Polyamide composite membrane with 3D honeycomb-like structure via acetone-regulated interfacial polymerization for high-efficiency organic solvent nanofiltration

High-performance organic solvent nanofiltration (OSN) membranes play an indispensable role in chemical separation processes. However, conventional OSN membranes such as thin-film composite polyamide (TFC-PA) membranes exhibit insufficient perm-selectivity. In this study, we developed a high-performance TFC-PA OSN membrane on a porous polyketone (PK) support by regulating interfacial polymerization (IP) with acetone as an organic co-solvent. The effect of the acetone co-solvent on the IP reaction and PA nanofilm morphology was investigated. Acetone serves as a regulator to mediate the IP reaction by facilitating the convective diffusion of monomers at the aqueous/organic interface. Furthermore, experimental results and molecular dynamics (MD) simulation analysis confirmed that the addition of acetone increases the width of the IP reaction zone, facilitates more violent exothermic reactions, and induces aggravated vaporization of acetone, resulting in the formation of a 3D honeycomb-like structure with an ultrahigh specific surface area. Compared with the TFC-PA membrane prepared by the conventional IP method, the TFC-PA-acetone membrane prepared by acetone-regulated IP (ARIP) exhibited 2.6 times higher methanol solvent permeance (7.0 LMH/bar) and comparable methyl orange rejection (94.6%). This work explores the underlying mechanism of acetone-regulated IP, providing a facile strategy for tailoring the membrane morphology with high-efficiency organic solvent nanofiltration.