Kinetics of Tc(VII) Reduction with Diformylhydrazine in a Nitric Acid Solution in the Presence of U(VI) Ions

The Tc(VII) reduction with 1,2-diformylhydrazine in nitric acid solutions in the presence of U(VI) was studied spectrophotometrically. The reduction of Tc(VII) to Tc(IV) through the intermediate form of Tc(V) was found. The optical spectra were decomposed into two components by methods of mathematical processing. Kinetic curves have S-like appearance. It has been suggested that the induction period is associated with the Tc(V) formation. The kinetic equation of the Tc(IV) formation in the studied conditions was obtained. It was found that the rate of Tc(V) formation increases with an increase in the 1,2-diformylhydrazine, U(VI), and initial Tc(VII) concentrations and in the temperature but decreases with an increase in the nitric acid concentration. The reaction rate constants and partial orders of reaction components were found on the basis of the obtained data.