Electrochemical reduction of uranium(VI) in nitric acid-hydrazine solution on glassy carbon electrode

Electrochemical reduction of U(VI) in nitric acid-hydrazine solution is greatly influenced by the concentration of nitric acid. In low acidity nitric acid solution such as 0.1M (M=mol/dm³) HNO₃, U(VI) was firstly reduced to U(V) and then partially reduced to U(IV). In high acidity nitric acid solution, e.g., 3-6M HNO₃, an electrode process of two-electron transfer was involved in the reduction of U(VI). A higher U(IV) yield could be achieved in nitric acid solution with higher concentration. Hydrazine was very effective in suppressing the reduction of concentrated nitric acid, and the optimal concentration of hydrazine added was 0.075 to 0.15M in 6M HNO₃ This revised version was published online in July 2006 with corrections to the Cover Date.