Department of Chemistry, College of Science, Nanjing Agricultural University, Nanjing 210095, China.
Department of Chemistry, College of Science, Nanjing Agricultural University, Nanjing 210095, China; State Key Laboratory of Bioelectronics, Southeast University, Nanjing 210096, China.
Sci Total Environ. 2022 Jul 15;830:154825. doi: 10.1016/j.scitotenv.2022.154825. Epub 2022 Mar 24.
Using boron-doped diamond (BDD) anodes to degrade bisphenol A (BPA) had been an active area of research interest within the past 20 years. A major concern about the process lie in the formation of toxic chlorinated aromatic by-products when chloride electrolytes were present in the reaction system. In this contribution, we highlighted the formation of complex poly-chlorinated oligomer by-products in electrochemical oxidation processes, which had often been overlooked in previous studies. Moreover, the distribution and complexity of the chlorinated oligomers were found to be strongly linked to the adopted initial chloride concentration. Formation of simple chlorinated by-products was ascribed to the electrophilic substitution reactions mediated by active chlorine species, while the oligomer by-products (including chlorinated dimers, trimers and tetramers) were generated through the coupling reactions between various chlorinated phenoxy radicals. The possible mechanisms describing the formation of these by-products were also proposed. The obtained results shed light on the possible risk of BDD technology in the treatment of phenolic wastewater containing chloride electrolytes.
在过去的 20 年中，使用掺硼金刚石（BDD）阳极降解双酚 A（BPA）一直是一个活跃的研究领域。该过程的一个主要关注点在于，当反应体系中存在氯化物电解质时，会形成有毒的氯化芳香族副产物。在本研究中，我们强调了电化学氧化过程中复杂的多氯化低聚物副产物的形成，这在以前的研究中经常被忽视。此外，还发现氯化低聚物的分布和复杂性与所采用的初始氯化物浓度密切相关。简单氯化副产物的形成归因于由活性氯物种介导的亲电取代反应，而低聚物副产物（包括氯化二聚体、三聚体和四聚体）则是通过各种氯化苯氧自由基之间的偶联反应生成的。还提出了描述这些副产物形成的可能机制。研究结果阐明了 BDD 技术在处理含氯化物电解质的酚废水时可能存在的风险。
