State Key Laboratory of Pollution Control and Resource Reuse, Shanghai Institute of Pollution Control and Ecological Security, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China.
Water Res. 2022 Jul 1;219:118545. doi: 10.1016/j.watres.2022.118545. Epub 2022 May 4.
Electrochemical filtration system (EFS) has received broad interest due to its high efficiency for organic contaminants removal. However, the porous nature of electrodes and flow-through operation mode make it susceptible to potential fouling. In this work, we systematically investigated the impacts of biofouling on sulfanilic acid (SA) removal and effluent toxicity in an EFS. Results showed that the degradation efficiency of SA slightly deteriorated from 92.3% to 81.1% at 4.0 V due to the electrode fouling. Surprisingly, after the occurrence of fouling, the toxicity (in terms of luminescent bacteria inhibition) of the EFS effluent decreased from 72.3% to 40.2%, and cytotoxicity assay exhibited similar tendency. Scanning electron microscopy and confocal laser scanning microscopy analyses revealed that biofouling occurred on the porous cathode, and live microorganisms were the dominant contributors, which are expected to play an important role in toxicity suppression. The relative abundance of Flavobacterium genus, related to the degradation of p-nitrophenol (an aromatic intermediate product of SA), increased on the membrane cathode after fouling. The analysis of degradation pathway confirmed the synergetic effects of electrochemical oxidation and biodegradation in removal of SA and its intermediate products in a bio-fouled EFS, accounting for the decrease of the effluent toxicity. Results of our study, for the first time, highlight the critical role of biofouling in detoxication using EFS for the treatment of contaminated water.
电化学过滤系统 (EFS) 因其对有机污染物去除的高效率而受到广泛关注。然而，由于电极的多孔性和穿透式操作模式，它容易受到潜在的污垢影响。在这项工作中，我们系统地研究了生物污垢对 EFS 中磺胺酸 (SA) 去除和流出物毒性的影响。结果表明，由于电极污垢，SA 的降解效率从 4.0 V 时的 92.3%略微恶化至 81.1%。令人惊讶的是，在发生污垢后，EFS 流出物的毒性（以发光细菌抑制为指标）从 72.3%下降至 40.2%，细胞毒性测定也表现出相似的趋势。扫描电子显微镜和共聚焦激光扫描显微镜分析表明，生物污垢发生在多孔阴极上，活的微生物是主要的贡献者，它们有望在抑制毒性方面发挥重要作用。在污垢后，膜阴极上与 p-硝基苯酚（SA 的芳香中间产物）降解有关的黄杆菌属的相对丰度增加。降解途径的分析证实了电化学氧化和生物降解在去除 SA 和其在生物污垢 EFS 中的中间产物方面的协同作用，这解释了流出物毒性的降低。我们的研究结果首次强调了生物污垢在使用 EFS 处理污染水时解毒的关键作用。
