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) from near-neutral solutions by the new chelating ion-exchange resin, Diphonix(TM), has been investigated. Diphonix is a polyfunctional resin containing 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 containing both sulfonic and monophosphonic acid groups, has shown that Diphonix binds the actinides via a different kind of chemical interaction, involving the,formation of chelate complexes through the phosphoryl groups of the gem-diphosphonic acids. As a consequence, Diphonix is superior to other resins in extracting actinide ions from very acidic solutions. A better performance of Diphonix is also observed with the uptake of uranium from neutral solutions. Conditions for efficient stripping of actinide species from the resin have been found.