Biomimetic asymmetric structural polyamide OSN membranes fabricated via fluorinated polymeric networks regulated interfacial polymerization

Abstract

Organic solvent nanofiltration (OSN) as a high-efficient membrane separation technology has play an important role in chemical industrial separation, clean energy production, and high-value resources recycling, etc. Inspired by the asymmetric biological structure of Desert beetle, herein a novel kind of polymeric OSN membranes with asymmetric structure have been fabricated via fluorinated polymeric networks (FPNs) regulated interfacial polymerization. The FPNs were formed with m-phenylenediamine (MPD), dopamine (DA) and 1H,1H,2H,2H-Perfluorodecane-thiol (PFDT) via the Michael addition and Schiff-base reaction. The FPNs tailored thin-film composite membrane (FPN-TFC) with biomimetic asymmetric structure, e.g., much hydrophilic looser front surface and much hydrophobic denser rear surface, exhibits an optimum ethanol permeance ~15.7 L m−2 h−1.MPa−1 and high rejection ~99.5% for Rose Bengal (RB) dye molecules (test with 0.05 g L−1 RB ethanol solution at 25 °C under 1.5 MPa), which is almost 6 times higher than that of the conventional TFC membranes. Moreover, there is a good stability for the FPN-TFC membrane tested with different polar solvents in long-term operation process. Therefore, this work provides a guidance for the development of advanced polymeric OSN membranes with both high solvent permeability and solute selectivity, as well as good stability in OSN process, which would have broad application prospects in chemical and other industrial fields.