Cr(VI) and Cr(VI)-diphenylcarbazide removal from aqueous solutions using an iron rotating disc electrode

This paper presents the results of the investigation on the removal of Cr(VI) and the complex Cr(VI)-diphenylcarbazide from aqueous solutions using an electrochemical reactor, with iron electrodes. A maximum value of 99% Cr(VI) removal from aqueous solutions is observed for both Cr(VI) and Cr(VI)-diphenylcarbazide, at initial concentrations from 150 to 800 mg l(-1). Cyclic voltammetry experiments of water show the presence of electroactive species in the oxidation and reduction zones previous to the treatment and how this presence diminishes as the electrochemical treatment is applied to the wastewater. UV-Vis analyses corroborate the improvement on the quality of aqueous solutions treated. Finally, scanning electron microscopy and energy dispersion spectra show that Cr and Fe are present as constituents of the sludge formed during the electrochemical treatment. It was demonstrated that the use of electrochemical methods for the treatment of Cr(VI) and Cr(VI)-diphenylcarbazide aqueous solutions is an effective and economical method.