Efficient preconcentration and separation of actinide elements from large soil and sediment samples

Large (similar to 10 g) soil and sediment samples are often required for an alysis of low-level man-made actinides for monitoring environmental radioac tivity, However, use of large environmental samples often results in signif icant chemical losses during chemical separations due to matrix interferenc es. We present a technique based on the ion-exchange resin Diphonix which s electively collects actinides and lanthanides into a common form, which the n behaves uniformly and predictably during subsequent separation schemes. D iphonix is attractive for this purpose because it has an extremely high aff inity for actinides and a low affinity for most common ions and is resistan t to hydrofluoric acid, After being adsorbed onto Diphonix resin in a colum n mode at a pH similar to 1, actinides are completely eluted with 0.5 M 1-h ydroxyethylidene-diphosphonic acid (HEDPA), After destruction of the HEDPA by ozonation or use of Fenton's reagent, Am, Pu, U, and Th are separated fr om each other and the remaining matrix by use of extraction chromatographic resins, We obtained high and consistent chemical recoveries (mean, 85%), a s well as excellent chemical separations, for Am, Pu, U, and Th through the entire procedure for several 10-g soil and sediment samples.