Development of novel pervaporation membranes for the separation of water-isopropanol mixtures using sodium alginate and NaY zeolite

Using solution technique, NaY zeolite-incorporated sodium alginate (SA) membranes were prepared and were subjected for the pervaporation separation of water-isopropanol mixtures. The resulting membranes were characterized by Fourier transform infrared spectroscopy, wide-angle X-ray diffraction and differential scanning calorimetry. The effects of zeolite loading and feed composition on the pervaporation performance of the membranes were analyzed. Both flux and selectivity increased simultaneously with an increase of zeolite content in the polymer matrix. This was explained on the basis of enhancement of hydrophilicity, selective adsorption and molecular sieving action including reduction of pore size of the membrane matrix. The membrane containing 30 mass% of zeolite shows the highest separation selectivity of 614.33 with a flux of 14.59 x 10(-2) kg/m(2) h for 5 mass% of water in the feed mixture at 30 degreesC. The total flux and flux of water are found to be almost close to each other throughout the investigated range, suggesting that the membranes developed are highly water selective. From the temperature dependent diffusion and permeation values, the Arrhenius activation parameters have been estimated. The resulting low activation energy values obtained for zeolite-incorporated membranes contribute to the superior performance of the PV process. (C) 2004 Elsevier B.V. All rights reserved.