High efficient water/ethanol separation by a mixed matrix membrane incorporating MOF filler with high water adsorption capacity

In order to promote the selective water permeation through porous filler, hydrophilic MOF-801 crystals with superior water adsorption ability were incorporated into chitosan (CS) matrix to fabricate MOF-801/CS mixed matrix membranes (MMMs) for pervaporation dehydration of ethanol. Both the experimental and molecular simulation results confirm the selective adsorption of water molecules in MOF-801 crystals, while the free volume and the lowest energy sorption sites analyses demonstrate the subdued diffusion of ethanol molecules through MOF-801. As a result, the porous structure in MOF-801 provides additional transport pathways for water molecules, and meanwhile makes the transport pathways of ethanol molecules more tortuous, thus achieving simultaneously enhanced flux and separation factor. The optimized membrane with MOF-801 loading of 4.8 wt% exhibits the total flux of 1937 g/m² h and separation factor of 2156.