Electrocoagulation studies on removal of cadmium using magnesium electrode

The removal of cadmium from aqueous solution was carried out by electrocoagulation using magnesium as anode and stainless steel 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 optimum removal efficiency of 98.6% was achieved at a current density of 0.2 A dm(-2) at a pH of 7.0. The experimental data were tested against different adsorption isotherm models for describing the electrocoagulation process. The adsorption of cadmium preferably fitting the Langmuir adsorption isotherm suggests monolayer coverage of adsorbed molecules. First and second-order rate equations were applied to study adsorption kinetics. The adsorption process follows second order kinetics model with good correlation. Temperature studies showed that adsorption was endothermic and spontaneous in nature.