Removal of chromium (VI) and lead from electroplating effluent using electrocoagulation

Abstract

The present study deals with the treatment of electro plating effluent (EPE) by electrocoagulation (EC) using iron as a sacrificial electrode. The initial concentration of chromium (VI) and lead (Pb) is found to be 55.3 and 3.5 mg/dm3 in EPE. With four-plate configurations, a current density (CD) = 73.5 A/m2 and pH = 3.5 was found to be best. At this operating condition, maximum 91.7% Cr (VI) (i.e., 4.92 mg/dm3) and 91.3% Pb (i.e., 0.304 mg/dm3) removal obtained in 90-min EC. Anode consumption was increased with a decrease in pH. It was also observed that energy consumption increased with an increase in pH. The settling characteristics of EC treated sludge were also analyzed at different pH and settling at pH 9.5 was found to best. Study indicated that EC treatment is successfully applicable to treat heavy-metal-oriented waste water. In addition, this technique is very effective to treat real waste water (electroplating effluent) along with minimum cost.