Characteristics of Cr(VI) Removal Using Aluminum Electrodes in Electrocoagulation Process

In this study, the potential for Cr(VI) removal using electro-coagulation with an aluminum (Al) electrode was evaluated. The effects of various parameters, including distance of electrode, applied voltage, initial Cr(VI) concentration, electrolyte type and concentration, and operating time, were investigated. The Cr(VI) removal efficiency and the changes in pH as well as electrical conductivity were analyzed. The removal efficiency was highest at 1 cm electrode distance (16.7%), and the removal rate constant showed a linear inverse relationship with electrode distance. Regarding the applied voltage, the highest removal efficiency of 86.5% was achieved at 15 V, where the removal rate increased linearly with rise in the applied voltage. The removal efficiency was highest at an initial Cr(VI) concentration of 150 mg/L (77.6%), and the removal rate increased linearly with the initial Cr(VI) concentration from 50 to 150 mg/L. In terms of electrolyte type and concentration, NaCl at 10 mM resulted in the highest removal efficiency of 91.8%, where no significant inhibition was caused by sulfate (SO₄^-) ions. This study demonstrates that electrocoagulation is an effective method for Cr(VI) removal, and optimizing factors such as electrode distance, applied voltage and initial concentration, as well as electrolyte type and concentration can significantly improve the efficiency of the process.