A novel H2O2-persulfate hybrid system supported by electrochemically induced acidic and alkaline conditions for organic pollutant removal

Abstract

Electro-Fenton (EF) and alkaline/persulfate systems are two important systems capable of producing ·OH and SO4−· for environmental remediation. However, the major drawbacks of these two processes are the necessity of operating in low pH (2.0–4.0) or high pH environments, where the acidification/alkalization steps and subsequent neutralization processes significantly increase the operation cost and limit their applicability. In this work, we propose a system that can simultaneously electrochemically develop acidic and alkaline environments in two divided compartments to solve this problem. pH values of 2.9–3.2 and 10.9–11.9 in two separated compartments were obtained, and the results show that the electrochemically developed acidic environment (pH of 3 and 4) enhances the EF process by facilitating H2O2 electrogeneration and Fe2+ regeneration. The alkaline environment (11 and 12) that was also developed electrochemically is effective for persulfate activation. Finally, the system was found to be effective for Rhodamine B removal using an acidic pH-enhanced EF process and an alkaline pH-supported persulfate process.