Department of Environmental Engineering, Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan 430079, China; College of Urban and Environmental Sciences, Hubei Normal University, Huangshi 435002, China.
Department of Environmental Engineering, Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan 430079, China.
Sci Total Environ. 2017 Dec 1;599-600:1181-1190. doi: 10.1016/j.scitotenv.2017.05.037. Epub 2017 May 13.
Electro-assisted iron-mediated persulfate (PS) activation process has been successfully employed to oxidize organic contaminant. However, a majority of iron-based catalysts used for PS activation was synthesized through complicated or demanding procedures and may have potential risks on environment during the preparation process. Herein, natural maghemite (NM) which is abundant on the earth was employed to activate peroxydisulfate (PDS) in an electrolytic cell. The voltage was provided by microbial fuel cell (MFC) instead of external power as reported in the previous studies, so as to establish a self-driven electro/natural maghemite/PDS system (MFC/NM/PDS) for the oxidation of acid orange 7 (AO7). The results showed that above 90% removal efficiency of AO7 was achieved in a wide range of pH (3.0-9.0) after 100min reaction. Singlet oxygen was identified for the first time during PDS activation and surface bound sulfate radicals served as the dominant active species responsible for AO7 oxidation. The underlying mechanism of AO7 elimination in the MFC/NM/PDS system was elucidated through quenching tests, electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS) techniques. The variation of TOC and cytotoxicity to Escherichia coli was explored. The intermediate products formed were identified using LC-TOF-MS technique and a possible pathway of AO7 degradation was proposed.
电辅助铁介导过硫酸盐 (PS) 活化过程已成功用于氧化有机污染物。然而，用于 PS 活化的大多数铁基催化剂是通过复杂或苛刻的程序合成的，并且在制备过程中可能对环境有潜在风险。在此，丰富存在于地球上的天然磁赤铁矿 (NM) 被用于在电解槽中激活过二硫酸盐 (PDS)。与之前的研究中报道的不同，电压由微生物燃料电池 (MFC) 提供，而不是外部电源，从而建立了自驱动电/天然磁赤铁矿/PDS 系统 (MFC/NM/PDS)，用于氧化酸性橙 7 (AO7)。结果表明，在 100min 反应后，在广泛的 pH 值 (3.0-9.0) 范围内，AO7 的去除率超过 90%。首次在 PDS 活化过程中鉴定出单线态氧，表面结合的硫酸根自由基是氧化 AO7 的主要活性物质。通过淬灭试验、电子顺磁共振 (EPR) 和 X 射线光电子能谱 (XPS) 技术阐明了 MFC/NM/PDS 系统中 AO7 消除的潜在机制。探讨了 TOC 的变化和对大肠杆菌的细胞毒性。使用 LC-TOF-MS 技术鉴定了形成的中间产物，并提出了 AO7 降解的可能途径。
