Extraction of Am(III) and Eu(III) from nitrate media with Cyanex (R)-301 and neutral N donor ligands: A thermodynamic study

Studies on the effect of temperature on the liquid liquid extraction behaviour of a trivalent actinide ion, Am3+ and a trivalent lanthanide ion, Eu3+ using a S-donor soft ligand, bis (2,4,4-trimethylpentyl) dithiophosphinic acid (Cyanex (R)-301) were carried out. The temperature effect on the enhancement in extraction as well as the selectivity which occurred in the presence of neutral soft donor auxiliary ligands with N donor atoms viz., bipyridyl (bipy) and 1,10-phenanthroline (phen) was also investigated. Thermodynamic parameters like the changes in the extraction enthalpy (Delta H degrees), entropy (Delta S degrees) and free energies (Delta G degrees) for both the binary as well as ternary extraction systems were obtained. These thermodynamic parameters could explain the nature of the species extracted with both Am(III) and Eu(III).