Quantification of the redox properties of microplastics and their effect on arsenite oxidation  

作　　者：Lin Chen Dengjun Wang Tianran Sun Tingting Fan Song Wu Guodong Fang Min Yang Dongmei Zhou 

机构地区：[1]State Key Laboratory of Pollution Control and Resource Reuse,School of the Environment,Nanjing University,Nanjing 210023,China [2]School of Fisheries,Aquaculture and Aquatic Sciences,Auburn University,Auburn,AL 36849,USA [3]State Key Lab of Urban and Regional Ecology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China [4]Ministry of Environmental Protection of the People’s Republic of China,Nanjing Institute of Environmental Sciences,Nanjing 210008,China [5]Key Laboratory of Soil Environment and Pollution Remediation,Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China

出　　处：《Fundamental Research》2023年第5期777-785,共9页自然科学基础研究（英文版）

基　　金：the National Natural Science Foundation of China(4197310);the Alabama Agricultural Experiment Station,and the Hatch Program of the National Institute of Food and Agriculture,U.S.Department of Agriculture(ALA016-1-19123).

摘　　要：Microplastics have attracted global concern.The environmental-weathering processes control their fate,transport,transformation,and toxicity to wildlife and human health,but their impacts on biogeochemical redox processes remain largely unknown.Herein,multiple spectroscopic and electrochemical approaches in concert with wet-chemistry analyses were employed to characterize the redox properties of weathered microplastics.The spectroscopic results indicated that weathering of phenol-formaldehyde resins(PFs)by hydrogen peroxide(H2O2)led to a slight decrease in the content of phenol functional groups,accompanied by an increase in semiquinone radicals,quinone,and carboxylic groups.Electrochemical and wet-chemistry quantifications,coupled with microbial-chemical characterizations,demonstrated that the PFs exhibited appreciable electron-donating capacity(0.264-1.15 mmol e-g^(-1))and electron-accepting capacity(0.120-0.300 mmol e-g^(-1)).Specifically,the phenol groups and semiquinone radicals were responsible for the electron-donating capacity,whereas the quinone groups dominated the electron-accepting capacity.The reversible redox peaks in the cyclic voltammograms and the enhanced electron-donating capacity after accepting electrons from microbial reduction demonstrated the reversibility of the electron-donating and-accepting reactions.More importantly,the electron-donating phenol groups and weathering-induced semiquinone radicals were found to mediate the production of H2O2 from oxygen for arsenite oxidation.In addition to the H2O2-weathered PFs,the ozone-aged PF and polystyrene were also found to have electron-donating and arsenite-oxidation capacity.This study reports important redox properties of microplastics and their effect in mediating contaminant transformation.These findings will help to better understand the fate,transformation,and biogeochemical roles of microplastics on element cycling and contaminant fate.

关 键 词：Microplastics WEATHERING Redox property Semiquinone radicals Electron-donating and-accepting capacity Arsenite oxidation 

分 类 号：O62[理学—有机化学]