Electrode reduction of actinyl ions followed by deposition in weak acid solution

Kitatsuji, Yoshihiro  ; Ouchi, Kazuki  ; Otobe, Haruyoshi  

Electrolytic reduction of actinide ions in the weak acidic solution was investigated by focusing the relation between redox and aggregation of the ions. Constant potential electrolysis of uranium (VI) ion was carried out using Au electrode. It was found that U(VI) was rapidly reduced to U(V) and further reduction to U(IV) was not observed at the beginning of electrolysis when acidity of the solution was lower than pH 2. However, the reduction of U(V) to U(IV) is catalyzed by the reduction product which is U(IV) deposited on the electrode. Unlike uranium, the electrodeposition occurred quickly with electrode reduction of Np(V). Then the reduction of Np(V) was inhibited by formation of deposit layer on the electrode.