Pore Occupancy Changes Water/Ethanol Separation in a Metal–Organic Framework—Quantitative Map of Coadsorption by IR

Abstract

The conventional distillation method to separate ethanol from water is energy-intensive and inefficient due to the presence of the azeotropic point of the binary system. Various processes have been proposed as potential separation techniques. Among them, preferential-adsorption-based separation is considered to be an efficient and energy-saving method for purification due to the easy regeneration under relatively mild conditions. In this work, the coadsorption of gaseous water and ethanol on a porous metal–organic framework [MIL-100(Fe)] in various proportions has been studied by coupling FTIR spectroscopy with in situ gravimetry (AGIR). The quantifications of coadsorbed water and ethanol on the MIL-100(Fe) have been performed under different conditions (P/Po). Ethanol is preferentially adsorbed on MIL-100(Fe). The vapor–liquid equilibrium of water/ethanol was altered when the pore volume of the MIL-100(Fe) was partially occupied. Our results suggest that the optimal conditions for the separation of H2O/E...