with a pH value of 6.0;

[0090] The concentration of the sodium hydroxide solution described in step 3 is 10 mol / L;

[0091] 4. Hydrothermal reaction:

[0092] The mixed solution with a pH value of 6.0 is placed in a stainless steel reactor, and then placed in an oven for hydrothermal reaction to obtain a reaction product;

[0093] The temperature of the hydrothermal reaction in step 4 is 105° C., and the time of the hydrothermal reaction is 24 h;

[0094] 5. Washing and drying:

[0095] The reaction product was centrifugally washed 5 times with anhydrous ethanol, then centrifugally washed 5 times with deionized water, and then placed in a vacuum drying oven for drying to obtain a yellow bismuth vanadate photocatalyst (BiVO4 catalyst) with oxygen vacancies;

[0096] In step 5, the speed of each centrifugal washing is 100 rpm and the time is 10 min;

[0097] The vacuum drying temperature in step 5 is 60° C., and the vacuum drying time is 12 h.

[0098] Example 4: A method for preparing a bismuth vanadate photocatalyst having oxygen vacancies is specifically completed by the following steps:

[0099] 1. Prepare a mixed solution of NaVO3 and CTAB:

[0100] 0.192 g of sodium metavanadate and 0.193 g of hexadecyltrimethylammonium bromide were added to 30 mL of water and stirred at 45 °C for 30 min to obtain a mixed solution of NaVO3 and CTAB;

[0101] 2. Preparation of bismuth nitrate solution:

[0102] Add 0.52 g Bi(NO3)3·5H2O to 15 mL nitric acid and stir for 30 min to obtain bismuth nitrate solution:

[0103] The concentration of nitric acid described in step 2 is 17.8mmol / L;

[0104] 3. adding the bismuth nitrate solution to the mixed solution of NaVO3 and CTAB, stirring for 30 minutes, and then adjusting the pH value to 6.0 with a sodium hydroxide solution to obtain a mixed solution with a pH value of 6.0;

[0105] The concentration of the sodium hydroxide solution described in step 3 is 10 mol / L;

[0106] 4. Hydrothermal reaction:

[0107] The mixed solution with a pH value of 6.0 is placed in a stainless steel reactor, and then placed in an oven for hydrothermal reaction to obtain a reaction product;

[0108] The temperature of the hydrothermal reaction in step 4 is 105° C., and the time of the hydrothermal reaction is 24 h;

[0109] 5. Washing and drying:

[0110] The reaction product was centrifugally washed 5 times with anhydrous ethanol, then centrifugally washed 5 times with deionized water, and then placed in a vacuum drying oven for drying to obtain a yellow bismuth vanadate photocatalyst (BiVO4 catalyst) with oxygen vacancies;

[0111] In step 5, the speed of each centrifugal washing is 100 rpm and the time is 10 min;

[0112] The vacuum drying temperature in step 5 is 60° C., and the vacuum drying time is 12 h.

[0113] Example 5: A method for preparing a bismuth vanadate photocatalyst having oxygen vacancies is specifically completed by the following steps:

[0114] 1. Prepare a mixed solution of NaVO3 and CTAB:

[0115] 0.192 g of sodium metavanadate and 0.232 g of hexadecyltrimethylammonium bromide were added to 30 mL of water and stirred at 45 °C for 30 min to obtain a mixed solution of NaVO3 and CTAB;

[0116] 2. Preparation of bismuth nitrate solution:

[0117] Add 0.52gBi(NO3)3·5H2O to 15mL nitric acid and stir for 30min to obtain bismuth nitrate solution:

[0118] The concentration of nitric acid described in step 2 is 17.8mmol / L;

[0119] 3. adding the bismuth nitrate solution to the mixed solution of NaVO3 and CTAB, stirring for 30 minutes, and then adjusting the pH value to 6.0 with a sodium hydroxide solution to obtain a mixed solution with a pH value of 6.0;

[0120] The concentration of the sodium hydroxide solution described in step 3 is 10 mol / L;

[0121] 4. Hydrothermal reaction:

[0122] The mixed solution with a pH value of 6.0 is placed in a stainless steel reactor, and then placed in an oven for hydrothermal reaction to obtain a reaction product;

[0123] The temperature of the hydrothermal reaction in step 4 is 105° C., and the time of the hydrothermal reaction is 24 h;

[0124] 5. Washing and drying:

[0125] The reaction product was centrifugally washed 5 times with anhydrous ethanol, then centrifugally washed 5 times with deionized water, and then placed in a vacuum drying oven for drying to obtain a yellow bismuth vanadate photocatalyst (BiVO4 catalyst) with oxygen vacancies;

[0126] In step 5, the speed of each centrifugal washing is 100 rpm and the time is 10 min;

[0127] The vacuum drying temperature in step 5 is 60° C., and the vacuum drying time is 12 h.

[0128] Example 6: A method for preparing a bismuth vanadate photocatalyst having oxygen vacancies is specifically completed by the following steps:

[0129] 1. Prepare a mixed solution of NaVO3 and CTAB:

[0130] 0.192 g of sodium metavanadate and 0.27 g of hexadecyltrimethylammonium bromide were added to 30 mL of water and stirred at 45 °C for 30 min to obtain a mixed solution of NaVO3 and CTAB;

[0131] 2. Preparation of bismuth nitrate solution:

[0132] Add 0.52gBi(NO3)3·5H2O to 15mL nitric acid and stir for 30min to obtain bismuth nitrate solution:

[0133] The concentration of nitric acid described in step 2 is 17.8mmol / L;

[0134] 3. adding the bismuth nitrate solution to the mixed solution of NaVO3 and CTAB, stirring for 30 minutes, and then adjusting the pH value to 6.0 with a sodium hydroxide solution to obtain a mixed solution with a pH value of 6.0;

[0135] The concentration of the sodium hydroxide solution described in step 3 is 10 mol / L;

[0136] 4. Hydrothermal reaction:

[0137] The mixed solution with a pH value of 6.0 is placed in a stainless steel reactor, and then placed in an oven for hydrothermal reaction to obtain a reaction product;

[0138] The temperature of the hydrothermal reaction in step 4 is 105° C., and the time of the hydrothermal reaction is 24 h;

[0139] 5. Washing and drying:

[0140] The reaction product was centrifugally washed 5 times with anhydrous ethanol, then centrifugally washed 5 times with deionized water, and then placed in a vacuum drying oven for drying to obtain a yellow bismuth vanadate photocatalyst (BiVO4 catalyst) with oxygen vacancies;

[0141] In step 5, the speed of each centrifugal washing is 100 rpm and the time is 10 min;

[0142] The vacuum drying temperature in step 5 is 60° C., and the vacuum drying time is 12 h.

[0143] Figure 1 The images of the BiVO4 catalysts in Examples 1 to 6 under XRD characterization;

[0144] It can be seen from the XRD diagram that the synthesized catalyst has diffraction peaks at 2θ of 18.67°, 28.82°, 30.55°, 34.49°, 35.22°, 39.78°, 42.46°, 45.43°, 46.71°, 49.96°, 53.31°, 55.27° and 59.26°, and the diffraction peaks correspond well to the standard card PDF#14-0688, which is consistent with the crystal structure of BiVO4 monoclinic scheelite, and there are no diffraction peaks of other substances and other crystalline phases of bismuth vanadate, indicating that the synthesized catalyst contains only bismuth vanadate.

[0145] Figure 2 It is the O1s image of the BiVO4 catalyst in Examples 1 to 6 under XPS characterization;

[0146] Figure 2The chemical bond energy and surface chemical state of the BiVO4 photocatalyst are shown. The XPS spectrum shows that the asymmetric O1s XPS spectrum can be fitted into three peaks, with the center positions of the peaks at 532.7, 531.3 and 529.1 eV, respectively. These three peaks correspond to chemically adsorbed oxygen (OC), oxygen vacancies (OV), and lattice oxygen (OL). The intensities of the oxygen vacancy (OV) peaks of Examples 1 to 6 are significantly different, indicating that different numbers of oxygen vacancies exist in the samples.

[0147] Application Example 1: A method for using a bismuth vanadate photocatalyst with oxygen vacancies to degrade antibiotics is accomplished by the following steps:

[0148] 1. Take 5 mg of the catalyst prepared in Examples 1 to 6 and add them to six reaction bottles containing 100 mL of 5 mg / L sulfamethoxazole solution (SMX solution), and stir and adsorb for half an hour in a dark place;

[0149] 2. Irradiate under a 150W xenon lamp, with the solution surface 10cm away from the light source, the light intensity is 132.5kLux, and the solution is kept in a stirring state during the degradation process;

[0150] 3. Take 2 mL of sample every 20 minutes into a small syringe, filter through a 0.22 μm filter membrane, and inject into a liquid phase vial for a total of 7 times: at (0, 20, 40, 60, 80, 100, 120 minutes);

[0151] 4. Use ultra-high performance liquid chromatography to draw a line and calculate the content of antibiotics.

[0152] Figure 3 The degradation efficiency diagram of SMX by BiVO4 catalyst in Examples 1 to 6 under light for 2 hours;

[0153] from Figure 3 It can be seen that after 2 hours of illumination, Example 5 has the best photocatalytic effect on SMX, which can remove 93% of SMX, while the degradation rates of SMX in Example 2, Example 3, Example 4, Example 6 and Example 1 are 63%, 73%, 78%, 14.5% and 51%, respectively.

[0154] Figure 4 is a scanning electron microscope image of the BiVO4 catalyst in Example 5;

[0155] SEM results show that as the amount of CTAB added increases, the morphology of Examples 1 to 6 changes from agglomerated particles to long rod-like structures and then to stacked short rod structures. Example 5 with the best catalytic activity is a regular long rod-like structure.

[0156] Comparative Example: Method for preparing bismuth vanadate nanosheets in the prior art:

[0157] 2.21 g of BiCl3 and 1.05 g of hexadecyltrimethylammonium bromide (CTAB) were dissolved in 60 mL of ethylene glycol and stirred vigorously. Then, 2.80 g of NaVO3 was added to the above system and stirred continuously for 30 min. The mixture was then transferred to a 50 mL polytetrafluoroethylene-lined autoclave, sealed and heated at 120 °C for 12 h. After the system was cooled to room temperature, the product was washed with ethanol and deionized water several times and then dried in a vacuum oven at 60 °C. Finally, the obtained sample was quickly calcined at 400 °C for 8 min to obtain bismuth vanadate nanosheets.

[0158] Degradation effect:

[0159] 1. Take 5 mg of bismuth vanadate nanosheets prepared in the control example and add them into a reaction bottle containing 100 mL of 5 mg / L sulfamethoxazole solution (SMX solution), and stir and adsorb for half an hour in a dark place;

[0160] 2. Irradiate under a 150W xenon lamp, with the solution surface 10cm away from the light source, the light intensity is 132.5kLux, and the solution is kept in a stirring state during the degradation process;

[0161] 3. Take 2 mL of sample every 20 minutes into a small syringe, filter through a 0.22 μm filter membrane, and inject into a liquid phase vial for a total of 7 times: at (0, 20, 40, 60, 80, 100, 120 minutes);

[0162] 4. Use ultra-high performance liquid chromatography to draw a line and calculate the content of antibiotics.

[0163] The results show that the degradation rate of SMX by the bismuth vanadate nanosheets prepared in the control example is 6.68%.

Claims

1. A method for preparing a bismuth vanadate photocatalyst having oxygen vacancies, characterized in that The preparation method is specifically completed according to the following steps:

1. Prepare a mixed solution of NaVO3 and CTAB: Sodium metavanadate and hexadecyltrimethylammonium bromide are added to water, heated and stirred for a period of time to obtain a mixed solution of NaVO3 and CTAB; 2. Preparation of bismuth nitrate solution: Add Bi(NO3)3·5H2O to nitric acid and stir for a while to obtain bismuth nitrate solution; 3. Adding the bismuth nitrate solution to the mixed solution of NaVO3 and CTAB, stirring for a period of time, and then adjusting the pH value to 6.0 with a sodium hydroxide solution to obtain a mixed solution with a pH value of 6.0; 4. Hydrothermal reaction: The mixed solution with a pH value of 6.0 is placed in a stainless steel reactor, and then placed in an oven for hydrothermal reaction to obtain a reaction product; 5. Washing and drying: The reaction product is centrifugally washed for several times, and then placed in a vacuum drying oven for drying to obtain a bismuth vanadate photocatalyst with oxygen vacancies.

2. The method for preparing a bismuth vanadate photocatalyst having oxygen vacancies according to claim 1, characterized in that The molar ratio of sodium metavanadate to hexadecyltrimethylammonium bromide described in step one is (1mmol-1.5mmol):(0.2mmol-1mmol); the volume ratio of the amount of sodium metavanadate described in step one to water is (1mmol-1.5mmol):(30mL-50mL); the temperature of heating and stirring described in step one is 40°C-50°C, and the time of heating and stirring is 20min-40min.

3. The method for preparing a bismuth vanadate photocatalyst having oxygen vacancies according to claim 1, characterized in that The concentration of nitric acid in step 2 is 17 mmol / L to 18 mmol / L; the stirring time in step 2 is 20 min to 40 min; the concentration of bismuth nitrate solution in step 2 is 1 mmol to 1.5 mmol.

4. The method for preparing a bismuth vanadate photocatalyst having oxygen vacancies according to claim 1, characterized in that The concentration of the sodium hydroxide solution described in step three is 10 mol / L; the molar ratio of hexadecyltrimethylammonium bromide in the mixed solution of bismuth nitrate and NaVO3 and CTAB described in step three is 1 mmol:(0.2 mmol to 1 mmol); the stirring time described in step three is 20 min to 40 min.

5. The method for preparing a bismuth vanadate photocatalyst having oxygen vacancies according to claim 1, characterized in that The temperature of the hydrothermal reaction in step 4 is 105° C., and the time of the hydrothermal reaction is 20 h to 24 h.

6. The method for preparing a bismuth vanadate photocatalyst having oxygen vacancies according to claim 1, characterized in that The rotation speed of each centrifugal washing in step 5 is 100 rpm, and the time is 10 min to 15 min; in step 5, the reaction product is first centrifugally washed 3 to 5 times with anhydrous ethanol, and then centrifugally washed 3 to 5 times with deionized water; the temperature of the vacuum drying in step 5 is 60° C. to 70° C., and the time of the vacuum drying is 10 h to 12 h.

7. Use of a bismuth vanadate photocatalyst having oxygen vacancies prepared by the preparation method according to claim 1, characterized in that A bismuth vanadate photocatalyst with oxygen vacancies for the degradation of antibiotics.

8. The use of a bismuth vanadate photocatalyst having oxygen vacancies according to claim 7, characterized in that The antibiotic is sulfamethoxazole.

9. The use of a bismuth vanadate photocatalyst having oxygen vacancies according to claim 7, characterized in that A method for using a bismuth vanadate photocatalyst with oxygen vacancies to degrade antibiotics is accomplished by the following steps:

1. Add the bismuth vanadate photocatalyst with oxygen vacancies into the antibiotic solution and stir for a period of time in the dark; 2. Degrade for a period of time under the conditions of 150W xenon lamp, 10cm away from the solution surface and 132.5kLux of light intensity to obtain a solution after removing antibiotics.

10. The use of a bismuth vanadate photocatalyst having oxygen vacancies according to claim 9, characterized in that The volume ratio of the mass of the bismuth vanadate photocatalyst with oxygen vacancies described in step one to the antibiotic solution is 5 mg:100 mL; the time of stirring in the dark described in step one is 0.5 h to 1 h; the concentration of the antibiotic solution described in step one is 5 mg / L; the degradation time described in step two is 100 min to 120 min.

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