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Understanding the Assisting Role of PMS in Low Current Electrochemical Processes for Degradation of Antibiotics.

Authors :
Ma, Dong
Ren, Xupicheng
Zhang, Bo
Zhao, Yan
Qian, Guangsheng
Hu, Xiaomin
Source :
Water, Air & Soil Pollution; Apr2023, Vol. 234 Issue 4, p1-17, 17p
Publication Year :
2023

Abstract

Electro-activated persulfate has displayed good performance in the oxidation of antibiotic pollutants in wastewater. However, high power consumption and the introduction of excessive sulfate ions hinder the application of this technology. This research provided a novel strategy for the applications of small power supply and simple devices in antibiotic pollutant treatment. It has been confirmed that sulfate radical ( SO 4 ∙ - ) could be generated at the boron-doped diamond (BDD) anode in both low and high current conditions. This study proposed a novel low current density electrochemical technology assisted by peroxymonosulfate (PMS) for the degradation of antibiotics. Adding 1 mg/L PMS at current density as low as 1.25 mA/cm<superscript>2</superscript> increased the electro-oxidation rates of ciprofloxacin 5-fold from 1.92 ± 0.67 h<superscript>−1</superscript>to 9.70 ± 0.10 h<superscript>−1</superscript>. According to the Butler-Volmer equation, the introduction of PMS changed the mechanism of electrode reactions, thermodynamic properties of the system therefore changed. The electron spin resonance (ESR) test has confirmed that hydroxyl radical (<superscript>•</superscript>OH), SO 4 ∙ - , and singlet oxygen (<superscript>1</superscript>O<subscript>2</subscript>) are all generated in low current electrochemical systems. Quenching experiments illustrate that both radical and non-radical ways play essential roles in electro-oxidation processes. The contribution rates of <superscript>•</superscript>OH, SO 4 ∙ - , and <superscript>1</superscript>O<subscript>2</subscript> were 15.6%, 33.2%, and 40.5%, respectively. An oxidation peak was observed in cyclic voltammetry (CV) around +1.2 V, indicating that PMS electrolyte may drive oxidation at this potential. Besides, the reaction pathways of ciprofloxacin were speculated. Four transformation pathways including stepwise piperazine ring cleavage, OH/F substitution, cyclopropane ring cleavage, and decarboxylation were proposed for ciprofloxacin degradation. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00496979
Volume :
234
Issue :
4
Database :
Complementary Index
Journal :
Water, Air & Soil Pollution
Publication Type :
Academic Journal
Accession number :
163414391
Full Text :
https://doi.org/10.1007/s11270-023-06259-y