@article {DU2022118113, title = {Hydrogen atom abstraction mechanism for organic compound oxidation by acetylperoxyl radical in Co(II)/peracetic acid activation system}, journal = {Water Research}, volume = {212}, year = {2022}, pages = {118113}, abstract = {Peracetic acid (PAA) has been widely used as an alternative disinfectant in wastewater treatment, and PAA-based advanced oxidation processes (AOPs) have drawn increasing attention recently. Among the generated reactive species after PAA activation, acetylperoxyl radical (CH3CO3{\textbullet}) plays an important role in organic compounds degradation. However, little is known about the reaction mechanism on CH3CO3{\textbullet} attack due to the challenging of experimental analysis. In this study, a homogeneous PAA activation system was built up using Co(II) as an activator at neutral pH to generate CH3CO3{\textbullet} for phenol degradation. More importantly, reaction mechanism on CH3CO3{\textbullet}-driven oxidation of phenol is elucidated at the molecular level. CH3CO3{\textbullet} with lower electrophilicity index but much larger Waals molecular volume holds different phenol oxidation route compared with the conventional {\textbullet}OH. Direct evidences on CH3CO3{\textbullet} formation and attack mechanism are provided through integrated experimental and theoretical results, indicating that hydrogen atom abstraction (HAA) is the most favorable route in the initial step of CH3CO3{\textbullet}-driven phenol oxidation. HAA reaction step is found to produce phenoxy radicals with a low energy barrier of 4.78~kcal mol-1 and free energy change of -12.21~kcal mol-1. The generated phenoxy radicals will undergo further dimerization to form 4-phenoxyphenol and corresponding hydroxylated products, or react with CH3CO3{\textbullet} to generate catechol and hydroquinone. These results significantly promote the understanding of CH3CO3{\textbullet}-driven organic pollutant degradation and are useful for further development of PAA-based AOPs in environmental applications.}, keywords = {Acetylperoxyl radical, Advanced oxidation process, Hydrogen atom abstraction, organic compound, Peracetic acid}, issn = {0043-1354}, doi = {http://doi.org/10.1016/j.watres.2022.118113}, url = {http://www.sciencedirect.com/science/article/pii/S0043135422000768}, author = {Du, Penghui and Junjian Wang and Guodong Sun and Long Chen and Liu, Wen} }