Beijing Key Lab for Source Control Technology of Water Pollution, College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, PR China.
The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, PR China.
Sci Total Environ. 2020 Jul 20;727:138696. doi: 10.1016/j.scitotenv.2020.138696. Epub 2020 Apr 15.
Ozone-based technologies are used for micro-pollutants removal in wastewater treatment. However, the generation of the toxic by-product bromate (BrO) is of a great concern. LaCoO (LCO) catalytic ozonation has been used to overcome this significant drawback in the sole ozonation, achieving better BrO elimination efficiency. However, a key challenge is how to enhance micro-pollutant (benzotriazole, BZA) degradation efficiency and to eliminate formed BrO synchronously under various water qualities in drinking water or wastewater treatment. Therefore, the objective of this study is to propose a practical strategy of BZA removal and BrO reduction synchronously in water or wastewater treatment. In this study, important factors influencing BZA removal and BrO reduction were investigated, including [catalyst], [BZA], initial pH solution, [NH-N] and [(bi)carbonate alkalinity]. Based on the performance and mechanism of these effects, a practical strategy for BZA degradation and BrO elimination with and without Br in the influent was developed. Additionally, the density functional theory (DFT) calculation successfully predicted the attack site on BZA by molecular ozone and formed hydroxyl radical (HO·) during LCO catalytic ozonation. Fukui indexes of f and f were calculated to forecast direct ozone molecule and HO· attack, respectively. Combination of DFT calculation with intermediates that identified through liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS), BZA degradation pathway was established more accurately. Additionally, four new intermediates were identified in this study. Overall, this study proposes a useful strategy for synchronous micro-pollutants degradation and BrO elimination, while also suggesting the feasibility of LCO catalytic ozonation for water or wastewater purification.
基于臭氧的技术用于污水处理中的微污染物去除。然而，有毒副产物溴酸盐（BrO）的生成引起了极大的关注。LaCoO（LCO）催化臭氧化已被用于克服单独臭氧化的这一显著缺点，从而实现更好的 BrO 消除效率。然而，一个关键的挑战是如何在饮用水或废水处理中的各种水质条件下，同时提高微污染物（苯并三唑，BZA）的降解效率并消除形成的 BrO。因此，本研究的目的是提出一种在水或废水中同步去除 BZA 和减少 BrO 的实用策略。在本研究中，研究了影响 BZA 去除和 BrO 还原的重要因素，包括[催化剂]、[BZA]、初始 pH 值、[NH-N]和[(碳酸)碱度]。基于这些效应的性能和机制，开发了一种在有和没有 Br 存在的情况下，在进水口中同步进行 BZA 降解和 BrO 消除的实用策略。此外，密度泛函理论（DFT）计算成功预测了 LCO 催化臭氧化过程中分子臭氧和形成的羟基自由基（HO·）对 BZA 的攻击位点。通过计算 f 和 f 的福井指数，分别预测了直接臭氧分子和 HO·的攻击。通过与液相色谱-四极杆飞行时间质谱（LC-Q-TOF-MS）鉴定的中间体相结合的 DFT 计算，更准确地建立了 BZA 降解途径。此外，本研究还鉴定了四个新的中间体。总的来说，本研究提出了一种同步去除微污染物和 BrO 的有用策略，同时还表明 LCO 催化臭氧化对于水或废水净化是可行的。
