Bird's nest -inspired fabrication of ZIF-8 interlayer for organic solvent nanofiltration membranes

Organic solvent nanofiltration (OSN), due to the characteristics of energy saving, mild operation conditions, and less waste generation, is an effective tool for purification, concentration and solvent exchange of high -value-added products. Introducing an interlayer containing ZIF-8, which features high surface areas and adjustable pore structures, can effectively regulate the interfacial polymerization process to optimize the performance of OSN membranes. However, due to the lack of nucleation sites with the substrate, it remains technologically challenging to design the ZIF-8 interlayer with structure and property persistence for interfacial polymerization under mild conditions. Inspired by the processes of birds' nesting, the processes of mixing PEG and ZIF precursor, coating, and fast heating are working here to stimulate the in-situ growth of ZIF-8 in a facile, green and ordered way. PEG allows uniform dispersion of ZIF-8 in one step and without involving organic solvents. Furthermore, the increased binding affinity between ZIF-8 and the membrane surface endows the composite membrane with uniform morphology and significantly enhanced stability. Overall, this strategy may provide a fast, eco-friendly, and scalable approach to design composite membranes with MOF and other nanoparticulate materials as interlayers.