Enhanced salt rejection of hydroxylated BaTiO3/Ti3C2Tx@polyvinyl alcohol composite nanofiltration membranes under electrochemical assistance

The influence of surface charge density of nanofiltration (NF) membranes could due to enhanced electrostatic interaction through electrically assisted. In this study, the hydro-xylated BaTiO3/Ti3C2Tx (HBT)@polyvinyl alcohol (PVA) (HBTA) composite NF membranes were prepared by crosslinking HBT on the surfaces of NF membranes. The optimized HBTA-0.06 sample exhibited a water contact angle of 43.7 degrees, zeta potential of -13.73 mV (pH = 6.5), average effective pore size of 0.319 nm, and pure water permeance of 55.1 L center dot m-2 center dot h-1. At an applied electric field of 3 V, the rejection rates of LiCl, NaCl, KCl, RbCl, and MgCl2 determined for HBTA-0.06 reached 73.3%, 60.1%, 53.6%, 49.4%, and 59.8%, respectively. HBTA-0.06 has good stabilization properties that are especially advantageous for water purification, indicating good long-term filtration stability within 168 h. Furthermore, HBT doping significantly increased the charge density of the HBTA membranes and the re-jection efficiency of chloride salts, both chlorine radicals (center dot Cl) and hydroxyl radicals (center dot OH) generation pathways were proposed under electrochemical assistance. Hence, electrical assistance represents a novel and effective technique for enhancing the salt rejection properties of multifunctional composite NF membranes.(c) 2023 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.