Electrochemical activation of periodate with graphite electrodes for water decontamination: Excellent applicability and selective oxidation mechanism

Mengfan Luo; Heng Zhang; Yang Shi; Jia Zhao; Can Feng; Jialong Yin; Yang Liu; Peng Zhou; Zhaokun Xiong; Bo Lai

doi:10.1016/j.watres.2023.120128

Electrochemical activation of periodate with graphite electrodes for water decontamination: Excellent applicability and selective oxidation mechanism

Water Res. 2023 Jul 15:240:120128. doi: 10.1016/j.watres.2023.120128. Epub 2023 May 25.

Authors

Mengfan Luo¹, Heng Zhang², Yang Shi³, Jia Zhao¹, Can Feng¹, Jialong Yin¹, Yang Liu¹, Peng Zhou¹, Zhaokun Xiong¹, Bo Lai⁴

Affiliations

¹ State Key Laboratory of Hydraulics and Mountain River Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China; Sino-German Centre for Water and Health Research, Sichuan University, Chengdu 610065, China.
² State Key Laboratory of Hydraulics and Mountain River Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China; Sino-German Centre for Water and Health Research, Sichuan University, Chengdu 610065, China. Electronic address: zhangheng01@scu.edu.cn.
³ State Key Laboratory of Hydraulics and Mountain River Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China.
⁴ State Key Laboratory of Hydraulics and Mountain River Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China; Sino-German Centre for Water and Health Research, Sichuan University, Chengdu 610065, China. Electronic address: laibo@scu.edu.cn.

PMID: 37247436
DOI: 10.1016/j.watres.2023.120128

Abstract

Advanced oxidation technologies based on periodate (PI, IO₄^-) have garnered significant attention in water decontamination. In this work, we found that electrochemical activation using graphite electrodes (E-GP) can significantly accelerate the degradation of micropollutants by PI. The E-GP/PI system achieved almost complete removal of bisphenol A (BPA) within 15 min, exhibited unprecedented pH tolerance ranging from pH 3.0 to 9.0, and showed more than 90% BPA depletion after 20 h of continuous operation. Additionally, the E-GP/PI system can realize the stoichiometric transformation of PI into iodate, dramatically decreasing the formation of iodinated disinfection by-products. Mechanistic studies confirmed that singlet oxygen (¹O₂) is the primary reactive oxygen species in the E-GP/PI system. A comprehensive evaluation of the oxidation kinetics of ¹O₂ with 15 phenolic compounds revealed a dual descriptor model based on quantitative structure-activity relationship (QSAR) analysis. The model corroborates that pollutants exhibiting strong electron-donating capabilities and high pK_a values are more susceptible to attack by ¹O₂ through a proton transfer mechanism. The unique selectivity induced by ¹O₂ in the E-GP/PI system allows it to exhibit strong resistance to aqueous matrices. Thus, this study demonstrates a green system for the sustainable and effective elimination of pollutants, while providing mechanistic insights into the selective oxidation behaviour of ¹O₂.

Keywords: Electrochemical activation; Periodate; Phenols; QSAR; Singlet oxygen.

MeSH terms

Decontamination
Electrodes
Environmental Pollutants*
Graphite* / chemistry
Oxidation-Reduction
Water
Water Pollutants, Chemical* / chemistry

Substances

Water
Graphite
metaperiodate
bisphenol A
Environmental Pollutants
Water Pollutants, Chemical