An r-mil-88a / o v-biobr photo-fenton catalyst rich in oxygen vacancies, and a preparation method and application thereof

Abstract

The application discloses a preparation method and application of an r-MIL-88A / OV-BiOBr photo-Fenton catalyst rich in oxygen vacancies. The photo-Fenton catalyst rich in oxygen vacancies is characterized in that, as shown by transmission electron microscopy and scanning electron microscopy, the morphology of an optimal ratio catalyst OV-BM-25 is that a certain amount of OV-BiOBr flower balls are attached to the surface of the r-MIL-88A rod-shaped structure. Under the irradiation of a low-power white light-emitting diode (LED), the optimal ratio catalyst OV-BM-25 prepared exhibits good photo-Fenton degradation activity, and can degrade and convert organic pollutants in pharmaceutical wastewater containing chloroquine phosphate and the like into non-toxic or low-toxic substances. The photo-Fenton catalyst preparation method provided by the application is simple, has high photo-catalytic efficiency, good mineralization effect, good stability, reusability and the like, has a good application prospect, and is easy to prepare on a large scale.

Description

Technical Field

[0001] This invention belongs to the field of photocatalysis technology, and particularly relates to an oxygen-vacancy-rich r-MIL-88A / OV-BiOBr photo-Fenton catalyst, its preparation method, and its application. Background Technology

[0002] Photo-Fenton technology is an important component of advanced oxidation processes, widely used for the degradation of organic pollutants due to its high efficiency, strong oxidizing power, and environmental friendliness. Chloroquine phosphate (CQ) is one such example. 18 H 32 CQ (ClN3O8P2) is generally used to treat extraintestinal amebiasis, connective tissue diseases, and photosensitivity disorders, and can also be used to inhibit COVID-19 in vitro. The migration, transformation, and degradation pathways of drugs and their metabolites in the aquatic environment have become a research hotspot in the environmental field, and are of great significance for improving water pollution control technologies. Because CQ is non-volatile and has good solubility and stability in water, the development of a novel and efficient method for treating CQ and other pharmaceutical wastewater is urgently needed.

[0003] BiOBr is a V-VI-VII ternary semiconductor compound with a unique crystal structure and excellent visible-light photocatalytic performance, making it one of the ideal visible-light photocatalytic materials. However, the positive conduction band position of a single BiOBr makes it difficult to effectively oxidize H2O molecules and activate O2 molecules to generate reactive oxygen species, resulting in low photodegradation efficiency. Therefore, improving the photocatalytic performance and yield of highly active oxide species of BiOBr-based photocatalysts under visible light irradiation remains a hot topic in the field of photocatalysis.

[0004] Fe-MOFs exhibit excellent performance in practical applications due to their low toxicity, wide photoreactivity range, and water stability. To date, successfully prepared Fe-MOFs include MIL-53 (Fe), MIL-68 (Fe), MIL-88A (Fe), MIL-88B (Fe), MIL-100 (Fe), and MIL-101 (Fe), among others. Among these, MIL-88A (Fe) possesses abundant unsaturated sites on its surface; under visible light irradiation, electrons can... 3+ Reduced to Fe 2+ This activates H2O2, generating active substances and effectively degrading environmental pollutants. Based on the structure and composition of MIL-88A(Fe), semiconductors containing oxygen vacancies can be used to construct heterojunctions, potentially accelerating electron / hole separation and Fe... 3+ To Fe 2+ The cycle can be improved to enhance the performance of photo-Fenton degradation of pollutants. However, the adsorption activity and photodegradation performance of MIL-88A(Fe) alone are poor. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing an oxygen-vacancy-rich r-MIL-88A / OV-BiOBr photo-Fenton catalyst, its preparation method, and its applications. This catalyst exhibits excellent photo-Fenton degradation ability, highly efficient carrier separation capability, and good structural stability. The preparation method is simple, low-cost, and suitable for large-scale production. It can significantly reduce the toxicity of pharmaceutical wastewater, meeting the needs of practical production. This invention achieves excellent degradation effects on pharmaceutical wastewater under visible light conditions.

[0006] The specific technical solution for achieving the objective of this invention is as follows:

[0007] A method for preparing an oxygen-vacancy-rich r-MIL-88A / OV-BiOBr composite photocatalyst, comprising the following steps:

[0008] Step 1: In a polytetrafluoroethylene-lined high-pressure reactor, add BiNO3·5H2O, KBr, and PVP, using ethylene glycol as the solvent, and stir for 1-2 hours. The stirring method is magnetic stirring at a speed of 800-900 rpm. The molar ratio of BiNO3·5H2O, KBr, and PVP is (80-120):(80-120):(0.8-1.2). The volume of the solvent is 3 / 5 to 2 / 5 of the volume of the high-pressure reactor.

[0009] Step 2: Weigh out rod-shaped r-MIL-88A and place it in the polytetrafluoroethylene-lined high-pressure reactor from Step 1, and stir for 1-2 hours; wherein the mass of rod-shaped r-MIL-88A is 1%-45% of the total mass of BiNO3·5H2O, KBr, and PVP;

[0010] Step 3: Tighten the reactor and heat it using an electric thermostatic drying oven at a reaction temperature of 120-170 ℃ for 8-12 h. Step 4: After the reaction in Step 3 is completed, allow it to cool naturally to room temperature, open the reactor, and recover the solid powder by centrifugation and washing. Specifically, the centrifuge speed is 6000-8000 rpm, the centrifugation time is 5-10 min, the powder is washed 3-5 times with deionized water, then washed 3-5 times with ethanol, and finally placed in a vacuum drying oven at a drying temperature of 40-60 ℃ for 8-12 h. Grind the powder to obtain the oxygen-vacancy-rich r-MIL-88A / OV-BiOBr photo-Fenton catalyst.

[0011] A photo-Fenton catalyst rich in oxygen vacancies, r-MIL-88A / OV-BiOBr, prepared by the above method, was shown by transmission electron microscopy and scanning electron microscopy to have a morphology of r-MIL-88A rod-like structure with OV-BiOBr flower-like structures attached to the surface.

[0012] The above-mentioned oxygen-vacancy-rich r-MIL-88A / OV-BiOBr photo-Fenton catalyst is applied to the degradation of organic pollutants in pharmaceutical wastewater. Under low-power white LED irradiation, the catalyst generates active oxygen species to degrade organic pollutants in pharmaceutical wastewater, with a degradation efficiency of 68.08%-97.19% after 60 min of irradiation.

[0013] The application specifically includes: placing the catalyst in pharmaceutical wastewater with a concentration of 5-20 mg / L, adjusting the pH using 1 mM sodium hydroxide or 1 mM hydrochloric acid solution, adding H2O2 with a concentration of 0.98-3.92 mM and mixing thoroughly; then, adsorbing in the dark for 30-60 min until adsorption equilibrium is reached, and then irradiating with a light source for 10-60 min; wherein the mass ratio of the catalyst to the volume of the pharmaceutical wastewater to the volume of H2O2 is 5-50 mg : 50-80 ml : 5-50 μL; pH = 3-9; and the light source is a white LED.

[0014] The photocatalyst prepared in this invention can degrade organic pollutants in wastewater containing pharmaceuticals such as CQ into non-toxic or low-toxic substances under low-power white LED irradiation, exhibiting good degradation activity. Even after five cycles, it maintains good photocatalytic activity and structural stability. The photocatalyst preparation method provided by this invention is simple, not only possessing high photocatalytic efficiency but also good stability and reusability, showing promising application prospects and ease of large-scale preparation.

[0015] The present invention has the following advantages:

[0016] 1. The oxygen-vacancy-rich r-MIL-88A / OV-BiOBr composite photocatalyst of the present invention exhibits excellent photo-Fenton catalytic activity and stability for CQ degradation.

[0017] 2. The introduction of oxygen vacancies helps to improve the efficiency of CQ adsorption, photodegradation, and H2O2 activation of the r-MIL-88A / OV-BiOBr heterojunction.

[0018] 3. The synergistic effect between heterostructure and oxygen vacancies promotes the efficient separation of photogenerated electron-hole pairs and Fe 3+ To Fe 2+ The cycle. Attached Figure Description

[0019] Figure 1 Scanning electron microscope images of r-MIL-88A, OV-BiOBr, and OV-BM-25, and elemental distribution map of OV-BM-25;

[0020] Figure 2This is a transmission electron microscope image of OV-BM-25 obtained in Example 3 of the present invention;

[0021] Figure 3 The electron paramagnetic resonance image of OV-BM-25 obtained in Example 3 of this invention;

[0022] Figure 4 XRD pattern of r-MIL-88A;

[0023] Figure 5 XRD patterns of OV-BiOBr and OV-BM composite materials prepared in Examples 1-5 of this invention;

[0024] Figure 6 Fourier transform infrared images of r-MIL-88A, OV-BiOBr, and OV-BM-25;

[0025] Figure 7 UV spectra of r-MIL-88A, OV-BiOBr, and OV-BM-25 solids;

[0026] Figure 8 Degradation performance diagrams for r-MIL-88A, OV-BiOBr, and OV-BM-25;

[0027] Figure 9 The graph shows the degradation efficiency of OV-BM-25 on pharmaceutical wastewater.

[0028] Figure 10 The TOC mineralization efficiency diagram for CQ;

[0029] Figure 11 A schematic diagram of the cycling performance of OV-BM-25 on the photo-Fenton degradation of CQ;

[0030] Figure 12 The XRD patterns and Fourier transform infrared (FTIR) images of OV-BM-25 before and after the fifth cycle test are shown.

[0031] Figure 13 This is a schematic diagram of the intermediate degradation products detected by UPLC-MS after photo-Fenton degradation of CQ by OV-BM-25.

[0032] Figure 14 This is a schematic diagram of the photo-Fenton degradation pathway of CQ by OV-BM-25;

[0033] Figure 15 This is a schematic diagram for toxicity assessment. Detailed Implementation

[0034] The invention will be further described with reference to the accompanying drawings. All reagents used in the following examples are conventional reagents of analytical purity and do not require further purification before use; the related preparation and detection methods are conventional methods.

[0035] The rod-shaped r-MIL-88A described in this invention was obtained by the hydrothermal method described in the literature "Applied Catalysis B: Environmental 259 (2019) 118064".

[0036] Example 1

[0037] 1) Place 0.395 g BiNO3·5H2O, 0.119 g KBr and 0.4 g PVP into a polytetrafluoroethylene-lined high-pressure reactor, using ethylene glycol as a solvent. The volume of the solvent should be 3 / 5 of the volume of the high-pressure reactor. Stir for 2 h using a magnetic stirrer at a speed of 900 rpm.

[0038] (2) Weigh 0.0152 g of rod-shaped r-MIL-88A and place it in the polytetrafluoroethylene-lined high-pressure reactor of step (1), and stir for 1 h;

[0039] (3) Tighten the reactor, the reaction temperature is 160 ℃, the reaction time is 10 h, and the heating instrument is an electric thermostatic drying oven.

[0040] (4) After the reaction in step (3) is completed, the mixture is allowed to cool naturally to room temperature. The reaction vessel is opened and the solid powder is recovered by centrifugation and washing. Specifically, the centrifuge speed is 8000 rpm, the centrifugation time is 5 min, the mixture is washed 3 times with high-purity water, then washed 3 times with ethanol, and finally placed in a vacuum drying oven at a drying temperature of 60 ℃ for 12 h. The solid powder obtained is named OV-BM-5.

[0041] Example 2

[0042] 1) Place 0.395 g BiNO3·5H2O, 0.119 g KBr and 0.4 g PVP into a polytetrafluoroethylene-lined high-pressure reactor, using ethylene glycol as a solvent. The volume of the solvent should be 2 / 5 of the volume of the high-pressure reactor. Stir for 1 h using a magnetic stirrer at a speed of 800 rpm.

[0043] (2) Weigh 0.0456 g of rod-shaped r-MIL-88A and place it in the polytetrafluoroethylene-lined high-pressure reactor of step (1), and stir for 2 h;

[0044] (3) Tighten the reactor, the reaction temperature is 170 ℃, the reaction time is 12h, and the heating instrument is an electric thermostatic drying oven.

[0045] (4) After the reaction in step (3) is completed, the mixture is allowed to cool naturally to room temperature. The reaction vessel is then opened and the solid powder is recovered by centrifugation and washing. Specifically, the centrifuge speed is 6000 rpm and the centrifugation time is 10 min. The mixture is washed 3 times with high-purity water, then 3 times with ethanol, and finally placed in a vacuum drying oven at a drying temperature of 60 ℃ for 10 h. The powder is then ground. The obtained solid powder is named OV-BM-15.

[0046] Example 3

[0047] 1) Place 0.395 g BiNO3·5H2O, 0.119 g KBr and 0.4 g PVP into a polytetrafluoroethylene-lined high-pressure reactor, using ethylene glycol as a solvent. The volume of the solvent should be 3 / 5 of the volume of the high-pressure reactor. Stir for 2 h using a magnetic stirrer at a speed of 900 rpm.

[0048] (2) Weigh 0.0760 g of rod-shaped r-MIL-88A and place it in the polytetrafluoroethylene-lined high-pressure reactor of step (1), and stir for 2 h;

[0049] (3) Tighten the reactor, the reaction temperature is 160 ℃, the reaction time is 10 h, and the heating instrument is an electric thermostatic drying oven.

[0050] (4) After the reaction in step (3) is completed, the mixture is allowed to cool naturally to room temperature. The reaction vessel is opened and the solid powder is recovered by centrifugation and washing. Specifically, the centrifuge speed is 8000 rpm, the centrifugation time is 5 min, the mixture is washed 3 times with high-purity water, then washed 3 times with ethanol, and finally placed in a vacuum drying oven at a drying temperature of 60 ℃ for 12 h. The solid powder obtained is named OV-BM-25.

[0051] See Figure 1-3 , Figure 1 a represents the morphology of r-MIL-88A, which is a rod-shaped structure with a length of 2 μm. Figure 1 b represents the morphology of OV-BiOBr, which is a flower-shaped specimen with a diameter of 1 μm. Figure 1 c and Figure 2 A large number of OV-BiOBr flower-like structures were found attached to the surface of r-MIL-88A in sample OV-BM-25. Figure 1 di shows that six elements, Fe, Bi, C, N, O and Br, are stably present in OV-BM-25.

[0052] Figure 2 b and Figure 3 The existence of oxygen vacancies in OV-BM-25 can be proven. For example... Figure 2As shown in b, oxygen vacancies disrupt the surface structure of OV-BiOBr, with an interplanar lattice spacing of 0.277 nm, dominated by the (110) plane. The presence of a paramagnetic signal at g = 2.003 in OV-BM-25 also confirms the existence of oxygen vacancies.

[0053] Example 4

[0054] 1) Place 0.395 g BiNO3·5H2O, 0.119 g KBr and 0.4 g PVP into a polytetrafluoroethylene-lined high-pressure reactor, using ethylene glycol as a solvent. The volume of the solvent should be 2 / 5 of the volume of the high-pressure reactor. Stir for 1.5 h using a magnetic stirrer at a speed of 800 rpm.

[0055] (2) Weigh 0.1064 g of rod-shaped r-MIL-88A and place it in the polytetrafluoroethylene-lined high-pressure reactor of step (1), and stir for 1.5 h;

[0056] (3) Tighten the reactor, the reaction temperature is 120 ℃, the reaction time is 12 h, and the heating instrument is an electric thermostatic drying oven.

[0057] (4) After the reaction in step (3) is completed, the mixture is allowed to cool naturally to room temperature. The reaction vessel is opened and the solid powder is recovered by centrifugation and washing. Specifically, the centrifuge speed is 7000 rpm, the centrifugation time is 8 min, the mixture is washed 3 times with high-purity water, then washed 3 times with ethanol, and finally placed in a vacuum drying oven at a drying temperature of 50 ℃ for 11 h. The solid powder obtained is named OV-BM-35.

[0058] Example 5

[0059] 1) Place 0.395 g BiNO3·5H2O, 0.119 g KBr and 0.4 g PVP into a polytetrafluoroethylene-lined high-pressure reactor, using ethylene glycol as a solvent. The volume of the solvent should be 3 / 5 of the volume of the high-pressure reactor. Stir for 2 h using a magnetic stirrer at a speed of 850 rpm.

[0060] (2) Weigh 0.1368 g of rod-shaped r-MIL-88A and place it in the polytetrafluoroethylene-lined high-pressure reactor of step (1), and stir for 2 h;

[0061] (3) Tighten the reactor, the reaction temperature is 160 ℃, the reaction time is 10 h, and the heating instrument is an electric thermostatic drying oven.

[0062] (4) After the reaction in step (3) is completed, the mixture is naturally cooled to room temperature. The reaction vessel is opened and the solid powder is recovered by centrifugation and washing. Specifically, the centrifuge speed is 8000 rpm, the centrifugation time is 5 min, the mixture is washed 3 times with high-purity water, then washed 3 times with ethanol, and finally placed in a vacuum drying oven at a drying temperature of 60 ℃ for 8 h. The solid powder obtained is named OV-BM-45.

[0063] Example 6

[0064] Weigh 10 mg of the catalyst and 50 ml of a 10 mg / L CQ solution separately, and place them in a 100 ml photocatalytic reactor. Adjust the pH to 5 using a 1 mM sodium hydroxide or hydrochloric acid solution, and add 10 μL of H2O2. Mix thoroughly. Then, allow the mixture to adsorb in the dark for 30-60 min until adsorption equilibrium is reached. After that, turn on the light source (white LED) for 10-60 min. Take a 2 mL sample every 10 min using a pipette, filter the catalyst using a 0.22 μm organic filter, and use a liquid UV spectrophotometer to detect changes in CQ concentration in the remaining liquid. Calculate the photodegradation efficiency based on the test results.

[0065] The procedures for the other five common antibiotics (tetracycline (TC), amoxicillin (AMZ), ciprofloxacin (CIP), sulfamethoxazole (SMZ), and bisphenol A (BPA)) are the same as above. After testing, the catalyst is recovered and washed 3-5 times by centrifugation with water and ethanol solutions, respectively. Finally, it is placed in a vacuum drying oven and dried at 60 °C for 12 h. The above procedures are repeated 5 times, constituting 5 test cycles, to demonstrate the catalyst's stability.

[0066] Referring to the accompanying drawings of this invention, the characteristics of the composite photocatalyst of this invention can be fully demonstrated. Figure 4 X-ray diffraction showed that r-MIL-88A had three sharp peaks at 8.2°, 10.2° and 13.0°, corresponding to the (100), (101) and (002) crystal planes, respectively. Figure 5 X-ray diffraction revealed that OV-BiOBr exhibited a broad peak at the (110) crystal plane at 32.8°. With increasing r-MIL-88A content, the peak intensity of the (110) crystal plane in all OV-BiOBr composites of this invention decreased, indicating the successful preparation of the OV-BM composites. Furthermore, the selective absorption of PVP as a surfactant and end-capping agent on certain specific crystal planes inhibited the growth of the (211) and (212) crystal planes, also indicating a strong interaction between r-MIL-88A and OV-BiOBr.

[0067] Figure 6 In the Fourier transform infrared (FTIR) spectrum, characteristic peaks of both r-MIL-88A and OV-BiOBr can be observed simultaneously in OV-BM-25. In particular, due to the stretching vibrations of the C-C bonds and Fe-O bonds, the characteristic peak of r-MIL-88A in OV-BM-25 is redshifted to 1275 cm⁻¹. -1 and 612 cm -1 This indicates a redistribution of charge among functional groups.

[0068] Figure 7 The UV diffuse reflectance spectra of OV-BiOBr, r-MIL-88A, and OV-BM-25 show that the absorption edges for light are located at 430, 500, and 520 nm, respectively. OV-BM-25 exhibits two-stage absorption edges in its diffuse reflectance spectrum, demonstrating that the heterojunction formed by OV-BM-25 can not only improve the separation efficiency of charge carriers but also broaden the photoresponse range, thus contributing to the improvement of photocatalytic efficiency.

[0069] Figure 8 The photo-Fenton test results showed that OV-BM-25 could achieve a degradation efficiency of 97.8% for CQ within 60 minutes, and a degradation efficiency of over 68% for the other 5 antibiotics. Figure 9 Therefore, OV-BM-25 can be regarded as a highly efficient photocatalyst.

[0070] Figure 10 OV-BM-25 showed the highest TOC mineralization rate for CQ (74.27%), which was 6.2 times and 2.1 times that of OV-BiOBr (11.95%) and r-MIL-88A (34.74%), respectively.

[0071] Figure 11 OV-BM-25 showed no significant inactivation after five consecutive cycles, and the CQ degradation rate remained at 89.9% after five cycles (only a loss of approximately 7.9%). Furthermore, according to XRD patterns after the fifth run... Figure 12 a) and FT-IR ( Figure 12 b) It was found that the structure and morphology of OV-BM-25 were stable, indicating that it is reusable and structurally stable.

[0072] Figure 13 The degradation of CQ solution was detected by UPLC-MS, revealing 13 main intermediate products, named BN, with relative molecular masses ranging from 99.10 to 291.15. Based on the reaction mechanism, two main degradation pathways were deduced. Figure 14The photocatalytic reaction (CQ) involves the substituent cleavage reaction of the parent CQ side chain and the oxidative ring-opening reaction of the aromatic ring. It primarily involves a series of successive deamination and decarbonization processes attacking the parent CQ side chain. Specifically, this process forms B, C( and D), which are further oxidized to F, G, and L. Furthermore, reactive oxygen species generated during photocatalysis directly break the CN and C-Cl bonds on the aromatic ring, forming products I, J, and E. The rings of the aromatic intermediates are further oxidized and opened, forming smaller molecules such as M and N. Finally, the intermediates decompose into compounds with even lower molecular weights, and may even eventually mineralize into H2O, CO2, and NO3. - and NH4 + The TOC results also confirm this.

[0073] Figure 15 The biotoxicity of the intermediate products was assessed using quantitative structure-activity relationship (QSAR). Figures show: (a) LC50 of Daphnia macrocarpa (48 hours); (b) LC50 of Daphnia magna (96 hours); (c) developmental toxicity; and (d) mutagenicity. Figure 15 ab indicates that the lethal doses of CQ in *Daphnia macrocarpa* and *Cyprinus maculatus* are 1.52 mg / L and 2.82 mg / L, respectively. Specifically, the developmental toxicity of all CQ degradation intermediates was lower than the initial lethal dose of CQ, and some intermediates were even harmless, demonstrating a reduction in the acute toxicity of the degradation intermediates. Simultaneously, the OV-BM-25 photo-Fenton system also reduced the developmental toxicity and mutagenicity of most degradation intermediates. Figure 15 (cd). The overall results indicate that the OV-BM-25 photo-Fenton system can effectively reduce the potential risks of CQ and related degradation intermediates to aquatic organisms.

[0074] As illustrated by the above embodiments, the preparation method and application of the oxygen-vacancy-rich r-MIL-88A / OV-BiOBr composite photocatalyst of the present invention are mainly used for the degradation of chloroquine phosphate in water, and can also be used for the degradation of other types of antibiotics, exhibiting good photo-Fenton degradation performance and structural stability.

[0075] This invention employs environmentally friendly photo-Fenton treatment technology to convert CQ into low-toxicity or even non-toxic small molecule substances, mostly mineralized H2O, CO2, and NO3. - and NH4 + This research will open up new perspectives for designing novel bismuth-based heterojunction photocatalysts for the treatment of water pollutants through photocatalysis.

Claims

1. The use of an oxygen vacancy-rich r-MIL-88A / OV-BiOBr photo-Fenton catalyst in the degradation of organic pollutants in pharmaceutical wastewater, characterized by, The preparation of the catalyst comprises the following steps: Step 1: In a polytetrafluoroethylene-lined high-pressure reaction kettle, BiNO3·5H2O, KBr and PVP are placed, ethylene glycol is used as a solvent, stirring for 1-2 h, the stirring mode is magnetic stirrer stirring, the stirring speed is 800-900 rpm; the molar ratio of BiNO3·5H2O, KBr and PVP is (80-120):(80-120):(0.8-1.2); the volume of the solvent is 3 / 5-2 / 5 of the volume of the high-pressure reaction kettle; Step 2: Weigh the rod-like r-MIL-88A and place it in the polytetrafluoroethylene-lined high-pressure reaction kettle of step 1, and stir for 1-2 h; wherein the mass of rod-like r-MIL-88A is 1%-45% of the total mass of BiNO3·5H2O, KBr and PVP; X-ray diffraction shows that r-MIL-88A appears three sharp peaks at 8.2°, 10.2° and 13.0°, respectively, corresponding to (100), (101) and (002) crystal planes; Step 3: Tighten the reaction kettle, heat it in an electric heating constant temperature air drying oven, the reaction temperature is 120-170 ℃, and the reaction time is 8-12 h; Step 4: After the reaction of step 3 is completed, naturally cool to room temperature, open the reaction kettle, and recover the solid powder by centrifugal washing; specifically: the centrifuge speed is 6000-8000 rpm, the centrifugal time is 5-10 min, deionized water is washed for 3-5 times, then ethanol is washed for 3-5 times, finally put into a vacuum drying oven, the drying temperature is 40-60 ℃, the drying time is 8-12 h, and grind; the r-MIL-88A / OV-BiOBr photo-Fenton catalyst rich in oxygen vacancies is prepared; The prepared catalyst is placed in drug wastewater with a concentration of 5-20 mg / L, the drug wastewater contains chloroquine phosphate, 1 mM sodium hydroxide or 1 mM hydrochloric acid solution is used to adjust the pH, and 0.98-3.92 mM H2O2 is added and mixed uniformly; then, adsorb for 30-60 min in the dark, after reaching adsorption equilibrium, turn on the light source to irradiate, the irradiation time is 10-60 min; wherein the mass of the catalyst:volume of the drug wastewater:volume of H2O2 ratio is 5-50 mg:50-80 mL:5-50 μL; pH=3-9; the light source is white light LED; under low-power white light LED irradiation, the catalyst can generate reactive oxygen species, degrade organic pollutants in the drug wastewater, and the degradation efficiency reaches 68.08%-97.19% after 60 min of irradiation.

2. The use of the oxygen-vacancy-rich r-MIL-88A / OV-BiOBr photo-Fenton catalyst according to claim 1 for degrading organic pollutants in pharmaceutical wastewater, characterized in that, The transmission electron microscope and scanning electron microscope show that the morphology of the catalyst is a rod-like structure of r-MIL-88A with OV-BiOBr flower balls attached to the surface.

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