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

Two types of hydrophobic zeolites Y were prepared by treating the NaY-type zeolite with SiCl4, with or without subsequent hydrothermal treatment. X-ra y diffraction analysis showed that the framework of the two modified zeolit es Y are more perfect than that of the NaY one, and the Si/Al ratio is grea tly enhanced by hydrothermal treatment. The determined sorption isotherms i ndicate an improvement of the ester-to-water sorption ratio with the increa se in Si/Al ratio. When the zeolite-filled silicone membranes are used in s eparation of ethyl acetate - water mixture by pervaporation, both the total permeation flux and the selectivity to the ester are improved by the use o f the hydrophobic zeolite Y as the filler in the membrane. The stronger the hydrophobicity of the zeolite Y, the higher the filled membrane selectivit y.