Highly efficient group separation of hexavalent actinides from lanthanides through a biphasic cooperative extraction system

Abstract

The implementation of actinide (An) and lanthanide (Ln) group separation is one of the most critical tasks for the GANEX process to adapt nuclear fuel cycle in the Generation IV nuclear energy system. In this work, we proposed a biphasic cooperative extraction system to fulfill this aim, achieving selective extraction of hexavalent An to the organic phase by a hydrophobic extractant, N,N-di-(2-ethylhexyl)butylamide (D2EHBA), while masking trivalent or tetravalent Ln in the aqueous phase by a hydrophilic ligand, N,N,N’,N’-tetraethyldiglycolamide (TEDGA). Efficient group separation of actinides from lanthanides was achieved with remarkable single-stage An/Ln separation factors over 102. Moreover, the mechanism of An(VI)/Ln(III/IV) selectivity was analyzed by UV–Vis, FT-IR and MALDI-TOF-MS spectroscopic analyses, indicating more hydrophobic nature of An(VI)-D2EHBA complex than Ln(III/IV)-D2EHBA complex as well as much stronger masking effect of Ln(III/IV) than An(VI) by TEDGA contributing striking An/Ln separation.