DEVELOPMENT OF CELLULOSE-ACETATE PROPIONATE MEMBRANE FOR SEPARATION OF ETHANOL AND ETHYL TERT-BUTYL ETHER MIXTURES

For pervaporation separation of ethanol and ethyl tert-butyl ether mix tures, a cellulose acetate propionate membrane was chosen as the exper imental membrane because of its high selectivity and good mass fluxes. The properties of the membranes were evaluated by the pervaporation s eparation of mixtures of ethyl tert-butyl ether/ethanol and the sorpti on experiments. The experimental results showed that the selectivity a nd the permeates depend on the ethanol concentration in the feed and t he experimental temperature. With increases of the ethanol weight frac tion in the feed and the temperature, the total and partial mass fluxe s increased. With respect to the temperature, ethanol mass flux obeys the Arrhenius equation. The selectivity of this membrane decreases as the temperature and the ethanol concentration in the feed increase. Th is membrane shows special characteristics at the azeotropic compositio n. In the vicinity of the azeotropic point, minimum values of ethanol concentration in the permeate and in sorption solution are obtained. T he swelling ratios increase when temperature and the ethanol concentra tion in the feed are increasing. The ethanol concentration in the sorp tion solution is also influenced by the temperature and the mixture's composition. When the temperature increases, the sorption selectivity of the membrane decreases.