Comparison of the Removal Efficiencies for Electro-Flotation and Electrocoagulation Wastewater Treatment Methods to Treat Effluents Discharged from Electroplating Industries

Abstract

Currently, rapid development, increasing world population, and industrialization such as electroplating sectors have caused an increase in wastewater, heavy metals, and toxic metals in the environment that directly and indirectly affect human beings and other living things. This study compared the efficiency of electro-flotation and electrocoagulation wastewater treatment methods to treat effluents discharged from electroplating industries based on removal efficiency, energy consumption, electrode consumption, and environmental aspects. Electro-flotation uses an electric current to generate hydrogen and oxygen bubbles, which allow contaminants to flow to the top of the treatment unit. However, the electrocoagulation process involves the use of direct current to accelerate the oxidation of the metal sacrificial anode and to generate positively charged ions that act as destabilizing agents for the emulsion. The electroplating wastewater sample solution (500ml) containing heavy metal ions (Zinc, Chromium, Nickel, Cadmium, and Copper) with a 50g/l metal ion concentration of each and a pH range of 7-10, were investigated using the two methods. Accordingly, the metal ions' degree of removal, energy consumption for the treatments, and electrode consumption 95-99%, 0.25-3.0 kWh/m3, and 2.0 kg/m3 respectively, were obtained using the elector-flotation. Whereas, 90–95% of metal ions' degree of removal, 1.0-5.0 kWh/m3 of energy consumption, and 10kg/m3 of electrode consumption, were obtained via the elector coagulation. The Fe-Fe electrode combination had the highest removal efficiencies of the heavy metal ions of Fe-Al, Al-Fe, and Al-Al combinations. Additionally, the effects of pH, time, and direct current on the removal efficiency of metal ions were investigated.