| With the improvement of the level of health care,the use of antibiotics has increased sharply and the demand for production has only increased.Therefore,the accumulation of antibiotic organic matter in water environment is increasing,especially quinolone antibiotics,which seriously affects the water quality and brings great risks and threats to human health and ecosystem.In order to promote the green and sustainable development of various fields,heterogeneous photo-Fenton composite catalysis was adopted in this paper.Perovskite photocatalysts were used in the reaction to explore the degradation process of simulative quinolone antibiotics such as ciprofloxacin（CIP）and levofloxacin（LVF）.The perovskite LaBO3/Diatomite photocatalyst was prepared by sol-gel method.The ratio of complexing agent,B component and content of diatomite in the photocatalyst preparation process were screened.The results showed that group B was Fe,the ratio of nitrate to complexing agent was 1:2 and the content of diatomite was 1.0 g,the catalyst performance was the best.That was,the optimal catalyst is LaFeO3/Diatomite（1.0 g）.The structure of LaFeO3/Diatomite（1.0 g）was characterized by XRD,FT-IR,SEM,EDS,UV-Vis,XPS and BET methods.The photoelectric activity of the LaFeO3/Diatomite photocatalyst was analyzed by electrochemical workstation.The results showed that the prepared perovskite catalyst had a typical perovskite structure,relatively complete morphology and excellent specific surface area.It also indicated that the best LaFeO3/Diatomite（1.0 g）photocatalyst was n-type semiconductor material,and had better photoelectric activity.The traditional Fenton method,photo-Fenton method,pure photocatalysis method and heterogeneous photo-Fenton method were used to degrade quinolone antibiotic wastewater.The results showed that heterogeneous photo-Fenton method had the best degradation effect on CIP,and the degradation rate of 100 m L 20 mg·L-1CIP reached 93.5%at 150 min,which was significantly higher than other processes.Then,the recycling performance of the photocatalyst with the optimum photocatalytic activity was tested.The results indicated that when the catalyst LaFeO3/Diatomite（1.0 g）was used for 4 times,the catalytic degradation rate of 100 m L and 20mg·L-1CIP simulated wastewater could reach 92.9%and the catalytic effect was still better.In the heterogeneous photo-Fenton reaction,the photocatalytic degradation of CIP and LVF by LaFeO3/Diatomite（1.0 g）composite photocatalyst was remarkable.In this paper,the process conditions such as the initial concentration,the amount of catalyst,the amount of H2O2and the p H of the solution were deeply explored.The results showed that the optimal initial concentration of CIP was 20 mg·L-1,the optimal catalyst concentration was 0.3 g·L-1,the optimal amount of H2O2was 3%and the optimal initial solution p H was 4.The maximum removal rate of CIP at 150 min was 99.6%,and the removal rate at just 10 min was also 90.9%.The optimal initial concentration of catalytic degradation of LVF was 20 mg·L-1,the optimal catalyst concentration was 0.2 g·L-1,the optimal dosage of H2O2was 1%,and the optimal initial solution p H was 7.The maximum removal rate of CIP at 150 min was 98.3%,and the removal rate at just 10 min was also 83.5%.The catalytic reactions of CIP and LVF under the optimal catalytic reaction conditions were tested by the UV-vis absorption spectra of the solution.This study provided a new idea for the degradation of antibiotic organic wastewater by composite photocatalyst with excellent photo-Fenton activity under visible light,which had potential green development significance. |
