Heavy metals in industrial wastewater especially chromium (VI) are considered as the main environmental pollutants

Heavy metals in industrial wastewater especially chromium (VI) are considered as the main environmental pollutants. Electrochemical cell made of plexiglass with a volume of 1.95 lit was used. Iron and graphite electrodes, electricity conductor, each with dimensions of 0.1×3×10 cm (width×length×height) were designed and built. Tests were carried out in various conditions of pH, concentrations of input chromium (VI), different amounts of electrolytes, electric currents and retention times. Measurement of samples was performed using of diphenylhydrazine method. Maximum removal efficiency for iron and carbon electrodes at about 99.8% and 88.3% was observed, respectively. The lowest among of Cr+3 in efficiency wastewater of system was recorded about 0.05 mg/l for Fe electrode. The results showed that the operation of the electrochemical cell, efficiency removal of Cr (VI) by iron electrode in the same process conditions is more than carbon electrode. Generally, despite in this method removal efficiency of hexavalent chromium from synthetic wastewater is acceptable however consume a lot of electrical energy. Thus, electrochemical method is usable for the removal of heavy metals in industrial scale.