Study On Treatment Of Three Antibiotics In Water By Different AOP Methods

With the rapid development of intensive aquaculture,antibiotics have been widely applied.Due to the discharge of aquaculture wastewater,more and more residual antibiotics are constantly flowing into the environment,witch contaminated water continuously eventually by various means like surface-runoff.Most of these antibiotics are highly persistent,cumulative,and difficult to degrade,affecting the ecological environment of soil and water and threatening human health.Therefore,the study of methods for treating residual antibiotics in water has important practical significance for protecting water environment and ecological environment.In this paper,three typical antibiotics namely tetracycline,oxytetracycline and norfloxacin were used as research objects,and they were degraded by five methods:Fenton method,Fenton-like method,UV-Fenton method,UV method and UV-TiO₂ method.Optimum treatment conditions with different methods and degradation effects were compared.The main findings are as follows:1.The treatment of tetracycline in water:?1?The optimal experimental conditions for degradation of tetracycline by Fenton method were pH=2,T=35?,Fe²⁺catalyst 0.05 mmol/L,Fe²⁺and H₂O₂ ratio 1:250.The reaction reached to its equilibrium after 100 min and the degradation rate was 93.58%;?2?The optimum experimental conditions for degradation of tetracycline by Fenton-like method were as follows:pH=2,T=35?,Fe³⁺catalyst 0.05 mmol/L,ratio of Fe³⁺to H₂O₂1:250.The reaction reached to its equilibrium after 90 min,and the degradation rate was93.08%;?3?UV-Fenton degradation of tetracycline optimum conditions for the pH=2,T=35?,Fe²⁺catalyst 0.05 mmol/L,Fe²⁺and H₂O₂ ratio 1:250.The reaction reached to its equilibrium after 30 min.The degradation rate was 94.72%;?4?UV degradation of tetracycline was not affected by the reaction conditions.The reaction reached its equilibrium in 360 min and the degradation rate was 99%;?5?The optimum experimental conditions for degradation of tetracycline by UV-TiO₂method were as follows:pH=4,T=30?,and TiO₂ catalyst 0.8 g/L.After 60 min of reaction,the degradation rate was 86.66%.2.The treatment of oxytetracycline in water:?1?The optimal experimental conditions for the degradation of oxytetracycline by Fenton were pH=2,T=35?,Fe²⁺catalyst 0.05mmol/L,Fe²⁺and H₂O₂ ratio=1:250,the reaction reached equilibrium in 90 min,the degradation rate was 93.96%;?2?The optimal experimental conditions for the degradation of oxytetracycline by Fenton-like method are pH=2,T=35?,Fe³⁺catalyst 0.05 mmol/L,Fe³⁺and H₂O₂ ratio 1:250,The reaction reached to its equilibrium in 80min,and the degradation rate was 92.77%;?3?The optimum experimental conditions for degradation of oxytetracycline by UV-Fenton method are pH=2,T=35?,Fe²⁺catalyst 0.05 mmol/L,Fe²⁺and H₂O₂ ratio 1:250The reaction reached to its equilibrium in 40 min,and the degradation rate was 96.12%;?4?The degradation of oxytetracycline by UV method was not affected by the reaction conditions.The reaction reached to its equilibrium after 480 min.The degradation rate was98.94%;?5?The optimal experimental conditions for degradation of oxytetracycline by UV-TiO₂method were as follows:pH=4,T=30?,TiO₂ catalyst 0.8 g/L.The reaction reached to its equilibrium in 70 min,and the degradation rate was 80.94%.3.The treatment of norfloxacin in water:?1?The optimal experimental conditions for the degradation of norfloxacin by Fenton's method were:pH=3,T=40?,Fe²⁺catalyst 0.05 mmol/L,Fe²⁺and H₂O₂ ratio 1:250,reaction reached to its equilibrium in 80 min,the degradation rate was 91.00%;?2?The optimum experimental conditions for the degradation of norfloxacin by Fenton-like method are:pH=3,T=40?,Fe³⁺catalyst 0.05 mmol/L,Fe³⁺and H₂O₂ ratio 1:250,the reaction reached to its equilibrium in 90 min,the degradation rate was 89.76%;?3?The optimum experimental conditions for degradation of norfloxacin by UV-Fenton method are:pH=3,T=35?,Fe²⁺catalyst 0.05 mmol/L,Fe²⁺and H₂O₂ ratio 1:50,After 30min,the reaction reached to its equilibrium,and the degradation rate was 97.22%;?4?The optimal experimental conditions for UV degradation of norfloxacin were pH=2,T=40?,the reaction reached equilibrium at 480 min,and the degradation rate was 92.86%;?5?The optimum experimental conditions for degradation of norfloxacin by UV-TiO₂method were as follows:pH=5,T=40?,and TiO₂ catalyst 0.8 g/L.After 60 min's reaction,the equilibrium was committed,and the degradation rate was 74.59%.4.Among the five methods,the best treatment of tetracycline and oxytetracycline wastewater is Fenton method.The UV-Fenton is the best way to treat norfloxacin wastewater.