@article {doi:10.1021/acs.est.1c00375, title = {Enhanced Oxidation of Organic Contaminants by Iron(II)-Activated Periodate: The Significance of High-Valent Iron{\textendash}Oxo Species}, journal = {Environmental Science \& Technology}, volume = {55}, number = {11}, year = {2021}, note = {PMID: 33706511}, pages = {7634-7642}, abstract = {Potassium periodate (PI, KIO4) was readily activated by Fe(II) under acidic conditions, resulting in the enhanced abatement of organic contaminants in 2 min, with the decay ratios of the selected pollutants even outnumbered those in the Fe(II)/peroxymonosulfate and Fe(II)/peroxydisulfate processes under identical conditions. Both 18O isotope labeling techniques using methyl phenyl sulfoxide (PMSO) as the substrate and X-ray absorption near-edge structure spectroscopy provided conclusive evidences for the generation of high-valent iron{\textendash}oxo species (Fe(IV)) in the Fe(II)/PI process. Density functional theory calculations determined that the reaction of Fe(II) with PI followed the formation of a hydrogen bonding complex between Fe(H2O)62+ and IO4(H2O)-, ligand exchange, and oxygen atom transfer, consequently generating Fe(IV) species. More interestingly, the unexpected detection of 18O-labeled hydroxylated PMSO not only favored the simultaneous generation of {\textperiodcentered}OH but also demonstrated that {\textperiodcentered}OH was indirectly produced through the self-decay of Fe(IV) to form H2O2 and the subsequent Fenton reaction. In addition, IO4{\textendash} was not transformed into the undesired iodine species (i.e., HOI, I2, and I3{\textendash}) but was converted to nontoxic iodate (IO3{\textendash}). This study proposed an efficient and environmental friendly process for the rapid removal of emerging contaminants and enriched the understandings on the evolution mechanism of {\textperiodcentered}OH in Fe(IV)-mediated processes.}, doi = {10.1021/acs.est.1c00375}, url = {http://doi.org/10.1021/acs.est.1c00375}, author = {Zong, Yang and Shao, Yufei and Zeng, Yunqiao and Shao, Binbin and Xu, Longqian and Zhao, Zhenyu and Liu, Wen and Wu, Deli} }