Co-gallate MOF Membrane for Efficient Pervaporation Separation of MeOH from MTBE

Abstract

The pervaporation (PV) technology is attractive for azeotrope component separation of the MeOH/MTBE mixture due to the reduced energy and cost relative to the traditional ternary distillation process. However, the membrane separation performance is largely affected by its microstructure including pore size and shape as well as its surface properties such as hydrophilicity. Herein, we report a Co-gallate MOF membrane that features preferential adsorption and diffusion of methanol (MeOH) relative to the methyl tert-butyl ether (MTBE) molecules during the PV separation process. The high-quality Co-gallate MOF membrane has been prepared by introducing a regulator of KOH. The MeOH flux of the Co-gallate MOF membrane was 0.565 kg m−2 h−1 and the separation factor was up to 721 at 15 wt% MeOH/MTBE feed composition. It is worth noting that the separation performance exceeds most of the reported membrane materials for MeOH/MTBE separation in the PV process. Furthermore, the separation performance of the Co-gallate MOF membrane for MeOH/MTBE mixtures remained almost unchanged over 70 h, indicating the reliable long-term stability of the membrane. Thus, the Co-gallate MOF membrane demonstrated a potential practical application for MeOH/MTBE separation.