Abstract：
A novel approach of visible light-emitting diode (Vis-LED) radiation was employed to activate permanganate (Mn(VII)) for efficient organic micropollutant (OMP) removal. The degradation rates of OMPs by Vis-LED/Mn(VII) were 2-5.29 times higher than those by Mn(VII) except for benzoic acid and atrazine. Increasing wavelengths (445-525 nm) suppressed the degradation of diclofenac (DCF) and 4-chlorophenol (4-CP) owing to the decreased quantum yields of Mn(VII). Comparatively, light intensity and Mn(VII) dosage had a positive effect on the degradation of DCF and 4-CP. Experimental data revealed that Mn(V) dominated the DCF degradation whereas Mn(III) was the active oxidant in the 4-CP degradation. Mn(V) and Mn(III) formed from the photo-decomposition of Mn(VII), meanwhile, Mn(III) also formed from the Mn(V) photo-decomposition. The increase in solution pH inhibited DCF degradation but had a positive impact on 4-CP degradation, mainly due to the changing speciation of DCF and 4-CP. Inorganic anions (Cl- and HCO3-) had little impact on DCF and 4-CP degradation, while humic acid (HA) showed a positive impact because of the π-π interaction between HA and DCF/4-CP. The transformation products of DCF and 4-CP were identified and transformation pathways were proposed. Finally, the Vis-LED/Mn(VII) exhibited great degradation performance in various authentic waters. Overall, this study boosts the development of Mn(VII)-based oxidation processes.
摘要：
采用可见光发光二极管（Vis-LED）辐射的新方法激活高锰酸盐（Mn（VII）），以有效去除有机微污染物（OMP）。除苯甲酸和阿特拉津外，Vis-LED/Mn（VII）对OMPs的降解率是Mn（VII）的2-5.29倍。由于Mn（VII）的量子产率降低，增加波长（445-525nm）抑制了双氯芬酸（DCF）和4-氯苯酚（4-CP）的降解。相对而言,光照强度和Mn(VII)用量对DCF和4-CP的降解有积极影响。实验数据表明，Mn（V）主导DCF降解，而Mn（III）是4-CP降解中的活性氧化剂。由Mn（VII）的光分解形成的Mn（V）和Mn（III），同时,Mn(III)也由Mn(V)光分解形成。溶液pH值的增加抑制了DCF降解，但对4-CP降解有积极影响，主要是由于DCF和4-CP的形态变化。无机阴离子(Cl-和HCO3-)对DCF和4-CP降解影响不大,而腐殖酸（HA）由于HA和DCF/4-CP之间的π-π相互作用而显示出积极的影响。鉴定了DCF和4-CP的转化产物，并提出了转化途径。最后,Vis-LED/Mn（VII）在各种真实水域中表现出良好的降解性能。总的来说,这项研究促进了Mn（VII）基氧化过程的发展。
