Pervaporation separation of water/dimethylformamide mixtures using poly(vinyl alcohol)-g-polyacrylamide copolymeric membranes

Abstract

Grafted copolymeric membranes of poly(vinyl alcohol) with acrylamide (PVA-g-AAm) were developed and used in the pervaporation separation of water-dimethylformamide mixtures by varying the amount of water in the feed from 0 to 100%. From these data, the permeation flux, pervaporation separation index, diffusion coefficient, swelling index, and separation selectivity were calculated at 25, 35, and 45°C. The Arrhenius activation parameters for permeation flux ranged between 22 and 63 kJ/mol, while the activation energy for diffusion ranged between 23 and 67 kJ/mol. Separation selectivity was between 15 and 22. The highest permeation flux of 0.459 kg m-2 h-1 was obtained for the 93% grafted membrane at 90% of water in the feed mixture. The results are discussed using the principles of the solution-diffusion model. © 2002 John Wiley & Sons, Inc. J. Appl. Polym. Sci.