Organic solvent nanofiltration membrane with improved permeability by in-situ growth of metal-organic frameworks interlayer on the surface of polyimide substrate

Organic solvent nanofiltration (OSN) has a good application prospect in the field of organic solvent separation, but low organic solvent permeance is the main obstacle restricting its application. This work reports a thin film composite (TFC) nanofiltration membrane prepared by interfacial polymerization (IP) on the HKUST-1 MOF interlayer grown in situ on a crosslinked polyimide (PI) substrate. The MOF interlayer improves the hydrophilicity and porosity of the support membrane. In addition, the MOF interlayer controls the diffusion of piperazine (PIP) during the IP process, which induced to form a thin and highly crosslinked polyamide (PA) separation layer. The increased effective membrane area and the reduced thickness of PA separation layer resulted in a methanol permeation flux up to 9.59 L·m−2·h−1·bar−1, while maintaining the rejection of the negatively charged Brilliant Blue G 250 dye (MW = 858.05 g·mol−1) at 98.8%. Furthermore, the stability of the TFC membranes in polar aprotic solvents such as N, N-dimethylformamide highlights their potential for OSN applications in chemical industries.