Degradation Of Ciprofloxacin And Sulfisoxazole By Bismuth Bromide Oxide Based Photocatalytic Materials

In recent years,with the development of science and the increasing attention to water environment,a variety of drugs and personal care products（PPCPs）,such as antibiotics and other new pollutants have gradually attracted people’s attention.Compared with other water pollution treatment methods,the advantages of photocatalytic oxidation technology are mainly reflected in the stability of effect,safety and environmental protection,convenience,wide application and high degradation efficiency.Among them,the composite semiconductor materials based on bismuth bromide oxide have rapidly become a research hotspot in the field of photocatalytic degradation of antibiotics and other organic pollutants due to their suitable band gap width,easy to be stimulated by visible light,expedite preparation method and stable physical and chemical properties.This article constructs the BiOBr/WO₃ heterojunction catalytic materials and Ag/BiOBr/WO₃ composite photocatalytic materials,through the degradation of ciprofloxacin and sulfisoxazole,and take multiple representation methods to study the chemical and physical properties of composite catalyst,concluded that the mechanism of the composite material of the light catalytic degradation,to study its catalytic performance improvement.The conclusions are as follows:（1）BiOBr/WO₃ composite semiconductor material was constructed by solvent-hydrothermal method combined with co-precipitation method,and was used to degrade ciprofloxacin（5 mg/L）.It was characterized by XRD,XPS,SEM,UV-vis DRS,FTIR,EIS and BET,et al.In all the BiOBr/WO₃ composites,BiOBr/WO₃ with 15%WO₃ had the highest degradation rate of ciprofloxacin.When the dosage reached 0.5 g/L,the degradation rate of the substrate was 94.9%in 180 min,and its degradation rate constants were 9.45 and 4.05 times of WO₃ and BiOBr,respectively.This indicated that the composite of BiOBr and WO₃ successfully improved the photocatalytic activity of semiconductor materials.The optimal dosage of catalyst material is 0.5 g/L,and the best photocatalytic effect is obtained at p H 7.After five cycles,BW-20 still has high catalytic activity,which indicates that the composite material can be recycled and has good stability.The active group in the catalytic system was investigated by free radical capture experiment.·O₂^-was the active group that played a major role in the system,and ¹O₂ and h⁺played a secondary role.It was inferred that the photocatalytic reaction mechanism of the composites was that WO₃ and BiOBr constructed p-n heterojunction,which enhanced the migration of photogenerated holes and electrons and slowed down their recombination,thus the photocatalytic activity of the composites was significantly improved.（2）In order to further improve the degradation effect of the composite catalytic material on antibiotics,a new type of Ag/BiOBr/WO₃ semiconductor catalytic material was structured by in-situ photodeposition method on the p-n heterojunction constructed of BiOBr/WO₃ materials,and it was used for the catalytic degradation of sulfisoxazole（5 mg/L）.The catalysts were characterized by XRD,XPS,SEM,TEM,UV-vis DRS,ESR and photocurrent response,et al.The Ag/BiOBr/WO₃ materials with 15%Ag content is the most efficient composite catalyst for the degradation of sulfisoxazole.When the dosage was 0.3 g/L,ABW-15 could degrade sulfisoxazole group of 5 mg/L in the solution 98.1%in 60min,and the degradation rate constants were 28.79,36.37and 7.59 times of BiOBr,WO₃ and BW-20,respectively.The optimal dosage of ABW-15 composite was 0.3 g/L,and the catalytic efficiency of ABW-15 composite was higher in the slightly alkaline to neutral environment.The catalytic efficiency of ABW-15 composite reached the highest when the p H value was 7.After five cycles,ABW-15material still has high photocatalytic activity,which indicates that the material can be recycled and has good stability.Through free radical capture experiments,it was found that·O₂^-was the most important active substance in the degradation system,and ¹O₂and h⁺played a secondary role.Combined with UV-vis,photocurrent response and EIS characterization results available,Ag/BiOBr/WO₃ compound semiconductor materials to promote the efficiency of photocatalysis is the main reason why the plasmon resonance effect of Ag elemental,right amount of Ag elemental loaded can extend the light response range of materials,improve photoproduction carrier separation efficiency,improving materials photocatalytic activity.