School of Civil Engineering, Wuhan University, No. 8, East Lake South Road, Wuhan, China; Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK8000 Aarhus C, Denmark; Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.
School of Environmental Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China.
J Hazard Mater. 2019 Feb 15;364:39-47. doi: 10.1016/j.jhazmat.2018.10.026. Epub 2018 Oct 11.
In order to overcome the inefficiency of heterogeneous electro-Fenton process for water treatment at neutral pH, single sheet iron oxide (SSI) derived from layered Fe(II)-Fe(III) double hydroxides (green rusts) was fabricated on an indium tin oxide electrode via layer by layer assembly and used in an undivided electrolysis cell. Use of radical scavengers demonstrated the formation of oxygen radicals by electrochemical reduction of oxygen at the SSI electrode, and the key role of hydroxyl radicals (OH) and superoxide anion (O) radicals in degradation of the azo dye orange II. Analysis of degradation products by UV-vis, LC-MS and GC-MS further demonstrated that direct reduction toke place in addition to indirect oxidation. The reactivity of SSI as a heterogeneous electro-Fenton catalyst is two order of magnitude higher than its homogenous counterparts. The SSI electrode was highly stable as the dye degradation did not decrease after use for 19 h with no Fe leaching. The high dye removal efficiency was maintained in a wide pH range from 7 to 10 and in different supporting electrolytes, demonstrating the application of this process under various conditions mimicking natural waters.
为克服中性 pH 条件下异相电芬顿处理水效率低下的问题，通过层层组装，将源自层状 Fe(II)-Fe(III) 双氢氧化物（绿锈）的单片状氧化铁（SSI）制备在氧化铟锡电极上，并用于无分隔电解槽中。自由基清除剂的使用表明，在 SSI 电极上通过氧气电化学还原生成了氧自由基，并且羟基自由基（OH）和超氧阴离子（O）自由基在偶氮染料橙 II 的降解中起关键作用。通过紫外-可见分光光度法、LC-MS 和 GC-MS 对降解产物进行分析进一步表明，除了间接氧化外，还发生了直接还原。SSI 作为多相电芬顿催化剂的反应活性比均相对应物高两个数量级。SSI 电极非常稳定，因为在 19 小时的使用后，染料降解没有减少，且没有铁浸出。在 7 至 10 的宽 pH 范围内和不同的支持电解质中，均保持了高染料去除效率，表明该过程可在模拟天然水的各种条件下应用。
