School of Environment & Natural Resources, Renmin University of China, Beijing 100872, China.
J Hazard Mater. 2017 Jul 15;334:150-159. doi: 10.1016/j.jhazmat.2017.04.008. Epub 2017 Apr 5.
The degradation of diclofenac in a like Fenton system, FeCeO-HO, was studied in details. The influencing factors, reaction kinetics, reaction mechanism and degradation pathways of diclofenac were investigated. The optimum conditions were at a solution pH of 5.0, HO concentration of 3.0mmol/L, diclofenac initial concentration of 0.07mmol/L, FeCeO dosage of 0.5g/L, and 84% degradation of diclofenac was achieved within 40min. The kinetics of FeCeO catalyzed HO process involved adsorption-dominating and degradation-dominating stages and fitted pseudo-second order model and pseudo-first order model, respectively. Singlet oxygen O was the primary intermediate oxidative species in the degradation process; superoxide radical anion O also participated in the reaction. The surface cerium and iron sites and the oxygen vacancies in the FeCeO catalyst were proposed to play an important role in HO decomposition and active species generation. The detected intermediates were identified as hydroxylated derivatives (m/z of 310, 326 and 298), quinone imine compounds (m/z of 308, 278 and 264) and hydroxyl phenylamine (m/z of 178). The majority intermediates were hydroxylated derivatives and the minority was hydroxyl phenylamine. The degradation pathways were proposed to involve hydroxylation, decarboxylation, dehydrogenation and CN bond cleavage.
用过硫酸盐（FeCeO-HO）芬顿体系详细研究了双氯芬酸的降解。考察了影响因素、反应动力学、反应机制和双氯芬酸的降解途径。在溶液 pH 值为 5.0、HO 浓度为 3.0mmol/L、双氯芬酸初始浓度为 0.07mmol/L、FeCeO 用量为 0.5g/L 的最佳条件下，40min 内双氯芬酸的降解率达到 84%。FeCeO 催化 HO 过程的动力学涉及吸附主导和降解主导阶段，分别符合准二级和准一级动力学模型。单线态氧 O 是降解过程中的主要中间氧化物质；超氧自由基阴离子 O 也参与了反应。FeCeO 催化剂表面的铈和铁位以及氧空位被认为在 HO 分解和活性物种生成中发挥了重要作用。检测到的中间产物被鉴定为羟基化衍生物（m/z 为 310、326 和 298）、醌亚胺化合物（m/z 为 308、278 和 264）和羟基苯胺（m/z 为 178）。大多数中间产物是羟基化衍生物，少数是羟基苯胺。提出的降解途径涉及羟基化、脱羧、脱氢和 CN 键断裂。
