College of Aerospace and Civil Engineering, Harbin Engineering University, Harbin, 150001, China; Department of Civil, Engineering and Geomatic Engineering, University College London (UCL), London, WC1E 6BT, UK.
School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310018, China.
J Hazard Mater. 2017 Jan 15;322(Pt B):461-468. doi: 10.1016/j.jhazmat.2016.09.062. Epub 2016 Sep 28.
Fenton or Fenton-like processes have been regarded as feasible methods to degrade a wide variety of contaminants by generating reactive species, but the efficiency is still challenged by the slow transformation from Fe(III) to Fe(II) and pH. This study employed hydroxylamine (HA) to improve the oxidation efficiency of Fe(II)/HSO (Fe(II)/PMS) process, by selecting sulfamethoxazole (SMX) as the target compound. The degradation efficiency and mechanism of SMX by the HA/Fe(II)/PMS process were elucidated for the first time. Compared with Fe(II)/PMS process, the HA/Fe(II)/PMS process showed about 4 times higher degradation efficiency of SMX at pH 3.0. The analysis of steady-state concentration of Fe species indicated that HA enhanced the transformation of Fe(III) to Fe(II), sustaining the rapid Fenton-like reactions. Both sulfate radicals and hydroxyl radicals accounted for the degradation of SMX, with the latter regarded as the dominant reactive species. Degradation intermediates of SMX were further analyzed, and three main transformation pathways were thus proposed. The HA/Fe(II)/PMS process was also effective in the removal of SMX and total organic carbon from real pharmaceutical wastewater. This work would broaden the scope of application of Fenton and Fenton-like processes enhanced by HA in contaminants treatment.
芬顿或类芬顿工艺被认为是通过生成活性物种来降解多种污染物的可行方法，但由于从 Fe(III)到 Fe(II)的缓慢转化和 pH 值的影响，其效率仍受到挑战。本研究采用羟胺 (HA) 通过选择磺胺甲恶唑 (SMX) 作为目标化合物来提高 Fe(II)/HSO（Fe(II)/PMS）工艺的氧化效率。首次阐明了 HA/Fe(II)/PMS 工艺对 SMX 的降解效率和机制。与 Fe(II)/PMS 工艺相比，在 pH 值为 3.0 时，HA/Fe(II)/PMS 工艺对 SMX 的降解效率提高了约 4 倍。Fe 物种的稳态浓度分析表明，HA 促进了 Fe(III)向 Fe(II)的转化，维持了快速的类芬顿反应。硫酸盐自由基和羟基自由基都参与了 SMX 的降解，后者被认为是主要的反应性物质。进一步分析了 SMX 的降解中间产物，提出了三种主要的转化途径。HA/Fe(II)/PMS 工艺也能有效去除实际制药废水中的 SMX 和总有机碳。这项工作拓宽了 HA 增强的芬顿和类芬顿工艺在污染物处理中的应用范围。
