UPTAKE OF METAL-IONS BY A NEW CHELATING ION-EXCHANGE RESIN .1. ACID DEPENDENCIES OF ACTINIDE IONS

The uptake of several actinide ions [U(VI), Pu(IV), Np(IV), Th(IV] and Am(III)) from nitric and hydrochloric acid solutions, and of U(VI) fr om near-neutral solutions by the new chelating ion-exchange resin, Dip honix(TM), has been investigated. Diphonix is a polyfunctional resin c ontaining sulfonic and gem-disphosphonic acid groups chemically bonded in a styrene-divinylbenzene polymeric network. Comparison of the acid dependencies of the actinide ions uptake measured with Diphonix with those obtained using a commercial sulfonic-type resin and a resin cont aining both sulfonic and monophosphonic acid groups, has shown that Di phonix binds the actinides via a different kind of chemical interactio n, involving the,formation of chelate complexes through the phosphoryl groups of the gem-diphosphonic acids. As a consequence, Diphonix is s uperior to other resins in extracting actinide ions from very acidic s olutions. A better performance of Diphonix is also observed with the u ptake of uranium from neutral solutions. Conditions for efficient stri pping of actinide species from the resin have been found.