Shafer, Jenifer C.Fletcher, Andrew2020-01-172022-02-032020-01-172022-02-032019https://hdl.handle.net/11124/173978Includes bibliographical references.2019 Fall.The aqueous-soluble diglycolamide TEDGA has recently been of interest as a selective trivalent f-element complexant. While initial studies show that TEDGA can improve Am3+/Cm3+ separations, solution behavior of lanthanide- and actinide-TEDGA complexes are not well-studied. This research evaluates TEDGA chemistry during complexation with trivalent lanthanides and actinides to gain an understanding of driving forces for selectivity. Using spectrophotometric, calorimetric, and chromatographic methods, TEDGA was shown to have thermodynamic selectivity for trivalent f-elements. Specifically, stability constants, formation enthalpies, and formation entropies were evaluated for [Ln(TEDGA)n]3+ complexes (Ln = Pr, Nd, Sm, Ho, Er), demonstrating a greater preference for [Ln(TEDGA)3]3+ for later lanthanides. In a chromatographic system, TEDGA was found to increase separations between adjacent actinides.born digitalmasters thesesengCopyright of the original work is retained by the author.lanthanide separationtetraethyl diglycolamidespeciationactinide separationText