Efficient actinide sequestration with ionic liquid-based extraction chromatography resins containing Aza-crown ether functionalized diglycolamides

Two new extraction chromatographic resins (ECRs) were prepared by impregnating two exotic diglycolamide (DGA) ligands (having three or four DGA moieties tethered to aza-crown ether scaffolds) dissolved in an ionic liquid onto an inert solid support. A room temperature ionic liquid (RTIL) was used for enhancing the performance of the ECRs. The ECR containing triaza-9-crown-3 functionalized with three DGA moieties (TAM-3-DGA), and tetraaza-12-crown-4 tethered with four DGA arms (TAM-4-DGA) were evaluated for the separation of Am³⁺ and Pu⁴⁺from nitric acid solutions. The resin capacity for Eu³⁺ was 9.52 mg/g and 7.24 mg/g for TAM-3-DGA and TAM-4-DGA resins, respectively. Similarly, the resin capacity for Pu⁴⁺was 7.44 mg/g and 5.72 mg/g for TAM-3-DGA and TAM-4-DGA resins, respectively. These maximum loading values corresponded to the formation of a 1:1 metal/ligand complex for the Eu³⁺ ion and a 1:2 metal/ligand complex for the Pu⁴⁺ ion. The sorption of Eu³⁺and Pu⁴⁺on the resins followed a chemisorption phenomenon on both resins. The sorbed Eu³⁺and Pu⁴⁺ions from the resin phase could be efficiently desorbed with complexing ligands such as guanidine carbonate/HEDTA and oxalic acid, respectively.