School of Environmental Engineering, Wuhan Textile University, No.1 Sunshine Avenue, Wuhan 430200, China; Research Center for Eco-Environmental Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 18 Shuang-qing Road, Beijing 100085, China.
School of Environmental Engineering, Wuhan Textile University, No.1 Sunshine Avenue, Wuhan 430200, China.
Water Res. 2020 Nov 1;186:116336. doi: 10.1016/j.watres.2020.116336. Epub 2020 Aug 24.
The feasibility of integrated UV/ozone (O)/peroxydisulfate (PDS) process for abatement of clofibric acid (CA) was systematically explored in this study with focus on the kinetic simulation and oxidation mechanisms. The results indicated the UV/O/PDS process was of prominent treatment capability with pseudo-first-order rate constant of CA degradation increased by 65.9% and 86.0% compared to UV/O and UV/PDS processes, respectively. A chemical kinetic model was developed and successfully employed to predict CA elimination as well as the specific contributions of UV, hydroxyl radical (OH) and sulfate radical (SO) under different PDS dosage, pH, natural organic matters, bicarbonate and chloride conditions in UV/O/PDS process. According to quantum chemical calculation, radical addition on ortho site of isopropoxy substituent and single electron transfer were corroborated to be the dominant reaction channels for the oxidation of CA by OH and SO, respectively. Additionally, the reactive sites and transformation pathways of CA were proposed via Fukui function calculation and UPLC-Q-TOF-MS analysis. Moreover, the performance of UV/O/PDS process was further evaluated with regard to the energy demand and bromate formation. This study first proposed a kinetic model in UV/O/PDS process and elucidated the regioselectivity and products distribution of CA during oxidative treatment.
本研究系统探讨了集成紫外/臭氧（O）/过一硫酸盐（PDS）工艺去除氯菊酸（CA）的可行性，重点研究了动力学模拟和氧化机制。结果表明，与 UV/O 和 UV/PDS 工艺相比，UV/O/PDS 工艺具有显著的处理能力，CA 降解的假一级速率常数分别提高了 65.9%和 86.0%。建立了一个化学动力学模型，并成功地用于预测 CA 的去除以及在不同 PDS 剂量、pH 值、天然有机物、碳酸氢盐和氯化物条件下 UV/O/PDS 工艺中 UV、羟基自由基（OH）和硫酸根自由基（SO）的特定贡献。根据量子化学计算，OH 和 SO 氧化 CA 的主要反应途径分别为邻位异丙氧基取代基的自由基加成和单电子转移。此外，通过福井函数计算和 UPLC-Q-TOF-MS 分析，提出了 CA 的反应活性位点和转化途径。此外，还评估了 UV/O/PDS 工艺的性能，包括能源需求和溴酸盐的形成。本研究首次在 UV/O/PDS 工艺中提出了一个动力学模型，并阐明了 CA 在氧化处理过程中的区域选择性和产物分布。
