Investigation of Me-TDDGA as Extractant for Grouped Actinides Separation from Lanthanides

The removal of minor actinides (MAs) from nuclear waste - in particular the separation of Am(III) from lanthanide (Ln) fission products - is an important step in the partitioning and transmutation (P&T) strategy aimed at reducing long-term heat load and radiotoxicity. In this study, a newly synthesized DGA ligand, 2-(2-[didecyl]-2-oxoethoxy)-N,N-didecylpropanamide (Me-TDDGA), was evaluated for its extraction performance and selectivity towards tri- and tetravalent actinides and trivalent lanthanides under different experimental conditions. While Me-TDDGA alone did not achieve significant separation between An(III) and Ln(III), the introduction of 2,6-bis(5,6-di(sulfophenyl)-1,2,4-triazin-3-yl)pyridine (SO₃-Ph-BTP) as a co-extractant showed remarkable improvements in separation factors. Additionally, the use of 2,6-bis[1-(propan-1-ol)-1,2,3-triazol-4-yl)]pyridine (PTD), a better alternative to SO3-Ph-BTP as it obeys the CHON principle, was investigated, and higher concentrations can further improve selectivity. These results highlight the potential of multi-component extraction systems and set the stage for future optimization towards more efficient actinide-lanthanide separations.