中文摘要：

磺胺类抗生素（SAs）是水环境中经常检出的一类微污染物，其检出浓度可达μg／L水平．抗生素因可诱导细菌抗药性及产生抗性基因而备受关注．光化学转化是抗生素类污染物在表层水体中的重要消减途径，影响其环境归趋和生态风险．水中溶解性物质可显著地影响抗生素的光化学行为．然而，水中溶解性有机质（DOM）及其与金属离子的相互作用对SAs光转化的影响机制仍不清楚．本文以水产和畜牧养殖中广泛使用的磺胺二甲基嘧啶（SMZ）为对象，考察了DOM及其与典型重金属离子Cu（II）的配合物对SMZ光转化的影响机理．结果表明，激发三重态DOM（3DOM＊）是促进SMZ光降解的主要活性物种，其反应机理为电子转移伴随质子转移．DOM—Cu（II）复合体系中，DOM—Cu（II）配合物可以通过光致电荷转移生成·OH促进SMZ的光降解．

英文摘要：

Sulfonamide antibiotics （SAs） are well-acknowledged micropollutants in the aquatic environment at concentrations as high as μg/L. SAs are of acute concern because they can trigger an increase of resistant bacteria and accelerate the development of antibiotic resistance genes. Phototransformation plays an important role in the degradation of antibiotics in surface waters, and influences the fate and ecological risks of antibiotics. The photochemical behavior of antibiotics was obviously impacted by water constituents. However, water constituents and their interactions with metal ions on antibiotics photodegradation are still unclear. In this study, sulfamethazine （SMZ） was selected as target compound due to its wide usage in aquaculture and livestock operations. The effects of dissolved organic matter （DOM） and its coordination with Cu（II） on SMZ photodegradation were investigated. Results show that excited triplet state DOM （3DOM＊） is largely responsible for the photolytic enhancement of SMZ in the presence of DOM and the reaction mechanism is identified as electron transfer followed proton transfer from SMZ to DOM. Additionally, the photogenerated ＂OH was found in the Cu（II）-DOM system, which promoted the photodegradation of SMZ.