Studies on the Uptake and Column Chromatographic Separation of Eu, Th, U, and Am by Tetramethylmalonamide Resin

A tetramethylmalonamide-functionalized resin (TMMA resin) has been developed and investigated for its ability to separate trivalent, tetravalent, and hexavalent actinide elements. As a fundamental study of the extraction mechanism and to design a chromatographic separation scheme, distribution coefficients (K d) for partitioning of Eu(III), Th(IV), U(VI), and Am(III) onto the resin from HNO3, NaNO3, HCl, and NaCl solutions have been determined. The partitioning of HNO3 onto the resin was also evaluated. The order of the K d values was Th(IV) > U(VI) > Am(III) = Eu(III) in all tested solutions. The competition between metal extraction and HNO3 extraction was confirmed by the extraction data and FT-IR spectra. The loading capacities of Eu(NO3)3 and UO2(NO3)2 at 3 M HNO3, determined by a dynamic method with TMMA resin (TMMA in the resin was 2.05 mmol/g), were 0.83 mmol/g and 1.6 mmol/g, respectively, implying that M:TMMA stoichiometry was 1:2 for Eu(III) and 1:1 for U. Because the K d values for Th(IV) and U...