Abstract
We prepared a CMC-Na+/PAA-Li+ type composite membrane in order to develop the new dehydration composite membrane having high selectivity and permeability. The new composite membrane was produced by casting CMC-(Na+) solution on the polyester nonwoven fabric and then casting PAA-(Li+) solution as the active separation layer on it. With the new composite membrane, we investigated the separation characteristics of n-propanol, iso-propanol, and ethanol aqueous solotions by pervaporation technique. The results obtained in this work are as follows The new composite membrane showed very stable permeation and separation characteristics in the range of experimental temperature. The activation energies for pervaporation were 7.88, 7.54, and 7.44 kcal/mol for the 80 wt% n-propanol, iso-propanol, and ethanol aqueous solution, respectively. The permeation rates of the composite membrane for 95 wt% alcohol aqueous solution at 6$0^{\circ}C$ were in the range 0.10~0.18 kg/$m^2$.hr and the value of separation factor was between 854 and 9856. The highest value of pervaporation separation index(PSI) which means the best pervaporation performance was 1900kg/$m^2$.hr for the 85~90 wt% iso-propanol aqueous solution at 6$0^{\circ}C$.