Evading the permeance-selectivity trade-off dilemma in electrospray-assisted interfacial polymerization polyamide thin-film composite membrane through electrospinning nanofibers interlayer

The permeance-selectivity trade-off has been a long-standing problem in membrane separation process, which has limited the application potential of many membrane separation techniques. Here we introduce chitosan (CS) nanofibers interlayer to optimize the substrate to improve the separation performance of thin-film composite (TFC) membrane fabricated by electrospray-assisted interfacial polymerization (EIP). A series of characterizations were conducted and the results showed that the introduction of CS nanofibers prevented polyamide from invading the substrate's pores, and increased the content of interfacial amine monomer to promote interfacial polymerization (IP) reaction. At the same time, the enhanced confinement effect formed a rougher selection layer, providing more water transport paths and enhancing the hydrophilicity of the membrane. Compared with the control TFC membrane with polyethersulfone (PES) substrate, the TFC/CS/PES membrane with CS/PES composite substrate showed excellent separation performance, achieving 4.5 times increase in permeance while maintaining a high MgCl 2 rejection. Our work provides a new strategy for optimizing the substrate and improving the properties of the membranes.