MXene-induced amine enrichment for simultaneous high flux and rejection in TFN membranes via one-step co-deposition

Polyamide nanofiltration membranes have been widely used in seawater desalination and water treatment. Enhancing water permeability while sustaining high rejection in nanofiltration (NF) membranes has garnered significant research interest. In this study, we combined the MXene intermediate layer and amine monomer enrichment by one-step co-deposition strategy and then fabricated MXene-based composite nanofiltration film (MCF) via interfacial polymerization (IP). Ethylenediamine (EDA) adsorbed onto MXene surfaces via hydrogen bonding or electrostatic interactions, thereby improving MXene dispersion, enhancing interfacial bonding with the polyamide (PA) selective layer, and optimizing the composite membrane structure. MXene doping enhanced surface roughness, hydrophilicity, and electronegativity of the composite membrane, strengthening Donnan exclusion and size sieving. The optimized membrane sample has a water permeability of 103.8 L m -2 h -1 at 6 bar, rejection rate for methylene blue (MB) and Congo red (CR) > 99%, and a high rejection rate of metal ions (Mg 2+ , Cu 2+ , and Ca 2+ > 93%, Na + >83%). This membrane overcomes the traditional trade-off effects between water permeance and salt selectivity, achieving simultaneous improvement in water flux and rejection rate. This work is expected to provide a new way for the preparation of nanofiltration membranes with excellent performance.