Improved hydrophobic zeolites to fill silicone membranes for ethyl acetate extraction from water by pervaporation

Abstract

Two types of hydrophobic zeolites Y were prepared by treating the NaY-type zeolite with SiCl4, with or without subsequent hydrothermal treatment. X-ray diffraction analysis showed that the framework of the two modified zeolites Y are more perfect than that of the NaY one, and the Si/Al ratio is greatly enhanced by hydrothermal treatment. The determined sorption isotherms indicate an improvement of the ester-to-water sorption ratio with the increase in Si/Al ratio. When the zeolite-filled silicone membranes are used in separation of ethyl acetate - water mixture by pervaporation, both the total permeation flux and the selectivity to the ester are improved by the use of the hydrophobic zeolite Y as the filler in the membrane. The stronger the hydrophobicity of the zeolite Y, the higher the filled membrane selectivity.Key words: hydrophobic zeolites Y, silicone-filled membranes, ethyl acetate - water mixture, sorption, pervaporation.