The Coupled Persulfate System Catalyzed The Degradation Of Tetracycline Hydrochloride And Ciprofloxacin In Water

Antibiotics,as a medicine for the prevention and treatment of bacterial diseases,are widely used in various industries such as the medical industry,pharmaceutical industry and aquaculture industry.Traditional wastewater treatment technologies can not effectively treat the antibiotics that enter water bodies,resulting in a large number of antibiotics remaining in the natural water bodies.This could increase the emergence of antibiotic resistance genes and pose a threat to ecosystems.Therefore,it is of great significance for environmental protection and human health to explore an efficient and low-cost antibiotic treatment technology.The advanced oxidation technology based on sulfate radical has been proved to be an effective method for antibiotic degradation.Persulfate（PS）can generate sulfate radicals(SO₄^·-)with higher potential through activation.The SO₄^·-is used to decompose organic compounds quickly and eventually lead to mineralization.In this study,ultraviolet light（UV）and Cu Fe₂O₄ were used to activate peroxydisulfate（PDS）to achieve rapid degradation of antibiotic pollutants.The research content mainly includes the preparation conditions of catalysts,the influencing factors in the system,the adaptability of natural water bodies,environmental friendliness and the degradation degree of antibiotic toxicity.The CuFe₂O₄ photocomposites were prepared by sol-gel method,and the effects of different calcination temperatures of the materials were investigated.The materials were characterized by SEM,XRD,Raman and FT-IR.The SEM showed that the unsmooth surface of Cu Fe₂O₄ could provide more active sites for PDS.The XRD shows that when the calcination temperature is 300℃,not only the crystallinity of the material can be improved,but also avoid the generation of other by-products.Raman spectra show that The Raman spectroscopy pattern shows that Cu Fe₂O₄ changes from cubic phase to tetragonal phase with the increase of calcination temperature.The FT-IR pattern shows the Fe³⁺-O^2-bond and Cu²⁺-O^2-bond appeared before and after the reaction,and the material can be reused.The performance and mechanism of the Cu Fe₂O₄/UV/PDS system for degradation of tetracycline hydrochloride（TC）were investigated.The degree of synergy after coupling was 33.3%.Compared to the Cu Fe₂O₄/PDS system,the removal rate was improved by 12.0%and the mineralization was 1.2 times higher.In the experiments with controlled variables,it was concluded that a TC solution of 20 mg/L,p H=7,catalyst dosing of 0.2 g/L,PDS concentration of 0.7 m M and UV intensity of 30 W could achieve a removal rate of 91.1%and k of 0.03051min^-1.The removal rate decreases with the increase of anion concentration,Cl^-,NO₃^-and SO₄^2-react with SO₄^·-to generate free radicals with low oxidation potential.Humic acid（HA）both attaches to the surface of the catalyst to hinder the reaction and activates activate PDS to form free radicals,but overall HA has a slightly greater inhibitory effect than activation effect.Fe³⁺has the greatest influence on the removal rate,which can reduce the removal rate by 35.8%.The degradation rate of TC was maintained above 84.0%with four reuse times.Through quenching experiments,it is found that there are SO₄^·-,·OH,h⁺and O₂^·-in the system.Compared with the single activation technique,the technical coupling improved the electron hole pair recombination problem on the surface of Cu Fe₂O₄ and increased the quantum rate of catalysis.The prepared CuFe₂O₄ was used as a precursor,and then put in 200℃tube furnace oxygen isolation calcined for 4h.After modification,reduced copper ferrate（R-Cu Fe₂O₄）was obtained.The degradation efficiency of ciprofloxacin（CIP）in water by R-Cu Fe₂O₄/UV/PDS system was investigated.Compared with R-Cu Fe₂O₄/PDS system,the addition of UV increased the removal rate by 85.3%and the mineralization rate by 49.6%.For 10mg/L CIP solution,under the optimal conditions of PDS dosing concentration of 0.8 m M,R-Cu Fe₂O₄dosing of 0.05 g/L,and UV intensity of 30 W,the removal rate reached 97.9%.The Cl^-,HCO₃^-,NO₃^-and HPO₄^2-all played an inhibitory role.When the concentration of HA increases to a certain amount,the removal rate will be slightly increased,and the recycling experiment proveed that it has environmental friendliness.The SO₄^·-,·OH and h⁺were all present in the R-Cu Fe₂O₄/UV/PDS system,and ¹O₂was also detected.The mung bean sprout experiment was used to calculate the toxicity,and the toxicity of the treated CIP wastewater was reduced by 42.9%.The CIP solution was prepared by using lake water and tap water on campus as solvents,which proves that the system can be applied in actual water bodies.