Effect of f-electron configurations on the adsorption of trivalent f-elements on tertiary pyridine resin in hydrochloric acid/alcohol mixed solvents

The separation of trivalent actinides (An) from lanthanides (Ln) is difficult because of their chemical similarities although it is necessary for various fields such as nuclear fuel-cycle process. In the present study, it was observed that the trivalent An (Am3+, Cm3+ and Cf3+) were adsorbed on tertiary pyridine type resins far more strongly than the Ln in HCl (LiCl solution)/methanol mixed solvents and the An were separated from the Ln by using a single separation process. On the other hand, the Dowex 1 x 8 showed no adsorption in the same conditions. Therefore, there is a possibility that the adsorption of An and Ln cations is caused by the complexation of the cations with the tertiary pyridine groups of the resins, not by the ionic interaction. There seems to be some relationship between the distribution coefficients (K-d) of trivalent f-elements (i.e. An and Ln) and the f-electron configurations of their cations, and their ionic size. (C) 2003 Elsevier B.V. All rights reserved.