New Anion-Exchange Resins for Improved Separations of Nuclear Material

We are developing bifunctional anion-exchange resins that facilitate anion uptake by carefully controlling the structure of the anion receptor site. Our new ion-exchange resins interface the rapidly developing field of ion-specific chelating ligands with robust, commercial ion-exchange technology. The basic scientific issues addressed are actinide complex speciation along with modeling of the metal complex/functional site interactions in order to determine optimal binding site characteristics. Resin materials that actively facilitate the uptake of actinide complexes from solution should display both improved selectivity and kinetic properties. Our implementation of the 'bifunctionality concept' involves N-derivatization of pyridinium units from a base poly(4- vinylpyridine) resin (PVP) with a second cationic site, such that the two anion-exchange sites are linked by 'spacer' arms of varying length and flexibility. The overall objective of our research is to develop a predictive capability that allows the facile design and implementation of multi-functionalized anion-exchange materials to selectively sorb metal complexes of interest from targeted process, waste, and environmental streams. Various Focus Areas and Crosscutting Programs have described needs that would be favorably impacted by the new materials:Tanks, Plutonium; Subsurface Contaminants; Mixed Waste; and Efficient Separations. Sites within the DOE complex which would benefit from the improved anion exchange technology include Hanford, Idaho, Los Alamos, Oak Ridge, and Savannah River