UPTAKE OF METAL IONS BY A NEW CHELATING ION-EXCHANGE RESIN. PART 4 : KINETICS

The rate of uptake of several actinide ions [Am(III), U(VI), Th(IV), Np(IV) and Pu(IV)] and of some transition-metal ions [Co(II), Zn(II), Fe(III) and Cr(III)] at tracer concentration level, from solutions of various compositions, by the new chelating ion-exchange resin, Diphonix Tm , has been investigated. Diphonix is a polyfunctional resin containing sulfonic and gem-diphosphonic acid groups chemically bonded in a styrene-divinylbenzene polymeric network. It binds actinide and other ions through the formation of chelate complexes with the phosphoryl groups of the gem-diphosphonic acids. The experiments discussed in this work have allowed us to establish the paramount importance of the presence of the sulfonic groups in obtaining practically useful rates of metal ions uptake. Comparison of the kinetic behavior of Diphonix with that of commercial sulfonic-type resins has shown that Diphonix reacts with the investigated ions as rapidly as do the other resins. Conditions for efficient and rapid stripping of all the investigated cations, including Cr(III), have been found.