Treatment method with electrocoagulation in wastewater that is dominant with zinc

Abstract

The electrocoagulation method was selected for the removal of Zn+2. The effects of the parameters such as current density, pH, and supporting electrolyte concentration on this method were studied. The Zn(+2 )concentration, mixing speed, and temperature were 250 mg/L, 150 rpm, and 293 K in the determination of the optimum pH the results obtained showed that a pH of 6 provided the highest Zn(+2 )removals. A pH of 6 was taken to be a constant optimum value while studying the effects of current density and supporting electrolyte concentration on removal. Current density values were chosen as 0.25, 0.50, 1.00, and 1.50 mA/cm(2). Increasing current density increased Zn(+2 )removals significantly. Removal of 48.86%, 71.03%, 84.12%, and 97.39% were found for current densities of 0.25, 0.50, 1.00, and 1.50 mA/cm(2) with an initial concentration of 250 mg/L with a reaction time of 30 minutes, respectively. An increase in current density caused an extreme increase in energy consumption. Energy consumption was 1.06 kW-h/m(3) for a current density of 0.25 mA/cm(2) with a reaction time of 30 minutes while it was 1.98, 3.46, and 5.31 kW-h/m(3) for a current density of 0.50, 1.00, and 1.50 mA/cm(2 )at a pH of 6, respectively. It was found that the effect of supporting electrolyte concentration on removal efficiency was negative. Aluminum anodes were used in electrocoagulation processes. As supporting electrolyte concentration increased, removal efficiency decreased, and the energy consumption rate increased. It was determined, as the result of the experiments, that Zn(+2 )ions can be removed at the rate of 84.12% with a pH of 6, a 250 mg/L Zn(+2)( )concentration, a 150 rpm mixing speed, a temperature of 293 K and a current density of 1.50 mA/cm(2) in an aqueous solution.