Site group interaction effects in zeolite-Y. Part 2.—Na–Ag selectivity in different site groups

Abstract

The influence of the nature of the ion neutralizing a certain site group on the selectivity in another group is studied in zeolite-Y. The high Ag to Na preference in the small cages in the binary system is reduced by filling the large cavities with Cs⁺ or NH⁺₄ ions. The selectivity data are fitted in terms of the occupancy and selectivity coefficient of 4 (binary system) and 2 (ternary system) types of sites. The calculated occupancies in each site agree with the observed ones, which are obtained from X-ray studies. The thermodynamic ion exchange formalism for the case of several groups of sites is discussed.