Hydroxyl and sulfate radicals-based electrochemical advanced oxidation process for treating dye-bearing wastewater – A review

Abstract

Dye-bearing wastewater presents a substantial ecological risk. Consequently, there is a critical requirement for efficient treatment strategies. Electrochemical advanced oxidation processes (EAOPs) utilizing hydroxyl and sulfate radicals emerge as viable alternatives to degrade dye pollutants effectively. This review article emphasizes the implementation of EAOPs in the treatment of both synthetic and actual dye-bearing wastewater. The fundamentals, chemistry, and recent developments concerning hydroxyl radicals-based EAOP, including anodic oxidation, electro-Fenton, and sulfate radicals-based EAOP, have been thoroughly reviewed. Furthermore, the article explores the comparative effectiveness of the individual hydroxyl and sulfate radical systems as well as the integrated hydroxyl and sulfate radical systems within a singular electrochemical cell. It has been established that sulfate radicals demonstrate a higher oxidation potential, greater pH adaptability, and a longer half-life in comparison to hydroxyl radicals, making them efficient for dye degradation when assessed against anodic oxidation and electro-Fenton processes. Thus, EAOPs represent a promising technological approach for the remediation of dye-bearing wastewater.