Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, 200 Xiao Ling Wei, Nanjing 210094, China.
Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, 200 Xiao Ling Wei, Nanjing 210094, China.
J Hazard Mater. 2021 May 15;410:124558. doi: 10.1016/j.jhazmat.2020.124558. Epub 2020 Nov 12.
Organoarsenicals such as roxarsone (ROX) pose a great threat to the eco-environment and human health. Herein, the degradation of ROX via UV-based advanced oxidation processes (AOPs) including UV/hydrogen peroxide (UV/HO), UV/peroxydisulfate (UV/PDS), and UV/peroxymonosulfate (PMS) processes are comparatively investigated. The removal efficiency of ROX in the UV-based AOPs follows the order of UV/HO >UV/PDS>UV/PMS at pH 7.0, while UV/PDS is the most effective process in reducing the total organic carbon (TOC). The second-order rate constants of ROX with hydroxyl radicals (OH) and sulfate radicals (SO) are determined to be (2.71 ± 0.27)× 10 and (7.68 ± 0.37)× 10 Ms, respectively. The degradation of ROX obeys the pseudo-first-order kinetics model, and the apparent rate constants (k) linearly increase with increasing the oxidants dosage from 0.10 to 1.0 mM. The solution pH (5.0-11.0) exhibits a limited effect on the oxidation of ROX in UV/HO and UV/PDS processes, but a great enhancement is observed at pH 11.0 in UV/PMS process. Humic acid and bicarbonate obviously suppress the photodegradation of ROX. In addition, arsenic in ROX is mainly converted to As(V) in the three UV-based AOPs. Overall, this study provides essential information for the degradation of ROX via the traditional UV-based AOPs.
有机胂化合物，如洛克沙胂（ROX），对生态环境和人类健康构成了巨大威胁。在此，通过基于紫外线的高级氧化工艺（AOPs）包括 UV/过氧化氢（UV/HO）、UV/过二硫酸盐（UV/PDS）和 UV/过一硫酸盐（PMS）过程，对 ROX 的降解进行了比较研究。在 pH 7.0 时，基于 UV 的 AOPs 中 ROX 的去除效率顺序为 UV/HO>UV/PDS>UV/PMS，而 UV/PDS 是降低总有机碳（TOC）最有效的工艺。ROX 与羟基自由基（OH）和硫酸根自由基（SO）的二级速率常数分别确定为（2.71±0.27）×10 和（7.68±0.37）×10 Ms。ROX 的降解遵循准一级动力学模型，表观速率常数（k）随氧化剂剂量从 0.10 增加到 1.0 mM 而线性增加。溶液 pH（5.0-11.0）对 UV/HO 和 UV/PDS 过程中 ROX 的氧化作用有一定的限制作用，但在 UV/PMS 过程中 pH 11.0 时观察到显著增强。腐殖酸和碳酸氢盐明显抑制了 ROX 的光降解。此外，ROX 中的砷主要在三种基于 UV 的 AOPs 中转化为 As(V)。总的来说，这项研究为传统基于 UV 的 AOPs 降解 ROX 提供了重要信息。
