Zeolitic Imidazolate Framework Membranes for Organic Solvent Nanofiltration: A Molecular Simulation Exploration

Organic solvents are intensively used in chemical and pharmaceutical industries. Their separation and recovery account for a significant portion of energy consumption and capital cost in many industrial processes. In this study, three microporous crystalline zeolitic imidazolate frameworks (ZIF-25, ZIF-71, and ZIF-96) are investigated as organic solvent nanofiltration (OSN) membranes by molecular simulations. The fluxes of five solvents (methanol, ethanol, acetone, acetonitrile, and n-hexane) are predicted. Despite the smallest aperture size among the three ZIFs, ZIF-25 exhibits the highest flux for polar solvents (methanol, ethanol, acetone, and acetonitrile) because of its hydrophobic nature, whereas hydrophilic ZIF-96 shows the highest flux for nonpolar n-hexane. The analysis of structural information and interaction energy reveals that the solvent–framework interaction is crucial to determine solvent permeation. Good correlations between solvent permeances and a combination of solvent properties are f...