Electrocoagulation for the Removal of Copper and Zinc Ions from Water Using Iron Electrodes

Abstract

Background: Many methods have been suggested for the removal of heavy metals from water to protect human health and the environment. Methods like precipitation and adsorption were proposed for this purpose. Objective: Electrocoagulation involves the generation of coagulant by the action of electricity on two metal electrodes (iron or aluminium) to aid the process of water decontamination. Methods: Electrodeposition cell was made with iron electrodes and application of voltage from the power supply (5-25 V) dipped in the working solution (Cu and Zn) at various concentrations (10-50 mg.mL-1) for 30-150 min. Samples were drawn and analysed by atomic absorption spectrophotometry. Results: The work indicated efficient removal of the metal ions. The dependence of removal efficiency on the three parameters was studied. The behaviour of the two metal ions was not identical. At low initial concentration, the electrolysis voltage was very important in the removal of Zn and Cu ions. Electrolysis time is essential in the removal process and shows a polynomial dependence of removal efficiency on time. Electrolysis time of 150 min resulted in almost complete removal (94-97%) regardless of the initial concentration. Both co-precipitation and adsorption mechanisms may be involved. Conclusion: The removal efficiency was directly dependent on the initial metal ion concentration and electrolysis time. The process gave removal efficiency for copper that is higher than that of the zinc.