科研之友
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摘要
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. ? 2022 Science Press.
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