In2O3 / ZnWO4 composite photocatalytic material as well as preparation method and application thereof

Abstract

The invention relates to an In2O3 / ZnWO4 composite photocatalytic material as well as a preparation method and application thereof, and relates to the technical field of photocatalyst materials. The invention relates to an In2O3 / ZnWO4 composite photocatalytic material, which is prepared by the following preparation method: MIL-68 (In) and ZnWO4 are sintered to obtain the In2O3 / ZnWO4 composite photocatalytic material, the sintering time is 1-3 hours, the sintering temperature is 450-550 DEG C, and the mass ratio of the MIL-68 (In) to the ZnWO4 is (0.5-5): 1. The In2O3 / ZnWO4 composite photocatalytic material can effectively improve the degradation efficiency of the In2O3 / ZnWO4 composite photocatalytic material in photocatalytic degradation of a high-concentration tetracycline hydrochloride aqueous solution, and has excellent long-term stability.

Description

Technical Field

[0001] The present invention relates to the technical field of catalyst materials, and more specifically, to an In 2 O 3 / ZnWO 4 composite photocatalytic material, its preparation method and application. Background Art

[0002] Antibiotics, as natural or synthetic compounds with antibacterial or bactericidal activity, can be used to treat and prevent various diseases caused by bacterial infections and are widely used in the medical and livestock industries. According to the mechanism of action, antibiotics mainly include tetracyclines (TCs), aminoglycosides (AGs), β-lactams, sulfonamides (SAs), fluoroquinolones (FQs), macrolides (MLs), etc. However, neither humans nor animals can completely metabolize antibiotics. Antibiotics are partially metabolized, then excreted through urine and feces, and then enter the environment through incomplete treatment in wastewater treatment plants. Currently, the pollution of antibiotics in water bodies mainly comes from the pharmaceutical industry, livestock industry, aquaculture, etc. The concentration ranges of various antibiotics in water are from ng / L to mg / L. Within the influence range of urban wastewater treatment plants, they are usually between 1 ng / L and >1 mg / L, while industrial wastewater, such as pharmaceutical and livestock wastewater, may contain higher concentrations, up to 100 mg / L. Different from other traditional organic pollutants such as dyes and pesticides, the concentration of antibiotics is mainly low, but they are highly toxic. The accumulation of antibiotics released into the environment at a certain concentration will affect the dynamic balance of the microbial community. This will lead to the generation of drug-resistant bacteria in humans and animals, and even gene mutations. The treatment cost of antibiotic wastewater is high, and the wastewater composition is complex, which is a kind of refractory organic wastewater. Tetracycline is one of the most widely used and largest consumption antibiotics, and it is of great significance to seek an efficient method for removing tetracycline.

[0003] Photocatalytic oxidation technology has the characteristics of being reusable and green, and is considered to be one of the most effective methods for treating antibiotic wastewater pollution. Photocatalytic technology is different from traditional sewage treatment technologies. It converts solar energy into chemical energy. The photo-generated electrons and holes generated during the photocatalytic process can decompose and mineralize sewage into carbon dioxide and water, which is an environmentally friendly technology.

[0004] Chinese Patent CN118513060A discloses a preparation method and application of a composite zinc tungstate / bismuth oxychloride heterojunction photocatalyst. The preparation method of the composite zinc tungstate / bismuth oxychloride heterojunction photocatalyst is to fully mix sodium chloride and bismuth nitrate, and then mix with ZnWO 4Perform a hydrothermal reaction together; after the reaction is completed, cool it to room temperature, wash, dry and grind it to obtain the composite photocatalyst, which is a stacked body of petal-shaped nanosheets and nanoparticles. Disperse 20 mg of the catalyst sample in 50 mL of aqueous tetracycline hydrochloride solution with a concentration of 20 mg / L, and stir it in the dark for 30 min to reach the adsorption-desorption equilibrium state. Measure the photocatalytic degradation efficiency of tetracycline hydrochloride by using a UV-visible spectrophotometer (UV-vis). The degradation rate of tetracycline hydrochloride under 60 min of irradiation is less than 65%. However, the photocatalytic degradation efficiency of tetracycline needs to be further improved. Summary of the Invention

[0005] The object of the present invention is to overcome the defect and deficiency that the degradation efficiency of the existing photocatalyst for degrading tetracycline hydrochloride needs to be further improved, and to provide an In 2 O 3 / ZnWO 4 composite photocatalytic material, which can effectively improve the degradation efficiency of its photocatalytic degradation of high-concentration aqueous tetracycline hydrochloride solution.

[0006] The above object of the present invention is achieved by the following technical solutions: An In 2 O 3 / ZnWO 4 composite photocatalytic material is prepared by the following preparation method: sinter MIL-68(In) and ZnWO 4 to obtain an In 2 O 3 / ZnWO 4 composite photocatalytic material, wherein the sintering time is 1 to 3 h, the sintering temperature is 450 to 550 °C, and the mass ratio of MIL-68(In) to ZnWO 4 is (0.5 to 5):1.

[0007] MIL-68(In) is a metal-organic framework (MOF) material. MIL-68(In) can be obtained commercially or prepared by oneself.

[0008] The present invention uses MIL-68(In) as a precursor to prepare an In 2 O 3 / ZnWO 4 composite photocatalytic material because the highly ordered pores and uniformly distributed metal sites of the MIL-68(In) metal-organic framework (MOF) material can be transformed into In 2 O 3 to form a special morphology of a porous nanostructure. This helps to increase the specific surface area of the photocatalyst, enhance light absorption and the diffusion performance of reactants. The metal ions in the MOF material are uniformly transformed into In during the pyrolysis process2 O 3 , enabling the catalyst to have highly dispersed active sites, which is beneficial to the improvement of reaction efficiency.

[0009] Moreover, In derived from metal-organic framework (MOF) 2 O 3 generates a large number of oxygen vacancies (OVs), which is beneficial to the separation of photoinduced electron-hole pairs. In with OVs 2 O 3 has higher molecular oxygen adsorption and activation sites, which leads to the generation of superoxide radicals, and it can be converted into singlet oxygen through a charge transfer process. The electrophilic reactive oxygen species (ROS) called singlet oxygen can initiate an attack on the electron-rich groups (such as benzene rings) present in the tetracycline molecule, thereby improving the overall degradation efficiency.

[0010] Zinc tungstate (ZnWO 4 ) has a band gap of 3.5 eV, and its band structure matches that of In 2 O 3 . The composite photocatalytic material of the present invention uses a sintering method to derive MIL-68(In) into In 2 O 3 and composites it with ZnWO 4 to successfully construct an In 2 O 3 / ZnWO 4 heterojunction In 2 O 3 / ZnWO 4 composite photocatalytic material, which is beneficial to promoting the separation and migration rate of photo-generated electrons and holes, reducing the recombination rate of photo-generated electrons and holes, and thus improving the activity and stability of the catalyst. It improves the degradation rate of high-concentration tetracycline hydrochloride antibiotic organic pollutants under visible light irradiation.

[0011] In the specific implementation manner, the sintering time can be 1 h, 1.5 h, 2 h, 2.5 h, 3 h.

[0012] In the specific implementation manner, the sintering temperature can be 450 °C, 480 °C, 500 °C, 520 °C, 550 °C.

[0013] In the specific implementation manner, the mass ratio of MIL-68(In) and ZnWO 4 can be 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5.

[0014] Preferably, the mass ratio of MIL-68(In) and ZnWO 4 is (3-4):1.

[0015] Preferably, before the sintering treatment, it further includes first mixing MIL-68(In) and ZnWO 4 Sinter at 100~130 °C for 1~3 hours. The sintering temperature can be 100 °C, 105 °C, 110 °C, 115 °C, 120 °C, 125 °C, 130 °C. The sintering time can be 1h, 1.5h, 2h, 2.5h, 3h.

[0016] MIL-68(In) has a one-dimensional pore structure and a large specific surface area. The porous environment provides sufficient adsorption sites for water molecules, and it may adsorb water even at low humidity. In the present invention, by first sintering at a lower temperature of 100~130 °C for 1~3 hours, the moisture in the MIL-68(In) sample powder can be removed.

[0017] Preferably, the preparation method of the MIL-68(In) includes the following steps: mixing indium nitrate, terephthalic acid and N,N-dimethylformamide, and reacting at a reaction temperature of 110~130 °C for 1~3h to obtain MIL-68(In).

[0018] The reaction conditions in the preparation method of MIL-68(In) will directly affect the final size of MIL-68(In).

[0019] ZnWO 4 can be obtained commercially or prepared by oneself. Usually, the size of commercially available ZnWO 4 is relatively large.

[0020] Preferably, the ZnWO 4 is in a nanorod-like structure, and the length of the nanorods is about 100~300 nm.

[0021] Preferably, the preparation method of the ZnWO 4 includes the following steps: mixing zinc nitrate and sodium tungstate, and reacting at a reaction temperature of 180~200 °C for 20~24h to obtain ZnWO 4 .

[0022] The present invention also protects the application of the In 2 O 3 / ZnWO 4 composite photocatalytic material in the photocatalytic degradation of antibiotics in water bodies.

[0023] Preferably, the antibiotic is tetracycline hydrochloride.

[0024] Preferably, the concentration of tetracycline hydrochloride in the water body is 20 mg / L, and the In 2 O 3 / ZnWO 4The addition amount of the composite photocatalytic material in water is 10-20 mg / 50 mL.

[0025] Preferably, the light wavelength of the photocatalysis is 420 nm.

[0026] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention provides an In 2 O 3 / ZnWO 4 composite photocatalytic material. By using the sintering method, MIL-68(In) is derivatized into In 2 O 3 and compounded with ZnWO 4 to successfully construct an In 2 O 3 / ZnWO 4 heterojunction In 2 O 3 / ZnWO 4 composite photocatalytic material, which is beneficial to promoting the separation and migration rate of photogenerated electrons and holes, reducing the recombination rate of photogenerated electrons and holes, thereby improving the activity and stability of the catalyst, and improving the degradation rate of high-concentration tetracycline hydrochloride antibiotic organic pollutants under visible light irradiation. And it has excellent long-term stability. Description of the Drawings

[0027] Figure 1 In (a) is the SEM image of Comparative Example 1. Figure 1 In (b) is the enlarged SEM image of Comparative Example 1. Figure 1 In (c) is the SEM image of Comparative Example 2. Figure 1 In (d) is the enlarged SEM image of Comparative Example 2. Figure 1 In (e) is the SEM image of Example 3. Figure 1 In (f) is the enlarged SEM image of Example 3.

[0028] Figure 2 is the XRD pattern fitted for MIL-68(In) and the experimentally measured XRD pattern.

[0029] Figure 3 XRD patterns and partial enlarged views of Examples 1 to 4, Comparative Example 1 and Comparative Example 2.

[0030] Figure 4 are the photocatalytic degradation curves of tetracycline hydrochloride by the catalysts of Examples 1 to 4, Comparative Example 1 and Comparative Example 2 at a dosage of 20 mg.

[0031] Figure 5Quasi-first-order reaction kinetic diagram of the degradation process of tetracycline hydrochloride by the catalysts of Examples 1 to 4, Comparative Example 1 and Comparative Example 2 at a dosage of 20 mg.

[0032] Figure 6 Photocatalytic degradation curves of tetracycline hydrochloride by the catalysts of Examples 1 to 4, Comparative Example 1 and Comparative Example 2 at a dosage of 10 mg.

[0033] Figure 7 Quasi-first-order reaction kinetic diagram of the degradation process of tetracycline hydrochloride by the catalysts of Examples 1 to 4, Comparative Example 1 and Comparative Example 2 at a dosage of 10 mg.

[0034] Figure 8 XRD comparison diagram before and after the reaction of Example 3. Detailed implementation mode

[0035] The present invention will be further described below in conjunction with the detailed implementation mode, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw material reagents used in the embodiments of the present invention are conventionally purchased raw material reagents.

[0036] Example 1 An In 2 O 3 / ZnWO 4 Composite photocatalytic material, prepared by the following preparation method: (1) Preparation of MIL-68(In): Dissolve 600 mg of In(NO 3 ) 3 ·3H 2 O and 600 mg of terephthalic acid (H 2 BDC) in 100 mL of N,N-dimethylformamide (DMF), stir for 10 min to form a clear solution. Then place the mixture in an oil bath and heat at 120 °C for 2 hours. After cooling to room temperature, collect the white precipitate by centrifugation and wash it several times with ethanol, and dry it at 60 °C for 12 hours to collect the white powder to obtain MIL-68(In).

[0037] (2) Preparation of ZnWO 4 : Dissolve 3 mmol of Zn(NO 3 ) 2 ·6H 2 O in 30 mL of deionized water to form solution A, and dissolve 3 mmol of NaWO 4 ·2H 2O was dissolved in 25 mL of deionized water to form solution B, and it was stirred for 10 minutes to completely dissolve. Then solution B was slowly added dropwise to solution A, and the pH of the solution was maintained at 8 by using ammonia water solution, and it was stirred for 30 minutes. Subsequently, the obtained mixture was heated in an 80 mL autoclave at 180 °C for 24 hours. After the hydrothermal reaction ended, the autoclave was allowed to cool naturally to room temperature, the obtained product was collected by centrifugation and washed several times with deionized water and ethanol, and the obtained product was dried at 60 °C for 12 hours, and the white powder was collected to obtain ZnWO 4 。

[0038] (3)In 2 O 3 / ZnWO 4 Preparation of composite material 0.1 g of MIL-68(In) and 0.1 g of ZnWO 4 were mixed evenly by grinding. Subsequently, the mixed powder was placed in a tubular furnace and heated to 120 °C at a rate of 5 °C / min for 2 hours and then heated to 500 °C and sintered for 2 hours to obtain In 2 O 3 / ZnWO 4 composite material (abbreviated as IZ-1); Among them, the mass ratio of MIL-68(In) and ZnWO 4 is 1:1.

[0039] Example 2 An In 2 O 3 / ZnWO 4 composite photocatalytic material, which is different from the preparation method of Example 1 in that: The mass ratio of MIL-68(In) and ZnWO 4 is 2:1. That is, in step (3), 0.2 g of MIL-68(In) and 0.1 g of ZnWO 4 were used.

[0040] The obtained material is abbreviated as IZ-2.

[0041] The rest is the same as that of Example 1 and will not be elaborated here.

[0042] Example 3 An In 2 O 3 / ZnWO 4 composite photocatalytic material, which is different from the preparation method of Example 1 in that: The mass ratio of MIL-68(In) and ZnWO 4 is 3:1. That is, in step (3), 0.3 g of MIL-68(In) and 0.1 g of ZnWO4 。

[0043] The obtained material is abbreviated as IZ-3.

[0044] The rest is the same as that in Example 1 and will not be elaborated here.

[0045] Example 4 An In 2 O 3 / ZnWO 4 composite photocatalytic material, different from the preparation method of Example 1 in that: The mass ratio of MIL-68(In) and ZnWO 4 is 4:1. That is, 0.4 g of MIL-68(In) and 0.1 g of ZnWO 4 .

[0046] The obtained material is abbreviated as IZ-4.

[0047] The rest is the same as that in Example 1 and will not be elaborated here.

[0048] Example 5 An In 2 O 3 / ZnWO 4 composite photocatalytic material, different from the preparation method of Example 3 in that: The mixed powder of MIL-68(In) and ZnWO 4 is heated in a tubular furnace at a rate of 5 °C / min to 120 °C and sintered for 2 hours, and then heated to 450 °C and kept sintered for 2 hours.

[0049] The rest is the same as that in Example 3 and will not be elaborated here.

[0050] Example 6 An In 2 O 3 / ZnWO 4 composite photocatalytic material, different from the preparation method of Example 3 in that: The mixed powder of MIL-68(In) and ZnWO 4 is heated in a tubular furnace at a rate of 5 °C / min to 120 °C and sintered for 2 hours, and then heated to 550 °C and kept sintered for 2 hours.

[0051] The rest is the same as that in Example 3 and will not be elaborated here.

[0052] Example 7 An In 2 O 3 / ZnWO 4 composite photocatalytic material, different from the preparation method of Example 3 in that: The mixed powder of MIL-68(In) and ZnWO 4 was heated to 120 °C at a rate of 5 °C / min in a tube furnace and sintered for 2 hours, then heated to 500 °C and sintered for 1 hour.

[0053] The rest is the same as in Example 3 and will not be elaborated here.

[0054] Example 8 An In 2 O 3 / ZnWO 4 composite photocatalytic material, different from the preparation method of Example 3 in that: The mixed powder of MIL-68(In) and ZnWO 4 was heated to 120 °C at a rate of 5 °C / min in a tube furnace and sintered for 2 hours, then heated to 500 °C and sintered for 3 hours.

[0055] The rest is the same as in Example 3 and will not be elaborated here.

[0056] Comparative Example 1 A preparation method of a ZnWO 4 catalyst is the same as the preparation method of ZnWO 4 in Example 1 and will not be elaborated here.

[0057] Comparative Example 2 A preparation method of an In 2 O 3 catalyst includes the following steps: (1) The preparation of MIL-68(In) is the same as in Example 1.

[0058] (2) The preparation of In 2 O 3 : Place a certain amount of MIL-68(In) powder in a tube furnace, heat it to 120 °C at a rate of 5 °C / min and sinter for 2 hours, then heat it to 500 °C and sinter for 2 hours, and collect the pale yellow powder to obtain In 2 O 3 .

[0059] Comparative Example 3 A preparation method of a ZnWO 4 / BiOCl catalyst includes the following steps: (1) Place 2 mmol of zinc nitrate hexahydrate and sodium tungstate dihydrate in a 50 ml beaker, add 25 ml of deionized water, and place the beaker on a magnetic stirrer and stir for 30 minutes. Then transfer the obtained homogeneous solution to a 50 ml stainless steel reaction kettle lined with polytetrafluoroethylene and place it in an oven. React at 180 °C for 15 h. After the reaction is completed, cool to room temperature, take out the reactants, centrifuge to collect the obtained precipitate, wash it alternately with deionized water and absolute ethanol 3 times, heat it at 60 °C for 12 h, grind the reactants obtained after drying, and obtain ZnWO 4 .

[0060] (2) Dissolve 2 mmol of bismuth nitrate pentahydrate in 25 ml of ethylene glycol, dissolve 2 mmol of sodium chloride in 25 ml of deionized water, place them on a magnetic stirrer and stir evenly respectively. Under continuous stirring, drop the sodium chloride aqueous solution into the bismuth nitrate pentahydrate solution, stir the mixed solution for 30 minutes to make it evenly distributed, and then add 0.058 g of the ZnWO 4 material prepared in step (1) into it, continue to stir for 3 h, then transfer the obtained uniformly mixed solution to a 100 ml stainless steel reaction kettle, place it in an oven, and react at 150 °C for 10 h. After the reaction is completed, cool to room temperature, centrifuge the obtained precipitate, and wash it alternately with deionized water and absolute ethanol 3 times, heat it at 60 °C for 12 h, grind the reactants obtained after drying, and obtain ZnWO 4 / BiOCl heterojunction photocatalyst material.

[0061] Comparative Example 4 A method for preparing an In 2 O 3 catalyst, comprising the following steps: (1) The preparation of MIL-68(In) is the same as that in Example 1.

[0062] (2) Preparation of In 2 O 3 : Place a certain amount of MIL-68(In) powder in a tubular furnace, heat it to 120 °C at a rate of 5 °C / min and sinter for 2 hours, then heat it to 400 °C and keep sintering for 2 hours, and collect the pale yellow powder to obtain In 2 O 3 .

[0063] Comparative Example 5 A method for preparing an In 2 O 3 catalyst, comprising the following steps: (1) The preparation of MIL-68(In) is the same as that in Example 1.

[0064] (2) In2 O 3 Preparation of In₂O₃: Place a certain amount of MIL-68(In) powder in a tubular furnace, heat it to 120 °C at a rate of 5 °C / min and sinter for 2 hours, then heat it to 600 °C and keep sintering for 2 hours. Collect the pale yellow powder to obtain In₂O₃. 2 O 3 .

[0065] Result Detection The catalysts prepared in Examples 1-8 and Comparative Examples 1-5 were respectively subjected to structural characterization and performance testing.

[0066] (1)SEM The morphological characteristics of the materials in Example 3, Comparative Example 1, and Comparative Example 2 were investigated by scanning electron microscopy (SEM), as Figure 1 shown. Figure 1 In (a) is the SEM image of Comparative Example 1. Figure 1 In (b) is the enlarged SEM image of Comparative Example 1. Figure 1 In (c) is the SEM image of Comparative Example 2. Figure 1 In (d) is the enlarged SEM image of Comparative Example 2. Figure 1 In (e) is the SEM image of Example 3. Figure 1 In (f) is the enlarged SEM image of Example 3. Among them, the ZnWO₄ in Comparative Example 1 4 is in a rod-like structure, and the length of the rod is about 100-300 nm. The In₂O₃ in Comparative Example 2 2 O 3 is in a granular structure of 50-100 nm. While Example 3 presents a mixed structure of In₂O₃ nanoparticles and ZnWO₄ nanorods. 2 O 3 nanoparticles and ZnWO 4 nanorods.

[0067] (2)XRD Test The crystal structures of MIL-68(In) and Examples 1-4, Comparative Example 1, and Comparative Example 2 were analyzed by X-ray diffraction (XRD), as Figure 2 , Figure 3 shown. Figure 2 The results show that the XRD pattern of the synthesized MIL-68(In) is basically consistent with the fitted pattern, indicating that the sample synthesis is successful. Figure 3 The peak positions of the characteristic diffraction peaks of In₂O₃ and ZnWO₄ in 2 O 3 , ZnWO 4 are basically consistent with the standard cards (PDF#71-2195) and (PDF#15-0774) respectively, and no characteristic peaks of other substances are observed, indicating that their purity is very high, and the sample synthesis is successful.Figure 3 In with different mass ratios 2 O 3 / ZnWO 4 From the XRD pattern and the partial enlarged view of the composite material of In 2 O 3 and ZnWO 4 it can be seen that the strongest characteristic peaks of In 4 and ZnWO 2 O 3 coincide. As the content of ZnWO Figure 3 decreases, its characteristic peak at 36.312° gradually weakens, and at the same time, the characteristic peak of In 2 O 3 at 35.462° gradually strengthens. From 4 it can be seen that after the combination of In 2 O 3 and ZnWO 4 the characteristic peaks of both In

[0068] (3) Photocatalytic degradation test of tetracycline hydrochloride Specific test method: Using a 420 nm LED light source, the photocatalytic activity was tested with tetracycline hydrochloride (TC-HCl) as the target pollutant. 10 mg and 20 mg of the material samples of Examples 1 to 8 and Comparative Examples 1 to 5 were respectively dispersed in 50 mL of a TC-HCl aqueous solution with a concentration of 20 mg / L, and stirred in the dark for 30 min to make the obtained samples and TC-HCl reach adsorption-desorption equilibrium. Then, visible light was turned on, and 4 mL of the mixed solution was collected every 10 min. After removing the photocatalyst powder by centrifugation, the absorbance (357 nm) of the supernatant tetracycline hydrochloride was measured using a UV-visible spectrophotometer (UV-vis), and compared with the absorbance of the initial solution to obtain the degradation efficiency of the photocatalyst.

[0069] The specific detection results of the degradation of tetracycline hydrochloride by each sample after 30 minutes and 60 minutes of reaction are shown in Table 1 below.

[0070] Table 1

[0071] As can be seen from the above results, the single ZnWO 4 and In 2 O 3 in Comparative Examples 1 and 2 have a low degradation rate for tetracycline hydrochloride. When In 2 O 3 and ZnWO 4The composite material is formed, and its photocatalytic activity is significantly improved. For the high-concentration aqueous solution of tetracycline hydrochloride at 20 mg / L, when the dosage of the catalyst is 10 mg, the degradation efficiency of tetracycline hydrochloride can reach 56.16% - 72.57%. When the dosage of the catalyst is 20 mg, the degradation efficiency of tetracycline hydrochloride can reach 73.65% - 79.33%. This shows that In 2 O 3 and ZnWO 4 The formed composite material has better visible light absorption ability and promotes the separation efficiency of photogenerated carriers, thus improving the photocatalytic performance. From Figure 4 、 Figure 6 The test results show that the increase in the content of In 2 O 3 makes the photocatalytic degradation performance of the composite catalyst for tetracycline hydrochloride improve. However, when the content of In 2 O 3 exceeds a certain amount, it will cause the aggregation of In 2 O 3 nanoparticles, affecting its photocatalytic performance.

[0072] It can be seen from Example 3 and Examples 5 - 8 that when MIL-68(In) and ZnWO 4 are sintered under the conditions of a sintering time of 1 - 3 h and a sintering temperature of 450 - 550 °C, the obtained catalysts can all have more excellent degradation efficiency for tetracycline hydrochloride.

[0073] The first-order kinetic equation is used to fit the experimental data to quantitatively understand the degradation performance of the photocatalyst for tetracycline hydrochloride. As Figure 5 、 Figure 7 shown, the results confirm that the reaction rate constants of each example are all above k = 0.012 min -1 , much higher than those of ZnWO 4 、In 2 O 3 in Comparative Example 1 and Comparative Example 2. Among them, IZ-3 has the highest reaction rate constants (k = 0.01954 min -1 and k = 0.01885 min -1 ), which are 3.32 times and 8.69 times those of pure ZnWO 4 (k = 0.00589 min -1 and k = 0.00217 min -1 ) and 1.43 times and 3.91 times those of In 2 O 3 (k = 0.01368 min -1 and k = 0.00482 min -11.43 times and 3.91 times of (), indicating that the composite photocatalyst of the present invention has great photocatalytic activity for photocatalytic degradation of tetracycline hydrochloride.

[0074] (4) Stability test: The degradation stability of the catalyst in Example 3 was evaluated, and the structural changes of Example 3 before and after the reaction were evaluated by X-ray diffraction (XRD). From Figure 8 The test results show that compared with the catalyst before the reaction, there is no obvious change in the crystal structure of Example 3 after use, and only the peak intensity is slightly weakened. This reflects the excellent stability of the IZ-3 composite material.

[0075] Obviously, the above-mentioned embodiments of the present invention are only examples for clearly explaining the present invention, and are not intended to limit the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. An In2O3 / ZnWO4 composite photocatalytic material, characterized in that: It is prepared by the following preparation method: MIL-68 (In) and ZnWO4 are sintered to obtain In2O3 / ZnWO4 composite photocatalytic material, wherein the sintering time is 1~3h, the sintering temperature is 450~550℃, and the mass ratio of MIL-68 (In) and ZnWO4 is (0.5~5):

1.

2. The In2O3 / ZnWO4 composite photocatalytic material according to claim 1, characterized in that: The mass ratio of MIL-68 (In) and ZnWO4 is (3~4):

1.

3. The In2O3 / ZnWO4 composite photocatalytic material according to claim 1, characterized in that: Before the sintering process, the method further includes sintering MIL-68 (In) and ZnWO4 at 100-130° C. for 1-3 hours.

4. The In2O3 / ZnWO4 composite photocatalytic material according to claim 1, characterized in that: The preparation method of MIL-68 (In) comprises the following steps: indium nitrate, terephthalic acid and N,N-dimethylformamide are mixed, and reacted at a reaction temperature of 110° C. to 130° C. for 1 to 3 hours to obtain MIL-68 (In).

5. The In2O3 / ZnWO4 composite photocatalytic material according to claim 1, characterized in that: The ZnWO4 is a nanorod structure, and the length of the nanorod is 100-300 nm.

6. The In2O3 / ZnWO4 composite photocatalytic material according to claim 5, characterized in that: The preparation method of ZnWO4 comprises the following steps: mixing zinc nitrate and sodium tungstate, reacting at a reaction temperature of 180-200°C for 20-24h to obtain ZnWO4.

7. Use of the In2O3 / ZnWO4 composite photocatalytic material according to any one of claims 1 to 6 in the photocatalytic degradation of antibiotics in water.

8. The use according to claim 7, wherein the antibiotic is tetracycline hydrochloride.

9. According to the use of claim 8, the concentration of tetracycline hydrochloride in the water is 20 mg / L, and the addition amount of the In2O3 / ZnWO4 composite photocatalytic material in the water is 10-20 mg / 50 mL.

10. The use according to claim 8, wherein the light wavelength of the photocatalysis is 420 nm.

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