ADSORPTION PROPERTIES OF LOW-SILICA ZEOLITE ZK-5

Water vapor, methanol, and argon adsorption isotherms, as well as the heat of adsorption of ammonia, methanol, and carbon dioxide have been determined on zeolite types A, ZK-4, and ZK-5. The results are explain ed by the distribution and the bond lengths of cations in the zeolite crystal lattice. It was shown that the exchange of 10-15% of the Na+ i ons with Li+ in zeolite ZK-5 leads to a deformation of the 8-membered ring impeding the diffusion of adsorbed molecules. Cations contained i n the 8-membered ZK-5 zeolite ring are bound more strongly to the fram ework, than in zeolite NaA, resulting in their smaller adsorption capa city.