Silane-modified NaA zeolite/PAAS hybrid pervaporation membranes for the dehydration of ethanol

Abstract

To improve the pervaporation selectivity of poly(acrylic acid) sodium (PAAS) membranes incorporated with NaA zeolite, the interface compatibility between zeolite nanocrystals and the polymer matrix was improved by modifying NaA zeolite using 3-aminopropyltriethoxysilane (APTES). Both X-ray photoelectron spectra and FTIR confirmed the chemical modification, while the results of zeolite particle size analysis and scanning electron microscopy revealed the improved dispersion of the modified zeolite. Transmission electron microscopy images of these hybrid membranes indicated that the interface between the polymer and modified zeolite phases had improved. The effects of loaded NaA zeolite on the pervaporation performance of hybrid membranes were investigated. The selectivity of hybrid membranes made from APTES-modified zeolite was higher than that using the original zeolite under the same conditions, because fewer voids resulted from the incompatibility between the zeolite and PAAS and the structure was more homogenous. Based on the Arrhenius plots, the activation energies of water and the ethanol ratio were lower for modified zeolite hybrid membranes, because water molecules experienced less restrictive passage through the membranes compared with the original zeolite-based hybrid membrane. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013