Organic solvent nanofiltration with nanoparticles aggregation based on electrostatic interaction for molecular separation

Organic solvent nanofiltration (OSN) has been regarded as a promising membrane-based separation technology with great potential in many fields. In this work, based on the strong electrostatic interaction between nano -particles (NPs) prepared by the quaternized P(VC-r-DMAEMA) (Q-PVD) and hydrolyzed polyacrylonitrile (HPAN) substrate membranes, separation nanochannels were successfully constructed on the surface of mem-branes by a one-step coating method. The types of the substrates and concentrations of NPs were optimized to obtain the proper performance. The surface morphology, chemical compositions, surface wettability, surface charge, and pore size were characterized. The obtained thin-film nanocomposite (TFN) membranes exhibited excellent stability in various common organic solvents, such as n-heptane, acetonitrile, ethanol, etc. Furthermore, composite membranes showed excellent retention for dyes with specific molecular weights, with a molecular weight cut-off (MWCO) of 825 Da. In particular, the rejection rates of Coomassie brilliant blue (BB) and Bengal rose red (RB) were 96.6% and 97.9%, respectively. Given the above characteristics, the composite membranes are expected to be used in the field of OSN.