Effect of Temperature on Pervaporation Dehydration of Water-Acetic Acid Binary Mixture

Dehydration of acetic acid was carried out in a small scale pervaporation pilot plant unit using commercial polyvinyl alcohol (PVA) membrane supported on polyether sulfone (PES). The hydrophilic membrane was able to selectively transport water molecules from the acetic-acid water mixture. It was observed that PVA membrane swelled significantly wheel the acetic acid concentration was increased in the feed solution. With increase in feed temperature degree of swelling decreased marginally. At 25 degrees C the maximum degree of swelling was found out to be 46.3%, which reduced to 39.5% at 65 degrees C. Although the pervaporation flux increased with increasing temperature of the liquid feed mixture, the separation factor decreased. From the temperature dependence of diffusion and permeation values, the Arrhenius apparent activation parameters have been estimated. The resulting activation energy values, obtained for water permeation being lower than those of acetic acid permeation values, suggest that the membranes have higher separation efficiency.