(376x) Organic Solvent Nanofiltration Via Zeolitic-Imidazolate Framework Membranes: Insights from Molecular Simulation

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 processes. Toward this end, switching from traditional distillation to membrane nanofiltration could reduce the energy cost and carbon emission to a large extent. In this study, three zeolitic-imidazolate framework (ZIF-25, -71 and -96) membranes were examined for their application in organic solvent nanofiltration (OSN) by molecular dynamics (MD) simulations. ZIF-25 membrane exhibits the highest flux and permeability for hydrophilic solvents due to its hydrophobic nature, despite the smallest window size among the three ZIFs; whereas ZIF-96 membrane shows the lowest flux due the strong interaction between its highly hydrophilic surface and solvent molecules. Good correlation between the combined solvent properties and solvent permeance is established. This study reveals that the chemical properties of the inner membrane surface, rather than the channel size, plays a more important role in determining the solvent flux during permeation process; and suggests that ZIFs are potential materials for organic solvent recovery.