Fenton degradation of 4-chlorophenol using H2O2in situ generated by Zn-CNTs/O2 system

Abstract

In this study, Zn-CNT composites were prepared by the infiltration fusion method and characterized by TEM, XPS and N₂ adsorption/desorption experiments. The reaction of Zn-CNTs and O₂ in aqueous solution was performed for the in situ generation of H₂O₂, which was employed to react with Fe²⁺ for the Fenton degradation of 4-chlorophenol (4-CP). The effect of various parameters, including the initial pH, dosage of Zn-CNTs and Fe²⁺ concentration on 4-CP degradation was examined. The removal efficiencies of 4-CP and TOC (total organic carbon) were 98.8% and 87.4%, respectively, when the Fe²⁺ concentration was 20 mg L⁻¹, initial pH was 2.0, Zn-CNT dosage was 2 g L⁻¹, reaction time was 20 min and O₂ flow rate was 400 mL min⁻¹. When 4-CP was spiked in the secondary effluent of a municipal wastewater treatment plant, the removal efficiency of 4-CP and TOC was 47.0% and 45.6%, respectively, under the above-mentioned conditions. The intermediate products were detected by LC-MS and IC, and the possible degradation pathway of 4-CP and the reaction mechanism of the Zn-CNTs/O₂/Fe²⁺ system were tentatively proposed.