Degradation of ronidazole by electrochemically simultaneously generated persulfate and ferrous ions

Fan Si; Yongqing Zhang; Chenhui Yao; Meimei Du; Imtyaz Hussain; Shaobin Huang; William Wen; Xijun Hu

doi:10.1016/j.chemosphere.2019.124579

Degradation of ronidazole by electrochemically simultaneously generated persulfate and ferrous ions

Chemosphere. 2020 Jan:238:124579. doi: 10.1016/j.chemosphere.2019.124579. Epub 2019 Aug 12.

Authors

Fan Si¹, Yongqing Zhang², Chenhui Yao¹, Meimei Du¹, Imtyaz Hussain¹, Shaobin Huang¹, William Wen³, Xijun Hu⁴

Affiliations

¹ School of Environment and Energy, Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, South China University of Technology, Guangzhou, 510006, China.
² School of Environment and Energy, Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, South China University of Technology, Guangzhou, 510006, China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou, 510006, China; State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, 510640, China. Electronic address: zhangyq@scut.edu.cn.
³ Centre for Clean Environment and Energy, Environmental Futures Research Institute, Griffith School of Environment, Griffith University, Gold Coast Campus, QLD, 4222, Australia.
⁴ Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.

PMID: 31434045
DOI: 10.1016/j.chemosphere.2019.124579

Abstract

Nitroimidazoles are found in pharmaceuticals and personal care products (PPCPs) and, when discharged into the environment, have adverse effects on human health and survival. Advanced oxidation technologies (AOTs) based on persulfate (PS) can rapidly and efficiently degrade organic pollutants via strong oxidizing radicals under activation conditions. This study investigated the degradation of ronidazole (RNZ) by indirect electrolytic generation of PS and its activator, ferrous ion (Fe²⁺). An electrochemical system was developed, with a high concentration of PS generated at the anode while the activator Fe²⁺ was produced at the cathode. It showed that ammonium polyphosphate (APP) could effectively promote the electrolysis of PS. A high current efficiency (88%) at the anode could be obtained after 180 min at a high current density (300 mA cm^-2). However, Fe²⁺ was inhibited at the cathode due to material control. The degradation of RNZ in the Fe²⁺/PS system generated from the electrochemical system was also explored. Increasing PS concentration and Fe²⁺/PS ratio were beneficial to the RNZ degradation. In homogeneous reactions, the degradation efficiency of RNZ could be improved by decreasing the Fe²⁺ addition rate through a peristaltic pump. Five intermediates were also detected and the degradation pathways were proposed. These findings provide a new method and mechanism for rapid and efficient degradation of RNZ.

Keywords: Electrolysis; Ferrous ion; Persulfate; Ronidazole.

MeSH terms

Electrochemical Techniques
Electrodes
Electrolysis
Environmental Restoration and Remediation / methods*
Ferrous Compounds / chemistry*
Iron
Oxidation-Reduction
Ronidazole / metabolism*
Sulfates / chemistry*
Water Pollutants, Chemical / analysis*

Substances

Ferrous Compounds
Sulfates
Water Pollutants, Chemical
Ronidazole
Iron