Silver phosphate composite material with antibiotic degradation and antibacterial efficacy and preparation method and application thereof

Abstract

The application discloses a silver phosphate composite material with antibiotic degradation and bacteria removal effects and a preparation method and application thereof. The method comprises the following steps: dissolving a nitrogen source and a sulfur source in an organic solvent, adding the obtained dispersion solution into a graphene oxide suspension, stirring to obtain a uniform suspension, and then annealing at high temperature to obtain NSG; adding the NSG into water to obtain an NSG suspension, adding a silver ion solution into the suspension, uniformly mixing, and obtaining an Ag + / NSG suspension; adding a hydrogen phosphate solution into the Ag + / NSG suspension, stirring and reacting, collecting the precipitate, and obtaining the composite material. The Ag3PO4 / NSG composite photocatalyst with antibiotic degradation and bacteria removal effects is prepared through a simple process. The Ag3PO4 / NSG composite photocatalyst is low in cost and can be reused.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor materials, and specifically relates to a silver phosphate composite material with antibiotic degradation and antibacterial effects, its preparation method, and its application. Background Technology

[0002] Currently, concerns about environmental pollution have sparked global research interest in photocatalytic degradation, which is generally considered one of the most ideal advanced oxidation processes. Photocatalytic degradation technology, with its mild reaction conditions, can directly utilize solar energy to degrade organic pollutants into non-toxic carbon dioxide and water, making it a green wastewater treatment method without secondary pollution.

[0003] Silver phosphate is a novel semiconductor photocatalytic material with strong photocatalytic oxidation capabilities. In recent years, silver phosphate has attracted widespread attention due to its excellent visible light response and unique band structure, which enables photogenerated holes in its valence band to possess strong oxidizing power, allowing for the direct oxidation and degradation of pollutants. However, silver phosphate suffers from slow surface reaction kinetics, rapid electron capture, and severe recombination of photogenerated carriers. Furthermore, silver ions in silver phosphate are easily reduced to elemental silver by photogenerated electrons, resulting in poor photostability. These factors hinder further improvement in the photocatalytic efficiency of silver phosphate monomers. Therefore, developing composite photocatalysts with other substances and silver phosphate to further expand the absorption range of silver phosphate, reduce its band width, improve its photocatalytic activity, reduce photocorrosion, and enhance its stability is of great significance to researchers.

[0004] Existing technologies have achieved the separation of photogenerated carriers by modifying the structure and properties of silver phosphate with the addition of modifiers. However, the modified silver phosphate catalysts still suffer from drawbacks such as low separation efficiency of photogenerated electron-hole pairs, weak resistance to photocorrosion, and weak photocatalytic activity. As a result, the modified silver phosphate catalysts cannot meet the requirements for efficient degradation and removal of organic pollutants and antibacterial effects, thus greatly limiting the promotion and application of existing silver phosphate composite photocatalysts. Summary of the Invention

[0005] To overcome the shortcomings and deficiencies of silver phosphate, the primary objective of this invention is to provide a low-cost, highly efficient antibiotic degradation treatment and a good bactericidal effect, as well as a method for preparing the nitrogen-sulfur-doped graphene-modified Ag3PO4 composite material. The Ag3PO4 composite nitrogen-sulfur-doped graphene photocatalytic material prepared by this invention expands the light absorption range of silver phosphate, reduces the bandgap, improves photocatalytic activity, reduces silver phosphate photocorrosion, improves its stability, and optimizes its application in water disinfection or antibacterial materials.

[0006] Another objective of this invention is to further expand the potential of the Ag3PO4 / nitrogen-sulfur-doped graphene system in water treatment applications by evaluating its antibiotic degradation performance through efficient degradation of amoxicillin.

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

[0008] A method for preparing a silver phosphate composite material with antibiotic degradation and antibacterial effects includes the following steps:

[0009] (1) Dissolve nitrogen source and sulfur source in organic solvent and disperse evenly to obtain dispersion solution; add the dispersion solution to graphene oxide aqueous suspension and stir to obtain uniform suspension. After drying, obtain brown powder. Under a protective atmosphere, anneal the brown powder at high temperature to obtain nitrogen sulfur doped graphene (NSG).

[0010] (2) Nitrogen-sulfur-doped graphene was added to water and dispersed evenly to obtain a nitrogen-sulfur-doped graphene suspension. Silver ion solution was added to the above suspension and mixed evenly to obtain Ag. + / NSG suspension;

[0011] (3) Add the solution containing hydrogen phosphate to the Ag + The Ag3PO4-NSG composite material was obtained by stirring and reacting in an NSG suspension and collecting the precipitate.

[0012] Preferably, the high-temperature annealing temperature is 600-800℃, and the annealing time is 1-2 hours.

[0013] Preferably, the heating rate during the annealing process is 5°C / min; and the gas flow rate of the protective gas during the annealing process is 100-200 mL / min.

[0014] Preferably, the nitrogen source is selected from urea, the sulfur source is selected from benzyl disulfide, and the organic solvent is selected from anhydrous ethanol.

[0015] Preferably, the concentration of the graphene oxide suspension in step (1) is 4.0-6.0 mg / mL; the amount of urea added is 0.004-0.04 g / mL; and the amount of benzyl disulfide added is 0.002-0.05 g / mL.

[0016] Preferably, in step (2), the amount of nitrogen-sulfur-doped graphene added to the nitrogen-sulfur-doped graphene suspension is 0.01–0.05 mg / mL; the concentration of the silver ion solution is 7.0–11.0 mmol / L, more preferably 9 mmol / L; the mixing time between the nitrogen-sulfur-doped graphene suspension and the silver ion solution is 10–12 h; and the step of adding the silver ion solution needs to be carried out under light-protected conditions.

[0017] Preferably, in the reaction system of step (3), HPO4 2- With Ag + The molar ratio is 1:2 to 4, and more preferably 1:3; the stirring reaction is carried out under light-protected conditions for 2 to 6 hours.

[0018] Preferably, in step (1), the mixture is subjected to ultrasonic treatment for 60-100 minutes before stirring, and the stirring time is 20-40 minutes; the protective gas is selected from at least one of argon, helium or nitrogen; the amount of urea added is 0.01875±0.00875 g / mL; the dispersion in step (2) is performed by ultrasonic treatment, and the ultrasonic treatment time is 30-120 minutes, more preferably 60 minutes.

[0019] After the step of collecting the precipitate, a purification step and a drying step may be included. The purification step includes washing the precipitate with deionized water, filtering or centrifuging. The drying temperature is 50°C to 70°C, preferably 55°C.

[0020] The silver phosphate composite material is used in the photocatalytic degradation of antibiotics.

[0021] The silver phosphate composite material is used in photocatalytic sterilization.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0023] (1) In the Ag3PO4-NSG composite material provided by the present invention, nitrogen-sulfur doped graphene and silver phosphate form a heterojunction structure, which expands the light absorption range of silver phosphate, reduces the band width, solves the problem that silver phosphate is prone to photocorrosion, which reduces its activity, and improves its stability and extends its service life.

[0024] (2) The process method adopted in this invention is simple and practical, and has low cost. It has low requirements for equipment processing conditions, high reusability, and saves resources. It has great potential for application in the field of water treatment and has broad prospects.

[0025] (3) The nitrogen-sulfur-doped graphene / silver phosphate photocatalyst prepared in this invention has a strong photocatalytic sterilization effect and is suitable as an antibacterial material.

[0026] (4) The nitrogen-sulfur-doped graphene / silver phosphate photocatalyst prepared in this invention can efficiently remove antibiotics from water, especially amoxicillin from water. Attached Figure Description

[0027] Figure 1 This is a scanning electron microscope image of NSG.

[0028] Figure 2 This is a scanning electron microscope image of Ag3PO4.

[0029] Figure 3 This is a scanning electron microscope image of Ag3PO4-NSG.

[0030] Figure 4 XRD patterns of NSG, Ag3PO4, and Ag3PO4-NSG. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto. The reagents used in the following embodiments are all commercially available.

[0032] Example 1

[0033] Preparation of NSG: Urea (0.5 g) and benzyl disulfide (0.3 g) were dissolved in 20 mL of anhydrous ethanol and mixed thoroughly to obtain a dispersion. This dispersion was then added to 100 mL of a 5.0 mg / mL GO aqueous suspension, sonicated for 60 min, and stirred for 30 min to obtain a mixed solution. The resulting mixture was freeze-dried under vacuum for 24 h to obtain a brown powder. The brown powder was transferred to a tube furnace and annealed at 700 °C under argon (150 mL / min) for 1 h (heating rate of the tube furnace was 5 °C / min). A black powder was obtained. The black powder was washed three times each with anhydrous ethanol and deionized water, and then dried at 60 °C. Nitrogen-sulfur-doped graphene (NSG).

[0034] Preparation of Ag + / NSG suspension: Prepare an aqueous dispersion of NSG at a concentration of 0.01875 mg / mL. Then, take 100 mL of the 0.01875 mg / mL NSG dispersion and add 1.53 g of AgNO3 granules. Stir vigorously in the dark for 12 hours until the AgNO3 granules are completely dissolved to obtain Ag... + / NSG suspension.

[0035] Preparation of Ag3PO4-NSG composite materials: to Ag + 25 mL of 120 mM Na2HPO4 aqueous solution was slowly added to the NSG suspension, and the mixture was stirred continuously in the dark for 6 h. The precipitate was collected, rinsed with deionized water, and dried in a vacuum drying oven at 55 °C for 12 h to obtain the Ag3PO4-NSG composite material.

[0036] Example 2: Repeat the steps of Example 1, except that the amount of NSG added in Example 1 is different, that is, the amount of NSG added in Example 2 is 0.01125 mg / mL.

[0037] Example 3: Repeat the steps of Example 1, except that the amount of NSG added in Example 1 is different, that is, the amount of NSG added in Example 3 is 0.01375 mg / mL.

[0038] Example 4: Repeat the steps of Example 1, except that the amount of NSG added in Example 1 is different, that is, the amount of NSG added in Example 4 is 0.01625 mg / mL.

[0039] Example 5: Repeat the steps of Example 1, except that the amount of NSG added in Example 1 is different, that is, the amount of NSG added in Example 5 is 0.02125 mg / mL.

[0040] Example 6: Repeat the steps of Example 1, except that the amount of benzyl disulfide added in Example 1 is different, that is, the amount of benzyl disulfide added in Example 6 is 0.15g.

[0041] Example 7: Repeat the steps of Example 1, except that the amount of urea added in Example 1 is different, that is, the amount of urea added in Example 7 is 0.25g.

[0042] Example 8: Repeat the steps of Example 1, except that the amount of urea and benzyl disulfide added in Example 1 is different, that is, the amount of urea and benzyl disulfide added in Example 8 is 0.25g and 0.15g, respectively.

[0043] Table 1. Material content in each embodiment

[0044] Example Urea (g) Benzyl disulfide (g) Nitrogen-sulfur-doped graphene (mg / mL) 1 0.5 0.3 0.01875 2 0.5 0.3 0.01125 3 0.5 0.3 0.01375 4 0.5 0.3 0.01625 5 0.5 0.3 0.02125 6 0.5 0.15 0.01875 7 0.25 0.3 0.01875 8 0.25 0.15 0.01875

[0045] Comparative Example 1

[0046] Preparation of NSG

[0047] Preparation of NSG: Urea (0.5 g) and benzyl disulfide (0.3 g) were dissolved in 20 mL of anhydrous ethanol and mixed thoroughly to obtain a dispersion. This dispersion was then added to 100 mL of a 5.0 mg / mL GO suspension, sonicated for 60 min, and stirred for 30 min to obtain a mixed solution. The resulting mixture was freeze-dried under vacuum for 24 h to obtain a brown powder. The brown powder was transferred to a tube furnace and annealed at 700 °C under argon (150 mL / min) for 1 h (heating rate of the tube furnace was 5 °C / min). A black powder was obtained. The black powder was washed three times each with anhydrous ethanol and deionized water, and then dried at 60 °C. Nitrogen-sulfur-doped graphene (NSG).

[0048] Comparative Example 2

[0049] Preparation of Ag3PO4

[0050] 1.53 g of AgNO3 granules were dissolved in 75 mL of deionized water and stirred vigorously in the dark for 6 h to ensure complete dissolution and homogeneity. Then, 25 mL of 3 mM Na2HPO4 aqueous solution was slowly added to the mixture, and stirring continued in the dark for 6 h. The precipitate was collected, and the resulting sample was rinsed with deionized water and dried in a vacuum drying oven at 55 °C for 12 h. Yellow Ag3PO4 granules were obtained.

[0051] Comparative Example 3

[0052] Preparation of Ag3PO4-GO

[0053] First, a concentration of 0.01875 mg·mL was obtained. -1 The GO dispersion was prepared. Then, 100 mL of the above GO suspension was taken, and 1.53 g of AgNO3 particles were added. The mixture was stirred vigorously in the dark for 6 hours until completely dissolved and homogeneous. Next, 25 mL of 3 mM Na2HPO4 aqueous solution was slowly added to the mixture, and the mixture was stirred continuously in the dark for 6 hours. The precipitate was collected, and the resulting sample was rinsed with deionized water and dried in a vacuum drying oven at 55 °C for 12 hours.

[0054] Comparative Example 4

[0055] Preparation of Ag3PO4-NG

[0056] Urea (0.5 g) was dissolved in 20 mL of anhydrous ethanol to obtain a well-dispersed solution. This clarified solution was then added to 100 mL of a 5.0 mg / mL GO suspension, sonicated for 60 min, stirred for 30 min, and the resulting aqueous suspension was freeze-dried under vacuum for 24 h to obtain a brown powder. The powder was transferred to a tube furnace and annealed at 700 °C under argon (150 mL / min) for 1 h. The resulting black powder was washed three times with anhydrous ethanol and deionized water, and then dried overnight at 60 °C in an oven. Finally, a black N-doped graphene (NG) sample was obtained.

[0057] Preparation of Ag3PO4-NG: First, a concentration of 0.01875 mg·mL was obtained. -1 The NG powder dispersion was prepared. Then, 100 mL of the above NG suspension was taken, and 1.53 g of AgNO3 particles were added. The mixture was stirred vigorously in the dark for 6 hours until completely dissolved and homogeneous. Next, 25 mL of 3 mM Na2HPO4 aqueous solution was slowly added to the mixture, and the mixture was stirred continuously in the dark for 6 hours. The precipitate was collected, and the resulting sample was rinsed with deionized water and dried in a vacuum drying oven at 55 °C for 12 hours.

[0058] Comparative Example 5

[0059] Preparation of Ag3PO4-SG

[0060] BDS (0.3 g) was dissolved in 20 mL of anhydrous ethanol to obtain a well-dispersed solution. This clarified solution was then added to 100 mL of a 5.0 mg / mL GO suspension, sonicated for 60 min, stirred for 30 min, and the resulting aqueous suspension was freeze-dried under vacuum for 24 h to obtain a brown powder. The powder was transferred to a tube furnace and annealed at 700 °C under argon (150 mL / min) for 1 h. The resulting black powder was washed three times with anhydrous ethanol and deionized water, and then dried overnight at 60 °C in an oven. Finally, a black S-doped graphene (SG) sample was obtained.

[0061] Preparation of Ag3PO4-SG: First, a concentration of 0.01875 mg·mL was obtained. -1 The SG powder dispersion was prepared. Then, 100 mL of the above SG suspension was taken, and 1.53 g of AgNO3 particles were added. The mixture was stirred vigorously in the dark for 6 hours until completely dissolved and homogeneous. Next, 25 mL of 3 mM Na2HPO4 aqueous solution was slowly added to the mixture, and the mixture was stirred continuously in the dark for 6 hours. The precipitate was collected, and the resulting sample was rinsed with deionized water and dried in a vacuum drying oven at 55 °C for 12 hours.

[0062] Comparative Example 6

[0063] Preparation of AgCl-NSG

[0064] Preparation of NSG: Urea (0.5 g) and benzyl disulfide (0.3 g) were dissolved in 20 mL of anhydrous ethanol and mixed thoroughly to obtain a dispersion. This dispersion was then added to 100 mL of a 5.0 mg / mL GO suspension, sonicated for 60 min, and stirred for 30 min to obtain a mixed solution. The resulting mixture was freeze-dried under vacuum for 24 h to obtain a brown powder. The brown powder was transferred to a tube furnace and annealed at 700 °C under argon (150 mL / min) for 1 h (heating rate of the tube furnace was 5 °C / min). A black powder was obtained. The black powder was washed three times each with anhydrous ethanol and deionized water, and then dried at 60 °C. Nitrogen-sulfur-doped graphene (NSG).

[0065] Preparation of Ag + / NSG suspension: Prepare a dispersion of NSG at a concentration of 0.01875 mg / mL. Then, take 100 mL of the 0.025 mg / mL NSG dispersion and add 1.53 g of AgNO3 granules. Stir vigorously in the dark for 12 hours until the AgNO3 granules are completely dissolved to obtain Ag... + / NSG suspension.

[0066] Preparation of AgCl-NSG composite materials: to Ag +25 mL of 3 mM NaCl aqueous solution was slowly added to the NSG suspension, and the mixture was stirred continuously in the dark for 6 h. The precipitate was collected, rinsed with deionized water, and dried in a vacuum drying oven at 55 °C for 12 h to obtain the AgCl-NSG composite material.

[0067] Experiment Example 1: Simulated Photocatalytic Inactivation of E. coli

[0068] Test subjects: NSG powder of Comparative Example 1, Ag3PO4 particles of Comparative Example 2, Ag3PO4-GO composite material of Comparative Example 3, Ag3PO4-NG composite material of Comparative Example 4, Ag3PO4-SG composite material of Comparative Example 5, AgCl-NSG composite material of Comparative Example 6, and Ag3PO4-NSG composite materials of Examples 1 to 8.

[0069] Test strain: Escherichia coli (ATCC-8739).

[0070] Test conditions: The initial concentration of E. coli culture was 3 × 10⁻⁶. 7 The bacterial concentration was CFU / mL, the solution volume was 100 mL, the photocatalyst dosage was 0.5 g / L, and the test was conducted after irradiation with visible light for 80 min. The bacterial concentration before and after the experiment was obtained by plate counting, and the test results were obtained by comparison.

[0071] E. coli removal efficiency (%) = -ln(E. coli colony count after sample use / E. coli colony count before sample use) * 100%

[0072] Experimental Example 2: Simulated Photocatalytic Degradation of Amoxicillin

[0073] Test subjects: NSG powder of Comparative Example 1, Ag3PO4 particles of Comparative Example 2, Ag3PO4-GO composite material of Comparative Example 3, Ag3PO4-NG composite material of Comparative Example 4, Ag3PO4-SG composite material of Comparative Example 5, AgCl-NSG composite material of Comparative Example 6, and Ag3PO4-NSG composite materials of Examples 1 to 8.

[0074] Tested contaminant: Amoxicillin

[0075] Test conditions: The initial concentration of amoxicillin solution was 200 mg / L, the solution volume was 100 mL, the photocatalyst dosage was 20 mg / L, and the test was conducted after 16 min of visible light irradiation. The concentration of amoxicillin before and after the experiment was determined by LC-20A high-performance liquid chromatography, and the degradation rate of amoxicillin in the sample was calculated.

[0076] Amoxicillin degradation rate (%) = (Amoxicillin concentration after sample application - Amoxicillin concentration before sample application) / Amoxicillin concentration before sample application * 100%

[0077] The test results are shown in Tables 2 and 3.

[0078] Table 2. Test results of photocatalytic degradation of amoxicillin by the materials.

[0079]

[0080]

[0081] Table 3. Test results of photocatalytic removal of E. coli by the materials.

[0082] Loop count 1 2 3 4 Comparative Example 1 4.62％ 5.25％ 5.56％ 4.87％ Comparative Example 2 43.43％ 38.24％ 35.31％ 30.14％ Comparative Example 3 74.55％ 68.96％ 64.21％ 59.31％ Comparative Example 4 50.37％ 46.20％ 42.55％ 38.51％ Comparative Example 5 51.41％ 46.12％ 43.71％ 40.24％ Comparative Example 6 87.74％ 82.31％ 77.25％ 71.24％ Example 1 100.0％ 100.0％ 98.34％ 96.24％ Example 2 98.42％ 93.42％ 91.23％ 88.31％ Example 3 99.25％ 96.78％ 93.34％ 90.25％ Example 4 100.0％ 98.87％ 95.71％ 93.02％ Example 5 98.68％ 95.46％ 92.24％ 89.74％ Example 6 97.42％ 94.57％ 91.05％ 87.23％ Example 7 98.17％ 95.32％ 92.45％ 88.53％ Example 8 98.66％ 96.41％ 92.43％ 89.47％

[0083] The number of cycles in the table refers to the number of times the device is reused.

[0084] The experimental data from Example 1 and Comparative Examples 1-2 in Tables 2 and 3 are summarized. The tables show that after four cycles of use, the single NSG prepared in Comparative Example 1 showed virtually no photocatalytic degradation effect on amoxicillin in *E. coli*; the single silver phosphate in Comparative Example 2 showed only 26.78% and 30.14% efficiency in oxidizing amoxicillin and removing *E. coli*, respectively, indicating limited effectiveness of single materials in oxidizing amoxicillin and removing *E. coli*. Specifically, the Ag3PO4-NSG photocatalyst of this invention has good interfacial contact between Ag3PO4 and NSG, enabling effective separation of photogenerated electrons and holes at the Ag3PO4-NSG interface, significantly enhancing photocatalytic activity. Under illumination, the Ag3PO4-NSG composite photocatalyst can generate a large amount of active oxides (h) + ·OH, ·O2 - This process disrupts the structure of amoxicillin and E. coli, leading to the degradation of amoxicillin and inactivation of the bacteria, thus exhibiting a significant photocatalytic effect.

[0085] The experimental data from Examples 1-8 and Comparative Examples 3-6 in Tables 1 and 2 were compiled. The difference between the Ag3PO4-NSG composite photocatalysts prepared in Examples 1-8 and Comparative Examples 3-5 lies in the different doping amounts of nitrogen and sulfur sources. In all experiments, the composite photocatalyst in Example 1 showed the best performance in degrading amoxicillin and in the sterilization process. After four cycles of use, the composite photocatalyst in Example 1 maintained an efficiency of over 90% in degrading amoxicillin and sterilization, while the composite photocatalysts in Comparative Examples 3-5 showed a significant decrease in efficiency in both degrading amoxicillin and sterilization. The efficiencies of Comparative Examples 3 (0 nitrogen and sulfur sources), 4 (0 nitrogen source), and 5 (0 nitrogen source) in degrading amoxicillin were only 40.38%, 36.93%, and 40.32%, respectively; and the efficiencies in inactivating Escherichia coli were only 59.31%, 38.51%, and 40.24%, respectively. The AgCl-NSG composite photocatalyst in Comparative Example 6 exhibited degradation efficiencies of 62.85% and E. coli inactivation efficiencies of 71.24%, significantly lower than the 94.26% and 96.24% in the examples. This demonstrates that Ag3PO4, with its high quantum efficiency and strong oxidizing power, demonstrates higher photocatalytic efficiency than AgCl. Furthermore, the doping of urea and benzyl disulfide, as excellent electron acceptors for Ag3PO4, can modulate the electronic structure of the graphene carbon lattice and play a crucial role in storing photogenerated electrons and transporting them to the acceptor. Simultaneously, NSG provides silver phosphate with more new active sites, achieving highly efficient degradation of AMX and antibacterial effects.

[0086] The experimental data from Examples 1-5 in Tables 2 and 3 were compiled. The preparation processes of the Ag3PO4-NSG composite photocatalysts in Examples 1-5 were similar, differing only in the amount of NSG added. The amounts of NSG added in Examples 1, 2, 3, 4, and 5 were 0.01875 mg / mL, 0.01125 mg / mL, 0.01375 mg / mL, 0.01625 mg / mL, and 0.02125 mg / mL, respectively. After four cycles, the Ag3PO4-NSG composite photocatalysts prepared in Examples 1-5 achieved an oxidation rate of over 90% for amoxicillin. Among them, the Ag3PO4-NSG composite photocatalysts prepared in Examples 2 and 5 had the lowest oxidation efficiency. The Ag3PO4-NSG composite photocatalysts prepared in Examples 1, 3, and 4 achieved a removal rate of over 90% for E. coli, while the Ag3PO4-NSG composite photocatalysts prepared in Examples 2 and 5 achieved a removal rate of less than 90%. The experimental results show that the amount of NSG added to the Ag3PO4-NSG composite photocatalyst is crucial. In summary, combining an appropriate amount of NSG with Ag3PO4 can significantly improve photocatalytic activity. The amount of NSG plays a vital role in the composite material. Too little or too much NSG fails to achieve the desired effect. When the amount of NSG is too small, it is not uniformly distributed on Ag3PO4, and the electron transfer ability of insufficient NSG is weak; when the amount of NSG is too large, the shielding effect weakens the photon-capturing ability of Ag3PO4. Furthermore, excessive NSG may form recombination centers for photogenerated electrons and holes. Therefore, the NSG addition amount in this invention should be set to 0.01375–0.01875 mg / mL.

[0087] The above experimental results demonstrate that the Ag3PO4-NSG composite photocatalyst prepared in this invention exhibits significant AMX degradation and antibacterial capabilities. The formation of a heterojunction in the Ag3PO4-NSG composite photocatalyst significantly enhances its photocatalytic activity. Under illumination, the Ag3PO4-NSG composite photocatalyst generates a large amount of active oxides (h) in water. + ·OH, ·O2 - Meanwhile, NSG provides silver phosphate with more new active sites, achieving efficient degradation of AMX and antibacterial effects.

[0088] Furthermore, the Ag3PO4-NSG composite photocatalyst prepared by this invention effectively solves the problems of low separation efficiency of photogenerated electron-hole pairs, poor photocatalytic activity, and poor reusability, and has strong practicality. The Ag3PO4-NSG composite photocatalyst of this invention can maintain high photocatalytic degradation of pollutants and antibacterial disinfection while also possessing the characteristics of simple operation and good recyclability, making it suitable for application in the fields of antibiotic degradation and antibacterial treatment in water.

Claims

1. The application of a silver phosphate composite material in photocatalytic degradation of antibiotics and photocatalytic sterilization, characterized in that, The preparation method of the silver phosphate composite material includes the following steps: (1) Dissolve the nitrogen source and sulfur source in an organic solvent and disperse them evenly to obtain a dispersion solution; add the dispersion solution to an aqueous suspension of graphene oxide and stir to obtain a uniform suspension. After drying, obtain a brown powder. Anneal the brown powder at high temperature under a protective atmosphere to obtain nitrogen-sulfur-doped graphene (NSG); the nitrogen source is selected from urea, the sulfur source is selected from benzyl disulfide, the amount of urea added is 0.004-0.04 g / mL, and the amount of benzyl disulfide added is 0.002-0.05 g / mL. (2) Nitrogen-sulfur-doped graphene (NSG) was added to water and dispersed evenly to obtain a nitrogen-sulfur-doped graphene (NSG) suspension. Silver ion solution was added to the above suspension and mixed evenly to obtain Ag. + / NSG suspension; in the nitrogen-sulfur-doped graphene suspension, the amount of nitrogen-sulfur-doped graphene NSG added is 0.01375~0.01875 mg / mL; (3) Add the solution containing hydrogen phosphate to the Ag + In an NSG suspension, the mixture is stirred and reacted, and the precipitate is collected to obtain a silver phosphate composite material Ag3PO4-NSG, in which nitrogen-sulfur doped graphene and silver phosphate form a heterojunction structure. The antibiotic is amoxicillin, and the bacterium is Escherichia coli.

2. The application according to claim 1, characterized in that, The high-temperature annealing temperature is 600-800℃, and the annealing time is 1-2 hours.

3. The application according to claim 2, characterized in that, The heating rate during the annealing process is 5℃ / min; the gas flow rate of the protective gas during the annealing process is 100~200 mL / min.

4. The application according to claim 3, characterized in that, The organic solvent is selected from anhydrous ethanol.

5. The application according to claim 4, characterized in that, The concentration of the graphene oxide aqueous suspension in step (1) is 4.0-6.0 mg / mL.

6. The application according to any one of claims 1 to 5, characterized in that, The concentration of the silver ion solution in step (2) is 7.0 to 11.0 mmol / L; the mixing time between the nitrogen-sulfur doped graphene suspension and the silver ion solution is 10 h to 12 h; the step of adding the silver ion solution needs to be carried out under light-protected conditions.

7. The application according to claim 6, characterized in that, Step (3) HPO4 in the reaction system 2- With Ag + The molar ratio is 1:2~4; the stirring reaction is carried out under light-protected conditions for 2 h~6 h.

8. The application according to claim 6, characterized in that, Before stirring in step (1), the mixture undergoes ultrasonic treatment for 60-100 min, and the stirring time is 20-40 min. The protective atmosphere is selected from at least one of argon, helium or nitrogen. The amount of urea added is 0.01875±0.00875 g / mL. In step (2), the dispersion is performed by ultrasonic treatment for 30-120 min.

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