Preparation of novel ZSM-5 zeolite-filled chitosan membranes for pervaporation separation of dimethyl carbonate/methanol mixtures

Novel mixed matrix membranes were prepared by incorporating ZSM-5 zeolite into chitosan polymer for the pervaporative separation of dimethyl carbonate (DMC) from methanol. These membranes were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) to assess their morphology, intermolecular interactions, and crystallinity. Sorption studies indicated that the degree of swelling for zeolite-filled membranes increased with zeolite content in the membrane increasing and the separation selectivity of DMC/methanol was dominated by solubility selectivity rather than diffusivity selectivity. The characteristics of these membranes for separating DMC/methanol mixtures were investigated by varying zeolite content, feed composition, and operating temperature. The pervaporation separation index (PSI) showed that 5 wt % of ZSM-5 zeolite-filled membrane gave the optimum performance in the PV process. From the temperature-dependent permeation values, the Arrhenius activation parameters were estimated. The resulting lower activation energy values obtained for zeolite-filled membranes contribute to the framework of the zeolite. (C) 2007 Wiley Periodicals, Inc.