PERVAPORATION SEPARATION OF ETHYL TERT-BUTYL ETHER AND ETHANOL MIXTURES WITH A BLENDED MEMBRANE

A new kind of membrane was prepared by blending cellulose acetate buty rate with cellulose acetate propionate. The properties of this membran e were evaluated by the pervaporation separation of ethyl tert-butyl e ther and ethanol mixtures. The experimental results showed that the se lectivity and the fluxes of this membrane depend on the blend and on t hat of processed feed mixtures. With respect to temperature, the overa ll and the ethanol fluxes obey the Arrhenius equation. The total and t he ethanol fluxes increase with the increase of the cellulose acetate butyrate content in the blended membrane, the ethanol concentration in the feed and the experimental temperature. But the selectivity decrea ses as the cellulose acetate butyrate content in the membrane and the experimental temperature are raised. When the feed composition is vari ed, the lowest selectivity is observed in the vicinity of the azeotrop ic composition. The swelling and the sorption experiments also gave th e same results.