Electrochemical degradation of m-nitrophenol using an innovative zeolite modified PbO2 anode: Electrode characterization, influence factors and degradation mechanism

Abstract

In this study, a zeolite-doped PbO2 (Zeo-PbO2) anode was fabricated via electrodeposition technology for electrochemical oxidation of m-nitrophenol (m-NP). The results of characterization revealed that doping zeolite efficiently promoted the oxygen evolution potential and active sites of PbO2 anode, thereby higher performance to generate •OH radical and degrade the m-NP. The •OH radical was confirmed to be the primary contributor to the electrochemical oxidation of m-NP by scavenging tests. Thus, the effect mechanism of current density, supporting electrolyte, and initial pH on the removal of m-NP in the electrochemical oxidation process was explored by the generation of •OH radicals at different conditions. Based on the vulnerable sites of m-NP to the attack of •OH radical supposed by the theoretical calculation and degradation intermediates identified by GC-MS and IC, the degradation pathways of m-NP in the electrochemical oxidation process were speculated. Besides, the good recyclability and stability of Zeo-PbO2 anode were exhibited in consecutive m-NP degradation, •OH generation experiments, and accelerated life tests.