Kinetic parameters for the reduction of U(VI) in carbonate solutions from measurements at thin mercury film electrodes

The electrochemical reduction of the uranyl(VI) ion at Pt, gold-plated Pt and Ni-based thin mercury film rotating disk electrodes was studied in sodium carbonate solutions by cyclic voltammetry. The stability of TMF electrodes and reproducibility of voltammetric curves was tested with respect to different amounts of mercury deposited, and mechanical resistivity against film rupture. It was shown that the kinetic parameters obtained using TMF electrodes are independent of the base metal nature, and that these can be used for hydrodynamic conditions up to Re = 6000. Results indicate that data on ksub(s) for irreversible reactions, overlapping with reduction of the ion of the supporting electrolyte, can be assessed only to an ultimate precision of +- 30%. (author)