Graphene oxide - Filled polyimide membranes in pervaporative separation of azeotropic methanol-MTBE mixtures

Graphene oxide (GO)-polyimide mixed matrix membranes (MMMs) were produced using chloroform by solvent evaporation. These membranes have been used, for the first time, in pervaporation (PV) for the separation of azeotropic methanol (MeOH)- methyl tert-butyl ether (MTBE) mixtures (14.3 and 85.7%, respectively). The effect of GO loading in the PV process was investigated. The PV experiments were carried out at different feed operating temperatures (25-45 degrees C). Furthermore, an analysis of the PV process through the Arrhenius relationship has been given. The feed temperature (in the range of 25-45 degrees C) affected the permeation of both components producing an increase in total permeate flux; however, separation factor was compromised. Indeed, the best permeate fluxes (ca. 0.091 kg m(-2) h(-1)) of the MMMs (4 wt% GO) were found at 45 degrees C, while the best separation factor (alpha = 28) was found at 1 wt% GO at 25 degrees C. In addition, the membranes were characterized by TGA, SEM, DSC, solvent uptake and mechanical test (Young's modulus). Finally, the performance of the GO-polyimide membranes was compared with other polymeric and MMMs membranes at the azeotropic conditions.