Guangdong Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 511443, China; Key Laboratory of Pollution Process and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; Tianjin Key Laboratory of Environmental Technology for Complex Trans-Media Pollution, Nankai University, Tianjin 300350, China; Université Paris-Est, Laboratoire Géomatériaux et Environnement, EA 4508, UPEM, 5 Bd Descartes, 77454 Marne-la-Vallée, Cedex 2, France.
Key Laboratory of Pollution Process and Environmental Criteria, Ministry of Education, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; Tianjin Key Laboratory of Environmental Technology for Complex Trans-Media Pollution, Nankai University, Tianjin 300350, China.
J Hazard Mater. 2020 Jul 5;393:122513. doi: 10.1016/j.jhazmat.2020.122513. Epub 2020 Mar 10.
The traditional electro-Fenton (EF) has been facing major challenges including narrow suitable range of pH and non-reusability of catalyst. To overcome these drawbacks we synthesized FeFe-layered double hydroxide modified carbon felt (FeFe LDH-CF) cathode via in situ solvo-thermal process. Chemical composition and electrochemical characterization of FeFe LDH-CF were tested and analyzed. The apparent rate constant of decay kinetics of ofloxacin (OFC) with FeFe LDH-CF (0.18 min) at pH 7 was more than 3 times higher than that of homogeneous EF (0.05 min) at pH 3 with 0.1 mM Fe under same current density (9.37 mA cm). Also, a series of experiments including evolution of solution pH, iron leaching, OFC removal with trapping agent and quantitative detection of hydroxyl radicals (OH) were conducted, demonstrating the dominant role of OH generated by surface catalyst via ≡ Fe/Fe on LDH cathode for degradation of organics as well contributing to high efficiency and good stability at neutral pH. Besides, formation and evolution of aromatic intermediates, carboxylic acids and inorganic ions (F, NH and NO) were identified by High-Performance Liquid chromatography, Gas Chromatography-Mass Spectrometry and ionic chromatography analyses. These findings allowed proposing a plausible degradation pathway of OFC by OH generated in the heterogeneous EF process.
传统的电芬顿（EF）面临着一些主要的挑战，包括 pH 值适用范围窄和催化剂不可重复使用。为了克服这些缺点，我们通过原位溶剂热法合成了 FeFe 层状双氢氧化物修饰的碳纤维毡（FeFe LDH-CF）阴极。对 FeFe LDH-CF 的化学组成和电化学特性进行了测试和分析。在 pH 7 下，FeFe LDH-CF（0.18 min）对氧氟沙星（OFC）的衰减动力学的表观速率常数比 pH 3 下的均相 EF（0.05 min）高 3 倍以上，且在相同电流密度（9.37 mA cm）下，Fe 浓度为 0.1 mM。此外，还进行了一系列实验，包括溶液 pH 值的演变、铁浸出、用捕集剂去除 OFC 和羟基自由基（OH）的定量检测，证明了通过 LDH 阴极表面催化剂上的 ≡ Fe/Fe 生成的 OH 在中性 pH 值下对有机物降解的主导作用，以及对高效和良好稳定性的贡献。此外，通过高效液相色谱、气相色谱-质谱和离子色谱分析，鉴定了芳香族中间体、羧酸和无机离子（F、NH 和 NO）的形成和演变。这些发现使我们能够提出一种 OH 在非均相 EF 过程中生成的 OFC 可能的降解途径。
