Dual‐Spatial Confinement Engineered Mixed Matrix Membranes Toward Ultra‐Efficient Isobutanol Separation

ABSTRACT Metal‐organic framework (MOF) based mixed‐matrix membranes (MMMs) present significant promise for biofuel recovery. However, they are still plagued by key challenges for practical applications, including poor dispersibility of fillers and insufficient selectivity. Herein, a novel dual‐spatial confinement strategy (D‐SCS) to design ionic liquid (IL)‐loaded graphene oxide (GO)/MOF‐polymer MMMs is proposed. MOFs are first confined onto the surface of GO to promote their ordered dispersion in the polymer matrix. Subsequently, ILs are incorporated into the MOF pores to enhance the intermolecular interactions between MOF and isobutanol. By optimizing the alkyl chain length and content of ILs in the MOF pores, the hydrophobicity and free volume of the filler can be balanced. With the application of D‑SCS strategy, the resulting membrane delivered a high permeation flux of 5049.1 g·m − 2 ·h − 1 and a separation factor of 61.01 at 50°C, which were enhanced by 200.6% and 223.5%, respectively, in comparison with the pristine polyether block amide (PEBA, Pebax 2533) membrane. Moreover, theoretical calculations indicate that isobutanol shows higher adsorption selectivity and faster diffusion in GO/MOF‑808‑BMIM/PEBA membrane than in MOF‑808/PEBA and other MOF‑808‑ILs/PEBA membranes. This work provides a new approach for the construction of high‐performance MMMs for efficient biofuel separation.