Zhao Wenjia, Nan Tingting, Xu Jiangyan, Zhang Chunyong, Fu Degang
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.
J Hazard Mater. 2022 Oct 15;440:129794. doi: 10.1016/j.jhazmat.2022.129794. Epub 2022 Aug 18.
Anodic oxidation with boron-doped diamond (BDD) has been regarded as outstanding option for wastewater treatment. However, in the presence of halide, the extreme promise of the technology may be hampered by the formation of toxic halogenated by-products. While the behaviors of chloride are relatively understood, little is currently known about the role of bromide and its effect on the generation of brominated transformation by-products (BTPs). Herein, we reported for the first time the bromide-mediated electrochemical mineralization of bisphenol A with BDD anodes. Firstly, we employed statistical methodology to determine the impacts of the main operating variables on the mineralization performance, and the novel and peculiar roles of bromides during the electrolytic oxidations were identified. Next, LC/MS analysis was used to identify the reaction intermediates, and plenty of BTPs (including oligomers of complex structures) were thus detected. Detailed transformation mechanisms responsible for the BTPs were also proposed. Lastly, we used ECOSAR program to determine the ecological toxicity of all detected by-products, and the structure-toxicity relation involved was discussed. Overall, the above results are of particular interest to understand BTPs formation mechanism in electrochemical oxidation processes, which as well provide guidelines to minimize potential risks of BDD technology for phenolic wastewater treatment.
掺硼金刚石（BDD）阳极氧化已被视为废水处理的卓越选择。然而，在卤化物存在的情况下，该技术的巨大潜力可能会因有毒卤代副产物的形成而受到阻碍。虽然对氯离子的行为已有相对深入的了解，但目前对于溴离子的作用及其对溴化转化副产物（BTPs）生成的影响知之甚少。在此，我们首次报道了用BDD阳极实现溴离子介导的双酚A电化学矿化。首先，我们采用统计方法来确定主要操作变量对矿化性能的影响，并确定了溴化物在电解氧化过程中新颖而独特的作用。接下来，利用液相色谱/质谱分析来鉴定反应中间体，从而检测到大量的BTPs（包括结构复杂的低聚物）。还提出了导致BTPs产生的详细转化机制。最后，我们使用ECOSAR程序来确定所有检测到的副产物的生态毒性，并讨论了其中涉及的结构-毒性关系。总体而言，上述结果对于理解电化学氧化过程中BTPs的形成机制尤为重要，同时也为将BDD技术用于酚类废水处理时潜在风险降至最低提供了指导方针。
