CAS Key Laboratory of Urban Pollutant Conversion, Department of Applied Chemistry, University of Science & Technology of China, Hefei, China.
College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China.
Water Res. 2020 Apr 15;173:115559. doi: 10.1016/j.watres.2020.115559. Epub 2020 Jan 28.
Peroxymonosulfate (PMS) is extensively used as an oxidant to develop the sulfate radical-based advanced oxidation processes in the decontamination of organic pollutants and various PMS activation methods have been explored. Visible-light-assisted PMS activation to construct a Fenton-like process has shown a great potential for pollution control. In our work, BiVO nanosheets were prepared using a hydrothermal process and used to activate PMS under visible light. A rapid degradation of ciprofloxacin (CIP) was achieved by dosing PMS (0.96 g/L), BiVO (0.32 g/L) under visible light with a reaction rate constant of 77.72-fold higher than that in the BiVO/visible light process. The electron spin resonance and free radical quenching experiments indicate that reactive species of O, h, •OH and SO all worked, where h, •OH and SO were found as the dominant contributors to the CIP degradation. The spectroscopic analyses further demonstrate that the photoinduced electrons were directly involved in the PMS activation process. The generated O was partially utilized to activate PMS and more •OH was produced because of the chain reactions between SO and HO/OH. In this process, PMS acted as an electron acceptor to transfer the photo-induced charges from the conduction band of BiVO and PMS was successfully activated to yield the high-powered oxidative species. From the degradation intermediates of CIP detected by a liquid-chromatography-mass spectrometer, the possible degradation pathways were proposed. The substantially decreased toxicity of CIP after the reaction was also observed. This work might provide new insights into the visible-light-assisted PMS activation mechanisms and is useful to construct environmentally-friendly catalytic processes for the efficient degradation of organic pollutants.
过一硫酸氢盐（PMS）被广泛用作氧化剂，以开发用于有机污染物去污的基于硫酸根自由基的高级氧化工艺，并且已经探索了各种 PMS 活化方法。可见光辅助 PMS 活化以构建类 Fenton 过程已显示出用于污染控制的巨大潜力。在我们的工作中，使用水热法制备了 BiVO 纳米片，并将其用于可见光下激活 PMS。通过在可见光下投加 PMS（0.96 g/L）和 BiVO（0.32 g/L），可以快速降解环丙沙星（CIP），反应速率常数比 BiVO/可见光过程高 77.72 倍。电子自旋共振和自由基猝灭实验表明，O、h、•OH 和 SO 的活性物质都起作用，其中 h、•OH 和 SO 被发现是 CIP 降解的主要贡献者。光谱分析进一步表明，光诱导电子直接参与了 PMS 活化过程。生成的 O 部分用于激活 PMS，并且由于 SO 和 HO/OH 之间的链式反应，产生了更多的•OH。在该过程中，PMS 充当电子受体，将光诱导电荷从 BiVO 的导带转移，并且 PMS 成功地被激活以产生高效的氧化性物质。通过液相色谱-质谱仪检测到的 CIP 降解中间体，提出了可能的降解途径。还观察到反应后 CIP 的毒性大大降低。这项工作可能为可见光辅助 PMS 活化机制提供新的见解，并有助于构建用于有效降解有机污染物的环保催化过程。
