Oxidative Degradation of EDTA in Aqueous Solution by the Bimetallic Fe–Cu

Abstract

Oxidative degradation of ethylenediaminetetraacetic acid (EDTA) in aqueous solution at normal temperature and pressure by the bimetallic Fe–Cu was investigated in this work. The results showed that the removal efficiency of EDTA, total organic carbon (TOC), and total nitrogen (TN) could be about 95, 62.5, and 39 %, respectively, after 3-h reaction. The degradation of EDTA followed the pseudo-first-order reaction kinetics and would not be affected by the continuous use of bimetallic Fe–Cu. The degradation products were iminodiacetate, formate, and acetate determined by ion chromatogram. The effects of initial pH, initial concentration of EDTA, Cu content, Fe–Cu loading, and atmosphere were also investigated. Significantly, the bimetallic Fe–Cu process exhibited higher reactivity than ZEA process for the degradation of EDTA and it would not cause new heavy metal pollution in effluent. Reactive oxygen species (ROS) of OH was generated in situ. The evidence of oxidative degradation of EDTA was verified by electron spin resonance (ESR) spectroscopy and the product of para-hydroxybenzoic acid (p-HBA) by OH and benzoic acid (BA).