The adsorption isotherms of nitrogen on the aluminium-extracted zeolites containing different aluminium contents in series were obtained at the temperature of liquid nitrogen and analysed by utilizing Langmuir's and Dubinin-Astakhov's equation.
These give rise to the conclusion that there are two types of adsorption site, and effective micropore volume of aluminium-extracted zeolites have a maximum value at about 35 aluminium atoms per unit cell but real volumes of the solids increase linearly with decreasing aluminium atom until the corruption of zeolite crystal structure is reached.
The properties of thermal resistance for some aluminium-extracted zeolites were compared to one another.