Preparation and characterization of high-performance electrospun forward osmosis membrane by introducing a carbon nanotube interlayer

Electrospun nanofibrous mats have been widely used as substrate to develop novel membranes for forward osmosis (FO) application due to its ultralow structure parameter (S). However, their large pore sizes usually hinder the formation of satisfied active layer. In this work, a novel composite FO membrane was designed and prepared with a carbon nanotubes (CNTs) interlayer between the dense polyamide (PA) layer and electrospun porous polyacrylonitrile (PAN) support layer. The presence of CNT interlayer minified the pore size of the substrate to provide a better platform for PA layer growth which inhibited the diffusion of the draw solute, thus keeping a stable osmosis pressure gradient on both side of the thin-film composite (TFC) membrane. The results revealed that the optimized FO membrane with CNTs interlayer exhibited water flux of 83.55% higher and reverse salt flux of 75.58% lower than the unmodified membrane in the active layer facing draw solution (AL-DS) mode. Such better overall FO performance suggested that the addition of CNTs interlayer would offer a promising avenue to prepare high-performance electrospinning-based FO membrane for practical application.