High-valent cobalt-oxo species triggers hydroxyl radical for collaborative environmental decontamination
Wu, Deli 1Zong, Yang 1Zhang, Hua 1Zhang, Xiaomeng 1Liu, Wen 2Xu, Longqian1
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作者信息
1. Tongji Univ, Coll Environm Sci & Engn, State Key Lab Pollut Control & Resources Reuse, Shanghai 200092, Peoples R China
2. Peking Univ, Coll Environm Sci & Engn, Key Lab Water & Sediment Sci, Minist Educ, Beijing 100871, Peoples R China
折叠
Abstract
The overlooked role of high-valent cobalt-oxo species (Co(IV)) in the Co(II)/peroxymonosulfate (PMS) process was uncovered recently using methyl phenyl sulfoxide (PMSO) as the probe. Herein, we further interestingly found that Co(IV) could trigger hydroxyl radical (center dot OH) formation, resulting in the oxidized products distribution of PMSO heavily relied on the relative concentration of PMSO. More significantly, the generation of a series of 18O-labeled hydroxylated products (i.e., hydroxylated methyl phenyl sulfone, nitrobenzene and 4-nitrobenzoic acid) in H218O conclusively verified that center dot OH was triggered by Co(IV) species. Density functional theory calculation demonstrated that Co(IV) initiated center dot OH formation via oxo ligand protonation-induced valence tautomerization. Moreover, the oxidative contribution of Co(IV) and center dot OH on organic degradation was specifically dependent on the type and concentration of the substrate. This study provided deeper insights into the evolution pathway of center dot OH mediated by Co(IV) species and enriched the understandings on the collaborative oxidation mechanism in Co(IV)-involved processes.
Key words
High-valent cobalt-oxo species/Hydroxyl radical/18O-isotope labeling/Substrate and concentration-dependent/oxidation
NSTL
Elsevier