• 关键词：四环素  环境因素  光解  活性氧  降解路径

• 基金项目：国家自然科学基金（No.41773107）；广东省基础与应用基础研究基金项目（No.2020a1515011560）；广州市科技计划项目（No.202002030297）

• 邓郁蓉
• 华南理工大学环境与能源学院，广州 510006

• 欧阳卓智
• 西北农林科技大学资源环境学院，咸阳 712100

• 杨琛
• 华南理工大学环境与能源学院，广州 510006;工业聚集区污染控制与生态修复教育部重点实验室，广州 510006

• 贺晓晗
• 华南理工大学环境与能源学院，广州 510006

• 何春凤
• 华南理工大学环境与能源学院，广州 510006

• 摘要：近年来，抗生素引发的水体环境污染问题日益受到关注，光解是其在环境中消减的重要过程，但其中的关键机制及影响因素尚不明确.本研究系统地考察了初始浓度、pH以及无机离子、溶解性有机物等环境因子对四环素（TC）光解的影响，明确了自然光解的关键活性氧物种（ROS），同时结合理论计算和降解产物的分析，揭示出了TC的自然光解路径及作用机制.结果表明，模拟自然光条件下TC可快速降解，5 μmol·L^-1 的TC在180 min内降解率为75.0%，符合一级反应动力学，反应速率常数为0.007 min^-1，远高于避光条件.随着TC初始浓度的上升，TC光解率和速率呈现出下降的趋势，并且碱性条件更有利于TC光解.水体中存在Cu（II）、Fe（III）和NO₃^-均能显著促进TC光解；富里酸（FA）则由于光屏蔽和淬灭作用对TC的光解产生显著抑制，但FA 和Fe（III）共存时，Fe（III）对光解的促进作用占主导.水体中TC的自然光解不仅存在直接光解，并且以超氧阴离子（O₂^-·）和羟基自由基（·OH）为关键ROS的自敏化光解在TC的光解过程中也起到重要作用.结合TC光解后的产物分析发现，发生间接光解后TC发生开环反应，相比于直接光解和自敏化光解降解地更充分.综上，TC在自然水体中的光解强烈受环境因素影响，可以通过增强活性氧介导的间接光解过程促进水体抗生素污染修复.

• Abstract：In recent years， the problem of water pollution caused by antibiotics has received increasing attention. Photolysis is an important antibiotics reduction process in the environment， nevertheless， the key mechanism and influencing factors of antibiotics photolysis are still unclear. This study systematically investigates the effects of initial concentration， pH， and environmental factors such as inorganic ions， and dissolved organic matter on the photolysis of tetracycline （TC）. The key reactive oxygen species （ROS） of TC natural photolysis is clarified， and TC natural photolysis pathway and mechanism are revealed by theoretical calculations and degradation products determination. The results show that TC can be rapidly degraded under simulated natural light irradiation conditions. The degradation efficiency of 5 μmol·L^-1 TC is 75.0% within 180 min， which fits well with the first-order kinetics， and the reaction rate constant is 0.007 min^-1， which is much higher than that under dark conditions. As the increase of TC initial concentrations， the photolysis rates and efficiencies of TC show a decreasing trend， and alkaline conditions are more conducive to the photolysis of TC. In addition， Cu（II）， Fe（III）， and NO₃^- can significantly promote the photolysis of TC in the water. Fulvic acid （FA） significantly inhibits the photolysis of TC due to light shielding and quenching， the promotion of Fe（III） to photolysis is dominant when FA and Fe（III） coexist. In addition to direct photolysis， self-sensitized photolysis also plays an important role in the photolysis process of TC， and the main ROS are superoxide anion （O₂^-·） and hydroxyl radical （·OH）. Moreover， the benzene ring structure of TC is destroyed after indirect photolysis by detecting the TC photolysis products， which is more sufficient degradation of TC compared with direct photolysis and self-sensitized photolysis. Overall， the photolysis of TC in natural water is strongly affected by environmental factors. The indirect photolysis process mediated by ROS can be enhanced to promote the remediation of antibiotic pollution.

• Key words：tetracycline  environmental factors  photolysis  reactive oxygen species  degradation pathway

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