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.