Ion exchange isotherms have been measured and plotted for the uptake of cesium, barium, cobalt, zinc, silver and amonium onto
clinoptilolite- and mordenite-rich tuffs of Slovakian origin selectively for both the natural and near homoionic Na form as
well, using the radioanalytical determination. The higher quality clinoptilolite-rich tuff has been proven to be effective
for a potential radionucleides removal in native form according to the following selectivity sequence: Ag+,Ba2,Cs+>NH4+>Co2+, while parent tuff in Na exchanged variety exhibited a little different sequence according to: Ag+ > NH4+ > Ba2+ > Cs+. The raw and Na exchanged mordenite-rich tuffs proved subsequently more or less similar selectivity : Ag+ > Zn2+ > Cs+, Ba2+ > Co2+ and Ag+ > Zn2+.