文献类型：期刊文献

英文题名：Mechanistic and kinetic aspects of florfenicol degradation by [rad]OH: Chloride moiety resistance

作者：Ding, Yanzhou[1]; Zhu, Yiwen[1]; Yu, Xia[1,2]; Lyu, Shuguang[1,2]; Wu, Yanlin[3]; Zhou, Lei[1,2]; Sui, Qian[1,2]

机构：[1] State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, 200237, China; [2] Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China; [3] Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai, 200433, China

年份：2024

卷号：479

外文期刊名：Chemical Engineering Journal

收录：EI(收录号：20234915145701)

语种：英文

外文关键词：Abstracting - Antibiotics - Association reactions - Atoms - Chlorine - Chlorine compounds - Computation theory - Degradation - Kinetics - Mass spectrometry - Photolysis - Rate constants - Reaction intermediates - Substitution reactions

摘要：Antibiotic residues in aquatic environments can be effectively degraded by hydroxyl radical ([rad]OH)-based advanced oxidation processes (AOPs). However, the reaction kinetics and mechanisms have not been comprehensive determined due to the limitations of conventional competition kinetic methods and mass spectrometry-based product identification, as these methods fail to exclude interference from secondary radicals and are unable to capture unstable intermediates or transient species. In this study, these limitations were overcome using laser flash photolysis (LFP) and density functional theory (DFT) calculations, allowing accurate determination of the [rad]OH-initiated reaction kinetics and degradation mechanisms of florfenicol (FF), a model veterinary antibiotic compound that is frequently detected in the environment. Based on the LFP experiment results, the second order rate constant (k) between [rad]OH and FF was determined to be 1.96 × 109 M?1 s?1 by tracking the typical signal of (SCN)2[rad]?. Furthermore, DFT calculations revealed two distinct mechanisms for [rad]OH addition to the benzene ring and identified hydrogen atom abstraction (HAA) reaction from chiral carbons as being the most favorable initial reaction for [rad]OH. In addition, the destruction of chlorine moiety occurred via hydroxylation-chlorine abstraction, rather than direct chlorine abstraction or substitution reactions. The resistance of chlorine moiety to degradation during the initial oxidation process, resulted in the formation of chlorine-containing by-products. This study provided a novel approach to comprehensively investigate the mechanisms of emerging contaminants elimination during [rad]OH-based AOPs. ? 2023 Elsevier B.V.