Simultaneously degradation of 2,4-Dichlorophenol and EDTA in aqueous solution by the bimetallic Cu–Fe/O2 system
2015
Liu, Xin | Fan, Jin-Hong | Ma, Luming
Oxidative degradation of aqueous organic contaminants 2,4-dichlorophenol (2,4-DCP) using ethylenediaminetetraacetic acid (EDTA)-enhanced bimetallic Cu–Fe system in the presence of dissolved oxygen was investigated. The proposed process was applied for the pH range of 3~7 with the degradation efficiency of 2,4-DCP and EDTA varying within 10 %, and achieved at 100 % degradation of 40 mg L⁻¹2,4-DCP in 1 h, at the initial pH of 3, 25 g L⁻¹of bimetallic Fe–Cu powder (WCᵤ/WFₑ = 0.01289) and initial EDTA of 0.57 mM. However, the removal efficiency of 2,4-DCP in control tests were 7.52 % (Cu–Fe/O₂system) and 84.32 % (EDTA-enhanced Fe/O₂process), respectively, after 3 h, reaction. The proposed main mechanism, involves the in situ generation of H₂O₂by the electron transfer from Fe⁰to O₂which was enhanced by ethylenediaminetetraacetic acid (EDTA), and the in situ generation of ·OH via advanced oxidation reaction. Accordingly, 2,4-DCP was attacked by ·OH to achieve complete dechlorination and low molecular weight organic acids, even mineralized. Systematic studies on the effects of initial EDTA and 2,4-DCP concentration, Cu–Fe dosing, Cu content, and pH revealed that these effects need to be optimized to avoid the excessive consumption of ·OH and new EDTA and heavy metal Cu pollution.
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