Effects of alternating and direct current in electrocoagulation process on the removal of cadmium from water – A novel approach

The main objective of this study is to investigate the effects of AC and DC on the removal of cadmium from water using zinc as anode and as cathode. Various operating parameters on the removal efficiency of cadmium were investigated, such as initial cadmium ion concentration, initial pH, current density and temperature. The results showed that the removal efficiency of 97.8% and 96.9% with the energy consumption of 0.665 and 1.236 kWh/m3 was achieved at a current density of 0.2 A/dm2 and pH of 7.0 using zinc as electrodes using AC and DC, respectively. For both AC and DC, the adsorption of cadmium was preferably fitting Langmuir adsorption isotherm, the adsorption process follows second order kinetics and the temperature studies showed that adsorption was exothermic and spontaneous in nature.

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► Very high removal efficiency of cadmium was achieved by electrocoagulation.
► Zinc anode prevents residual aluminum in treated wate.
► Alternating current (AC) avoids oxide layer and high corrosion on anode surface.
► Good current transfer between anode and cathode results more removal efficiency.
► Compact treatment facility and complete automation.