Advanced treatment of copper smelting wastewater by the combination of internal micro-electrolysis and electrocoagulation

ABSTRACT

In this study, a combined process of internal micro-electrolysis (IME)–electrocoagulation was developed at lab scale for treating a real copper smelting wastewater. By IME, 92.4% of Cu, 88.6% of Pb, and 72.2% of Zn were removed after 30 min at an initial solution pH of 3, a Fe/C dosage of 40 g/L, and a Fe/C mass ratio of 1:1. Removal of residual metals by electrocoagulation was affected by wastewater pH and current density. Electrocoagulation with iron/aluminum electrodes at a current density of 5 mA/cm², electrocoagulation time of 30 min, and pH 8 resulted in 99.3% Cu, 99.5% Pb, and 98.6% Zn removal. The final effluent quality could satisfy the National Discharge Standard of China. This work demonstrates that the hybrid system has the potential to be applied for the advanced treatment of high-strength copper smelting wastewater.