A ternary composite photocatalytic material of NH2-MIL-53(Al)@BiOBr@CQDs, its preparation method and application

Abstract

This invention discloses an NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material, its preparation method, and its application. The preparation method first prepares serrated aqueous solutions of NH2-MIL-53(Al) and CQDs via hydrothermal synthesis. Then, during the preparation of BiOBr, the NH2-MIL-53(Al) and CQDs aqueous solutions are added. After centrifugation and drying, the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material is obtained. The NH2-MIL-53(Al)@BiOBr@CQDs prepared by this invention forms a Z-shaped heterojunction. The addition of CQDs provides a bridge for carrier transfer between NH2-MIL-53(Al) and BiOBr, while retaining the highly oxidized h... + , reducing activity e ‑ It is used to degrade pollutants such as antibiotics, and has high photocatalytic activity, good chemical stability, low cost, and simple preparation.

Description

Technical Field

[0001] This invention belongs to the field of functional materials technology, and relates to composite photocatalytic materials, specifically to an NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material, its preparation method, and its application. Background Technology

[0002] The earliest antibiotics were substances produced by microorganisms and possessed the property of inhibiting or killing other microorganisms. As the discovery and research of antibiotics deepened, their application gradually became more widespread. However, over time, the overuse and inappropriate use of antibiotics have led to an increasingly serious problem of antibiotic resistance. Antibiotics can enter water bodies and soil through various pathways, such as municipal sewage discharge, industrial production, livestock farming, and landfill leachate, ultimately ending up in wastewater treatment plants. Many antibiotics, due to their antibacterial properties, cannot be effectively removed by the activated sludge in wastewater treatment plants; therefore, wastewater treatment plants are a major source of antibiotic release into the environment. Currently, environmental pollution mainly stems from the overuse, inappropriate use, and improper treatment of antibiotics, making antibiotic control an urgent priority.

[0003] Currently, various methods exist for removing antibiotics from water, including biodegradation, advanced oxidation, photocatalysis, electrochemical treatment, and adsorption. In comparison, photocatalysis is widely used for degrading antibiotic pollutants due to its simple operation, low energy consumption, lack of secondary pollution, high efficiency, low operating costs, and the use of sunlight as the reaction light source. To improve photocatalytic efficiency, the construction of heterojunctions is particularly important; traditional ternary photocatalysts offer advantages such as high reducing and oxidizing activity.

[0004] Deeksha et al. used a simple solution method to synthesize a novel ternary composite material composed of BiFeO3, g-C3N4, and functionalized carbon nanofibers (f-CNF). Their study found that the decrease in photoluminescence intensity of the ternary composite material indicated suppressed photoexcited electron recombination, leading to more charge carriers available for the photocatalytic process and thus improving photocatalytic activity. (Journal of Alloys and Compounds, 2023, 171073). Ma et al. prepared a ternary heterojunction indium zinc sulfide / metal / semiconductor composite photocatalyst using a simple low-temperature stirring method. The formation of a heterojunction on the metal / semiconductor surface using indium zinc sulfide effectively improved the photoresponse region of the semiconductor and enhanced its light absorption capacity. The metal, acting as a co-catalyst, improved the photocatalytic activity under visible light. (CN117160490A). Liu et al. prepared a nanophotocatalyst, NC-15, by loading Ni3C nanosheets (NSs) and Ni nanoparticles (NPs) onto the surface of CdS nanowires (NWs). Ni NPs provide active sites in photocatalysis, and the internal electric field at the CdS / Ni3C and Ni3C / Ni interfaces can accelerate the separation and migration of photogenerated carriers. CdS-based ternary nanocatalysts have great potential for practical application in photodegradation reactions (Chemical Engineering Journal, 2023, 147242). However, the materials used in these methods are expensive, the preparation process is complex, and energy consumption is high, which is not conducive to large-scale preparation. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide an NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material with high photocatalytic activity, good chemical stability, low cost, and simple preparation method, as well as its preparation method and application.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] A method for preparing an NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material includes the following steps:

[0008] Step 1: Add 0.1~1 g of 2-aminoterephthalic acid and 0.1~1 g of Al(NO3)3·9H2O to deionized water and disperse by ultrasonication. After the dispersion is complete, mix and stir evenly. Place the mixed solution in an oven and perform hydrothermal reaction at 10~300 ℃ for 1~10 h. After the reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, then centrifuge to separate the solid product and dry it to obtain NH2-MIL-53(Al).

[0009] Step 2: Add 1-10 g of urea and 1-10 g of citric acid to 10 ml of deionized water and ultrasonically disperse. After the mixture is complete, stir it evenly and place the mixed solution in an oven for hydrothermal reaction at 100-300 ℃ for 1-10 h. After the reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, then centrifuge and save the supernatant to obtain CQDs aqueous solution.

[0010] Step 3: Add 1~10 mmol KBr and 0.1~1 g NH2-MIL-53(Al) to deionized water to make solution A, and add 1~10 mmol Bi(NO3)3·5H2O and 1~20 ml acetic acid to deionized water to make solution B. Stir the two solutions A and B separately until they are homogeneous. After stirring, mix the two solutions A and B and add 40 μL of CQDs aqueous solution. Then stir again until the dispersion is homogeneous. After completion, let stand, centrifuge, wash and dry to obtain the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material.

[0011] The present invention also has the following technical features:

[0012] Preferably, the ultrasonic dispersion time in steps one and two is 5 to 60 minutes.

[0013] Preferably, the stirring described in steps one and two is performed using a magnetic stirrer for 10 to 50 minutes.

[0014] The centrifugation described in step one involves using N,N-dimethylformamide and ethanol as solvents, and centrifuging three times at a speed of 9000 rpm and a centrifugation time of 5 min.

[0015] The drying process described in steps one and three involves maintaining the temperature at 70 °C for 24 hours in a vacuum drying oven with a pressure of -0.09 MPa.

[0016] The centrifugation speed in step two is 10,000 rpm, and the centrifugation time is 30 min.

[0017] The stirring described in step three involves stirring with a magnetic stirrer for 1 hour.

[0018] The re-stirring mentioned in step three involves stirring with a magnetic stirrer for 1 to 10 hours.

[0019] Preferably, the centrifugal washing agent used in step three is deionized water and ethanol, which are centrifuged three times at 9000 rpm and 5 min respectively.

[0020] This invention also protects an NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material prepared by the method described above and its application in the photocatalytic degradation of antibiotics.

[0021] Compared with the prior art, the present invention has the following technical effects:

[0022] The preparation method of this invention first prepares serrated NH2-MIL-53(Al) via a hydrothermal method, then obtains an aqueous solution of CQDs via a hydrothermal method, and finally adds the NH2-MIL-53(Al) and CQDs aqueous solution during the preparation of BiOBr. After centrifugation and drying, a ternary composite photocatalytic material of NH2-MIL-53(Al)@BiOBr@CQDs is obtained. The serrated NH2-MIL-53(Al) has a large surface area, which makes it easier for the nanoflower-like BiOBr to combine. NH2-MIL-53(Al)@BiOBr@CQDs forms a Z-shaped heterojunction. The addition of CQDs provides a bridge for the transfer of charge carriers between NH2-MIL-53(Al) and BiOBr, while retaining the high oxidation and reduction activity of NH2-MIL-53(Al)@BiOBr@CQDs. + e - It is used to degrade pollutants such as antibiotics;

[0023] The preparation process of this invention is simple, and the prepared ternary composite material has high photocatalytic activity and good chemical stability. It is also low in cost and easy to prepare, and has extremely high benefits in the degradation of antibiotic wastewater. Attached Figure Description

[0024] Figure 1 This is a scanning electron microscope image of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalyst material prepared in this invention;

[0025] Figure 2 This is a transmission image of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material prepared in this invention;

[0026] Figure 3 The UV-Vis absorbance curve of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalyst material prepared in this invention;

[0027] Figure 4 This is a graph showing the free radical capture performance of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material prepared in this invention;

[0028] Figure 5This is a graph showing the recycling performance of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalyst material prepared in this invention;

[0029] Figure 6 These are XRD patterns of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalyst material prepared in this invention before and after use;

[0030] Figure 7 This is a graph showing the photocatalytic performance of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material prepared in this invention. Detailed Implementation

[0031] The specific content of the present invention will be further explained in detail below with reference to the embodiments.

[0032] Example 1

[0033] Step 1: Add 0.1 g of 2-aminoterephthalic acid to 15 ml of deionized water and sonicate for 5 min. Add 1 g of Al(NO3)3·9H2O to 15 ml of deionized water and sonicate for 5 min. Add both solutions to a beaker and stir for 30 min. After stirring, place the beaker in an oven and perform a hydrothermal reaction at 100 ℃ for 1 h. After the hydrothermal reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature. Centrifuge three times each with N,N-dimethylformamide and ethanol at 9000 rpm for 5 min. Place the precipitate obtained by centrifugation in a vacuum drying oven with a pressure of -0.09 MPa and keep it at 70 ℃ for 24 h to obtain NH2-MIL-53(Al).

[0034] Step 2: Add 5 g of urea and 2 g of citric acid to 10 ml of deionized water, sonicate for 10 min, stir for 10 min, and after stirring, put it into an oven for hydrothermal reaction at 100 ℃ for 10 h. After the hydrothermal reaction is completed, wait for the temperature of the reactor to drop to room temperature, centrifuge at 10000 rpm for 30 min, and put the supernatant obtained by centrifugation into a 5 ℃ refrigerator to store and obtain CQDs aqueous solution.

[0035] Step 3: Add 1 mmol KBr and 0.1 NH2-MIL-53(Al) to 100 ml of deionized water to make solution A. Add 10 mmol Bi(NO3)3·5H2O and 5 ml acetic acid to 100 ml of deionized water to make solution B. Stir solutions A and B separately for 1 h. After stirring, mix solutions A and B and add 40 μL of CQDs aqueous solution. Stir for 10 h, let stand for 1 h, and centrifuge three times each at 9000 rpm and 5 min using deionized water and ethanol. Place the precipitate obtained by centrifugation in a vacuum drying oven with a pressure of -0.09 MPa and keep it at 70 ℃ for 24 h to obtain the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material.

[0036] like Figure 1 These are scanning images of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalyst material prepared by this method. Figure 1 It can be seen that the flower-shaped BiOBr and the serrated NH2-MIL-53(Al) are closely bonded, indicating that the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material was successfully prepared.

[0037] Example 2

[0038] Step 1: Add 0.48 g of 2-aminoterephthalic acid to 15 ml of deionized water and sonicate for 5 min. Add 0.1 g of Al(NO3)3·9H2O to 15 ml of deionized water and sonicate for 5 min. Add both solutions to a beaker and stir for 30 min. After stirring, place the beaker in an oven and perform a hydrothermal reaction at 140 ℃ for 4 h. After the hydrothermal reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature. Centrifuge three times each with N,N-dimethylformamide and ethanol at 9000 rpm for 5 min. Place the precipitate obtained by centrifugation in a vacuum drying oven with a pressure of -0.09 MPa and keep it at 70 ℃ for 24 h to obtain NH2-MIL-53(Al).

[0039] Step 2: Add 1 g of urea and 5 g of citric acid to 10 ml of deionized water, sonicate for 10 min, stir for 50 min, and after stirring, place in an oven for hydrothermal reaction at 100 ℃ for 10 h. After the hydrothermal reaction is completed, wait for the temperature of the reactor to drop to room temperature, centrifuge at 10000 rpm for 30 min, and put the supernatant obtained by centrifugation into a 5 ℃ refrigerator to store and obtain CQDs aqueous solution.

[0040] Step 3: Add 5 mmol KBr and 0.3 NH2-MIL-53(Al) to 100 ml of deionized water to make solution A. Add 10 mmol Bi(NO3)3·5H2O and 10 ml acetic acid to 100 ml of deionized water to make solution B. Stir solutions A and B separately for 1 h. After stirring, mix solutions A and B and add 40 μL of CQDs aqueous solution. Stir for 6 h, let stand for 1 h, and centrifuge three times each at 9000 rpm and 5 min with deionized water and ethanol. Place the precipitate obtained by centrifugation in a vacuum drying oven with a pressure of -0.09 MPa and keep it at 70 ℃ for 24 h to obtain the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material.

[0041] like Figure 2 Transmission images of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalyst material prepared in this embodiment. Figure 2 It can be seen that the flower-shaped BiOBr and the serrated NH2-MIL-53(Al) are closely bonded, indicating that the heterojunction interface of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material was successfully prepared.

[0042] Example 3

[0043] Step 1: Add 0.33 g of 2-aminoterephthalic acid to 15 ml of deionized water and sonicate for 5 min. Add 0.1 g of Al(NO3)3·9H2O to 15 ml of deionized water and sonicate for 5 min. Add both solutions to a beaker and stir for 20 min. After stirring, place the beaker in an oven and perform a hydrothermal reaction at 150 ℃ for 6 h. After the hydrothermal reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature. Centrifuge three times each with N,N-dimethylformamide and ethanol at 9000 rpm for 5 min. Place the precipitate obtained by centrifugation in a vacuum drying oven with a pressure of -0.09 MPa and keep it at 70 ℃ for 24 h to obtain NH2-MIL-53(Al).

[0044] Step 2: Add 1 g of urea and 10 g of citric acid to 10 ml of deionized water, sonicate for 5 min, stir for 50 min, and after stirring, place in an oven for hydrothermal reaction at 180 ℃ for 3 h. After the hydrothermal reaction is completed, wait for the temperature of the reactor to drop to room temperature, centrifuge at 10000 rpm for 30 min, and put the supernatant obtained by centrifugation into a 5 ℃ refrigerator to store and obtain CQDs aqueous solution.

[0045] Step 3: Add 10 mmol KBr and 0.1 NH2-MIL-53(Al) to 100 ml of deionized water to make solution A. Add 5 mmol Bi(NO3)3·5H2O and 20 ml acetic acid to 100 ml of deionized water to make solution B. Stir solutions A and B separately for 1 h. After stirring, mix solutions A and B and add 40 μL of CQDs aqueous solution. Stir for another 1 h and let stand for 1 h. Centrifuge three times each with deionized water and ethanol at 9000 rpm for 5 min. Place the precipitate obtained by centrifugation into a vacuum drying oven with a pressure of -0.09 MPa and keep it at 70 ℃ for 24 h to obtain the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material.

[0046] like Figure 3 The UV-Vis absorbance curve of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalyst material prepared in this embodiment is shown below. Figure 3 It can be seen that the absorbance of NH2-MIL-53(Al)@BiOBr@CQDs extends to 503 nm, broadening the absorption range of the photocatalyst.

[0047] Example 4

[0048] Step 1: Add 0.33 g of 2-aminoterephthalic acid to 15 ml of deionized water and sonicate for 15 min. Add 0.1 g of Al(NO3)3·9H2O to 15 ml of deionized water and sonicate for 15 min. Add both solutions to a beaker and stir for 20 min. After stirring, place the beaker in an oven and perform a hydrothermal reaction at 150 ℃ for 6 h. After the hydrothermal reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature. Centrifuge three times each with N,N-dimethylformamide and ethanol at 9000 rpm for 5 min. Place the precipitate obtained by centrifugation in a vacuum drying oven with a pressure of -0.09 MPa and keep it at 70 ℃ for 24 h to obtain NH2-MIL-53(Al).

[0049] Step 2: Add 5 g of urea and 3 g of citric acid to 10 ml of deionized water, sonicate for 20 min, stir for 30 min, and after stirring, place in an oven for hydrothermal reaction at 120 ℃ for 5 h. After the hydrothermal reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, centrifuge at 10000 rpm for 30 min, and put the supernatant obtained by centrifugation into a 5 ℃ refrigerator to store and obtain CQDs aqueous solution.

[0050] Step 3: Add 10 mmol KBr and 0.3 NH2-MIL-53(Al) to 100 ml of deionized water to make solution A. Add 5 mmol Bi(NO3)3·5H2O and 9 ml acetic acid to 100 ml of deionized water to make solution B. Stir solutions A and B separately for 1 h. After stirring, mix solutions A and B and add 40 μL of CQDs aqueous solution. Stir for 4 h, let stand for 1 h, and centrifuge three times each with deionized water and ethanol at 9000 rpm for 5 min. Place the precipitate obtained by centrifugation in a vacuum drying oven with a pressure of -0.09 MPa and keep it at 70 ℃ for 24 h to obtain the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material.

[0051] like Figure 4 To assess the free radical capture performance of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalyst material prepared in this embodiment, from... Figure 4 It can be seen that the active substances play a significant role in degrading antibiotics, among which ·O 2- Free radicals > ·OH free radicals > h + ,·O 2- Free radicals are the main active species in the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material.

[0052] Example 5

[0053] Step 1: Add 0.77 g of 2-aminoterephthalic acid to 15 ml of deionized water and sonicate for 20 min. Add 0.1 g of Al(NO3)3·9H2O to 15 ml of deionized water and sonicate for 20 min. Add both solutions to a beaker and stir for 20 min. After stirring, place the beaker in an oven and perform a hydrothermal reaction at 150 ℃ for 6 h. After the hydrothermal reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature. Centrifuge three times each with N,N-dimethylformamide and ethanol at 9000 rpm for 5 min. Place the precipitate obtained by centrifugation in a vacuum drying oven with a pressure of -0.09 MPa and keep it at 70 ℃ for 24 h to obtain NH2-MIL-53(Al).

[0054] Step 2: Add 6 g of urea and 5 g of citric acid to 10 ml of deionized water, sonicate for 60 min and stir for 50 min. After stirring, place in an oven and carry out a hydrothermal reaction at 180 ℃ for 3 h. After the hydrothermal reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, centrifuge at 10000 rpm for 30 min, and put the supernatant obtained by centrifugation into a 5 ℃ refrigerator to store and obtain CQDs aqueous solution.

[0055] Step 3: Add 10 mmol KBr and 0.1 NH2-MIL-53(Al) to 100 ml of deionized water to make solution A. Add 10 mmol Bi(NO3)3·5H2O and 1.6 ml acetic acid to 100 ml of deionized water to make solution B. Stir solutions A and B separately for 1 h. After stirring, mix solutions A and B and add 40 μL of CQDs aqueous solution. Stir for 4 h, let stand for 1 h, and centrifuge three times each at 9000 rpm and 5 min with deionized water and ethanol. Place the precipitate obtained by centrifugation into a vacuum drying oven with a pressure of -0.09 MPa and keep it at 70 ℃ for 24 h to obtain the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material.

[0056] like Figure 5 To assess the recyclability of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalyst material prepared in this embodiment, from... Figure 5 It can be seen that the cycle efficiency of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalyst material decreased slightly. This is because some antibiotics are still adsorbed on the surface of the composite material. However, the photocatalytic cycle degradation efficiency of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalyst material is relatively stable.

[0057] Example 6

[0058] Step 1: Add 1 g of 2-aminoterephthalic acid to 15 ml of deionized water and sonicate for 50 min. Add 0.5 g of Al(NO3)3·9H2O to 15 ml of deionized water and sonicate for 50 min. Add both solutions to a beaker and stir for 10 min. After stirring, place the beaker in an oven and perform a hydrothermal reaction at 300 ℃ for 1 h. After the hydrothermal reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature. Centrifuge three times each with N,N-dimethylformamide and ethanol at 9000 rpm for 5 min. Place the precipitate obtained by centrifugation in a vacuum drying oven with a pressure of -0.09 MPa and keep it at 70 ℃ for 24 h to obtain NH2-MIL-53(Al).

[0059] Step 2: Add 6 g of urea and 5 g of citric acid to 10 ml of deionized water, sonicate for 10 min, stir for 30 min, and after stirring, place in an oven for a hydrothermal reaction at 300 ℃ for 1 h. After the hydrothermal reaction is complete, allow the temperature of the reactor to drop to room temperature. Centrifuge at 10000 rpm for 30 min, and store the supernatant obtained by centrifugation in a 5 ℃ refrigerator to obtain a CQDs aqueous solution.

[0060] Step 3: Add 10 mmol KBr and 0.3 g NH2-MIL-53(Al) to 100 ml deionized water to make solution A, and add 10 mmol Bi(NO3)3·5H2O and 1.6 ml acetic acid to 100 ml deionized water to make solution B. Stir solutions A and B separately for 1 h. After stirring, mix solutions A and B and add 40 μL of CQDs aqueous solution. Stir for 6 h, let stand for 1 h, and centrifuge three times each with deionized water and ethanol at 9000 rpm for 5 min. Place the precipitate obtained by centrifugation in a vacuum drying oven with a pressure of -0.09 MPa and keep it at 70 ℃ for 24 h to obtain the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material.

[0061] like Figure 6 XRD patterns of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalyst material prepared in this embodiment before and after use, from... Figure 6 It can be seen that the XRD pattern of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalyst material did not change before and after use, indicating that the structure of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalyst material is stable.

[0062] Example 7

[0063] Step 1: Add 0.33 g of 2-aminoterephthalic acid to 15 ml of deionized water and sonicate for 60 min. Add 1 g of Al(NO3)3·9H2O to 15 ml of deionized water and sonicate for 60 min. Add both solutions to a beaker and stir for 50 min. After stirring, place the beaker in an oven and perform a hydrothermal reaction at 10 ℃ for 10 h. After the hydrothermal reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature. Centrifuge three times each with N,N-dimethylformamide and ethanol at 9000 rpm for 5 min. Place the precipitate obtained by centrifugation in a vacuum drying oven with a pressure of -0.09 MPa and keep it at 70 ℃ for 24 h to obtain NH2-MIL-53(Al).

[0064] Step 2: Add 10 g of urea and 1 g of citric acid to 10 ml of deionized water, sonicate for 10 min, stir for 30 min, and after stirring, place in an oven for hydrothermal reaction at 120 ℃ for 3 h. After the hydrothermal reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, centrifuge at 10000 rpm for 30 min, and put the supernatant obtained by centrifugation into a 5 ℃ refrigerator to store and obtain CQDs aqueous solution.

[0065] Step 3: Add 10 mmol KBr and 1 g NH2-MIL-53(Al) to 100 ml deionized water to make solution A. Add 1 mmol Bi(NO3)3·5H2O and 1 ml acetic acid to 100 ml deionized water to make solution B. Stir solutions A and B separately for 1 h. After stirring, mix solutions A and B and add 40 μL of CQDs aqueous solution. Stir for 6 h, let stand for 1 h, and centrifuge three times each with deionized water and ethanol at 9000 rpm for 5 min. Place the precipitate obtained by centrifugation in a vacuum drying oven with a pressure of -0.09 MPa and keep it at 70 ℃ for 24 h to obtain the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material.

[0066] Figure 7 The photocatalytic performance of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material prepared in this embodiment is shown. The photocatalytic degradation efficiency of ciprofloxacin is as high as 94.24%, and the construction of the ternary system improves the photocatalytic activity.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material, characterized in that, Includes the following steps: Step 1: Add 0.1~1 g of 2-aminoterephthalic acid and 0.1~1 g of Al(NO3)3·9H2O to deionized water and disperse by ultrasonication. After the dispersion is complete, mix and stir evenly. Place the mixed solution in an oven and hydrothermally react at 100~300 ℃ for 1~10 h. After the reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, then centrifuge to separate the solid product and dry it to obtain NH2-MIL-53(Al). Step 2: Add 1-10 g of urea and 1-10 g of citric acid to 10 mL of deionized water and disperse by ultrasonication. After the mixture is completed, stir it evenly and place the mixed solution in an oven for hydrothermal reaction at 100-300 ℃ for 1-10 h. After the reaction is completed, wait for the temperature of the reaction vessel to drop to room temperature, then centrifuge and save the supernatant to obtain CQDs aqueous solution. Step 3: Add 1~10 mmol KBr and 0.1~1 g NH2-MIL-53(Al) to deionized water to make solution A, and add 1~10 mmol Bi(NO3)3·5H2O and 1~20 mL acetic acid to deionized water to make solution B. Stir the two solutions A and B separately until they are homogeneous. After stirring, mix the two solutions A and B and add 40 μL of CQDs aqueous solution. Then stir again until the dispersion is homogeneous. After completion, let stand, centrifuge, wash and dry to obtain NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material.

2. The preparation method of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material as described in claim 1, characterized in that, The ultrasonic dispersion time mentioned in steps one and two is 5 to 60 minutes.

3. The preparation method of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material as described in claim 1, characterized in that, The stirring described in steps one and two involves stirring with a magnetic stirrer for 10 to 50 minutes.

4. The preparation method of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material as described in claim 1, characterized in that, The centrifugation described in step one involves using N,N-dimethylformamide and ethanol as solvents, and centrifuging three times at a speed of 9000 rpm and a centrifugation time of 5 min.

5. The preparation method of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material as described in claim 1, characterized in that, The drying process described in steps one and three involves maintaining the temperature at 70 °C for 24 hours in a vacuum drying oven with a pressure of -0.09 MPa.

6. The preparation method of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material as described in claim 1, characterized in that, The centrifugation speed in step two is 10,000 rpm, and the centrifugation time is 30 min.

7. The preparation method of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material as described in claim 1, characterized in that, The stirring described in step three involves stirring with a magnetic stirrer for 1 hour. The re-stirring mentioned in step three involves stirring with a magnetic stirrer for 1 to 10 hours.

8. The preparation method of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material as described in claim 1, characterized in that, The centrifugal washing described in step three involves centrifuging three times each with deionized water and ethanol at 9000 rpm for 5 min.

9. A ternary composite photocatalytic material of NH2-MIL-53(Al)@BiOBr@CQDs prepared by the method according to any one of claims 1 to 8.

10. The application of the NH2-MIL-53(Al)@BiOBr@CQDs ternary composite photocatalytic material as described in claim 9 in the photocatalytic degradation of antibiotics.

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