Preparation and properties of organophilic membranes for pervaporation of water-organics mixtures

Several dense membranes made of polydirriethylsiloxane (PDMS), poly(ether block amide) (PEBA) and ZSM-5-type, zeolite-filled PEBA were prepared by the casting method. Morphology of membranes was determined by using differential scanning calorimetry (DSC) and wide-angle x-ray scattering method (WAXS). The swelling and pervaporation properties of prepared membranes were investigated in the contact with water-methyl t-butyl ether (H2O-MTBE), water-butyl acetate (H2O-BuAc), and water-methyl acetate (H2O-MeAc) mixtures. It was found that transport and selectivity properties depended both on the kind of a membrane and the kind of a liquid mixture. PDMS membranes showed the best pervaporation properties. Both the PEBA and zeolite-filled PEBA membranes showed similar selectivity during pervaporation. The presence of zeolite filler in the PEBA membrane enhanced transport of both water and organic component of the separated mixture.