Keywords: cadmium removal, industrial effluent, cementation, zinc powder, wastewater treatment
Cadmium removal from industrial effluents by cementation with zinc powder
This work presents the study of the cementation with zinc of a cadmium containing effluent, as an alternative process to chemical precipitation. The effluent, which was produced in the regeneration cycle of the ion–exchange columns of a metal plating waste–water treatment plant, contains: [Cd(II)] = 3500 mg/L; [Cr(III)] = 1230 mg/L; [Cu(II)] = 4575 mg/L; [Fe(II)] = 985 mg/L; [Zn(II)] = 325 mg/L and a pH. To minimise the consumption of zinc it is convenient to carry out the cementation at pH ≥ 4 to obtain an effluent containing 1.5 mg/L of cadmium, 0.1 mg/L of chromium, 0.1 mg/L of copper, 0.3 mg/L of iron and 3850 mg/L of zinc.