A solvent extraction method was used to determine the stability constants of Np(V) complexes with fluoride and sulfate in 1.0 M NaClO4 from 25 degrees C to 60 degrees C. The distribution ratio of Np(V) between the organic and aqueous phases was found to decrease as the concentrations of fluoride and sulfate were increased. Stability constants of the 1:1 Np(V)-fluoride complexes and the 1:1 Np(V)-sulfate and 1:2 Np(V)-sulfate complexes, dominant in the aqueous phase under the experimental conditions, were calculated from the effect of [F-] and [SO42-] on the distribution ratio. The enthalpy and entropy of complexation were calculated from the stability constants at different temperatures by using the Van’t Hoff equation.
Revised: August 9, 2006 |
Published: July 31, 2006
Citation
Xia Y., J.I. Friese, D.A. Moore, and L. Rao. 2006.Stability Constants of Np(V) Complexes with Fluoride and Sulfate at Variable Temperatures.Journal of Radioanalytical and Nuclear Chemistry 268, no. 3:445-451.PNNL-SA-45798.