Zhang Hong, Qiao Lina, He Jing, Li Na, Zhang Dongmei, Yu Kai, You Hong, Jiang Jie
School of Marine Science and Technology, Harbin Institute of Technology at Weihai Weihai Shandong 264209 P. R. China
State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology Harbin Heilongjiang 150090 P. R. China.
RSC Adv. 2019 Aug 30;9(47):27224-27230. doi: 10.1039/c9ra04789a. eCollection 2019 Aug 29.
Activation of peroxymonosulfate (PMS) by halogenated and methylated quinones for destroying sulfamethoxazole (SMX) was investigated, where 2,6-dimethyl-1,4-benzoquinone (DMBQ), 2,6-dichloro-1,4-benzoquinone (DCBQ), and tetrafluoro-1,4-benzoquinone (TFBQ) were chosen as model quinones. The PMS could be activated by halogenated and methylated quinones efficiently for SMX degradation, and the process showed high pH and quinones dependency. Different from PMS activated by ultraviolet (UV), singlet oxygen (O) instead of hydroxyl radical (˙OH) and sulfate radical (SO˙) was the primary oxidizing species in the activation process. The formation of O was confirmed by various quenching studies combined with chemical probes (9,10-diphenylanthracene (DPA)). By sampling and monitoring in real time, droplet spray ionization mass spectrometry (DSI-MS) was applied to capture and identify the intermediates generated in the activation process. A possible mechanism for PMS activation was proposed accordingly. It was found that a series of reactions between PMS and halogenated/methylated quinones formed a dioxirane intermediate, and the subsequent decomposition of this intermediate produced the O. These findings would help to better understand the interactions between PMS and quinones, and provide a novel activator for PMS activation toward environmental contaminants.
研究了卤代和甲基化醌类对过氧单硫酸盐（PMS）的活化作用以降解磺胺甲恶唑（SMX），其中选择2,6-二甲基-1,4-苯醌（DMBQ）、2,6-二氯-1,4-苯醌（DCBQ）和四氟-1,4-苯醌（TFBQ）作为模型醌类。PMS可被卤代和甲基化醌类有效活化以降解SMX，该过程表现出对pH和醌类的高度依赖性。与紫外线（UV）活化的PMS不同，单线态氧（O）而非羟基自由基（˙OH）和硫酸根自由基（SO˙）是活化过程中的主要氧化物种。通过各种猝灭研究结合化学探针（9,10-二苯基蒽（DPA））证实了O的形成。通过实时采样和监测，应用液滴喷雾电离质谱（DSI-MS）捕获和鉴定活化过程中产生的中间体。据此提出了PMS活化的可能机制。发现PMS与卤代/甲基化醌类之间的一系列反应形成了二环氧乙烷中间体，该中间体的后续分解产生了O。这些发现将有助于更好地理解PMS与醌类之间的相互作用，并为PMS活化环境污染物提供一种新型活化剂。
