Uptake of metal ions by a new chelating ion exchange resin .8. Simultaneous uptake of cationic and anionic species

The uptake of tri-, tetra- and hexa-valent actinides as well as of pertechnetate actions by some new multifunctional ion exchange resins has been investigated. The new resins, identified as Diphonix A, for anionic Diphonix, contain the same geminally substituted diphosphonic acid groups bonded to a styrenic-based polymer matrix as the regular Diphonix resin, plus strong base anion exchange groups such as the tetraalkylammonium (Diphonix A - Type 1 resins) or the quaternized pyridinium (Diphonix A - Type 2 resins) groups. Our uptake measurements have shown that the Type 2 Diphonix A resins are as effective as the regular Diphonix resin in the rapid uptake of actinides from acidic solutions, while at the same time sorbing pertechnetate anions in a manner comparable to existing commercial anion exchange resins. The failure of the Type 1 Diphonix A resins to perform equally well has been explained as a consequence of the mutual interaction of adjacent diphosphonic acid groups and tetraalkylammonium groups. Uptake data have also been obtained with Se(IV). The behavior of the Diphonix A resins toward Se(IV) uptake in acidic solutions is comparable to that of commercial anion exchange resins.