Transport characteristics and removal efficiency of copper ions in the electrodialysis process under electroconvection operation

Results indicated that ED system operated under electroconvection conditions was able to achieve high Cu2+ removal efficiency (around 74% in 4-min treatment) at high electricity efficiency as the theoretical calculation (based on Cu2+ transport number close to 1.0). The pH of copper wastewater in the ED system decreased slightly from 4.7 to 4.0 under electroconvection operation. The interface at the membrane-water was perturbed by the electroconvection operation, which facilitated ions transport across the membrane. An equivalent circuit composed of the Rs, Cm and Rm (parallel circuit representing the CEM), and constant phase element described well the Cu2+ transport behavior in the membrane-solution system according to the p value is greater than 1.0.