School of Environmental and Chemical Engineering, Foshan University, Foshan, 528000, China.
Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China.
J Environ Manage. 2022 Aug 15;316:115219. doi: 10.1016/j.jenvman.2022.115219. Epub 2022 May 7.
The influence of Cl on the formation mechanism of active components is often neglected in the Fe/peroxydisulfate (PDS) system containing a large amount of ferryl ion reactive specie (Fe(Ⅳ)). In the current investigation, the effects of Cl concentration on the removal of methyl phenyl sulfoxide (PMSO), the formation of methyl phenyl sulfone (PMSO), the transformation of reactive species and oxidation products were investigated under different reaction conditions that included Fe dosage, PDS dosage, and pH. The results showed that Cl complexing Fe increased the formation path of sulfate radical (SO) in the Fe/PDS system. Fe dosage and pH value affected the content and morphology of Fe-Cl complex, thus affecting the composition of reactive species. According to the experiment of free radical steady-state concentration, it was found that low concentration of Cl reacted with SO and increased the steady-state concentration of chlorine radicals (8.09 × 10 M [·Cl] at 1.41 mM Cl), while at high concentration of Cl, the contents of SO, hydroxyl radical (·OH) and dichloride anion radicals (Cl) increased and the contents of Fe(Ⅳ) and ·Cl decreased. ·Cl had strong reactivity with PMSO, and PMSO and its oxidation products were chlorinated under the combined action of ·Cl and Cl. This work reveals the reaction mechanism and environmental application risks of Fe/PDS technology and lays the groundwork for subsequent industrial application of Fe/PDS system.
在含有大量高铁离子活性物种（Fe(Ⅳ)）的过一硫酸盐（PDS）体系中，氯（Cl）通常会忽略对活性成分形成机制的影响。在当前的研究中，考察了不同反应条件（包括 Fe 投加量、PDS 投加量和 pH 值）下 Cl 浓度对甲基苯基亚砜（PMSO）去除、甲基苯磺酸（PMSO）生成、活性物种和氧化产物转化的影响。结果表明，Cl 与 Fe 络合增加了 Fe/PDS 体系中硫酸根自由基（SO）的生成途径。Fe 投加量和 pH 值影响 Fe-Cl 配合物的含量和形态，从而影响活性物种的组成。根据自由基稳态浓度实验发现，低浓度的 Cl 与 SO 反应并增加了氯自由基的稳态浓度（在 1.41 mM Cl 时为 8.09×10 M [·Cl]），而在高浓度的 Cl 下，SO、羟基自由基（·OH）和二价氯自由基（Cl）的含量增加，Fe(Ⅳ)和·Cl 的含量降低。·Cl 与 PMSO 具有很强的反应性，在·Cl 和 Cl 的共同作用下，PMSO 及其氧化产物发生氯化。这项工作揭示了 Fe/PDS 技术的反应机制和环境应用风险，为后续 Fe/PDS 体系的工业应用奠定了基础。
