State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China.
School of Chemical Engineering, Sichuan University, Chengdu, 610065, PR China.
Chemosphere. 2018 Jun;201:197-205. doi: 10.1016/j.chemosphere.2018.03.005. Epub 2018 Mar 2.
The advanced oxidation process (AOP) based on SO radicals draws an increasing interest in water and wastewater treatment. Producing SO radicals from the activation of peroxymonosulfate (PMS) by transition metal ions or oxides may be problematic due to high operational cost and potential secondary pollution caused by metal leaching. To address this challenge, the present study reports the efficient production of SO radicals through visible-light-driven photocatalytic activation (VL-PCA) of PMS by using Cu(OH)PO single crystal for enhanced degradation of a typical recalcitrant organic pollutant, i.e., 2,4-dichlorophenol (2,4-DCP). It took only 7 min to achieve almost 100% removal of 2,4-DCP in the Cu(OH)PO/PMS system under visible-light irradiation and pH-neutral condition. The 2,4-DCP degradation was positively correlated to the amount of Cu(OH)PO and PMS. Both OH and SO radicals were responsible for enhanced degradation performance, indicated by radical scavenger experiments and electron spin resonance (ESR) measurements. The Cu(OH)PO single crystal exhibited good cyclic stability and negligible metal leaching. According to density functional theory (DFT) calculations, the visible-light-driven transformation of two copper states between trigonal bipyramidal sites and octahedral sites in the crystal structure of Cu(OH)PO facilitates the generation of OH and SO radicals from the activation of PMS and cleavage of O-O bonds. This study provides the proof-in-concept demonstration of activation of PMS driven by visible light, making the SO radicals-based AOPs much easier, more economical and more sustainable in engineering applications for water and wastewater treatment.
基于 SO 自由基的高级氧化工艺（AOP）在水和废水处理中引起了越来越多的关注。通过过渡金属离子或氧化物将过一硫酸盐（PMS）活化产生 SO 自由基可能会由于操作成本高和金属浸出引起的潜在二次污染而成为问题。为了解决这一挑战，本研究通过使用 Cu(OH)PO 单晶体可见光驱动光催化活化（VL-PCA）来高效地产生 SO 自由基，从而增强了典型难降解有机污染物 2,4-二氯苯酚（2,4-DCP）的降解。在可见光照射和中性 pH 条件下，Cu(OH)PO/PMS 体系仅需 7 分钟即可实现 2,4-DCP 的几乎 100%去除。2,4-DCP 的降解与 Cu(OH)PO 和 PMS 的用量呈正相关。通过自由基捕获实验和电子自旋共振（ESR）测量表明，OH 和 SO 自由基都对增强的降解性能有贡献。Cu(OH)PO 单晶体表现出良好的循环稳定性和可忽略的金属浸出。根据密度泛函理论（DFT）计算，Cu(OH)PO 晶体结构中两个铜状态在三角双锥位点和八面体位点之间的可见光驱动转化促进了 PMS 的活化和 O-O 键的断裂，从而产生 OH 和 SO 自由基。本研究提供了可见光驱动 PMS 活化的概念验证，使得基于 SO 自由基的 AOP 在水和废水处理的工程应用中更加容易、经济和可持续。
