Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 18 Shuang-qing Road, Beijing 100085, China.
Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 18 Shuang-qing Road, Beijing 100085, China.
Water Res. 2017 Sep 15;121:178-185. doi: 10.1016/j.watres.2017.05.030. Epub 2017 May 17.
Ultraviolet (UV)/chlorine process is considered as an emerging advanced oxidation process for the degradation of micropollutants. This study investigated the degradation of chloramphenicol (CAP) and formation of disinfection by-products (DBPs) during the UV/chlorine treatment. It was found that CAP degradation was enhanced by combined UV/chlorine treatment compared to that of UV and chlorination treatment alone. The pseudo-first-order rate constant of the UV/chlorine process at pH 7.0 reached 0.016 s, which was 10.0 and 2.0 folds that observed from UV and chlorination alone, respectively. The enhancement can be attributed to the formation of diverse radicals (HO and reactive chlorine species (RCSs)), and the contribution of RCSs maintained more stable than that of HO at pH 5.5-8.5. Meanwhile, enhanced DBPs formation during the UV/chlorine treatment was observed. Both the simultaneous formation and 24-h halonitromethanes formation potential (HNMsFP) were positively correlated with the UV/chlorine treatment time. Although the simultaneous trichloronitromethane (TCNM) formation decreased with the prolonged UV irradiation, TCNM dominated the formation of HNMs after 24 h (>97.0%). According to structural analysis of transformation by-products, both the accelerated CAP degradation and enhanced HNMs formation steps were proposed. Overall, the formation of diverse radicals during the UV/chlorine treatment accelerated the degradation of CAP, while also enhanced the formation of DBPs simultaneously, indicating the need for DBPs evaluation before the application of combined UV/chlorine process.
紫外线（UV）/氯工艺被认为是一种新兴的高级氧化工艺，可用于降解微量污染物。本研究考察了在 UV/氯处理过程中氯霉素（CAP）的降解和消毒副产物（DBPs）的形成。结果表明，与单独 UV 和氯化处理相比，组合 UV/氯处理可增强 CAP 的降解。在 pH 7.0 时，UV/氯工艺的假一级速率常数达到 0.016 s，分别是单独 UV 和氯化的 10.0 和 2.0 倍。这种增强可归因于形成了多种自由基（HO 和活性氯物种（RCSs）），并且在 pH 5.5-8.5 时，RCSs 的贡献比 HO 更稳定。同时，在 UV/氯处理过程中观察到增强的 DBPs 形成。同时形成和 24 小时卤代硝甲烷形成潜能（HNMsFP）与 UV/氯处理时间呈正相关。尽管随着 UV 照射时间的延长，同时形成的三氯硝甲烷（TCNM）形成减少，但 TCNM 在 24 小时后主导 HNMs 的形成（>97.0%）。根据转化副产物的结构分析，提出了 CAP 降解加速和 HNMs 形成增强的步骤。总体而言，UV/氯处理过程中多种自由基的形成加速了 CAP 的降解，同时也增强了 DBPs 的形成，这表明在应用组合 UV/氯工艺之前需要进行 DBPs 评估。
