Removal of Cr(VI) from Model Solutions by a Combined Electrocoagulation Sorption Process

The elimination of hexavalent chromium from synthetic effluents in a batch stirred electrocoagulation cell with aluminum electrodes coupled with a sorption process using red onion skin adsorbent is addressed. The effect of process variables such as medium pH and adsorbent concentration was investigated in an attempt to optimize the removal capacity. Adsorption and electrocoagulation were first considered separately, with maximum Cr(VI) removal yields of 47% and 78 %, respectively, at pH 2. When combining the two processes, a removal of 97% of the total Cr(VI) in a pH range of 3-6 was achieved. The almost total elimination observed for the considered pollutant demonstrated the feasibility and the synergistic effect of the coupled process.