[Cu2(bdc)2(bpy)]n/SPES-C mixed matrix membranes for separation of methanol/methyl tert-butyl ether mixtures

As a new type of filler for mixed matrix membranes (MMMs), metal-organic frameworks (MOFs) have received increasing attention. As a kind of MOFs, [Cu2(bdc)2(bpy)]n is successfully synthesized in this work and characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), wide angle X-ray diffraction (WAXRD), thermogravimetric analysis (TGA) and adsorption isotherms. [Cu2(bdc)2(bpy)]n is found to preferentially adsorb methanol (MeOH) over methyl tert-butyl ether (MTBE). For this reason, the [Cu2(bdc)2(bpy)]n is incorporated into sulfonated polyarylethersulfone with cardo (SPES-C) to form [Cu2(bdc)2(bpy)]n/SPES-C MMMs for the separation of MeOH/MTBE mixtures. Both the sorption selectivity and the diffusion selectivity are found to increase with the addition of [Cu2(bdc)2(bpy)]n leading to an increase in the separation factor. With increasing [Cu2(bdc)2(bpy)]n loading from 5 to 20 wt%, the flux increased up to 0.288 kg m−2 h−1 at 20 wt% loading. A threshold of [Cu2(bdc)2(bpy)]n loading is approximately 20 wt% where the flux remains almost constant regardless of further increasing the [Cu2(bdc)2(bpy)]n content. This work demonstrates an improved performance of the [Cu2(bdc)2(bpy)]n/SPES-C MMMs for the separation of MeOH/MTBE mixtures.