SEPARATION AND PRECONCENTRATION OF ACTINIDES FROM ACIDIC MEDIA BY EXTRACTION CHROMATOGRAPHY

A systematic examination of the effect of nitric and hydrochloric acid concentrations and of macro levels of selected elements on the sorpti on of actinide ions by a novel extraction chromatographic resin compri sed of a solution of tyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphin e oxide in tri-n-butyl phosphate supported on an inert polymeric subst rate is described. Actinide sorption is demonstrated to be most effici ent at high ( > 1 M) nitric acid concentrations, although tetra- and h exavalent actinides are strongly retained even from dilute (e.g., 0.05 M) nitric acid solutions. Macro concentrations of several common anio ns (e.g., PO43- and SO42-) or complexing agents (e.g., oxalic acid) ar e shown not to adversely affect the sorption of trivalent actinides, w hile reducing the sorption of tetravalents. Such effects, together wit h oxidation state adjustments, are shown to provide a basis for the se quential elution of individual actinides and for actinide isolation fr om environmental and biological matrices.