Bis-tris-based polyester nanofiltration membranes fabricated via one-step interfacial polymerization for desalination

Abstract

To obtain high-performance polyester (PE) nanofiltration (NF) membranes for desalination, most PE NF membranes are fabricated with high aqueous monomer concentration, or high reaction temperature, or long reaction time. The interfacial polymerization (IP) reaction rate between hydroxyl groups and acyl chloride groups is promoted but the cost of membrane fabrication is also increased. In this work, Bis-tris (bis(2-hydroxyethyl)-amino-tris(hydroxymethyl)methane) with rich hydroxyl groups is first utilized as an aqueous monomer to fabricate PE membranes under conventional IP conditions. The fabricated Bis-tris PE membranes feature strong hydrophilicity, excellent electronegativity, and ultra-thin selective layers, which are conducive to improving desalination performance. The optimized Bis-tris PE membrane shows excellent water permeance of 22.5 L m−2 h−1 bar−1 and a satisfactory Na2SO4 rejection of 96.9 %. Additionally, the Bis-tris PE membrane displays superior long-term stability and chlorine resistance under 96 h cross-flow filtration. This research enlightens the promising potential of Bis-tris as a novel and economic aqueous monomer for the fabrication of high-performance PE NF membranes.