Metal-organic framework membranes for gas separation and pervaporation

Upon the development of metal-organic framework (MOF), great efforts have been made for the fabrication of polycrystalline MOF membranes for gas separations as well as for liquid phase separations. In this chapter we first discuss the state-of-the-art pure MOF membranes for gas separations, involving mixtures of H2/N2, H2/CH4, H2/CO2, CO2/N2, CO2/CH4, and C3H6/C3H8. We summarize the performance of pure MOF membrane in Robeson plots, in which we compare the permeability and selectivity of various types of pure MOF membranes and comment on the unique properties from the high-performing ones. We also review the computational efforts in the performance prediction of pure MOF membranes. We also lay out various computational approaches to identifying MOF materials with high selectivity for various gas mixtures. We point out critical structural properties that render MOFs with high separation performance. Finally, we summarize reports on pure MOF membranes for liquid phase separations via membrane pervaporation. We discuss pure MOF membranes for the separation of water and alcohols as well as those for the separation of nonalcohol small organic molecules. From the comprehensive literature review, we provide the outlook on pure MOF membranes for gas separations as well as for pervaporation.