Replacement/Reduction reactions for copper removal using scrap iron packed electrode

摘要

In this study, Cu/EDTA was removed by electrocoagulation using scrap iron while packing inside a cage made of titanium mesh. Fe~(2+) released could chelate with EDTA and release free Cu~(2+), and the detached Cu~(2+) ions were reduced. The role of Fe~(2+) released, the mechanism of Cu/EDTA removal, and the effect of DO and pH on the removal of Cu/EDTA were explored. The removal of Cu increased slowly and reached 80% after 110 min reaction. Once Fe ions generated, the complexation of Fe/EDTA formed and released Cu~(2+), and free Cu~(2+) ions were reduced on the cathode/scrap iron surface. The trends of Cu removal as a function of Fe generated were linear along to the slope of 1/3, corresponding to 3 mole Fe(Ⅱ) generated per mole of Cu removed. TOC removal efficiencies are all less than 10%, indicating that Cu removal is mainly through the replacement/reduction mechanism.