Ligand structure and diluent nature in defining improved Am3+ and Cm3+ separation using diglycolamides: a combined solvent extraction and DFT study

Abstract

Separation of Am³⁺ and Cm³⁺ is one of the most challenging yet unavoidable steps in the back end of the nuclear cycle. Various ligands evaluated for Am/Cm separation have their own merits and demerits, and not a single ligand has been uniquely proposed for this purpose. In the present work, we evaluated N,N,N′,N′-tetra-n-octyldiglycolamide (TODGA) vis-à-vis N,N,N′,N′-tetra-2-ethylhexyldiglycolamide (T2EHDGA) in combination with a hydrophilic 2,6-bis(1,2,4-triazinyl)pyridine (SO₃PhBTP) derivative in the aqueous phase for the separation of Am³⁺ and Cm³⁺ from nitric acid medium. The results showed that marginal selectivity for Am³⁺ over Cm³⁺ was observed with T2EHDGA in the presence of SO₃PhBTP, which was attributed to the difference in the entropy change for their extraction from both the temperature-dependent liquid–liquid extraction and computational studies.