Abstract
This work investigates improving the performance of an electrocoagulation reactor for a hexavalent chromium reduction process by introducing gas sparging as a simple, cheap, and efficient method to improve the rate of mass transfer within the reactor. The effect of several variables on the reactor performance were investigated, such as the gas flow rate, initial Cr(VI) concentrations, the concentration of sodium chloride as an electrolyte solution, and the current density. Results show that, depending on current density employed, gas sparging can produce a 40 to 50% improvement in Cr(VI) reduction and up to 90% reduction in cell potential. Moreover, SEM and EDX analysis reveal that increasing gas flow rate leads to a decrease in the percentage of chromium adsorbed on the iron surface, which in turn decreases the possibility of anode surface passivation and enhances dissolution rate of iron anode and improves the unit performance.