Metal-organic polyhedron membranes for molecular separation

Pore constructing in polyamide thin film composite (TFC) membranes through the mixed matrix strategy is of great interest to the production of nanofiltration membranes with high liquid permeance, however still facing challenges in fine control of filler distribution and filler-polymer interfacial microstructure. Herein, ZrT-1-NH2, one kind of water stable metal-organic polyhedron (MOP) molecular cages with intrinsic porosity, was exploited to construct porous MOP membranes through interfacial polymerization assembly for the first time. Continuous and defect-free separating layer can be facilely assembled on polymer ultrafiltration support by crosslinking ZrT-1-NH2 with trimesoyl chloride (TMC). The permanent pores inherited from ZrT-1-NH2 and the network pores originated from the mismatch in molecular volume of ZrT-1-NH2 and TMC offer the MOP membrane great water permeance (82.0 L·m−2·h−1·bar−1), as well as attractive dye rejection (99.7% for congo red) and dye/salt separation performance. Moreover, the ZrT-1-NH2/TMC composite membrane also exhibited good antifouling and antibacterial properties. The MOP membrane can well combine the developed porous structure of thin film nanocomposite membranes with the advantages of polyamide membranes in simplicity and scalability of membrane fabrication, showing good potential for application in practical molecular separations.