新疆水环境中低浓度抗生素的光化学行为、慢性毒性及光催化降解机理研究

Antibioties have been increasingly detected in waters as emerging contaminants, photochemieal degradation is a central factor in determining the fate of antibiotics. The study on the photochemical behavior of antibiotics and the toxicity and photocatalytic degradation has attracted much attention in recent years. Therefore, this project selected 3 kinds of antibiotics (Chloramphenicols, Tetracyclines and Macrolides) which are often detected in the water environment in Xinjiang as model compounds to investigate their photochemical behavior. In this project, simulation photolysis experiment is used to study the photodegradation types, photolysis kinetics and degradation pathways of antibiotics at low concentration levels, the effects of the pH value of water and the coexisting substances in natural water on the photodegradation are analyzed, the complex effects of dissolved substances on their photolysis, and reveal the mechanism are quantitatively expressed. The new visible light catalyst was explored, that could reveal the mechanism of its effect on the degradation of antibiotics. Preparation of new type of visible light catalyst, reveal the mechanism of its effect on the degradation of antibiotics, and application to the actual water. Further study the chronic toxicity of 3 kinds of antibiotics and the change of toxicity in the photolysis process to evaluate the ecological and health risks. Through the above research, it is expected for us to clarify the influence mechanism of water environmental factors and photocatalytic on the degradation of antibiotics, and reveal the photochemical behavior of different types of antibiotics at different concentrations and their toxic changes so as to provide theoretical support for the ecological risk management and pollution control of antibiotics.

抗生素是一类在水体中不断被监测到的新兴污染物，光化学降解是其重要的消减方式。针对近年来备受关注的抗生素光化学行为及其毒性和光催化降解问题，本项目以新疆水环境中常检出的 3大类抗生素(氯霉素类、四环素类和大环内酯类)为研究对象，研究其光化学行为。采用模拟光解实验的方法，考察低浓度水平下3类抗生素的光降解类型、光解动力学及降解路径。分析水体pH值及自然水体中的共存物质对3类抗生素降解的影响，定量表达溶解性物质对其光解的复合影响，揭示影响机理。探索制备新型可见光催化剂，揭示其对抗生素降解的影响机理，并应用到实际水体中。深入研究3大类抗生素的慢性毒性及光解过程中毒性的变化，评价其生态与健康风险。通过以上研究，阐明水环境因子及光催化剂对抗生素降解的影响机制，揭示不同类别的抗生素在不同浓度水平下的光化学行为规律及其毒性变化具有重要意义，为抗生素类污染物的生态风险管理及污染防治提供理论支持。

抗生素是一类在水体中不断积累，而且会给生态环境和人体健康带来有害影响的新兴污染物，光化学降解是其重要的消减方式。本项目以新疆水环境中常检出的 3大类抗生素(氯霉素类、四环素类和大环内酯类)为研究对象，研究其光化学行为、光解动力学、慢性毒性实验，探索制备新型可见光催化剂，揭示其对抗生素降解的影响机理，阐明水环境因子及光催化剂对抗生素降解的影响机制，为抗生素类污染物的生态风险管理及污染防治提供理论支持。.研究结果表明：（1）不同光源照射下，MLs和TCs的光降解速率常数有很大差异，基本表现为：高压汞灯＞氙灯＞太阳光，而CAPs在不同光源照射5 h的情况下很难被光降解；溶液pH对MLs的光降解有明显的影响，在不同的pH值条件下其光解反应符合准一级反应动力学，TCs的降解速率和降解效率也随着pH值的增加而提高，而CAPs在pH为9.0时的光降解有较大影响；腐殖酸（HA）的存在对MLs的光降解影响是HA浓度升高，抑制率增大，而低浓度HA的加入对TCs和CAPs的降解有促进效果；NO3-对3类抗生素的光解都有促进作用；TCs和CAPs的光降解率与Fe3+浓度呈正相关，起到了促进作用。（2）MLs对羊角月牙藻的毒性变化研究表明，SPI光降解过程中产生了对羊角月牙藻毒性较低的产物，ROX、CLA和TYL在光降解过程中产生了对羊角月牙藻毒性较高的产物；TCs对羊角月牙藻的毒性变化研究表明，OTC光降解过程中产生了对羊角月牙藻毒性较低的产物，DC、CTC和TC产生了对羊角月牙藻毒性较高的产物，且这四种抗生素对羊角月牙藻的毒性表现为：TC>DC>CTC>OTC；300 W汞灯光照下甲砜霉素的抑菌活性比未照光的相比活性降低，500瓦金卤灯照射1h条件下，氟苯尼考的抑菌活性比未照光的相比活性降低，此结果也能够证明CAPs能够被光解.（3）通过水热法成功制备0.8I-BiI/BWO光催化剂，在350W氙灯的照射下，四环素（初始浓度10 mg/L）在80 min内降解90%，并验证起着至关重要作用的自由基是·OH和·O2-；通过水热法制备出Er3+-Bi2WO6可见光催化剂，通过Uv-vis和ESR验证了光催化降解机理，提出了可能的光催化降解机理；通过溶剂热法制备了BiOCl-Bi2MoO6光催化剂，通过LC-MS测试的降解中间体，提出了TC降解的途径，为后续高效降解奠定基础。