Characteristic Of Antibiotic Pollution In Drinking Water Sources In Zhejiang Province And Study On The Mechanism Of Infrared Enhanced Photocatalytic Degradation Of Antibiotics

China is the world's largest producer and consumer of antibiotics.Due to the overuse of antibiotics and incomplete end treatment,most of the water in the area is contaminated with antibiotics.Antibiotics entering drinking water are usually present at ultra-trace concentrations(pg L^-1-ng L^-1),but such concentrations still pose ecological risks to human health.Therefore,it is urgent to investigate the status of antibiotic residues in drinking water.However,due to the lack of universality in the analysis methods of antibiotics in environmental samples,the research on the characteristics of antibiotic contamination is limited to a certain extent.Therefore,it is necessary to establish a method for the determination of trace antibiotics in drinking water.In addition,there is a lack of targeted treatment technology for antibiotic removal in terminal treatment at present.Photocatalytic technology has been applied to the degradation of antibiotics due to its green and environmental advantages.However,photocatalytic treatment of antibiotics for the current use of sunlight is only 50%,the lack of the use of infrared light.In recent years,related studies have found that infrared light can cooperate with photocatalytic reaction to improve the removal ability of pollutants.It is of great significance to apply infrared photocatalysis technology to the removal of antibiotic contamination.Based on this,the purpose of this study was to develop an accurate method for the determination of ultra-trace concentration of antibiotics,and to analyze the characteristic distribution of antibiotic contamination in drinking water sources in Zhejiang province.After that,the degradation of antibiotics was carried out through infrared cooperative photocatalytic technology to explore the synergistic mechanism,screen and analyze the degradation products and pathways.The main contents and conclusions of this paper are as follows:?1?Development of analytical methods for ultra-trace amounts of antibiotics.By optimizing the pretreatment and detection method,the conditions of the method were established,that is,the water samples of 500 mL pH=5 were enriched with Oasis HLB cartridge,and after 15 mins of drying,the target antibiotics were eluted in the cartridge by 5%ammonia methanol?5%NH₄OH MeOH?.After concentration,accurate quantitative analysis was carried out in UPLC-MS/MS with C₁₈ column and0.1%formic acid water and methanol as the stationary and mobile phases.The quantification limit?LOQ?was 0.3-3.1 ng L^-1,the precision?RSD%?was below 20%,and the linearity?r?was over 0.998,which could realize the analysis of antibiotics at the ultra-trace level;?2?Distribution characteristics of antibiotic residues in drinking water sources in Zhejiang province.Through the analysis of antibiotic residues in 55 drinking water sources of Zhejiang province,it was found that the residual concentration of antibiotics ranged between Nd-74.0 ng L^-1,with 11 main contaminated antibiotics.In Zhejiang province,the degree of antibiotic pollution in drinking water sources gradually decreased from north to south,and except Quzhou,fluoroquinolones were the most seriously polluted.Centralized drinking water sources suffered slightly higher than decentralized drinking water sources of antibiotic pollution.The residues of three major categories of antibiotics in drinking water sources in Zhejiang province were positively correlated with SO₄^2-,Cl^-,pH,TP,Zn,NH₃-N,COD and BOD₅,and negatively correlated with DO and NO₃^-;?3?Mechanism of infrared enhanced photocatalytic degradation of antibiotics.It was determined through the study of WO₃ photocatalytic mechanism that infrared light plays a synergistic role in photocatalytic reaction,with promoting the generation of active free radicals such as O₂^·-and H₂O₂,so as to improve the degradation ability.Through screening and analysis of TMP degradation products,19 antibiotic degradation products?including 9 first discovered degradation products,13discovered in drinking water sources?.To sum up,the establishment of a variety of ultra-trace antibiotic analysis methods provides technical support for the investigation of antibiotic contamination characteristics.At the same time,the study of infrared enhanced photocatalytic degradation of antibiotics also provides an application direction for the prevention and control of antibiotic pollution in drinking water sources.