A photocatalyst, its preparation method, and its application in the degradation of antibiotics.
By preparing photocatalysts from small-sized photosensitive metal nanoclusters, the problem of antibiotic removal from wastewater has been solved, achieving a highly efficient degradation effect and an economically feasible solution.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZJU HANGZHOU GLOBAL SCI & TECH INNOVATION CENT
- Filing Date
- 2026-04-20
- Publication Date
- 2026-06-30
AI Technical Summary
Existing technologies are insufficient to efficiently remove antibiotics from wastewater, especially at low concentrations where it is difficult to meet food safety standards. Conventional methods are costly, unstable, and have low recyclability.
A photocatalyst for preparing small-sized photosensitive metal nanoclusters was developed by synthesizing hydroxyl organic imine cages via a hydrothermal reaction. The photosensitive metal salts were stabilized using hydroxyl organic amine cation cages to form small-sized metal nanoclusters with good water solubility and dispersibility, thus achieving efficient photocatalytic degradation of antibiotics.
It achieves efficient degradation of antibiotics at low concentrations, improves catalytic efficiency, has a high reusability rate, controls economic costs, and is suitable for industrial applications.
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Figure CN122057576B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of antibiotic wastewater treatment technology, specifically to a photocatalyst, its preparation method, and its application in degrading antibiotics. Background Technology
[0002] Antibiotics are drugs used to treat bacterial infections and are widely used to disinfect bacteria in human and poultry lesions. Due to the continuous development of the antibiotic manufacturing industry, antibiotics in the environment are attracting increasing attention, prompting a widespread search for possible control methods. The emergence of antibiotic resistance genes and antibiotic-resistant bacteria in organisms accelerates the spread of antibiotic resistance, posing a threat to human health and ecosystems.
[0003] Over the past decade, various strategies have been employed to address the problem of antibiotics in wastewater. Wastewater treatment is generally considered the primary method for managing these antibiotics, as it incorporates emissions from hospitals, industry, and agriculture. However, increasing research confirms that conventional treatment technologies have limited capacity to remove these predominantly water-soluble, non-volatile, and non-biodegradable pollutant compounds. Biological elimination and abiotic processes, including adsorption, hydrolysis, bacterial biodegradation, and redox reactions, have attracted significant attention. (Yang et al. (Yang, S.-F.; Lin, C.-F.; Yu-Chen Lin, A.; Andy Hong, P.-K. Sorption and Biodegradation of Sulfonamide Antibiotics by Activated Sludge: Experimental Assessment Using Batch Data Obtained Under Aerobic Conditions) Water Res. (2011, 45, 3389–3397.) This study investigated the adsorption, desorption, and biodegradation performance of activated sludge for sulfonamide antibiotics in the presence and absence of NaN3 bactericide. The experimental results showed that antibiotics were removed through adsorption and biodegradation by activated sludge. (Liu et al. (Liu, P.; Zhang, H.; Feng, Y.; Yang, F.; Zhang, J. Removal of Trace Antibiotics from Wastewater: A Systematic Study of Nanofiltration Combined with Ozone-Based Advanced Oxidation Processes) Chem. Eng. J.(2014, 240, 211–220.) The highest antibiotic removal efficiency (>87%) was achieved by targeting four antibiotics: norfloxacin, ofloxacin, roxithromycin, and azithromycin.
[0004] However, these methods are limited in application due to their high cost, poor stability, and low recyclability. Therefore, scientists have been seeking new methods for degrading antibiotics in wastewater, making the exploration of efficient degradation technologies a popular research direction for environmental and chemical researchers.
[0005] Photocatalysis has attracted widespread attention as one of the most promising strategies for degrading antibiotic pollutants due to its low cost, high efficiency, and environmental friendliness, as it can degrade antibiotics under ambient conditions. However, most antibiotics are difficult to decompose due to their stable molecular structures; therefore, the development, design, and preparation of suitable photocatalysts with high photocatalytic activity are urgently needed. Summary of the Invention
[0006] This invention addresses the issue that antibiotic concentrations in wastewater are relatively low, making it difficult to achieve removal efficiency that meets national food safety standards. It provides a method for efficiently preparing small-sized photosensitive metal nanoclusters, and the photocatalyst prepared by this method can achieve efficient antibiotic degradation.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0008] A method for preparing a photocatalyst, comprising the following steps:
[0009] Step 1: Disperse 2-hydroxypyromellitic aldehyde in a solvent, add a solution of diamine ligand and mix well, obtain crystals through hydrothermal reaction, and then obtain hydroxy organic imine cages by washing and drying;
[0010] Step 2: Dissolve the hydroxy organic imine cage obtained in Step 1 in a solvent, add sodium borohydride to carry out a reduction reaction to obtain a flexible hydroxy organic imine molecular cage;
[0011] Step 3: Add inorganic acid to the flexible hydroxy organic amine molecular cage obtained in Step 2 until the solution becomes clear, and freeze dry to obtain the hydroxy organic amine cationic cage.
[0012] Step 4: Stabilize the photosensitive metal salt using the hydroxy organic amine cation cage obtained in Step 3, and then immobilize the photosensitive metal nanoclusters in the hydroxy organic amine cation molecular cage by reduction.
[0013] Because the concentration of antibiotics in industrial and domestic wastewater is relatively low, their removal is extremely difficult. Although existing photocatalysts have some degradation effect on antibiotics, it is still difficult to meet the GB 31650-2019 standard, "National Food Safety Standard: Maximum Residue Limits for Veterinary Drugs in Food". This invention prepares a hydroxyl organic amine cation cage, which utilizes the abundant cation sites on its periphery to stabilize a photosensitive metal salt. These photosensitive metal salts undergo a reduction reaction to yield small-sized metal atoms, which aggregate to form photosensitive metal nanoclusters immobilized within the hydroxyl organic amine cation cage. The metal nanoclusters stabilized by the hydroxyl organic amine cation cage exhibit good water solubility and dispersibility in water, allowing for sufficient contact with antibiotic substrates and achieving highly efficient photocatalytic degradation of antibiotics.
[0014] The solvent in step 1 includes one or more of N,N-dimethylformamide (DMF), N,N-dimethylacetamide, acetonitrile, and acetone.
[0015] The hydrothermal reaction time in step 1 is 24-96 h, and the hydrothermal temperature is 80-130℃.
[0016] The two raw materials react for a relatively long time under high temperature and pressure, resulting in good crystallinity. However, the longer the reaction time, the higher the probability of amine oxidation. During crystallization, the solvent does not volatilize, leading to impurities depositing on the hydrothermal reactor wall and contaminating the crystals. Therefore, within this range, the crystallization effect is good and the yield is high. The hydrothermal crystallization method of this invention for synthesizing organic imine cages has the advantages of simple synthesis method and relatively high synthesis yield. The hydroxyl organic amine cationic cages prepared through structural modification can not only stabilize extremely small-sized photosensitive metal clusters, but also have good water solubility and dispersibility, which can greatly improve the contact with antibiotics and is expected to achieve efficient degradation of antibiotics at low concentrations.
[0017] More preferably, the hydrothermal reaction time in step 1 is 72 h, and the hydrothermal temperature is 90-120℃.
[0018] The diamine ligand includes any one or more of (1R,2R)-cyclopentanediamine, (1S,2S)-cyclopentanediamine, (1R,2R)-cyclohexanediamine, and (1S,2S)-cyclohexanediamine.
[0019] Preferably, the diamine ligand is one or more of (1R,2R)-cyclohexanediamine and (1S,2S)-cyclohexanediamine; the amino group on the ligand and the aldehyde group on the hydroxymethyltrimethylaldehyde have a more suitable condensation angle and spatial distance, making it easier to synthesize hydroxyimine cages.
[0020] The molar ratio of 2-hydroxytrimethylbenzaldehyde to the diamine ligand is 1:1-3.
[0021] The solvent in step 2 includes one or more of methanol, acetone, dichloromethane, and deionized water.
[0022] The molar ratio of the hydroxyl organic imine cage to sodium borohydride is 1:12-60.
[0023] In step 2, the reduction reaction temperature is 0-50℃ and the reaction time is 9-48 h.
[0024] Preferably, the reduction reaction temperature in step 2 is 20-25℃, and the reaction time is 24 h.
[0025] The inorganic acid in step 3 includes one or more of hydrochloric acid (HCl), nitric acid (HNO3), and sulfuric acid (H2SO4). The photosensitive metal salt in step 4 includes one or more of tetrachloroauric acid, potassium chloropalladium, sodium tellurite, and sodium selenite.
[0026] Preferably, the photosensitive metal salt includes one or more of sodium selenite and sodium tellurite.
[0027] In step 4, the reducing agent is one or two of sodium borohydride (NaBH4), methanol, and sodium citrate.
[0028] In step 4, the reduction reaction temperature is 0-40℃ and the reaction time is 10 s-10 min.
[0029] The preparation method of this invention has high yield, short time, relatively mild reaction conditions, and low equipment requirements, and can achieve a yield of over 75%, or even over 80%.
[0030] On the other hand, the present invention also provides a photocatalyst prepared by the preparation method described above.
[0031] In another aspect, the present invention also provides the application of the aforementioned photocatalyst in the photocatalytic degradation of antibiotics, including the steps of: placing the catalyst and antibiotics in a photoreaction bottle at a certain concentration ratio, introducing gas, reacting for a certain time under different light sources, and testing the degradation performance by ultraviolet-visible spectroscopy (UV-vis) and high performance liquid chromatography (HPLC).
[0032] The antibiotics mentioned include one or more of sulfamethoxazole, roxithromycin, ciprofloxacin, tetracycline, and levofloxacin.
[0033] Preferably, the antibiotics include one or more of levofloxacin and ciprofloxacin.
[0034] The concentration ratio of the photocatalyst to the antibiotic is 25:1 to 2.5:1.
[0035] The gas is one of oxygen (O2), nitrogen (N2), and carbon dioxide (CO2).
[0036] Preferably, the gas is O2 or N2.
[0037] More preferably, the gas is O2, which helps generate hydroxyl radicals and has a better degradation effect on antibiotics.
[0038] The light source is one of white light, blue light, or violet light; wherein, white light corresponds to a mixed wavelength, blue light corresponds to wavelengths at positions of 420 nm, 450 nm, and 485 nm, and violet light corresponds to wavelengths at positions of 365 nm and 385 nm.
[0039] Preferably, the light source is violet light, with a corresponding wavelength of 365 nm.
[0040] The reaction time is 3-36 h.
[0041] Compared with the prior art, the present invention has the following beneficial effects:
[0042] (1) Unlike molecular cage tandem catalysts without hydroxyl groups, the present invention prepares hydroxyl organic amine cationic cages, which introduce hydroxyl groups as photosensitive active sites to enable photocatalytic reactions. Furthermore, thanks to the open channels of the hydroxyl organic amine cationic cages, their stable photosensitive metal nanoclusters have fully exposed active sites, which enhance the photoreaction activity in synergy with the photosensitive sites. They are ideal photocatalysts and can improve catalytic efficiency.
[0043] (2) The present invention prepares hydroxy organic amine cationic cage stabilized photosensitive metal nanoclusters as photocatalysts for degrading antibiotics. The nanoclusters have small size, high surface activation energy, good hydrophilicity, and synergistic improvement of water solubility / dispersibility. They also achieve uniform immobilization of sub-nano clusters, which can fully contact and efficiently degrade antibiotics in water.
[0044] (3) By recovering the catalyst with alkali, the reusability of photocatalysis is improved, the economic cost is controlled, and it is expected to be further applied to industrial applications. Attached Figure Description
[0045] Figure 1 This is the X-ray powder diffraction (XRD) pattern of the hydroxyl organic imine cage CC3-OH obtained in Example 1.
[0046] Figure 2 This is the 1H NMR spectrum of the hydroxyl organic imine cage levorotatory CC3-OH in Example 2 ( 1 (H NMR) image.
[0047] Figure 3This is a high-resolution transmission electron microscope (HRTEM) image of the photocatalyst Se@ICC3-OH obtained in Example 3.
[0048] Figure 4 This is an HRTEM image of the photocatalyst Te@ICC3-OH obtained in Example 4.
[0049] Figure 5 This is a graph showing the effect of Te@ICC3-OH on the degradation of levofloxacin in Example 1.
[0050] Figure 6 This is a graph showing the effect of Te@ICC3-OH on the degradation of ciprofloxacin in Application Example 2.
[0051] Figure 7 The image shows the effect of Te@ICC3-OH on the degradation of levofloxacin in Example 3. Detailed Implementation
[0052] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention, without departing from the spirit and scope of the invention, should be covered within the protection scope of this invention.
[0053] All raw materials used in the following specific implementation methods were purchased from the market.
[0054] Example 1
[0055] 400 mg of 2-hydroxypyromellitic aldehyde was dissolved in 60 mL of DMF, and 400 mg of (1R,2R)-cyclohexanediamine was dissolved in 40 mL of DMF. The two solutions were mixed thoroughly in a 150 mL hydrothermal reactor. Initially, the mixture was a clear, transparent yellow solution. The reactor was placed in an oven and heated to 90 °C for 72 h. Yellow crystals formed on the reactor wall were scraped off with a spatula, washed with acetone, and dried in an oven at 80 °C to obtain a hydroxyl organic imine cage CC3-OH with a yield of 632 mg. This method yielded a high CC3-OH yield of 79%. The XRD pattern of the synthesized material is shown below. Figure 1 As shown, the hydroxyl organic imine molecular cage was successfully synthesized.
[0056] Weigh 500 mg CC3-OH and disperse it in 30 mL of mixed solvent (methanol:dichloromethane volume ratio = 1:1). Add 500 mg NaBH4 at 25 °C for 24 h to reduce the solvent. Remove the dichloromethane solvent by rotary evaporation. Wash the sample with deionized water to remove excess boride and generate flexible hydroxyl organic amine molecular cage RCC3-OH. Dry it in an oven at 80 °C for later use.
[0057] Weigh 0.25 g of the flexible organic amine molecular cage sample of RCC3-OH, add it to 10 mL of 0.5 M HCl solution at room temperature until the sample is completely dissolved, and freeze-dry the resulting clear solution to obtain the hydroxy organic amine cationic cage ICC3-OH, which is then stored for later use.
[0058] Example 2
[0059] 400 mg of 2-hydroxytrimethylammonium aldehyde was dissolved in 60 mL of DMF, and 400 mg of (1S,2S)-cyclohexanediamine was dissolved in 40 mL of DMF. The two solutions were mixed thoroughly in a 150 mL hydrothermal reactor. Initially, the mixture was a clear, transparent yellow solution. The reactor was placed in an oven and heated to 120 °C, and the reaction was continued for 72 h. Yellow crystals formed on the reactor wall were scraped off with a spatula, washed with acetone, and dried in an oven at 80 °C to obtain 556 mg of levorotatory CC3-OH, a hydroxyl organic imine cage. The yield of levorotatory CC3-OH synthesized by this method was 69.5%. The synthesized material... 1 H NMR spectrum as follows Figure 2 As shown, the levorotatory hydroxyl organic imine molecular cage was successfully synthesized.
[0060] Weigh 500 mg of levorotatory CC3-OH and disperse it in 30 mL of mixed solvent (methanol:dichloromethane volume ratio = 1:1). Add 500 mg of NaBH4 at 20 °C and reduce for 15 h. Then add 2 mL of deionized water and continue the reduction for 9 h. Remove the dichloromethane solvent by rotary evaporation. Wash the sample with deionized water to remove excess borate and generate levorotatory RCC3-OH, a flexible hydroxyl organic amine molecular cage. Dry it in an oven at 80 °C for later use.
[0061] Weigh 0.25 g of a flexible organic amine molecular cage sample of levorotatory RCC3-OH, add it to 10 mL of 0.5 M HNO3 solution at room temperature until the sample is completely dissolved, and freeze-dry the resulting clear solution to obtain a hydroxyl organic amine cationic cage of levorotatory ICC3-OH, which is then stored for later use.
[0062] Example 3
[0063] Weigh 15 mg of the ICC3-OH prepared in Example 1 and add it to 9 mL of deionized water, then add 1 mL of sodium selenite aqueous solution (1 mg / mL). -1 After mixing thoroughly, allow the mixture to stand for 10 minutes to age. Then, place the liquid in a cooling circulation pump to lower the temperature, control the rate of subsequent reduction reactions, and prevent the agglomeration of the generated nanoclusters.
[0064] Subsequently, 2 mg of NaBH4 solid was added under vortex oscillation conditions, and vortex oscillation was continued for 10 min at a temperature of 0-40℃ to carry out the reduction reaction. The resulting orange solution was lyophilized to obtain the photocatalyst Se@ICC3-OH. The HRTEM of the synthesized photocatalyst is as follows: Figure 3 As shown, the average size of the photosensitive metal nanoclusters we synthesized is 5 nm.
[0065] Example 4
[0066] Weigh 15 mg of the ICC3-OH prepared in Example 1 and add it to 9 mL of deionized water, then add 1 mL of sodium tellurite aqueous solution (1 mg / mL). -1 After mixing thoroughly, allow the mixture to stand for 10 minutes to age. Then, place the liquid in a cooling circulation pump to lower the temperature, control the rate of subsequent reduction reactions, and prevent the agglomeration of the generated nanoclusters.
[0067] Subsequently, 2 mg of NaBH4 solid was added under vortex oscillation conditions, and vortex oscillation was continued for 10 min at a temperature of 0-40℃ to carry out the reduction reaction. The resulting black solution was lyophilized to obtain the photocatalyst Te@ICC3-OH. The HRTEM of the synthesized photocatalyst is as follows: Figure 4 As shown, we have synthesized sub-nanometer-sized photosensitive metal nanoclusters with an average size of 0.7 nm.
[0068] The Te nanoclusters prepared by this method are encapsulated in the cavity of a hydroxy organic amine cation molecular cage. They have sub-nanometer size, higher surface activation energy, and more exposed active sites, making them ideal photocatalysts.
[0069] Application Example 1
[0070] In a photocatalyst 10 mg of Te@ICC3-OH from Example 4 was weighed into a photocatalyst 50 ppm of levofloxacin solution, and then oxygen was continuously introduced. The mixture was then irradiated with 365 nm ultraviolet light at a rotation speed of 200 r for 12 h. The degradation efficiency of the resulting solution was monitored by UV-vis spectroscopy and HPLC. Figure 5 The data calculated that the degradation efficiency of levofloxacin was 82.3%.
[0071] Application Example 2
[0072] In a photocatalyst 10 mg of Example 4, Te@ICC3-OH, was weighed and added to a 50 ppm ciprofloxacin solution. Oxygen was then continuously introduced, and the mixture was irradiated with 365 nm UV light at a rotation speed of 200 rpm for 12 h. The degradation efficiency of the resulting solution was monitored by UV-vis spectroscopy and HPLC. Figure 6 The data calculated that the degradation efficiency of ciprofloxacin was 95.1%.
[0073] Application Example 3
[0074] In a photocatalyst 10 mg of Te@ICC3-OH from Example 4 was weighed into a photocatalyst 50 ppm of levofloxacin solution, and then nitrogen gas was continuously introduced. The mixture was then irradiated with 365 nm ultraviolet light at a rotation speed of 200 r for 12 h. The degradation efficiency of the resulting solution was monitored by UV-vis spectroscopy and HPLC. Figure 7 The data calculated that the degradation efficiency of levofloxacin was 45.0%.
[0075] This data comparison illustrates that introducing different gases has a significant impact on the degradation effect.
[0076] In summary, based on this, the hydroxyl organic amine cation cage prepared in this invention utilizes the abundant cation sites on the periphery of the hydroxyl organic amine cation cage to stabilize photosensitive metal salts. These photosensitive metal salts can be reduced to obtain small-sized metal atoms, which aggregate to form photosensitive metal nanoclusters immobilized within the hydroxyl organic amine cation cage. The metal nanoclusters stabilized by the hydroxyl organic amine cation cage exhibit good water solubility and dispersibility in water, forming transparent or semi-transparent solutions. This is a near-homogeneous catalysis, allowing for sufficient contact with antibiotic substrates and achieving highly efficient photocatalytic degradation of antibiotics. Specifically, firstly, the ammonium cations on the molecular cage framework of the organic amine cation cage can firmly anchor negatively charged photosensitive metal precursors (such as selenite and tellurite) through electrostatic interactions. After reduction, the metal atoms are confined within the nanocavities of the cage, preventing them from growing into large particles. The smaller the size, the higher the surface activation energy and the stronger the catalytic activity. Secondly, hydroxyl groups can form additional coordination or hydrogen bonds with the surface of the metal clusters, further passivating the cluster surface and improving its stability. This specific structural synergy enabled the preparation of ultra-small, highly stable metal clusters.
[0077] Compared to other approaches that use porous materials (such as MOFs) as a matrix to bind hydroxyl groups, this invention requires the use of an organic amine cationic cage molecular framework as the matrix for binding hydroxyl groups; the two cannot be separated. This is because, with existing porous materials, catalysts often exist as suspended particles, with the reaction occurring on the surface of the solid particles and within the pores. This leads to severe mass transfer limitations; antibiotic molecules must first diffuse to the surface of the porous material before entering the pores to contact the active sites. For low concentrations of antibiotics, this heterogeneous catalytic efficiency is typically lower than that of homogeneous catalysis, making it difficult to achieve uniform immobilization of sub-nano clusters, resulting in extremely low utilization of active sites and a significantly lower catalytic efficiency compared to the hydroxyl organic amine cationic cage prepared in this invention. Therefore, the photocatalyst provided by this invention can fully contact and efficiently degrade antibiotics in water.
Claims
1. A method for preparing a photocatalyst, characterized in that, Including the following steps: Step 1: 2-hydroxypyromellitic aldehyde is dispersed in a solvent, and a solution of a diamine ligand is added and mixed evenly. Crystals are obtained through a hydrothermal reaction, and then the crystals are obtained by washing and drying. The diamine ligand includes one or more of (1R,2R)-cyclopentanediamine, (1S,2S)-cyclopentanediamine, (1R,2R)-cyclohexanediamine, and (1S,2S)-cyclohexanediamine. Step 2: Dissolve the hydroxy organic imine cage obtained in Step 1 in a solvent, add sodium borohydride to carry out a reduction reaction to obtain a flexible hydroxy organic imine molecular cage; Step 3: Add inorganic acid to the flexible hydroxy organic amine molecular cage obtained in Step 2 until the solution becomes clear, and freeze dry to obtain the hydroxy organic amine cationic cage. Step 4: Stabilize the photosensitive metal salt using the hydroxy organic amine cation cage obtained in Step 3, and then immobilize the photosensitive metal nanoclusters in the hydroxy organic amine cation molecular cage through a reduction reaction; wherein the photosensitive metal salt includes one or more of sodium tellurite and sodium selenite.
2. The method for preparing the photocatalyst according to claim 1, characterized in that, In step 1, the molar ratio of 2-hydroxytrimethylammonium aldehyde to the diamine ligand is 1:1-3.
3. The method for preparing the photocatalyst according to claim 1, characterized in that, The hydrothermal reaction time in step 1 is 24-96 h, and the hydrothermal temperature is 80-130℃.
4. The method for preparing the photocatalyst according to claim 1, characterized in that, In step 2, the molar ratio of the hydroxyl organic imine cage to sodium borohydride is 1:12-60; In step 2, the reduction reaction temperature is 0-50℃ and the reaction time is 9-48 h.
5. The method for preparing the photocatalyst according to claim 1, characterized in that, The reducing agent used in step 4 is one or two of sodium borohydride, methanol, and sodium citrate; In step 4, the reduction reaction temperature is 0-40℃ and the reaction time is 10 s-10 min.
6. The photocatalyst prepared by the method according to any one of claims 1-5.
7. The application of the photocatalyst according to claim 6 in the degradation of antibiotics, characterized in that, The steps include: placing the catalyst and antibiotic in a photoreaction bottle at a certain concentration ratio, introducing oxygen, reacting for a certain time under different light sources, and testing the degradation performance by ultraviolet-visible spectroscopy and high-performance liquid chromatography.
8. The application of the photocatalyst according to claim 7 in the degradation of antibiotics, characterized in that, The mass concentration ratio of photocatalyst to antibiotic is 25:1-2.5:1; The antibiotics mentioned include one or more of sulfamethoxazole, roxithromycin, ciprofloxacin, tetracycline, and levofloxacin.
9. The application of the photocatalyst according to claim 7 in the degradation of antibiotics, characterized in that, The light source is one of white light, blue light, or violet light.