SELECTIVITY OF ION-EXCHANGE ON CRYSTALLINE ANTIMONIC ACID RADIOTRACERSTUDY ON HEAVY-METALS IN HYDROCHLORIC-ACID AND AMMONIA SOLUTIONS

Ion exchange of Zn2+, Cd2+, Hg2+, and Ag+ (radiotracers) on cc-crystal line antimonic acid (CAA) was studied as a function of the aqueous pha se concentration of complexing species: ammonia or hydrochloric acid. Strong adsorption of Cd2+ Hg2+, and Ag+ is the result of a good match between the size of the ions and the ion-exchange centers in the cryst alline structure of CAA (ion-size recognition). The composition of the adsorbed species and factors controlling the ion-exchange equilibria have been studied. The ion-size-recognition properties of CAA, combine d with different complexing abilities of metal ions, make this ion exc hanger suitable for numerous selective separations in analytical chemi stry and radiochemistry.