<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Long Chen</style></author><author><style face="normal" font="default" size="100%">Duan, Jun</style></author><author><style face="normal" font="default" size="100%">Du, Penghui</style></author><author><style face="normal" font="default" size="100%">Weiliang Sun</style></author><author><style face="normal" font="default" size="100%">Bo Lai</style></author><author><style face="normal" font="default" size="100%">Liu, Wen</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Accurate identification of radicals by in-situ electron paramagnetic resonance in ultraviolet-based homogenous advanced oxidation processes</style></title><secondary-title><style face="normal" font="default" size="100%">Water Research</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Advanced oxidation processes</style></keyword><keyword><style  face="normal" font="default" size="100%">Electron paramagnetic resonance</style></keyword><keyword><style  face="normal" font="default" size="100%">Homogeneous</style></keyword><keyword><style  face="normal" font="default" size="100%">Radical</style></keyword><keyword><style  face="normal" font="default" size="100%">Ultraviolet</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2022</style></year></dates><urls><web-urls><url><style face="normal" font="default" size="100%">https://www.sciencedirect.com/science/article/pii/S004313542200700X</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">221</style></volume><pages><style face="normal" font="default" size="100%">118747</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Accurate identification of radicals in advanced oxidation processes (AOPs) is important to study the mechanisms on radical production and subsequent oxidation-reduction reaction. The commonly applied radical quenching experiments cannot provide direct evidences on generation and evolution of radicals in AOPs, while electron paramagnetic resonance (EPR) is a cutting-edge technology to identify radicals based on spectral characteristics. However, the complexity of EPR spectrum brings uncertainty and inconsistency to radical identification and mechanism clarification. This work presented a comprehensive study on identification of radicals by in-situ EPR analysis in four typical UV-based homogenous AOPs, including UV/H2O2, UV/peroxodisulfate (and peroxymonosulfate), UV/peracetic acid and UV/IO4− systems. Radical formation mechanism was also clarified based on EPR results. A reliable EPR method using organic solvents was proposed to identify alkoxy and alkyl radicals (CH3C(=O)OO·, CH3C(=O)O· and ·CH3) in UV/PAA system. Two activation pathways for radical production were proposed in UV/IO4− system, in which the produced IO3·, IO4·, ·OH and hydrated electron were precisely detected. It is interesting that addition of specific organic solvents can effectively identify oxygen-center and carbon-center radicals. A key parameter in EPR spectrum for 5,5-dimethyl-1-pyrroline N-oxide (DMPO) spin adduct, AH, is ranked as: ·CH3 (23 G) &amp;gt;·OH (15 G) &amp;gt;IO3· (12.9 G) &amp;gt;O2·− (11 G) ≥·OOH (9–11 G) ≥IO4· (9–10 G) ≥SO4·− (9–10 G) &amp;gt;CH3C(=O)OO· (8.5 G) &amp;gt; CH3C(=O)O· (7.5 G). This study will give a systematic method on identification of radicals in AOPs, and shed light on the insightful understanding of radical production mechanism.</style></abstract></record></records></xml>