ADSORPTION PROPERTIES OF HIGH-SILICA MORDENITES

Adsorption of benzene, water, and ammonia on high-silica mordenites, w hich were prepared by direct synthesis followed by dealumination, was studied, Analysis of the adsorption isotherms of C6H6 shows that when a small amount of aluminum is removed by the acid treatment, the micro pore volume significantly increases, The deeper dealumination results in the formation of the system of secondary pelts with radii of 1.9 an d 2.5 mm. When the Si/Al ratio increases, mordenites exhibit hydrophob ic properties, and water is adsorbed on these samples at low pressures in the form of clusters containing 2-3 molecules. The appearance of v ery strong acid sites with the heat of ammonia adsorption above 150 kJ /mol was observed on high-silica mordenites by the adsorption-calorime tric technique.