Cu-s-bi4nbo8br photocatalyst, preparation method and application thereof

Abstract

The application belongs to the technical field of water purification, and particularly relates to a Cu-S-Bi4NbO8Br photocatalyst, a preparation method and application. The photocatalyst takes Bi4NbO8Br as a base body, introduces copper elements and sulfur elements to form a composite photocatalytic material through a co-doping mode; the copper elements are in an atomic dispersion form to replace Bi atoms in a Bi4NbO8Br crystal lattice, and the sulfur elements are doped in a gap or a surface of the Bi4NbO8Br crystal lattice; and the doping amount of the copper elements is less than 1.0% of the mass of the Bi4NbO8Br base body. The Cu-S-Bi4NbO8Br photocatalyst provided by the application has excellent performance in degrading antibiotics, inactivating drug-resistant bacteria and degrading resistance genes, can achieve a degradation efficiency of more than 99% on tetracycline within 10 minutes, realizes complete inactivation on drug-resistant bacteria, and has a degradation rate constant of 2.2 min ‑1 on resistance genes, and has good environmental anti-interference performance and cycle stability on actual wastewater, and has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of water purification technology, specifically relating to a Cu-S-Bi4NbO8Br photocatalyst, its preparation method, and its application. Background Technology

[0002] The release of antibiotics, antibiotic-resistant bacteria (ARBs), and antibiotic resistance genes (ARGs) into water systems exacerbates the global spread of antimicrobial resistance (AMR), posing a serious threat to public health and necessitating advanced water treatment solutions. While traditional water treatment processes such as physical adsorption and biodegradation can partially remove conventional pollutants, their removal efficiency for these emerging and highly hazardous pollutants is often limited, failing to achieve complete harmlessness and potentially even leading to further accumulation and spread of resistant bacteria and resistance genes.

[0003] Against this backdrop, advanced oxidation processes based on semiconductors, particularly advanced photocatalysis, have attracted significant attention due to their immense potential in environmental remediation. This technology utilizes light energy to drive catalysts to generate highly oxidizing active species, offering advantages such as low energy consumption, reliance on solar energy, the ability to achieve deep mineralization of pollutants, no secondary pollution, and mild reaction conditions. It is considered one of the most promising green technology pathways for addressing antibiotic and AMR pollution issues.

[0004] However, the transition of this technology from laboratory research to practical engineering applications still faces a series of key bottlenecks, primarily stemming from the inherent limitations of traditional semiconductor photocatalyst materials. Extensively studied typical materials such as TiO2, ZnO, and MnO2, while possessing advantages like good stability and non-toxicity, typically have photoresponse ranges limited to the ultraviolet region, exhibiting extremely low utilization efficiency for the visible light that constitutes the majority of the solar spectrum. Furthermore, these materials generally suffer from inherent defects such as the rapid recombination of photogenerated electron-hole pairs, low charge separation and migration efficiency, and a limited number of surface active sites. These material-level deficiencies directly lead to the core contradiction in the photocatalytic process: on the one hand, limited light absorption restricts the initial yield of ROS; on the other hand, even when charge carriers are generated, their short lifetimes prevent them from effectively migrating to the catalyst surface to participate in the reaction before internal recombination. Therefore, overcoming the performance bottlenecks of traditional photocatalysts and designing and developing novel photocatalytic materials with broad spectral response, efficient charge separation capabilities, and abundant surface active sites is a prerequisite and core research task for truly applying photocatalysis technology to the in-depth treatment of new pollutants.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] To address the limitations of existing photocatalysts in removing antibiotics, drug-resistant bacteria, and drug-resistant genes from water, as well as their low visible light utilization efficiency, this invention provides a Cu-S-Bi4NbO8Br photocatalyst, its preparation method, and its applications. This photocatalyst, through the synergistic effect of co-doping with copper and sulfur, forms a stronger internal electric field within Bi4NbO8Br, significantly promoting the separation and transfer of photogenerated charges, increasing the lifetime of photogenerated carriers, and realizing the utilization of reactive oxygen species (…). 1 It achieves efficient generation of O2 and •OH, thus possessing excellent photocatalytic performance.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A Cu-S-Bi4NbO8Br photocatalyst is disclosed, which uses Bi4NbO8Br as a matrix and introduces copper and sulfur elements through co-doping to form a composite photocatalytic material. The copper elements replace Bi atoms in the Bi4NbO8Br lattice in an atomically dispersed form, and the sulfur elements are doped in the interstitial spaces or surface of the Bi4NbO8Br lattice. The doping amount of the copper elements is less than 1.0% of the mass of the Bi4NbO8Br matrix.

[0009] Furthermore, the amount of copper doping is 0.2% to 1.0% of the mass of the Bi4NbO8Br matrix; the sulfur element is introduced by sublimation sulfur, and the amount of sulfur doping is 1% to 3% of the mass of the copper-doped Bi4NbO8Br composite material.

[0010] Furthermore, the Cu-S-Bi4NbO8Br photocatalyst has a rectangular nanoplate structure with a length of 300~900 nm and a thickness of 150~170 nm; the band gap of the Cu-S-Bi4NbO8Br photocatalyst is 2.0~2.2 eV.

[0011] In addition, the present invention also provides a method for preparing the Cu-S-Bi4NbO8Br photocatalyst as described above, comprising the following steps:

[0012] S1. Prepare Bi4NbO8Br matrix material, disperse it in water to form a dispersion, and then treat it with ultrasound for later use;

[0013] S2. Add copper chloride solution to the dispersion in step S1, stir the reaction under inert gas protection, and obtain copper-doped Bi4NbO8Br composite material powder by centrifugation, washing and drying.

[0014] S3. Mix the copper-doped Bi4NbO8Br composite powder from step S2 with sublimed sulfur in an organic solvent, heat and stir until the solvent is completely evaporated to obtain a solid mixture.

[0015] S4. The solid mixture from step S3 is calcined under an inert gas atmosphere to obtain the Cu-S-Bi4NbO8Br photocatalyst.

[0016] Further, in step S1, the Bi4NbO8Br matrix material is prepared by the following method: Bi2O3, BiOBr, Nb2O5, NaBr and KBr are mixed and ground in a certain proportion, then calcined, cooled, washed and dried to obtain Bi4NbO8Br; wherein, the molar ratio of Bi2O3, BiOBr, Nb2O5, NaBr and KBr is (2.8~3.3):(1.8~2.2):(0.8~1.2):30:30; the grinding method is ball milling, the ball milling time is 80~100 minutes, the calcination temperature is 650~950℃, and the calcination time is 4~6 hours; ultrapure water with a temperature of 95℃ or higher is used for washing;

[0017] And / or, the concentration of Bi4NbO8Br in the dispersion is 5~7 g / L, the ultrasonic treatment temperature is 0~4℃, and the ultrasonic treatment time is 40~60 minutes.

[0018] Further, in step S2, the mass ratio of copper element to Bi4NbO8Br matrix material in the copper chloride solution is (0.002~0.01):1, and the concentration of copper chloride solution is 3~7 g / L;

[0019] And / or, the temperature of the stirring reaction is 30~50℃, the stirring time is 1~2 hours, the inert gas is argon, and the argon flow rate is 30~50 mL / min.

[0020] Further, in step S3, the organic solvent is a mixture of carbon tetrachloride and ethanol, with a volume ratio of carbon tetrachloride to ethanol of (2~5):1; the heating temperature is 40~80℃.

[0021] Furthermore, in step S4, the calcination temperature is 600~700℃, the calcination time is 2~4 hours, the inert gas is argon, and the argon flow rate is 60~80 mL / min.

[0022] In addition, the present invention also provides an application of the Cu-S-Bi4NbO8Br photocatalyst as described above in water purification, for removing antibiotics, drug-resistant bacteria and drug-resistant genes from wastewater.

[0023] Furthermore, the antibiotic is tetracycline, the drug-resistant bacterium is Staphylococcus aureus MRSA, and the drug resistance gene is the tetracycline resistance gene tetA.

[0024] Compared with the prior art, the technical solution of the present invention has at least the following technical effects:

[0025] (1) The Cu-S-Bi4NbO8Br photocatalyst provided by this invention has the advantages of high efficiency, rapid degradation, and green economy. Its degradation efficiency for tetracycline reaches more than 99% within 10 minutes, its inactivation efficiency for ARB can reach 100%, and its degradation rate for ARG can reach 2.2 min. -1 Copper doping and sulfur doping work synergistically to create a stronger internal electric field within Bi4NbO8Br, which synergistically promotes the separation and transfer of photogenerated charges, improves the lifetime of photogenerated carriers, and achieves ROS (Reactive Oxygen Spectroscopy). 1 Efficient generation of O2 and •OH.

[0026] (2) The Cu-S-Bi4NbO8Br photocatalyst obtained by the preparation method of the present invention can still maintain a high efficiency in removing antibiotics, antibiotic-resistant bacteria (ARBs) and antibiotic resistance genes (ARGs) in the secondary effluent of sewage treatment plants after 20 hours of continuous treatment. The copper ion leaching amount of Cu-S-Bi4NbO8Br material is lower than the water quality standard requirements, and there is no secondary pollution, which fully reflects the characteristics of high efficiency, stability and environmental friendliness.

[0027] (3) The photocatalyst of the present invention has a simple preparation process, mild conditions, and is easy to industrialize. It also has a wide visible light response range, high catalytic efficiency, and good cycle stability. (The Cu-S local electron pairs formed by Cu-S co-doping induce uneven charge distribution within the lattice, constructing a stable built-in electric field. This electric field will not decay due to long-term reaction, continuously providing directional driving force for photogenerated electron-hole pairs, significantly reducing the recombination rate (the steady-state photoluminescence spectrum peak intensity remains at a low level for a long time), ensuring the survival of reactive oxygen species.) 1 With advantages such as continuous generation of O2 and OH radicals and environmental friendliness, it can quickly and efficiently remove antibiotics, drug-resistant bacteria and drug-resistant genes from wastewater, providing a new technical solution for the treatment of emerging pollutants in water bodies. It has important practical application value and broad market prospects. Attached Figure Description

[0028] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein:

[0029] Figure 1 SEM image of the Cu-S-Bi4NbO8Br photocatalyst prepared in Example 1 of this invention;

[0030] Figure 2 The images shown are TEM and HRTEM images of the Cu-S-Bi4NbO8Br photocatalyst prepared in Example 1 of this invention. Figure 2 (a) in the image is a TEM image. Figure 2 (b) in the figure is the HRTEM diagram;

[0031] Figure 3 HAADF-STEM image of the Cu-S-Bi4NbO8Br photocatalyst prepared in Example 1 of this invention;

[0032] Figure 4 The UV-Vis diffuse reflectance spectra and band gap diagrams of the Cu-S-Bi4NbO8Br photocatalyst prepared in Example 1 of this invention and the materials prepared in Comparative Examples 1 and 2 are shown below. Figure 4 In the image, (a) represents the ultraviolet-visible diffuse reflectance spectrum. Figure 4 (b) in the diagram is the bandgap diagram;

[0033] Figure 5 Steady-state photoluminescence spectra of the Cu-S-Bi4NbO8Br photocatalyst prepared in Example 1 of the present invention and the materials prepared in Comparative Examples 1 and 2;

[0034] Figure 6 The EPR spectra of the Cu-S-Bi4NbO8Br photocatalyst prepared in Example 1 of this invention and the materials prepared in Comparative Examples 1 and 2 are shown below, indicating the generation of active oxygen species. Figure 6 (a) in the middle is 1 EPR spectrum of O2 Figure 6 (b) in the image is the EPR spectrum of •OH. Figure 6 (c) in the text represents O2. •- EPR spectrum;

[0035] Figure 7 The Cu-S-Bi4NbO8Brr photocatalyst prepared in Example 1 of this invention and the materials prepared in Comparative Examples 1 and 2 are generated during the photocatalytic process. 1 O2, •OH and O2 •- Concentration results graph;

[0036] Figure 8 The graph shows a comparison of the degradation efficiency of tetracycline by the Cu-S-Bi4NbO8Br photocatalysts prepared in Examples 1-6 of this invention and the materials prepared in Comparative Examples 1 and 2.

[0037] Figure 9 The graph shows a comparison of the inactivation efficiency of Cu-S-Bi4NbO8Br photocatalysts prepared in Examples 1-6 of this invention with the materials prepared in Comparative Examples 1 and 2 for MRSA.

[0038] Figure 10 This is a comparison of the degradation rate and degradation efficiency of the Cu-S-Bi4NbO8Br photocatalyst prepared in Examples 1-6 of this invention with the materials prepared in Comparative Examples 1 and 2 against the tetracycline resistance gene (tetA).

[0039] Figure 11 The degradation efficiency of Cu-S-Bi4NbO8Br photocatalyst prepared in Example 1 of this invention on tetracycline and its effect on MRSA under different dosages. tetA The removal efficiency, of which Figure 11 In the figure, (a) represents the degradation efficiency of tetracycline. Figure 11 (b) represents the removal efficiency of MRSA and tetA;

[0040] Figure 12 This is a physical image of a continuous flow reactor used in this invention to test the removal performance of the Cu-S-Bi4NbO8Br photocatalyst prepared in Example 1 and the material prepared in Comparative Example 1 on tetracycline, drug-resistant bacteria and drug-resistant genes in actual wastewater treatment.

[0041] Figure 13 The graph shows the results of treating actual wastewater using a continuous flow reactor prepared with the Cu-S-Bi4NbO8Br photocatalyst prepared in Example 1 of this invention and the material prepared in Comparative Example 1. Figure 13 (b) represents the tetracycline degradation efficiency. Figure 13 (c) in the figure represents sterilization efficiency. Figure 13 (d) in the middle is tetA Removal efficiency Figure 13 (e) in the figure represents the changes in water flow rate and Cu ion leakage over time. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Those skilled in the art should understand that the embodiments described are merely illustrative of the invention and should not be considered as specific limitations thereof. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Process parameters not specifically specified in the following embodiments are generally performed under conventional conditions.

[0043] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0044] According to a first aspect of the present invention, a Cu-S-Bi4NbO8Br photocatalyst is provided, which uses Bi4NbO8Br as a matrix and introduces copper and sulfur elements through co-doping to form a composite photocatalytic material; wherein the copper elements replace Bi atoms in the Bi4NbO8Br lattice in an atomically dispersed form, and the sulfur elements are doped in the interstitial spaces or surface of the Bi4NbO8Br lattice; the doping amount of the copper elements is less than 1.0% of the mass of the Bi4NbO8Br matrix, preferably 0.2% to 1.0%. The sulfur elements are introduced by sublimation sulfur, and the doping amount of the sulfur elements is 1% to 3% of the mass of the copper-doped Bi4NbO8Br composite material.

[0045] This photocatalyst has a rectangular nanoplate structure with a length of 300–900 nm, a thickness of 150–170 nm, a band gap of 2.0–2.2 eV, and a visible light absorption edge of no less than 550 nm. Under visible light irradiation with a wavelength ≥420 nm, this photocatalyst can simultaneously generate singlet oxygen (…). 1 This photocatalyst exhibits excellent photocatalytic performance, containing two reactive oxygen species: O2 and hydroxyl radicals (•OH). Under conditions of light intensity of 50–150 mW / cm², dosage of 20–100 mg / L, and reaction temperature of 20–30 °C, the photocatalyst achieves a degradation efficiency of over 99% for tetracycline within 10 minutes, a 100% inactivation efficiency for antibiotic-resistant bacteria (ARBs), and a degradation rate of antibiotic resistance genes (ARGs) of up to 2.2 min. -1 Furthermore, the photocatalyst exhibits good cycle stability. After continuously treating actual wastewater for 20 hours, its degradation efficiency for tetracycline remains no less than 98%, its removal rate of the tetracycline resistance gene (tetA) remains no less than 99.9%, and its copper ion leaching amount is less than 15 μg / L, with no risk of secondary pollution.

[0046] In the photocatalyst of this invention, the co-doping of Cu and S is not a simple elemental superposition, but rather a highly efficient synergistic system of "electron transport-charge separation-active species generation" is constructed through multi-dimensional interactions such as electronic structure regulation, charge separation enhancement, and active site synergy. This significantly improves the photocatalytic performance of Cu-S-Bi4NbO8Br. The specific synergistic mechanism is as follows:

[0047] (1) Cu + / Cu 2+ The 3d orbital energy level of Cu-S forms a coupling effect with the 3p orbital energy level of S, further reconstructing the band structure. This results in a more continuous energy level gradient between the impurity energy level and the conduction and valence bands of Cu-S-Bi4NbO8Br, which broadens the absorption edge to 558.8 nm and narrows the band gap to 2.01 eV, significantly improving the capture efficiency of visible light (especially in the 420~600 nm range).

[0048] (2) Although Cu doping alone can pass through Cu + / Cu 2+ The redox cycle traps photogenerated electrons, but it easily forms local electron-rich regions, leading to charge aggregation. While lattice defects introduced by S doping alone can provide charge-trapping sites, excessively high defect densities can turn them into recombination centers. Cu atoms form cation doping sites by substituting Bi atoms in the Bi4NbO8Br lattice, while S atoms exist in interstitial spaces or surface adsorption forms. These two atoms spatially form local "Cu-S" electron pairs. This structural difference causes uneven charge distribution within the lattice, creating a stronger internal electric field. This internal electric field provides a directional driving force for photogenerated electron-hole pairs, enabling photogenerated electrons to rapidly transfer from the conduction band of Bi4NbO8Br to Cu. + The photogenerated carriers are then transferred to the catalyst surface via electron bridging of S atoms; simultaneously, photogenerated holes are captured by the 3p orbitals of S and remain near the valence band. This cooperative transport path significantly shortens the charge migration distance, resulting in a significant reduction in the recombination rate of photogenerated carriers (the steady-state photoluminescence peak intensity is reduced by more than 50% compared to single doping).

[0049] (3) Cu doping alone can only weakly promote the generation of •OH, and S doping alone cannot effectively activate molecular oxygen to generate reactive oxygen species. 1 O2 and •OH result in limited catalytic oxidation ability. Cu + / Cu 2+ The redox cycle and the synergistic effect of S doping jointly optimize the triplet sensitization capability of the catalyst: the Cu active center promotes the chemisorption and activation of molecular oxygen, forming an interface structure more conducive to energy transfer; the S doping enhances the separation of photogenerated carriers and the yield of triplet excitons by adjusting the local electronic structure of the material. Under this synergistic effect, the photoexcited triplet excited state of the catalyst can directly and efficiently transfer energy to the adsorbed ground-state oxygen molecules (…). 3 O2, thus selectively activating it into singlet oxygen ( 1 O2); on the other hand, Cu 2+ Synergistically interacting with holes in the valence band of Bi4NbO8Br, it activates adsorbed water on the surface to generate •OH, after co-doping 1 The generation of O2 and •OH is increased by 3 to 4 times compared with single doping. The two active oxygen species work synergistically to form a dual effect of "oxidation-destruction" on tetracycline, drug-resistant bacteria and drug-resistant genes, which greatly improves the degradation and inactivation efficiency.

[0050] (4) In the photocatalytic reaction, Cu 2+ Reduced to Cu by photogenerated electrons + S supplements Cu through electron transfer. +Electron depletion, maintaining Cu⁺ / Cu 2+ The redox cycle is regulated; at the same time, the presence of S inhibits the leaching of Cu ions from the lattice, ensuring the structural stability of the active sites and enabling the catalyst to maintain high efficiency after 20 hours of continuous operation.

[0051] In summary, Cu-S co-doping, through the synergistic effect of bandgap modulation, charge separation, active species generation, and surface adsorption, breaks through the performance bottleneck of single-element doping, enabling Bi4NbO8Br to possess efficient and stable photocatalytic activity under visible light, thus providing a foundation for the deep removal of antibiotics, drug-resistant bacteria, and drug-resistant genes from water.

[0052] According to a second aspect of the present invention, a method for preparing the Cu-S-Bi4NbO8Br photocatalyst as described above is provided, comprising the following steps:

[0053] S1. Prepare Bi4NbO8Br matrix material, disperse it in water to form a dispersion, and then treat it with ultrasound for later use;

[0054] S2. Add copper chloride solution to the dispersion in step S1, stir the reaction under inert gas protection, and obtain copper-doped Bi4NbO8Br composite material powder by centrifugation, washing and drying.

[0055] S3. The copper-doped Bi4NbO8Br composite powder from step S2 is mixed with sublimed sulfur (sublimed sulfur has inherent losses such as low mass transfer efficiency, easy volatility and competitive side reactions with the substrate during co-calcination, so the actual amount of material must be several times the theoretical value to ensure effective doping reaction kinetics) in an organic solvent, and heated and stirred until the solvent is completely evaporated to obtain a solid mixture.

[0056] S4. The solid mixture from step S3 is calcined under an inert gas atmosphere to obtain the Cu-S-Bi4NbO8Br photocatalyst.

[0057] Based on the above scheme, as a preferred embodiment, in step S1, the Bi4NbO8Br matrix material is prepared by the following method: Bi2O3, BiOBr, Nb2O5, NaBr and KBr are mixed in a molar ratio of (2.8~3.3):(1.8~2.2):(0.8~1.2):30:30, and the mixture is ball-milled for 80~100 minutes. Then, the mixture is calcined at 650~950℃ for 4~6 hours, naturally cooled to room temperature (20~25℃), washed with ultrapure water above 95℃ to remove impurities, and vacuum dried to obtain the Bi4NbO8Br matrix material.

[0058] In step S1, the concentration of Bi4NbO8Br in the dispersion is 5~7 g / L, the ultrasonic treatment temperature is 0~4℃, and the ultrasonic treatment time is 40~60 minutes to ensure that Bi4NbO8Br is fully dispersed.

[0059] In step S2, the mass ratio of copper element to Bi4NbO8Br matrix material in the copper chloride solution is (0.002~0.01):1, and the concentration of copper chloride solution is 3~7 g / L; the stirring temperature is 30~50℃, the stirring time is 1~2 hours, and argon gas is introduced for protection during stirring, with an argon gas flow rate of 30~50 mL / min; after the reaction is completed, the precipitate is collected by centrifugation (10000 r / min, 5 min), washed sequentially with anhydrous ethanol and ultrapure water, and vacuum dried (60℃, 24 h) to obtain copper-doped Bi4NbO8Br powder.

[0060] In step S3, the organic solvent is a mixture of carbon tetrachloride and ethanol, with a volume ratio of carbon tetrachloride to ethanol of (2~5):1; the heating temperature is 40~80℃, and the mixture is stirred until the solvent is completely evaporated to obtain a solid mixture.

[0061] In step S4, the calcination temperature is 600~700℃, the calcination time is 2~4 hours, and argon gas is introduced for protection during the calcination process, with an argon gas flow rate of 60~80 mL / min.

[0062] According to a third aspect of the present invention, an application of the Cu-S-Bi4NbO8Br photocatalyst as described above in water purification is provided, specifically for removing antibiotics, drug-resistant bacteria, and drug-resistant genes from wastewater; wherein the antibiotic is tetracycline, the drug-resistant bacteria is Staphylococcus aureus MRSA, and the drug-resistant gene is a tetracycline-resistant gene (tetA). The wastewater includes secondary effluent from a wastewater treatment plant.

[0063] In application, the Cu-S-Bi4NbO8Br photocatalyst is added to the wastewater to be treated, with the dosage controlled at 20~100 mg / L, the wastewater temperature at 20~30℃ (preferably 25℃), and a xenon lamp is used to simulate visible light irradiation, with the light intensity of the xenon lamp being 50~150 mW / cm² (preferably 100 mW / cm²). 2 Photocatalytic reactions can efficiently remove target pollutants from wastewater.

[0064] The present invention will now be described in detail with reference to embodiments thereof. These examples are provided by way of explanation and not by way of limitation. In fact, those skilled in the art will recognize that modifications and variations can be made to the present invention without departing from its scope or spirit. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the present invention encompass such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0065] In the embodiments of the present invention, unless otherwise specified, the experimental methods used are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0066] The sources of the pharmaceuticals involved in the following examples are as follows: bismuth oxide (99%, Aladdin), bismuth oxybromide (99%, Aladdin), niobium pentoxide (99%, Aladdin), sodium bromide (99%, Aladdin), potassium bromide (99%, Aladdin), copper chloride (98%, Aladdin), anhydrous ethanol (99%, Maclean), and sublimed sulfur (98%, Maclean).

[0067] The drug-resistant bacterium is Staphylococcus aureus MRSA.

[0068] The drug resistance gene is the tetracycline resistance gene (tetA), which contains 210 base pairs. The method for obtaining it can be found in DOI:10.1016 / j.cej.2016.10.107.

[0069] The instruments involved in the following embodiments are as follows: magnetic stirrer (HJ-3 type), digital display constant temperature water bath (HH.S21-8), vacuum drying oven (DZF-6020 type), ultrasonic cleaner (SB-3200DT), high-speed centrifuge (TG16-WS), tube furnace (OTF-1200X), xenon lamp (CEL-S500 / 350).

[0070] Examples 1-4

[0071] Examples 1-4 provide a Cu-S-Bi4NbO8Br photocatalyst, the specific steps of which are as follows:

[0072] (1) Bi2O3, BiOBr, Nb2O5, NaBr and KBr were ground in a ball mill for 90 minutes. Then, the mixture was placed in an alumina crucible and calcined at 850°C for 5 hours in an argon atmosphere in a tube furnace. After naturally cooling to room temperature, impurities were removed by washing with ultrapure water at 100°C and vacuum dried to obtain Bi4NbO8Br, wherein the molar ratio of Bi2O3, BiOBr, Nb2O5, NaBr and KBr was 3:2:1:30:30;

[0073] (2) Disperse Bi4NbO8Br in ultrapure water to obtain a first solution. Sonicate the first solution at 0°C for 50 minutes to obtain a Bi4NbO8Br dispersion. The concentration of Bi4NbO8Br in the first solution is 6 g / L.

[0074] (3) Add copper chloride aqueous solution (concentration of 5 g / L) dropwise to Bi4NbO8Br dispersion to obtain a second solution. The mass ratios of copper in the copper chloride solution and Bi4NbO8Br in the Bi4NbO8Br dispersion are shown in Table 1. Stir the second solution at 50°C for 1.5 hours under argon protection, with an argon flow rate of 40 mL / min. Collect the precipitate by centrifugation, wash with anhydrous ethanol and ultrapure water, and vacuum dry to obtain a yellow powder.

[0075] Table 1. Mass ratio of copper to Bi4NbO8Br in Examples 1-4

[0076]

[0077] The naming convention for catalysts is "CuX%-SY / Bi4NbO8Br", where:

[0078] “X%” indicates the actual doping mass fraction of copper in the Bi4NbO8Br matrix (e.g., “Cu0.8%” means that the copper doping amount is 0.8wt%).

[0079] “Y” means that the mass of sublimed sulfur is Y times that of copper-doped Bi4NbO8Br composite material (e.g., S10 means that the mass of sublimed sulfur is 10 times that of copper-doped Bi4NbO8Br composite material).

[0080] (4) The powder obtained in step (3) is mixed with sublimed sulfur at a mass ratio of 0.1:1 in a mixture of carbon tetrachloride and ethanol (volume ratio of carbon tetrachloride to ethanol is 4:1), and heated and stirred at 60°C until the liquid is completely evaporated to obtain the powder.

[0081] (5) The powder obtained in step (4) was calcined at 650°C for 3 hours under an argon atmosphere to obtain Cu-S-Bi4NbO8Br photocatalyst, wherein the flow rate of argon gas was 70 mL / min.

[0082] The copper loading of the Cu-S-Bi4NbO8Br photocatalysts prepared in Examples 1-4 was 0.78wt%, 0.21wt%, 0.47wt%, and 0.96wt%, respectively (the copper loading method was impregnation, during which it is impossible for all Cu ions in the solution to be loaded onto Bi4NbO8Br; some Cu ions will remain in the solution, so the actual loading is lower than the theoretical loading). The composite material was ground uniformly, dried at 105℃ for 2-4 hours to remove adsorbed water, and approximately 0.0500-0.1000g of sample was accurately weighed using an analytical balance, dispersed in aqua regia, heated in a 100℃ water bath for 30 minutes to completely dissolve the solid powder material, cooled, washed repeatedly with 2% dilute nitric acid solution, transferred to a 50mL volumetric flask, diluted to the mark, and shaken well. The concentration of Cu in the solution was then detected using an ICP-MS instrument.

[0083] The total mass difference of the solid mixture before and after calcination in step (4) is the sulfur doping amount. By accurate weighing, the sulfur doping amounts of the Cu-S-Bi4NbO8Br photocatalysts prepared in Examples 1 to 4 are 1.58wt%, 1.36wt%, 1.47wt%, and 1.62wt%, respectively.

[0084] Examples 5-6

[0085] Examples 5-6 provide a Cu-S-Bi4NbO8Br photocatalyst, the preparation method of which is basically the same as that of Examples 1-4, except that the mass ratio of sublimated sulfur to Cu-Bi4NbO8Br is different in step (4). The specific steps are as follows:

[0086] (1) Bi2O3, BiOBr, Nb2O5, NaBr and KBr were ground in a ball mill for 90 minutes. Then, the mixture was placed in an alumina crucible and calcined at 850°C for 5 hours in an argon atmosphere in a tube furnace. After naturally cooling to room temperature, impurities were removed by washing with ultrapure water at 100°C and vacuum dried to obtain Bi4NbO8Br, wherein the molar ratio of Bi2O3, BiOBr, Nb2O5, NaBr and KBr was 3:2:1:30:30;

[0087] (2) Disperse Bi4NbO8Br in ultrapure water to obtain a first solution. Sonicate the first solution at 0°C for 50 minutes to obtain a Bi4NbO8Br dispersion. The concentration of Bi4NbO8Br in the first solution is 6 g / L.

[0088] (3) Add copper chloride aqueous solution (concentration of 5 g / L) dropwise to Bi4NbO8Br dispersion to obtain a second solution, wherein the mass ratio of copper in copper chloride solution to Bi4NbO8Br in Bi4NbO8Br dispersion is 0.008:1. Stir the second solution at 50°C for 1.5 hours under argon protection, wherein the flow rate of argon gas is 40 mL / min. Collect the precipitate by centrifugation, wash with anhydrous ethanol and ultrapure water, and vacuum dry to obtain a yellow powder.

[0089] (4) The powder obtained in step (3) is mixed with sublimed sulfur in a mixture of carbon tetrachloride and ethanol at a mass ratio.

[0090] In the mixture (volume ratio of carbon tetrachloride to ethanol is 4:1), the mass ratio of Cu-Bi4NbO8Br to sublimed sulfur is shown in Table 2. The mixture is heated and stirred at 60°C until the liquid is completely evaporated to obtain powder.

[0091] Table 2. Mass ratio of Cu-Bi4NbO8Br to sublimed sulfur in Examples 5-6

[0092]

[0093] The total mass difference of the solid mixture before and after calcination in step (4) is the sulfur doping amount. By accurate weighing, the sulfur doping amounts of the Cu-S-Bi4NbO8Br photocatalysts prepared in Example 5 and Example 6 were 1.13wt% and 2.7wt%, respectively.

[0094] (5) The powder obtained in step (4) was calcined at 650°C for 3 hours under an argon atmosphere to obtain Cu-S-Bi4NbO8Br photocatalyst, wherein the flow rate of argon gas was 70 mL / min.

[0095] Comparative Example 1

[0096] Preparation of S-Bi4NbO8Br material:

[0097] Bi₂O₃, BiOBr, Nb₂O₅, NaBr, and KBr (molar ratio 3:2:1:30:30) were ground in a ball mill for 90 minutes. The mixture was then placed in an alumina crucible and calcined at 850°C for 5 hours in an argon atmosphere in a tube furnace. After natural cooling to room temperature, impurities were removed by washing with 100°C ultrapure water, and the mixture was vacuum dried to obtain Bi₄NbO₈Br powder. The Bi₄NbO₈Br powder was mixed with sublimed sulfur in a mixture of carbon tetrachloride and ethanol, and heated and stirred until the liquid was completely evaporated to obtain the powder. The mass ratio of Bi₄NbO₈Br powder to sublimed sulfur was 0.1:1, and the volume ratio of carbon tetrachloride to ethanol was 4:1. The heating temperature was 60°C. The obtained powder was calcined at 650°C for 3 hours under an argon atmosphere with an argon flow rate of 70 mL / min to obtain S-Bi₄NbO₈Br material.

[0098] Comparative Example 2

[0099] Preparation of Cu-Bi4NbO8Br materials

[0100] Bi₂O₃, BiOBr, Nb₂O₅, NaBr, and KBr (molar ratio 3:2:1:30:30) were milled in a ball mill for 90 minutes. The mixture was then placed in an alumina crucible and calcined at 850°C for 5 hours in a tube furnace under an argon atmosphere. After natural cooling to room temperature, impurities were removed by washing with ultrapure water at 100°C, and the mixture was vacuum dried to obtain Bi₄NbO₈Br powder. Bi₄NbO₈Br was dispersed in ultrapure water to obtain a first solution, which was then sonicated at 0°C for 50 minutes to obtain a Bi₄NbO₈Br dispersion. The concentration of Bi₄NbO₈Br in the first solution was 6 g / L. A copper chloride aqueous solution was added dropwise to a Bi₄NbO₈Br dispersion to obtain a second solution. This second solution was stirred at 50°C for 1.5 hours under argon protection, with an argon flow rate of 40 mL / min. The precipitate was collected by centrifugation, washed with anhydrous ethanol and ultrapure water, and vacuum dried to obtain a yellow powder. The mass ratio of copper in the copper chloride solution to Bi₄NbO₈Br in the Bi₄NbO₈Br dispersion was 0.008:1, and the concentration of copper chloride in the copper chloride solution was 5 g / L. The obtained yellow powder was calcined at 650°C for 3 hours under argon protection, with an argon flow rate of 70 mL / min, to obtain Cu-Bi₄NbO₈Br material.

[0101] Performance testing and characterization

[0102] 1. Morphological and crystal structure characterization:

[0103] SEM characterization: The Bi4NbO8Br photocatalyst prepared in Example 1 was subjected to SEM testing, and the results are as follows: Figure 1As shown, the photocatalyst exhibits a regular rectangular nanoplate structure with uniform thickness, measured to be approximately 160 nm. This morphological structure is beneficial for increasing the specific surface area of ​​the catalyst and providing more active sites.

[0104] TEM and HRTEM characterization: Figure 2 (a) is a TEM image of the Bi4NbO8Br photocatalyst prepared in Example 1. It can be seen that the catalyst is composed of rectangular nanoplates with a length of 600±300 nm. The surface is smooth and no obvious aggregation of copper or sulfur particles was observed, indicating that copper and sulfur elements are uniformly dispersed in the Bi4NbO8Br matrix. Figure 2 In the HRTEM image (b), 0.39 nm lattice fringes can be clearly observed, corresponding to the (110) crystal plane of Bi4NbO8Br, proving that the catalyst has a good crystal structure and that the doping process does not destroy the lattice integrity of the matrix.

[0105] HAADF-STEM characterization: Figure 3 The image shows the HAADF-STEM image of the Cu-S-Bi4NbO8Br photocatalyst prepared in Example 1. It can be observed from the image that copper atoms are uniformly distributed in the Bi4NbO8Br lattice in an atomically dispersed manner, and no copper particle agglomeration is observed, which further confirms that copper elements have been successfully doped into the Bi4NbO8Br lattice by substituting Bi atoms.

[0106] 2. Optical performance characterization:

[0107] UV-Vis Diffuse Reflectance Spectroscopy and Band Gap Analysis: UV-Vis diffuse reflectance spectroscopy was performed on the materials prepared in Example 1 and Comparative Examples 1 and 2. The results are shown in Figure 4(a). Cu-S-Bi4NbO8Br, S-Bi4NbO8Br, and Cu-Bi4NbO8Br exhibit typical semiconductor adsorption peaks. The absorption edges of S-Bi4NbO8Br and Cu-Bi4NbO8Br are near 526.1 nm and 528.3 nm, respectively, indicating visible light-driven photocatalytic activity. The absorption edge of Cu-S-Bi4NbO8Br reaches 558.8 nm, much larger than that of S-Bi4NbO8Br and Cu-Bi4NbO8Br, indicating that co-doping with copper and sulfur atoms broadens the absorption range for visible light. Based on the UV-Vis diffuse reflectance spectral data, the band gaps of Cu-S-Bi4NbO8Br, S-Bi4NbO8Br, and Cu-Bi4NbO8Br were calculated using Formulas 1 and 2. The results are shown in Figure 4(a). Figure 4 As shown in (b) of the diagram.

[0108] E g = 1240 / λ (1)

[0109] αhv = A(hv – E g ) n / 2 (2)

[0110] In the formula, α is the absorption coefficient, h is Planck's constant, v is the optical frequency, and E is the optical frequency. g Let λ represent the band gap, λ be the wavelength corresponding to the absorption edge of the material (in nm), and A be a constant. Since Cu-S-Bi4NbO8Br, S-Bi4NbO8Br, and Cu-Bi4NbO8Br possess indirect semiconductor properties, n is 4. The results show that the band gaps of Cu-S-Bi4NbO8Br, S-Bi4NbO8Br, and Cu-Bi4NbO8Br are 2.01 eV, 2.38 eV, and 2.31 eV, respectively. Therefore, the band gap of S-Bi4NbO8Br is significantly reduced after copper doping modification. This may be attributed to the formation of a sub-band gap within S-Bi4NbO8Br due to copper doping, which reduces the energy required for electron transitions.

[0111] Steady-state photoluminescence spectroscopy analysis: Figure 5 shows the steady-state photoluminescence spectra (excitation wavelength 365 nm) of the materials prepared in Example 1 and Comparative Examples 1 and 2. Figure 5 A broad emission peak was observed in S-Bi4NbO8Br near 500 nm, indicating significant recombination of photogenerated electrons and holes. Compared to S-Bi4NbO8Br and Cu-Bi4NbO8Br, the peak intensity of the Cu-S-Bi4NbO8Br photocatalyst was significantly reduced, suggesting that copper and sulfur co-doping significantly reduced the recombination of photogenerated electrons and holes, prolonged carrier lifetime, and provided sufficient active species for the photocatalytic reaction.

[0112] 3. Detection of reactive oxygen species

[0113] Electron paramagnetic resonance spectroscopy was used to detect the types of reactive oxygen species (•OH, O2) generated during the photocatalytic reaction of the Cu-S-Bi4NbO8Br material prepared in Example 1, the S-Bi4NbO8Br material prepared in Comparative Example 1, and the Cu-Bi4NbO8Br material prepared in Comparative Example 2. •- and 1 O2). When detecting •OH generated in the photocatalytic system, the catalyst (100 mg·L⁻¹) was used. -1 ), DMPO (50 μmol·L -1 Mix 20 mL of O2 and 20 mL of ultrapure water in a beaker and irradiate with a 300 W xenon lamp (CEL-HXF300) equipped with a UV filter (to filter out light with λ < 420 nm) for 2 minutes. Then transfer the mixture to a capillary tube and place the capillary tube into an EPR spectrometer to detect the EPR signal. •-When detecting •OH, the procedure is the same as for the detection of •OH, except that the background solution is replaced with methanol instead of ultrapure water. 1 For O2, the procedure is the same as for •OH detection, except that the trapping agent is changed from DMPO to TEMP. Test results are as follows: Figure 6 As shown in (a), no DMPO- was detected in the S-Bi4NbO8Br system under visible light irradiation. 1 Characteristic signals of O2 adducts were detected, and DMPO- was detected in both Cu-S-Bi4NbO8Br and Cu-Bi4NbO8Br systems. 1 Characteristic signals of O2 adducts, but DMPO- detected in the Cu-S-Bi4NbO8Br system 1 The characteristic signal intensity of the O2 adduct is significantly stronger than that of the S-Bi4NbO8Br system, indicating that the introduction of copper and sulfur atoms significantly improves the formation of... 1 The ability of O2. For example... Figure 6 As shown in (b), under visible light irradiation, no characteristic signal of the DMPO-•OH adduct was detected in the S-Bi4NbO8Br system, while characteristic signals of the DMPO-•OH adduct were detected in both the Cu-S-Bi4NbO8Br and Cu-Bi4NbO8Br systems. However, the intensity of the characteristic signal of the DMPO-•OH adduct detected in the Cu-S-Bi4NbO8Br system was significantly stronger than that in the S-Bi4NbO8Br system. This indicates that the introduction of copper and sulfur atoms significantly improved the ability to generate •OH. Figure 6 As shown in (c), DMPO-O2 was not detected in the Cu-S-Bi4NbO8Br, S-Bi4NbO8Br, and Cu-Bi4NbO8Br photocatalytic systems. •- The six characteristic peaks of the adduct indicate that no O2 was generated in the Cu-S-Bi4NbO8Br, S-Bi4NbO8Br, and Cu-Bi4NbO8Br systems. •- Or the generated O2 •- The concentration was very low and did not reach the instrument's detection limit.

[0114] ROS Concentration Test: Molecular probe experiments were used to quantitatively detect the concentration of reactive oxygen species generated during photocatalysis in the Cu-S-Bi4NbO8Br material prepared in Example 1, the S-Bi4NbO8Br material prepared in Comparative Example 1, and the Cu-Bi4NbO8Br material prepared in Comparative Example 2. Specifically, the materials were added to an aqueous solution of terephthalic acid (TPA) and irradiated with a 300 W xenon lamp (CEL-HXF300) equipped with an ultraviolet filter (filtering out light with λ < 420 nm) to carry out the catalytic reaction. Starting at 0 min, samples were taken after 10 minutes of irradiation. The intensity of the fluorescence peak appearing at 426 nm under 312 nm excitation was measured using a FluoroMax-P spectrophotometer to obtain the concentration of •OH generated during photocatalysis. 9,10-Diphenylanthracene (DPA) was used as a chemical probe to detect the concentration of •OH generated during the photocatalysis. 1 O2 concentration. DPA and 1 O2 reacts to form an indicative internal peroxide (DPAO2), and the experimental procedure is consistent with the quantitative analysis of •OH, except that DPA is used instead of TPA; nitrotetrazolium chloride (NBT) is used as an indicator to detect O2 in the system. •- The concentration of yellow NBT. •- The NBT was reduced to blue formazan, and its concentration was measured at 259 nm using a UV-Vis spectrophotometer. The experimental procedure was consistent with that for the quantitative analysis of •OH, except that NBT was used instead of TPA. The test results are as follows: Figure 7 As shown, at 10 minutes, the Cu-S-Bi4NbO8Br system... 1 O2, •OH and O2 •- The concentrations reached 8.3 mmol / L, 5.3 mmol / L, and 0.2 mmol / L, respectively. Therefore, the main active species in the Cu-S-Bi4NbO8Br system are •OH and 1 O2. And the •OH and •OH generated in the S-Bi4NbO8Br and Cu-Bi4NbO8Br systems 1 The concentration of O2 is much lower than that of the Cu-S-Bi4NbO8Br system.

[0115] 4. Photocatalytic performance test

[0116] Tetracycline degradation efficiency: The photocatalytic removal of tetracycline by the catalyst was conducted in a 200 mL beaker at a temperature of 25 ± 0.2℃ and an initial solution pH of ~7. The catalyst was dispersed in 100 mL of tetracycline solution (10 mg·L⁻¹). -1In a 100W xenon lamp (CEL-HXF300) equipped with a UV filter (to filter out light with λ < 420nm), the mixture was continuously stirred for 40 minutes to reach adsorption-desorption equilibrium. Then, the mixture was irradiated with a 300W xenon lamp (CEL-HXF300) to begin the photocatalytic degradation experiment. Every 3 minutes, 3 mL of the reaction solution was taken out, filtered through a 0.22 μm microporous membrane to remove the catalyst, and the absorbance (wavelength approximately 360 nm) was measured on a UV-Vis spectrophotometer. The catalyst dosage was 60 mg / L, and the catalysts were the Cu-S-Bi4NbO8Br materials prepared in Examples 1-6, the S-Bi4NbO8Br material prepared in Comparative Example 1, and the Cu-Bi4NbO8Br material prepared in Comparative Example 2, respectively. The light intensity was 100 mW / cm². 2 The test results are as follows: Figure 8 As shown, compared with Cu-Bi4NbO8Br material (Comparative Example 2), the sulfur-doped Cu-S-Bi4NbO8Br material (Examples 1, 5, and 6) exhibits a significantly higher degradation efficiency for tetracycline. Furthermore, the degradation efficiency of the catalyst for tetracycline is affected by the copper and sulfur content. When the copper content is below 0.8 wt% (Comparative Examples 1, 2, and 3), the tetracycline degradation efficiency increases with increasing copper content. When the copper content exceeds 0.8 wt% (Example 4), the tetracycline degradation efficiency no longer increases. The optimal tetracycline degradation efficiency is achieved when the copper content is 0.8 wt% and the mass ratio of Cu-Bi4NbO8Br to sublimed sulfur is 0.1:1 (Example 1), significantly higher than when the copper content is 0.8 wt% and the mass ratio of Cu-Bi4NbO8Br to sublimed sulfur is 0.05:1 (Example 5) and when the copper content is 0.8 wt% and the mass ratio of Cu-Bi4NbO8Br to sublimed sulfur is 0.15:1 (Example 6). Therefore, the Cu-S-Bi4NbO8Br material with a copper content of 0.8wt% and a mass ratio of Cu-Bi4NbO8Br to sublimed sulfur of 0.1:1 has the best sterilization effect, and its degradation efficiency of tetracycline exceeds 95% within 10 minutes.

[0117] MRSA inactivation effect: MRSA was added to ultrapure water to prepare an initial MRSA concentration of 10. 7The catalyst was prepared in an aqueous solution at cfu / mL (copy number 7-log) at 25 ± 0.2℃ with an initial pH of ~7. The catalyst was dispersed in 20 mL of MRSA aqueous solution, and the mixture was irradiated under a 300 W xenon lamp (CEL-HXF300) equipped with a UV filter (filtering out light < 420 nm) to begin the photocatalytic sterilization experiment. Samples were taken every 3 minutes, and bacterial density was calculated using the standard plate count method. The catalyst dosage was 60 mg / L, and the catalysts were the Cu-S-Bi4NbO8Br materials prepared in Examples 1-6, the S-Bi4NbO8Br material prepared in Comparative Example 1, and the Cu-Bi4NbO8Br material prepared in Comparative Example 2, respectively. The light intensity was 100 mW / cm². 2 The test results are as follows: Figure 9 As shown, Example 1 also showed the best inactivation efficiency against ARB, completely inactivating MRSA within 10 minutes, demonstrating that co-doping significantly enhances the catalyst's ability to inactivate drug-resistant bacteria.

[0118] Drug resistance gene degradation efficiency: tetA was added to ultrapure water to prepare an initial tetA concentration of 10. 9 The catalyst was dispersed in 20 mL of tetA aqueous solution at a temperature of 25 ± 0.2℃ and an initial pH of ~7. The mixture was then irradiated under a 300 W xenon lamp (CEL-HXF300) with a UV filter (filtering out light < 420 nm) to begin the photocatalytic degradation of ARGs. Samples were taken every 3 minutes, and the tetA in the reaction solution was quantitatively analyzed using real-time quantitative PCR (qPCR) to obtain the cycle threshold. The gene copy number was calculated based on the standard curve. The difference between the gene copy number at time t and the initial gene copy number (9-log) was the degradation effect of the material on tetA. The apparent rate constant (k) was obtained by first-order kinetic fitting of the degradation curve based on the degradation effect, representing the degradation rate of tetA by the catalyst. The catalyst dosage was 60 mg / L, and the catalysts were the Cu-S-Bi4NbO8Br materials prepared in Examples 1-6, the S-Bi4NbO8Br materials prepared in Comparative Example 1, and the Cu-Bi4NbO8Br materials prepared in Comparative Example 2, respectively. The light intensity was 100 mW / cm². 2 The test results are as follows: Figure 10 As shown, Example 1 exhibited the best degradation effect on tetA, achieving a degradation efficiency of 4.2-log within 10 minutes and an apparent rate constant (k) of 2.2 min. -1 Therefore, Cu-S-Bi4NbO8Br material with a copper content of 0.8wt% is the optimal photocatalyst.

[0119] The removal efficiency of the Cu-S-Bi4NbO8Br material prepared in Example 1 on tetracycline, MRSA, and tetA was tested under different catalyst dosages. The test methods were basically the same as those described above for "Testing the Catalyst's Removal Efficiency for Tetracycline," "Testing the Catalyst's Inactivation Efficiency for MRSA," and "Testing the Catalyst's Degradation Efficiency for ARGs," with the only difference being that only the Cu-S-Bi4NbO8Br material prepared in Example 1 was used as the catalyst, and the catalyst dosages were 20 mg / L, 40 mg / L, 60 mg / L, 80 mg / L, and 100 mg / L. The test results are as follows: Figure 11 As shown, the catalyst dosage affects its effect on tetracycline ( Figure 11 (a) of MRSA and tetA Figure 11 The removal effect of (b) in Example 1. When the catalyst dosage is below 60 mg / L, the removal effect of Cu-S-Bi4NbO8Br material prepared in Example 1 on tetracycline, MRSA and tetA increases with the increase of catalyst dosage. When the catalyst dosage exceeds 60 mg / L, the removal effect of Cu-S-Bi4NbO8Br material prepared in Example 1 on tetracycline, MRSA and tetA no longer increases. Therefore, 60 mg / L is the optimal dosage for Cu-S-Bi4NbO8Br material prepared in Example 1.

[0120] To facilitate catalyst recovery and prevent secondary pollution caused by catalyst loss, we used an impregnation method (1g of the prepared material was dispersed in 20ml of ultrapure water, 200ul of naphthol was added, and the mixture was ultrasonically dispersed; carbon felt was added to the dispersion; the mixture was heated and stirred in a 60℃ water bath until the water was completely evaporated; the carbon felt was then removed and dried at 60℃ for 24 hours). The Cu-S-Bi4NbO8Br material prepared in Example 1 and the S-Bi4NbO8Br material prepared in Comparative Example 1 were loaded onto carbon felt (carbon felt dimensions: a cylinder with a length of 8cm, a diameter of 2cm, a porosity of 90%, and a specific surface area of ​​1000m²). 2 On the carbon felt ( / g), the large specific surface area and porous structure of the carbon felt provide a stable fixation of the catalyst, preventing its detachment during the reaction. To evaluate the potential application of the catalyst in practical water treatment, we established a continuous flow reactor composed of catalyst-loaded carbon felt to treat actual wastewater under simulated solar irradiation. The continuous flow reactor continuously removed antibiotics, bacteria, and ARGs from the wastewater without requiring catalyst washing for the next reaction. The catalyst loading on the carbon felt was 500 mg. Figure 12 This image shows a continuous flow reactor, a continuous flow photocatalytic water treatment device based on a Cu-S-Bi4NbO8Br photocatalyst. Its core function is to efficiently remove antibiotics, drug-resistant bacteria, and drug-resistant genes from wastewater. The structure and function are described below:

[0121] Core structure:

[0122] Water inlet beaker: 5 L capacity, made of glass, used to store wastewater to be treated;

[0123] Peristaltic pump: Model BT100-1F, hose material is fluororubber (acid and alkali resistant), flow rate adjustment range 0.01~1L / h, accuracy ±0.01 L / h, used to stably transport wastewater in the inlet beaker to the reactor;

[0124] Reactor: The core is a quartz syringe (10 cm in length, 2 cm in inner diameter, and approximately 31.4 cm³ in volume). Both ends of the syringe are sealed with PTFE connectors. The inside is tightly filled with carbon felt loaded with Cu-S-Bi4NbO8Br catalyst (carbon felt dimensions: 8 cm in length and 2 cm in diameter, with no gap between it and the inner wall of the syringe). The carbon felt loading is 500 mg (the catalyst is uniformly dispersed in the pores of the carbon felt). The syringe inlet is located at the bottom of one end, and the outlet is located at the top of the other end, ensuring full contact between the wastewater and the carbon felt.

[0125] Xenon lamp: 300 W power, model CEL-HXF300, equipped with a 420 nm cutoff filter (filters ultraviolet light with λ < 420 nm), operating current 1.5 A, horizontal distance from the quartz injector is 11 cm, at which time the light intensity on the carbon felt surface is 100 mW / cm²; the xenon lamp is equipped with an air-cooled heat dissipation device to prevent the water temperature in the reactor from exceeding 30℃ due to heat generated by light;

[0126] Water outlet beaker: 5 L capacity, made of glass, used to collect purified wastewater.

[0127] Complete workflow:

[0128] Pretreatment: Add tetracycline to the inlet beaker of wastewater to be treated (such as secondary effluent from the Nankai University Wastewater Treatment Plant, with tetracycline added to an initial concentration of 1 mg / L);

[0129] Start-up: Set the peristaltic pump flow rate to 0.25 L / h (corresponding to a hydraulic retention time of ≈7.5 minutes, matching the catalyst's high-efficiency degradation characteristics within 10 minutes), start the peristaltic pump, and pump the wastewater into the reactor inlet through the hose from the inlet beaker;

[0130] Photocatalytic reaction: Wastewater flows slowly along the pores of the carbon felt in the reactor while a xenon lamp (with visible light filtered through a filter) is turned on. The Cu-S-Bi4NbO8Br catalyst supported on the carbon felt is generated under visible light. 1 O2 and ·OH reactive oxygen species rapidly degrade tetracycline in wastewater, inactivate MRSA-resistant bacteria, and degrade the tetA resistance gene;

[0131] Effluent collection: The purified wastewater flows out of the reactor outlet and into the effluent beaker, where samples can be taken periodically to test the tetracycline degradation rate, bacterial inactivation rate and tetA removal rate.

[0132] Continuous operation: The entire system operates under normal pressure and can work continuously and stably for 20 hours. During this period, the peristaltic pump flow feedback and xenon lamp current monitoring ensure stable operating parameters and copper ion leaching is less than 15 μg / L.

[0133] To test the performance of the continuous flow reactor, secondary effluent from the Nankai University Wastewater Treatment Plant (Tianjin, China) was used to evaluate the removal performance of tetracyclines, bacteria, and ARGs from the water by the Cu-S-Bi4NbO8Br and S-Bi4NbO8Br-based continuous flow reactors. The water quality parameters of the secondary effluent are shown in Table 3. The initial bacterial abundance of the secondary effluent was approximately 10⁻⁶. 4.3 cfu / mL, initial tetA abundance was approximately 8.6 × 10⁻⁶. 5 copies / mL. Because the antibiotic content in the secondary effluent was below the detection limit, tetracycline was added to the sample to bring the initial concentration to 1 mg / L. For example... Figure 13 As shown in (b), after 20 hours of continuous operation, the Cu-S-Bi4NbO8Br reactor still exhibited a degradation rate of over 98% for tetracycline, significantly higher than that of the S-Bi4NbO8Br reactor (33%). Figure 13 As shown in (c), the Cu-S-Bi4NbO8Br reactor can completely inactivate bacteria in the secondary effluent, meeting the discharge standards stipulated in the Chinese National Standard (GB18918-2002). Figure 13 As shown in (d), the Cu-S-Bi4NbO8Br reactor maintained a tetA removal rate of over 99.9% after 20 hours of continuous operation, significantly higher than the S-Bi4NbO8Br reactor (61%). Figure 13 As shown in (e), no flow rate change was observed during the 20-hour long-term operation, and the copper ion concentration in the solution was below 15 μg / L. Therefore, the Cu-S-Bi4NbO8Br photocatalyst prepared in this invention has the potential to treat practical wastewater.

[0134] Table 3

[0135]

[0136] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any technical solutions obtained by means of equivalent substitution or equivalent transformation should be covered within the protection scope of the present invention.

Claims

1. A Cu-S-Bi4NbO8Br photocatalyst, characterized in that, Using Bi4NbO8Br as the matrix, copper and sulfur elements are introduced through co-doping to form a composite photocatalytic material; the copper element replaces the Bi atoms in the Bi4NbO8Br lattice in an atomically dispersed form, and the sulfur element is doped in the interstitial spaces or surface of the Bi4NbO8Br lattice. The copper doping amount is 0.2% to 1.0% of the mass of the Bi4NbO8Br matrix; the sulfur element is introduced by sublimation sulfur, and the sulfur doping amount is 1% to 3% of the mass of the copper-doped Bi4NbO8Br composite material.

2. The Cu-S-Bi4NbO8Br photocatalyst according to claim 1, characterized in that, The Cu-S-Bi4NbO8Br photocatalyst has a rectangular nanoplate structure with a length of 300~900 nm and a thickness of 150~170 nm; the band gap of the Cu-S-Bi4NbO8Br photocatalyst is 2.0~2.2 eV.

3. A method for preparing the Cu-S-Bi4NbO8Br photocatalyst as described in claim 1 or 2, characterized in that, Includes the following steps: S1. Prepare Bi4NbO8Br matrix material, disperse it in water to form a dispersion, and then treat it with ultrasound for later use; S2. Add copper chloride solution to the dispersion in step S1, stir the reaction under inert gas protection, and obtain copper-doped Bi4NbO8Br composite material powder by centrifugation, washing and drying. S3. Mix the copper-doped Bi4NbO8Br composite powder from step S2 with sublimed sulfur in an organic solvent, heat and stir until the solvent is completely evaporated to obtain a solid mixture. S4. The solid mixture from step S3 is calcined under an inert gas atmosphere to obtain the Cu-S-Bi4NbO8Br photocatalyst.

4. The preparation method according to claim 3, characterized in that, In step S1, the Bi4NbO8Br matrix material is prepared by mixing and grinding Bi2O3, BiOBr, Nb2O5, NaBr and KBr in proportion, followed by calcination, cooling, washing and drying to obtain Bi4NbO8Br; The molar ratio of Bi₂O₃, BiOBr, Nb₂O₅, NaBr, and KBr is (2.8~3.3):(1.8~2.2):(0.8~1.2):30:30; the grinding method is ball milling, with a milling time of 80~100 minutes; the calcination temperature is 650~950℃, and the calcination time is 4~6 hours; ultrapure water with a temperature above 95℃ is used for washing. And / or, the concentration of Bi4NbO8Br in the dispersion is 5~7 g / L, the ultrasonic treatment temperature is 0~4℃, and the ultrasonic treatment time is 40~60 minutes.

5. The preparation method according to claim 3, characterized in that, In step S2, the mass ratio of copper element to Bi4NbO8Br matrix material in the copper chloride solution is (0.002~0.01):1, and the concentration of copper chloride solution is 3~7 g / L; And / or, the temperature of the stirring reaction is 30~50℃, the stirring time is 1~2 hours, the inert gas is argon, and the argon flow rate is 30~50 mL / min.

6. The preparation method according to claim 3, characterized in that, In step S3, the organic solvent is a mixture of carbon tetrachloride and ethanol, with a volume ratio of carbon tetrachloride to ethanol of (2~5):1; the heating temperature is 40~80℃.

7. The preparation method according to claim 3, characterized in that, In step S4, the calcination temperature is 600~700℃, the calcination time is 2~4 hours, the inert gas is argon, and the argon flow rate is 60~80 mL / min.

8. The application of the Cu-S-Bi4NbO8Br photocatalyst as described in claim 1 or 2 in water purification, characterized in that: Used to remove antibiotics, drug-resistant bacteria, or drug-resistant genes from wastewater.

9. The application according to claim 8, characterized in that, The antibiotic is tetracycline, the resistant bacterium is Staphylococcus aureus MRSA, and the resistance gene is the tetracycline resistance gene tetA.

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