Dependence of the Adsorption Capacity and Thermal Stability of Y Zeolites upon Si/Al Ratio

Abstract

Three series of dealuminated Y zeolites have been prepared by different procedures. The adsorption of n-hexane and water and the thermal stability have been studied with respect to their dependence on the content of framework aluminium. The reduction of their micropore volume can be calculated from the loss of framework aluminium. The water uptake decreases strongly below an aluminium content of 30 atoms per unit cell. At an aluminium content ≤8 atoms the zeolitic micropore structure is hydrophobic. Two ranges of thermal stability can be distinguished with decreasing aluminium content.