Reduction of chromium(VI) in aqueous solution by treatment with direct-current discharge at atmospheric-pressure in air

Abstract

The kinetics of reduction of Cr(VI) by treating its aqueous solution in atmospheric pressure dc discharge in air has been studied at the discharge current range of 20–80 mA and the concentration range of 1.25–12.5 mg/L. The solution has served as the discharge cathode. It has been shown that the discharge treatment leads to a decrease in the Cr(VI) concentration to its steady-state value, with the latter depending on the discharge current and the initial concentration of the solution. The effective rate constants of the forward and reverse processes have been determined, the energy efficiency of the process has been evaluated, and possible mechanisms of the reactions involved have been discussed.