可见光催化降解对抗生素生物毒性及其消毒副产物生成势的影响机制研究

Residual antibiotics in the environment brought the problems of bacterial resistance and resistance genes. Moreover, some antibiotics are also found to be the precursors of disinfection by-products (DBPs). However, some of the DBPs can induce bacterial antibiotic resistance at low exposure antibiotic levels in water. Visible photocatalytic oxidation is a promising method of antibiotic degradation, but its effect on the formation potential of DBPs from oxidized antibiotics is not yet clear. The subject is based on a number of visible light nanocomposite catalysts that can efficiently degrade antibiotics. Tetracycline, chloramphenicol and ciprofloxacin, which have large residual capacity in the environment and high formation potential of DBPs, were selected to identify the changes in toxicity and DBPs formation potential before and after visible photocatalytic oxidation. The main objective of this study is to find out the intrinsic factors affecting the changes of acute toxicity, cytotoxicity and the DBPs formation potential of antibiotics caused by visible light photocatalytic oxidation. The mechanism of visible photocatalytic degradation on the effect of formation potential of DBPs of antibiotics will be revealed by the relationship between catalysts structure, photoelectric properties and photocatalytic pathways, functional groups changes of antibiotics, the distribution of intermediate products and the formation potential of DBPs. The achievements of the research is of great theoretical and realistic significance for ensuring the safety and reliability of drinking water and aquaculture products and optimizing the application of visible light photocatalytic oxidation technology in water environment.

环境中的残留抗生素会带来细菌耐药性和抗性基因的问题，一些抗生素也被发现是消毒副产物的前驱物，而这些消毒副产物能诱导细菌在低抗生素浓度下就产生抗生素耐药性。可见光催化氧化是当前抗生素降解的热点研究技术，但其对抗生素消毒副产物生成势的影响尚不明确。课题以“环境中残留容量大、消毒副产物生成势较高”的四环素、氯霉素、环丙沙星为对象，针对能高效降解抗生素的可见光纳米复合催化剂，明确可见光催化降解后其生物毒性和DBPs生成势的变化规律；解析可见光催化氧化引起抗生素急性毒性和细胞毒性变化的内在原因；建立催化剂结构特性、光电性能、光催化机理、抗生素微观结构官能团变化、中间产物分布与DBPs生成势之间的关联，揭示可见光降解过程影响抗生素的DBPs生成势的内在原因与作用机制。研究成果对保障饮用水和水产养殖产品的安全可靠性以及可见光催化氧化技术在水环境中的安全应用具有重要的理论和现实意义。

环境中的残留抗生素因其自身毒理特性、引起细菌耐药性和抗性基因等问题，受到世界范围内的广泛关注。研究发现抗生素也是消毒副产物的前驱物。可见光催化氧化作为当前抗生素降解的热点研究技术，其对抗生素消毒副产物生成势的影响尚不明确。本项目以“环境中残留容量大、消毒副产物生成势较高”的四环素、环丙沙星抗生素为目标物，制备了Ag/g-C3N4、Bi2WO6-TiO2、g-C3N4/TiO2、Bi3O4Br/rGO、Bi4V2O11/Ag/AgCl等一系列能高效降解抗生素的可见光纳米复合催化剂。对四环素类抗生素的降解效能为80%-96%，对环丙沙星的抗生素降解效能高达70%-98%。系统研究了可见光催化降解后其生物毒性和DBPs生成势的变化规律；研制筛选出的上述5种催化剂在可见光催化降解后均能降低四环素等抗生素的生物毒性，通过中间产物测定分析和模型评估两类方法解析了可见光催化氧化引起抗生素毒性变化的内在原因；对DBPs生成势而言，Ag/g-C3N4不能抑制DBPs的生成，反而大幅促进了THMs、HANs、TCNM的生成势；通过综合比对分析，筛选出了能高效降低DBPs生成势的可见光复合催化剂：g-C3N4/TiO2和Bi4V2O11/Ag/AgCl；进一步开展了外在反应条件和内在影响机制研究，明确了可见光催化降解反应时间、催化剂投量、pH值、光强对DBPs的作用与影响规律，解析了催化剂结构特性、光催化机理、抗生素中间产物与DBPs生成势之间的关联，初步明确了可见光降解过程影响抗生素的DBPs生成势的关键因素和内在作用机制。研究成果对保障饮用水和水产养殖产品的安全可靠性以及可见光催化氧化技术在水环境中的安全应用具有重要的理论和现实意义。