Key Laboratory of Groundwater Resources and Environment (Ministry of Education), College of New Energy and Environment, Jilin University, Changchun 130021, China; National and Local Joint Engineering Laboratory for Petrochemical Contaminated Site Control and Remediation Technology, Jilin University, Changchun 130021, China.
Key Laboratory of Groundwater Resources and Environment (Ministry of Education), College of New Energy and Environment, Jilin University, Changchun 130021, China; National and Local Joint Engineering Laboratory for Petrochemical Contaminated Site Control and Remediation Technology, Jilin University, Changchun 130021, China.
Sci Total Environ. 2022 Dec 1;850:157963. doi: 10.1016/j.scitotenv.2022.157963. Epub 2022 Aug 9.
Electro-oxidation (EO) has received increasing attention as an efficient and green method for removing pollutants from wastewater. Chloride anions (Cl), which commonly exist in wastewater, can act as an electrolyte for the EO process. However, the role of reactive chlorine species (RCS) generated near electrodes is often underestimated. In this study, we generated hydroxyl radicals (OH) and RCS in a boron-doped diamond (BDD) electrode system and investigated its degradation mechanism for ofloxacin (OFX) removal. The findings suggested that OFX degradation was dominated by OH existing near the anode in solution, with RCS playing a supporting role. Based on the produced intermediates, we proposed an OFX decomposition pathway. The biological toxicities of the intermediates were evaluated through the ECOSAR and T.E.S.T. procedure. Nearly half of the intermediates are less toxic than the parent compound. After optimizing the operating parameters by the response surface methodology, 20 mg/L OFX was almost completely degraded after 10 min of reaction in 1.45 g/L NaCl with a current density (j) of 18 mA/cm, and the total organic carbon was decreased by 30.55 %. The energy consumption and current efficiency were 0.648 kW·h/g and 8.65 %, respectively. Comparing the operating costs of the proposed and other EO methods, our method emerged as a viable new treatment scheme for similar polluted wastewaters. This study aims to comprehensively understand the potential application value of BDD electrodes in the treatment of Cl containing organic wastewater.
电氧化（EO）作为一种从废水中去除污染物的高效且绿色的方法受到了越来越多的关注。氯离子（Cl）通常存在于废水中，可作为 EO 过程的电解质。然而，电极附近生成的活性氯物种（RCS）的作用往往被低估。在这项研究中，我们在掺硼金刚石（BDD）电极系统中生成了羟基自由基（OH）和 RCS，并研究了其对氧氟沙星（OFX）去除的降解机制。结果表明，OFX 的降解主要由溶液中阳极附近存在的 OH 主导，RCS 起辅助作用。根据生成的中间产物，我们提出了 OFX 的分解途径。通过 ECOSAR 和 T.E.S.T.程序评估了中间产物的生物毒性。几乎一半的中间产物比母体化合物毒性更小。通过响应面法优化操作参数后，在电流密度（j）为 18 mA/cm、NaCl 浓度为 1.45 g/L 时，20 mg/L OFX 在 10 min 内几乎完全降解，总有机碳减少了 30.55%。能耗和电流效率分别为 0.648 kW·h/g 和 8.65%。将所提出的方法与其他 EO 方法的运行成本进行比较，我们的方法为处理类似污染废水提供了一种可行的新处理方案。本研究旨在全面了解 BDD 电极在处理含 Cl 有机废水方面的潜在应用价值。
