Ultrathin 12-nm-thick solvent-resistant composite membranes from biosourced dialdehyde starch and priamine building blocks

Biomass-based thin film composites (TFCs) fabricated only from abundant natural resources are emerging as next-generation organic solvent nanofiltration membranes. However, most of the existing membrane fabrication processes still use toxic chemicals, harsh solvents, and fossil-based supports. We report a plant-based, green TFC membrane based solely on sustainable resources. It is the thinnest defect-free nanofilm (only 12-nm-thick) fabricated only from natural resources. Dialdehyde starch was crosslinked with priamine at the interface of a water–eucalyptol solvent system. Interfacial polymerization occurred on a biodegradable cellulose acetate support obtained using phase inversion. The membrane has an ultrathin (12-nm-thick) selective layer, and the molecular weight cut-off and permeance were fine-tuned between 366 and 624 ​g ​mol⁻¹ and 7 and 23 ​L ​m⁻² ​h⁻¹ ​bar⁻¹, respectively. Stable nanofiltration performance under continuous crossflow filtration was achieved for seven days. The sustainability of the membrane fabrication platform was compared with those of other platforms. Our TFC membrane fabrication platform enables the conversion of biomass-based building blocks into high-value-added products.