Study of the reduction mechanism and the adsorption properties of uranium (VI)-cupferron complexes using various electrochemical techniques

The reduction mechanism of uranium(VI)-cupferron was studied by different electrochemical techniques such as stripping voltammetry and cyclic voltammetry. It is proposed that the U(VI) ions in the form of adsorbed complexes with cupferron are reduced at -0.46 V to U(V). The further reduction to U(III) is followed by a parallel catalytic reaction, which results in a chemical re-oxidation of the latter to U(V), with cupferron playing the double role of complexing and oxidizing agent. The strong adsorption properties of the complexes were studied by applying the recently developed three-dimensional phase-sensitive alternating current voltammetry.