Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510006, China.
Department of Civil Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR 999077, China.
Water Res. 2024 Mar 15;252:121212. doi: 10.1016/j.watres.2024.121212. Epub 2024 Jan 31.
The aim of this study was to investigate the removal of metronidazole (MNZ) from seawater using a bioelectrochemical system (BES). Single-chamber BES (i.e., S-BES) and dual-chamber BES (i.e., D-BES) were constructed with carbon brush as the anode and cathode. With the inoculum of sea mud and 2 g/L of glucose as the substrate in seawater, S-BES and D-BES were acclimated to test the MNZ removal. Results showed that S-BES could remove almost 100 % of 200 mg/L MNZ within 120 h and remain stable within 10 cycles of operation (∼50 d) under the applied voltage of 0.8 V. The MNZ removal reached ∼100 % and 60.2 % in the cathodic and anodic chambers of D-BES fed by 100 mg/L MNZ under 0.8 V, respectively. The MNZ concentration of 200 mg/L significantly inhibited the sulfur metabolism, decreased the ratio of live to dead cells in the electrode biofilms, and thus reduced the SO removal in the S-BES. The MNZ degradation and S oxidation was mainly attributed to the cathodic and anodic biofilms of S-BES, respectively. Three degradation pathways of MNZ were proposed based on the identified intermediates and results of density functional theory calculations. The synergies among different genus species in the bacterial communities of biofilms, and between anodic and cathodic reactions could be responsible for the high performance of S-BES. Results from this study should be not only useful for the MNZ removal but also for effective MNZ inhibition of sulfate-reducing bacteria induced microbiologically influenced corrosion in seawater.
本研究旨在利用生物电化学系统（BES）去除海水中的甲硝唑（MNZ）。采用碳刷作为阳极和阴极，构建单室 BES（即 S-BES）和双室 BES（即 D-BES）。以海泥接种物和 2 g/L 葡萄糖作为海水中的底物，S-BES 和 D-BES 经过驯化以测试 MNZ 的去除效果。结果表明，S-BES 在 0.8 V 的外加电压下，在 120 h 内可去除 200 mg/L 的 MNZ 近 100%，在 10 个运行周期（约 50 天）内保持稳定。在 0.8 V 下，D-BES 的阴极和阳极室分别以 100 mg/L 的 MNZ 为底物时，MNZ 的去除率分别达到了约 100%和 60.2%。200 mg/L 的 MNZ 浓度显著抑制了硫代谢，降低了电极生物膜中活细胞与死细胞的比例，从而降低了 S-BES 中的 SO 去除率。MNZ 的降解和 S 的氧化主要归因于 S-BES 的阴极和阳极生物膜。根据鉴定的中间产物和密度泛函理论计算结果，提出了 MNZ 的三种降解途径。生物膜中不同属种之间以及阳极和阴极反应之间的协同作用可能是 S-BES 性能高的原因。本研究的结果不仅对 MNZ 的去除有用，而且对有效抑制海水中硫酸盐还原菌诱导的微生物影响腐蚀也有重要意义。
