Pervaporation Performance of Novel Chitosan-POSS Hybrid Membranes: Effects of POSS and Operating Conditions

Four types of polyhedral oligosilsesquioxane (POSS)-octaanion, octaammonium, octanitrophenyl, and octaaminophenyl-were incorporated into chitosan (CS) to fabricate inorganic-organic hybrid membranes. The hybrid membranes were employed for the pervaporation dehydration of ethanol aqueous solutions. The performance of the hybrid membranes was found to be influenced by the type and loading amount of POSS. In comparison with the neat CS membranes which showed a separation factor of 65.2 for 10 wt % water in the feed at 303 K, the hybrid membranes containing 5 wt % of octaanion and octaaminophenyl POSS showed high separation factors of 305.6 and 373.3, respectively. The effects of the operating conditions such as the feed composition and temperature on the pervaporation performance of the membranes were investigated. Activation energies for permeation in the membranes were estimated from Arrhenius relationship. The activation energies for ethanol permeation in the hybrid membranes were much higher than that in the CS membrane, which may account for the large enhancements in the selectivity of the hybrid membranes. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 2185-2192, 2010