Am3+ and Eu3+/alkali cation exchange selectivity on mordenite and zeolite L

Am3+ and Eu3+/alkali cation exchange selectivity was studied on mordenite a nd zeolite L at 25 to 60 degreesC to examine the effect of their openings o f ion-exchange sites. The corrected selectivity coefficient at the infinite simal exchange increased in the order of Eu3+ < Am3+ on mordenite and Am3< Eu3+ On zeolite L. The selectivity reversal did not reflect the effect of the ionic form, but reflected the dimension of the opening of the ion-exch ange site and charge of trivalent cations, since the crystal ionic radii of alkali cations were much smaller than the openings of these zeolites (7-8 Angstrom).