Matrimid®5218 dense membrane for the separation of azeotropic MeOH-MTBE mixtures by pervaporation

Matrimid®5218 dense membranes were produced using NMP by solvent evaporation. The membranes have been used, for the first time, in pervaporation (PV) separation of azeotropic methanol (MeOH)- methyl tert-butyl ether (MTBE) mixtures (14.3 and 85.7 wt%, respectively). The membranes were characterized by TGA, SEM, DSC, contact angle and swelling tests. The PV experiments were carried out at different feed temperatures (25-45°C) and vacuum pressures (0.0538, 0.2400, 2.1000 mbar). Moreover, an analysis of the PV process through the Arrhenius relationship has been provided. The feed temperature (in the range of 25-45 °C) affected mainly the MeOH permeation producing an increasing on its partial permeate flux and separation factor as well. Indeed, the best performances of Matrimid® were found at 45 °C and 0.054 mbar, where a permeate flux and a separation factor of about 0.073 kg m-2 h-1 and 21.16, respectively, were obtained. Finally, the Matrimid PV performance was compared with other polymeric membranes at the azeotropic conditions.