Electro-assisted removal and selective recovery of Cu(II) from aqueous solution with a chitosan-containing composite electrode application in capacitive deionization

This study presents a simple and effective method of enhanced removal and selective recovery of Cu(II) from aqueous solution using a chitosan composite electrode in a capacitive deionization system. The electrode was composed of chitosan, polyvinyl alcohol (PVA), and activated carbon powder. Its physico chemical and electrochemical characteristics were investigated by SEM, BET, FT-IR analyses and by cyclic voltammetry, respectively. The electrical potential for the electrosorptive removal of Cu(II) and the regeneration of the electrode were determined, and its Cu(II) selectivity was examined. It was shown that the Cu(II) removal capacity and kinetics were dependent on the applied potentials and reached a maximum capacity at 0.6 V with a composition of chitosan:PVA:ACP of 1:1:3. This result explains the significant influence of the electrical potential by the formation of an electrical double layer on the surface of the chitosan electrode, accelerating the removal of Cu(II). The electrode was successfully regenerated under a reverse electrical potential above 2.5 V with flowing deionized water without the use of chemicals. Moreover, the particular selectivity of Cu(II) from various cation mixture solutions using this system was confirmed. This finding implies that the suggested chitosan composite electrode system may be suitable for industrial utilization for the removal and therefore concentration of Cu(II) from wastewater.