Polymeric membranes with highly homogenized nanopores for ultrafast water purification

Abstract

Membrane nanofiltration is widely used in various chemical separation and water purification processes. However, obtaining high water permeance and high solute removal selectivity for achieving energetically efficient precise separation in nanofiltration membranes remains challenging due to their inherent pore heterogeneity. Here we introduce a cinnamate-mediated polymerization method to fabricate nanofiltration membranes with highly homogenized and well-tailored nanopores to address this challenge. Our experimental data and molecular dynamics simulation results show that cinnamate-mediated polymerization can manipulate monomer diffusion and intermolecular void size to create a homogenized and tailored selective layer in a highly homogenized membrane. The obtained membrane exhibited a high water permeance of 104.3 l m−2 h−1 bar−1, which is substantially higher than that of the pristine membrane synthesized without cinnamate mediation, superior molecular sieving ability, excellent salt/dye separation factor and good operational stability, outperforming state-of-the-art membranes. Overall, this work enables the design and fabrication of nanofiltration membranes that combine other mutually exclusive properties for energetically efficient water purification applications towards a sustainable water–energy nexus. Nanofiltration membranes play a crucial role in water purification, but it remains challenging to combine high water permeance and solute removal selectivity due to their inherent pore heterogeneity. Here the authors introduce a cinnamate-mediated polymerization method to resolve such a challenge, enabling energetically efficient water purification.