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In this article a modified polydimethylsiloxane (PDMS) blended polystyrene (PS) interpenetrating polymer network (IPN) membranes supported by Teflon (polytetrafluoroethylene) ultrafiltration membrane were prepared for the separation of ethanol in water by pervaporation application. The relationship between the surface characteristics of the surface-modified PDMS membranes and their permselectivity for aqueous ethanol solutions by pervaporation are discussed. The IPN supported membranes were prepared by sequential IPN technique. The IPN supported membrane were tested for the separation performance on 10 wt % ethanol in water and were characterized by evaluating their mechanical properties, swelling behavior, density, and degree of crosslinking. The results indicated that separation performance, mechanical properties, density, and the percentage of swelling of IPN membranes were influenced by degree of crosslink density. Depending on the feed temperature, the supported membranes had separation factors between 2.03 and 6.00 and permeation rates between 81.66 and 144.03 g m À2 h À1 . For the azeotropic water-ethanol mixture (10 wt % ethanol), the supported membrane had at 30 C a separation factor of 6.00 and a permeation rate of 85 g m À2 h À1 . Compared to the PDMS supported membranes, the PDMS/PS IPN supported blend membrane ones had a higher selectivity but a somewhat lower permeability.

Sodium zeolite-Y (NaY zeolite) filled chitosan polymeric membranes were developed and characterized. The impact of adding different concentrations of NaY zeolite into the homogeneous chitosan membrane was investigated. The surface morphology, mechanical-physical properties, sorption, and pervaporation performance for the dehydration of isopropanol-water mixture separation by the pervaporation process were studied and evaluated. A homogeneous chitosan membrane showed preferential water sorption and permeation compared to isopropanol. The optimum concentration of NaY zeolite added to the homogeneous chitosan membrane was 0.4 wt %, which showed that the dispersion of the NaY zeolite was the most homogeneous and finely covered by the chitosan polymer in the zeolite-chitosan polymer interface. The tensile strength and percent strain at maximum of this membrane were 59.347 MPa and 27.5%, respectively. The sorption experiments showed that the degree of swelling was 6.54% with 1.01 wt % isopropanol sorbed in these membranes. The pervaporation separation tests demonstrated that the NaY zeolite filled chitosan membrane was capable for isopropanol-water mixture separation and improved the pervaporation separation index from 272 (homogeneous chitosan membrane) to 2687.

Nanohybrid (GO-PEI) membranes with hydrophilic property were synthesized and can be used to dehydrate biofuels such as n-butanol with high permeation and separation factor.

Chitosan membranes crosslinked with glutaraldehyde (GA) were prepared through a solution method, where the dry homogeneous chitosan membranes were immersed into the reaction solutions containing 1.25 x 10-3 wt. % of glutaraldehyde (GA). The extent of the crosslinking was controlled by varying the crosslinking time from 1 to 5 minutes. The prepared crosslinked membranes were used for pervaporation dehydration of isopropanol-water mixtures. The influence of feed composition on the separation characteristics has been investigated. The 2-minute-crosslinked-membrane yields the highest water concentrations in the permeate with moderate flux at 50 wt. % of isopropanol in the feed solution. The overall pervaporation results for the homogeneous and crosslinked membranes are compared in term of pervaporation separation index (PSI). The crosslinked membranes showed higher pervaporation separation index (PSI) than that of uncrosslinked membranes especially for isopropanol in feed solution below 78 wt. %.