| Popis: |
Heats of adsorption of propane and water vapour on X and Y zeolites with varying content of exchange cations Li+, Na+ and K+ were measured in a calorimeter at ≈ 20°C. Adsorption isotherms of propane on Li- and K-forms of X and Y zeolites were measured in the temperature range 0–130°C. They are described by the virial equation. Henry's constants Kns, p, 1 calculated according to this equation, change considerably on varying the type and concentration of exchange cations in the zeolites. A decrease in exchange cation concentrations in the zeolites results in a reduction in the amount adsorbed and in the heat of adsorption, not only for water, but also for propane. The decrease in the concentration of exchange cations apparently occurs first as a result of the removal of cations from the surface of the large cavities in the zeolites (from sites III). |
