Oxidation of diclofenac by birnessite: Identification of products and proposed transformation pathway  

作　　者：Yue Zhao Fei Liu Min Wang Xiaopeng Qin 

机构地区：[1]Institute of Quality Standards and Testing Technology for Agro-Products,Key Laboratory of Agro-Product Quality and Safety,Chinese Academy of Agricultural Sciences,Beijing 100081,China [2]School of Water Resources and Environment,and Beijing Key Laboratory of Water Resources and Environmental Engineering,China University of Geosciences(Beijing),Beijing 100083,China [3]Department of Technology Assessment,Technical Centre for Soil,Agricultural and Rural Ecology and Environment,Ministry of Ecology and Environment,Beijing 100012,China

出　　处：《Journal of Environmental Sciences》2020年第12期169-178,共10页环境科学学报（英文版）

基　　金：supported by the National Program of Control and Treatment of Water Pollution (No. 2018ZX07109-004);the project from the China Geological Survey (No. DD20190323);the Agricultural Science and Technology Innovation Program of China。

摘　　要：Diclofenac(DCF), a widely used non-steroidal anti-inflammatory, reacted readily with birnessite under mild conditions, and the pseudo first order kinetic constants achieved 8.84 × 10^-2 hr^-1. Five products of DCF including an iminoquinone product(2,5-iminoquinone-diclofenac) and four dimer products were observed and identified by tandem mass spectrometry during the reaction. Meanwhile, 2,5-iminoquinone-diclofenac was identified to be the major product, accounting for 83.09% of the transformed DCF. According to the results of spectroscopic Mn(III) trapping experiments and X-ray Photoelectron Spectroscopy, Mn(IV) contained in birnessite solid was consumed and mainly converted into Mn(III) during reaction process, which proved that the removal of DCF by birnessite was through oxidation. Based on the identified products of DCF and the changes of Mn valence state in birnessite solid, a tentative transformation pathway of DCF was proposed.

关 键 词：BIRNESSITE DICLOFENAC Oxidation mechanism Transformation pathway Emerging contaminants 

分 类 号：X703[环境科学与工程—环境工程]