Uptake of Metal Ions by a New Chelating Ion Exchange Resin. Part 9: Silica Grafted Diphosphonic Acid*

A new chelating ion exchange resin, Diphonix®, containing geminally substituted diphosphonic acid ligands bonded to a styrene-based polymeric matrix, was recently developed and characterized. To overcome some of the problems associated with the stripping of actinide elements from the resin, a new version of the Diphonix resin has been prepared, where the chelating diphosphonic acid groups are grafted to a silica support. The new material is called Diphosil, for Diphonix on silica. The properties of the new material have been investigated with regard to its equilibrium and kinetic behavior in the uptake of actinide and other ions from acidic solutions. In this work data comparing the Diphonix and Diphosil resins are presented and discussed. The Diphosil resin appears particularly well suited for those cases where the recovery and further processing of the sorbed actinides is not required and the loaded resin can be considered as a solid waste. Because about 90 % of the Diphosil resin weight is silica, the problem of possible generation of gaseous compounds due to the slow radiolytical degradation of the organic components of the resin is minimized.