Enhanced decomposition of long-chain perfluorocarboxylic acids (C9-C10) by electrochemical activation of peroxymonosulfate in aqueous solution

Kaixuan Wang; Dahong Huang; Weilai Wang; Yang Li; Lei Xu; Jiayin Li; Yunqing Zhu; Junfeng Niu

doi:10.1016/j.scitotenv.2020.143666

Enhanced decomposition of long-chain perfluorocarboxylic acids (C9-C10) by electrochemical activation of peroxymonosulfate in aqueous solution

Sci Total Environ. 2021 Mar 1:758:143666. doi: 10.1016/j.scitotenv.2020.143666. Epub 2020 Nov 20.

Authors

Kaixuan Wang¹, Dahong Huang², Weilai Wang³, Yang Li³, Lei Xu², Jiayin Li³, Yunqing Zhu⁴, Junfeng Niu⁵

Affiliations

¹ Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, PR China; State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China.
² Research Center for Eco-environmental Engineering, Dongguan University of Technology, Dongguan, Guangdong 523808, PR China.
³ State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China.
⁴ School of Environmental Science and Engineering, Shaanxi University of Science & Technology, Xi'an 710021, PR China.
⁵ Research Center for Eco-environmental Engineering, Dongguan University of Technology, Dongguan, Guangdong 523808, PR China. Electronic address: niujf@dgut.edu.cn.

PMID: 33257073
DOI: 10.1016/j.scitotenv.2020.143666

Abstract

The decomposition of long-chain perfluorocarboxylic acids (PFCAs), including perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA), were investigated by electrochemical activation of peroxymonosulfate (PMS) on porous Ti/SnO₂-Sb membrane anode. The results indicated that PMS activation could efficiently promote PFNA/PFDA decomposition, with pseudo-first-order rate constants about 3.12/2.06 times as compared with that of direct electro-oxidations. The energy consumptions of PFNA and PFDA decomposition were 36.31 and 37.46 kWh·m^-3·order^-1, respectively. The quantitative detection results of •OH with electron paramagnetic resonance (EPR) demonstrated that PMS activation promoted •OH formation. The inhibited performance in radical scavengers indicated both •OH and SO₄^•- might be mainly involved in PFNA decomposition, while SO₄^•- might be mainly involved in PFDA decomposition during PMS activation process. The mineralization mechanism for long-chain PFCAs decomposition which was mainly by repeating CF₂-unzipping cycle via radical reaction based on the intermediates verification and mass balance of C and F, was proposed. These results suggested that electrochemical activation of PMS on porous Ti/SnO₂-Sb membrane anode exhibited high efficiency in mineralizing PFNA and PFDA under mild conditions. This work might provide an efficient way for persistent organic pollutants, including, but not limited to long-chain PFCAs elimination from wastewater.

Keywords: Hydroxyl radical; Long-chain perfluorocarboxylic acids; Peroxymonosulfate activation; Porous Ti/SnO(2)-Sb membrane anode; Sulfate radical.