DIPHONIX(R) RESIN - A REVIEW OF ITS PROPERTIES AND APPLICATIONS

The recently developed Diphonix(R) resin isa new multifunctional chela ting ion exchange resin containing geminally substituted diphosphonic acid ligands chemically bonded to a styrene-based polymeric matrix. Di phonix can be regarded as a dual mechanism polymer, with a sulfonic ac id cation exchange group allowing for rapid access, mostly non-specifi c, of ions into the polymeric network, and the diphosphonic acid group responsible for specificity (recognition) for a number of metal catio ns. The Diphonix resin exhibits an extraordinarily strong affinity for actinides, especially in the tetra- and hexavalent oxidation states. Therefore the resin has potential for applications in TRU and mixed wa ste treatment and characterization, and in the development of new proc edures for rapid actinide preconcentration and separation from environ mental samples. Metal uptake studies have been extended to alkaline ea rth cations, to transition and post-transition metal species, and to m etal sorption from neutral or near neutral solutions. Also the kinetic behavior of the resin has been investigated in detail. In view of the above applications the influence of the most commonly occurring matri x constituents (Na, Ca, Al, Fe, hydrofluoric, sulfuric, oxalic and pho sphoric acids) on the uptake of actinide ions has been measured. This review paper summarizes the most important results obtained in the stu dies on the properties of the Diphonix resin and gives an overview of the applications already in existence or under development in the fiel ds of mixed waste treatment, actinide separation procedures, treatment of radwaste from nuclear power and fuel processing plants, and remova l of iron from copper electrowinning solutions.