Melamine‐Based Microporous Organic Framework Thin Films on an Alumina Membrane for High‐Flux Organic Solvent Nanofiltration

Microporous polymer frameworks have attracted considerable attention to make novel separation layers owing to their highly porous structure, high permeability, and excellent molecular separation. This study concerns the fabrication and properties of thin melamine‐based microporous polymer networks with a layer thickness of around 400 nm, supported on an α‐alumina support and their potential use in organic solvent nanofiltration. The modified membranes show excellent solvent purification performances, such as n‐heptane permeability as high as 9.2 L m−2 h−1 bar −1 in combination with a very high rejection of approximately 99 % for organic dyes with molecular weight of ≥457 Da. These values are higher than for the majority of the state‐of‐the‐art membranes. The membranes further exhibit outstanding long‐term operation stability. This work significantly expands the possibilities of using ceramic membranes in organic solvent nanofiltration. Let's make it thin: High‐flux organic solvent nanofiltration membranes with enhanced separation performance are manufactured by fabricating a thin layer of microporous polymer networks composed of melamine and bis‐aldehyde on top of an α‐alumina ceramic support. The long‐term operation stability of the developed membrane is assessed and compared with state‐of‐the‐art membranes, thereby confirming its superior behavior.