Removal of Chromium (VI) from Aqueous Solution Using Electro-Fenton Process

Chromium (Cr) is considered to be mutagenic and carcinogenic, and is one of the most important pollutants that have been widely used in various industrial applications. Due to its adverse health impacts, Cr must be removed from effluents before being released into the water environments. The objective of the present study was to investigate the effect of electro-Fenton process (EFP) using iron electrodes in presence of sodium sulfate salt on the elimination of Cr(VI) from aqueous solution. The effect of various parameters such as pH, voltage, initial Cr(VI) concentration, hydrogen peroxide dosage and cyanide concentration (as interference ion), on the process efficiency of Cr(VI) removal have also been tested. The results indicate that the optimum pH, voltage and hydrogen peroxide dosage in EFP were determined to be 3, 30 V and 50 mL/L, respectively. The results of this research also demonstrated that EFP efficiency decreased with increasing initial Cr(VI) concentration. Moreover, EFP efficiency Cr(VI) removal decreased with increasing cyanide concentration; accordingly, the cyanide acts as interference ion in EFP and can reduce the removal efficiency of Cr(VI). According to the obtained results, the maximum removal efficiency of Cr(VI) at optimum condition was 97 % after 25 min. These findings suggest that EFP is suitable option for removing Cr(VI) from aqueous solution.