Enhancing interfacial adhesion of MXene nanofiltration membranes via pillaring carbon nanotubes for pressure and solvent stable molecular sieving

Highly permeable two-dimensional membranes are desirable for efficient molecular sieving and resource recovery through confined-space mass transfer via nanosheets restacking. However, their application requires addressing the swelling issue of 2D nanosheets in solvents, weak interfacial interaction between the adjacent nanosheets , and performance declination caused by over-restacking. This study reports an interfacial adhesion enhanced MXene membrane via pillaring carbon nanotubes (CNTs) combined with an upgraded post-treatment method consisting of fan-drying and air-drying. The combined drying method induces the nanosheets stacking to a partial-dehydration membrane structure, granting the neat MXene membrane with stable anti-swelling property. The strong π-π interactions and van der Waals forces of CNTs impel the close-fitting of MXene nanosheets for enhanced anti-swelling property and interfacial bonding force. The CNTs with confined-space mass transfer effect and high mechanical strength elevate the pillared MXene/CNTs-CTAB membrane performance for 5 times (the pure water permeance was enhanced from 20.09 L·m -2 ·h -1 ·bar -1 to 100.89 L·m -2 ·h -1 ·bar -1 ), endowing the membrane with high anti-pressure property. The membrane with precise molecular sieving property exhibits great potential in resource recovery and energy-saving.