Simultaneous efficient degradation and dechlorination of chloramphenicol using UV/sulfite reduction: Mechanisms and product toxicity

Chloramphenicol (CAP) is of great concern due to its extensive use and nonnegligible impact on the eco-environment. Herein, the degradation performance and mechanism of CAP by UV/sulfite advanced reduction processes (ARPs) were systematically investigated. 90.67 % degradation efficiency and 92.22 % dechlorination of CAP were simultaneously achieved within 50 min using UV/sulfite-ARPs. The degradation and dechlorination efficiency of the CAP remained elevated with the increase of sulfite concentration, and eventually complete degradation and dechlorination were achieved. Hydrated electrons (eaq) and direct UV photolysis dominated in the degradation and dechlorination of CAP at pH 5-11. The presence of commonly co-existing anions, humic acid and various water matrices exhibited negligible effect on the CAP degradation and dechlorination efficiencies. Possible degradation pathways of CAP were proposed. Ecotoxicity prediction and seed germination experiments indicated that the acute and chronic ecotoxicity of CAP solution was significantly reduced after the treatment with UV/sulfite-ARPs. Overall, this study demonstrated that UV/sulfite-ARPs could be a promising approach for the CAP purification from wastewaters.

Automated summary

This study systematically investigated the degradation performance and mechanism of chloramphenicol (CAP) using UV/sulfite advanced reduction processes (ARPs). The results showed that UV/sulfite-ARPs achieved simultaneous degradation efficiency of 90.67% and dechlorination efficiency of 92.22% within 50 minutes. The study also found that the degradation and dechlorination of CAP were influenced by sulfite concentration, and complete degradation and dechlorination were achieved. The presence of co-existing anions and water matrices had negligible effect on the degradation and dechlorination efficiencies of CAP.