Pervaporation of water/alcohol mixtures through chitosan/cellulose acetate composite hollow-fiber membranes

For the purpose of separating aqueous alcohol by the use of pervaporation technique, a composite membrane of chitosan (CT) dip-coated cellulose acetate (CA) hollow-fiber membranes, CT-d-CA, was investigated. The effects of air-gap distance in the spinning of CA hollow-fiber membranes, chitosan concentration, and sorts of aqueous alcohol solutions on the pervaporation performances were studied. Compared with unmodified CA hollow-fiber membrane, the CT-d-CA composite hollow-fiber membrane effectively increases the permselectivity of water. The thickness of coating layer increases with an increase in chitosan concentration. As the concentration of chitosan solution increased, the permeation rate decreased and the concentration of water in the permeate increased. In addition, the effects of feed composition and feed solution temperature on the pervaporation performances were also investigated. The permeation rate and water content in permeate at 25degreesC for a 90 wt % aqueous isopropanol solution through the CT-d-CA composite hollow-fiber membrane with a 5-cm air-gap distance spun, 2 wt % chitosan dip-coated system were 169.5 g/M(2)h and 98.9 wt %, respectively. (C) 2004 Wiley Periodicals, Inc.