Polyamide reverse osmosis membranes containing 1D nanochannels for enhanced water purification

Abstract

Thin-film composite (TFC) reverse osmosis (RO) membrane is the gold-standard for desalination and water reuse. Recent literature highlights the importance of polyamide (PA) rejection layer containing nanovoids to manipulate the water permeability and salt rejection. In this study, a facile template-assisted approach was applied to generate one-dimensional (1D) nanochannels in the polyamide rejection layer of RO membranes by preloading copper nanorods inside the PA layer followed by acid etching. In addition, a TFC RO membrane containing 0D nanovoids was also fabricated to compare the dimensional effect of nanochannels on membrane morphologies and performances. Specifically, the TFC-0D membrane only exhibited 61% higher water permeability compared to that of the control TFC, while the TFC-1D membrane showed 126% higher water flux with similar NaCl rejection, probably due to the dimensional improvement of the nanochannels inside the rejection layer. This templates-assisted approach paves a feasible way for fabricating high-performance next-generation RO membranes.