Surface silanation of alumina-silica zeolites for adsorption heat pumping

Alumino-silica zeolites A, X and Y have been synthesized and reacted with organosilane compounds. The effect of the silane chemisorption on the zeolites surface has been evaluated by vacuum water adsorption measurements. Results showed that in certain conditions the original hydrophilic character was partially attenuated, demonstrated by a shift in the adsorption isotherms towards a more hydrophobic behavior. The best results were obtained for zeolite 4A modified with dimethoxydimethyl silane and zeolite 13X modified with propyltrimethoxy silane.