Reaction rate and electrochemical stability of conducting polymer films used for the reduction of hexavalent chromium

Abstract

The reduction of toxic hexavalent chromium to its trivalent state at conducting polymers films was studied. The process is based on the capacity of conducting polymers to spontaneously donate electrons to the Cr(VI) species. Electrodes of polyaniline and polypyrrole, deposited as films on reticulated vitreous carbon (RVC), were prepared. The process of Cr(VI) reduction was studied under open and closed circuit conditions. It was observed that polyaniline was only suitable for use only under closed circuit conditions, whereas polypyrrole did not perform well under either open or closed circuit conditions. The electrocatalytic power of polyaniline for Cr(VI) reduction was demonstrated when the reaction rates for bare RVC and RVC/PANI were compared.