Du Xinghui, Xie Wenxi, Long Xianhu, Li Dazhen, Huang Weixiong, Zhang Igor Ying, Huang Rongfu
Sichuan Provincial Key Laboratory of Universities on Environmental Science and Engineering, MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China.
MOE Key Laboratory of Groundwater Quality and Health, School of Environmental Studies, China University of Geosciences, Wuhan 430078, China.
Molecules. 2025 Feb 25;30(5):1056. doi: 10.3390/molecules30051056.
In recent years, the pollutant sulfamethoxazole (SMX) that is widely used in medical therapy has been frequently detected in different water systems. Thereby, it is necessary to develop green and effective advanced oxidation strategies, especially the electro-oxidation process. In this study, an electro-oxidation system featuring a boron-doped diamond (BDD) anode and NaCl as the supporting electrolyte was implemented to effectively remove sulfamethoxazole (SMX) without the addition of external oxidants. The operational parameters were optimized using the response surface methodology with a pH 7.5, current density of 4.44 mA/cm, and NaCl concentration of 20 mmol/L. The optimization significantly enhanced the degradation efficiency of SMX to obtain 100% removal in 5 min. Results of scavenging and chemical probe experiments indicated the presence of hydroxyl radicals (OH) and chlorine radicals (Cl), with the latter primarily forming between the reaction of Cl and OH. A competition experiment further revealed the relative oxidative contribution of Cl of 38.6%, highlighting its significant role in the degradation process. Additionally, ion chromatography analysis confirmed the presence of Cl without the formation of harmful by-products such as ClO, affirming the environmentally friendly nature of the system. The toxicity of the degradation by-products was also assessed. The application of current was investigated to explore the influence of coexistence ions as well as repeatability. Overall, this work highlighted the effectiveness of the electro-oxidation system for the degradation of organic pollutants in saline wastewater, demonstrating the significance of optimization of operational parameters for efficient and sustainable environmental remediation.
近年来，在不同水体中频繁检测到广泛用于医学治疗的污染物磺胺甲恶唑（SMX）。因此，有必要开发绿色高效的高级氧化策略，尤其是电氧化工艺。在本研究中，采用以硼掺杂金刚石（BDD）为阳极、NaCl为支持电解质的电氧化系统，在不添加外部氧化剂的情况下有效去除磺胺甲恶唑（SMX）。使用响应面法对操作参数进行优化，pH值为7.5，电流密度为4.44 mA/cm，NaCl浓度为20 mmol/L。优化显著提高了SMX的降解效率，在5分钟内实现了100%的去除率。清除和化学探针实验结果表明存在羟基自由基（OH）和氯自由基（Cl），后者主要在Cl与OH的反应之间形成。竞争实验进一步揭示了Cl的相对氧化贡献为38.6%，突出了其在降解过程中的重要作用。此外，离子色谱分析证实了Cl的存在，且未形成诸如ClO等有害副产物，证实了该系统的环境友好性。还评估了降解副产物的毒性。研究了电流的应用，以探讨共存离子的影响以及重复性。总体而言，这项工作突出了电氧化系统对含盐废水中有机污染物的降解效果，证明了优化操作参数对高效可持续环境修复的重要性。
