Biomineralized metal-organic framework membrane with high-crystallinity for ultrafast molecular separation

Abstract

Metal-organic frameworks (MOFs) possess uniform and controllable pore structure, holding significant promise for the creation of efficient molecular separation membranes. Nevertheless, the challenge lies in constructing MOF membranes with high crystallinity and effectively utilizing their ordered crystal channels for molecular separation. Drawing inspiration from natural biomineralization processes, an in-situ trace graphene oxide (GO)-mediated crystallization strategy was adopted here to manipulate the crystallization of Zr-MOF (MIP-202(Zr)) membranes. GO nanosheets with abundant oxygen-containing groups could interact with the MOF precursor, furnishing numerous growth sites for the subsequent MOF growth, thereby facilitating the crystallization process during membrane formation within only 60 min. The resultant GO/MIP-202(Zr) composite membrane, composed of highly crystalline MIP-202(Zr) and trace amount of GO nanosheets, overcame the trade-off between MOF crystallinity and membrane formation. Benefiting from the interconnected pore structure, the resulting GO/MIP-202(Zr) membrane presented ultrahigh water permeability (1698.9 L m⁻² h⁻¹ bar⁻¹), surpassing that of the pure GO membrane (258.9 L m⁻² h⁻¹ bar⁻¹) by 6.5 times, while maintaining a comparable rejection for common dye molecules. Furthermore, the membrane displayed satisfied recyclability and structural stability. This study provides important perspectives for the fabrication of advanced membranes derived from MOFs aimed at enhancing molecular separation processes.