Electrosprayed thin film nanocomposite polyamide nanofiltration with homogeneous distribution of nanoparticles for enhanced separation performance

The water transport channel brought about by nanoparticles enables to improve the permeability of thin film nanocomposite (TFN) membranes. For the TFN nanofiltration membranes fabricated by conventional interfacial polymerization, most nanoparticles are concentrated and agglomerate in the bottom of the separation layer. Therefore, the efficient utilization of nanoparticles for homogeneous water channel formation remains a challenge. In this study, we propose to prepare TFN polyamide nanofiltration membrane by nanoparticles involved electrosprayed interfacial polymerization. TiO2 nanoparticles with particle size <10 nm were dispersed in the aqueous phase for electrosprayed polymerization, and the nanoparticles were evenly distributed inside the polyamide separation layer, which regulated the uniform distribution of newly formed interfacial water transport channels around the nanoparticles in the separation layer. With adopting a low concentration of 0.015 wt% TiO2, the water flux of TFN membrane increased by >60 %, achieving a water flux of 101.5 L m−2 h−1 under 5 bar. Meanwhile, rejection for Na2SO4 was still kept as high as 91.1 %. This study provides a simple and controllable strategy for homogeneous distribution of water transport channels inside polyamide separation layer.