Antifouling, high-flux oil/water separation carbon nanotube membranes by polymer-mediated surface charging and hydrophilization

A facile approach to fabricating the antifouling, high-flux oil/water separation carbon nanotube (CNT) nanohybrid membranes was explored by polymer-mediated surface charging and hydrophilization through vacuumassisted self-assembly process. The controlled stacking of CNT imparted the membranes hierarchical nanostructure and high water permeation reaching 4592 L m(-2) h(-1) bar(-1), which was about 10 folds of commercial ultrafiltration membranes used for oil/water separation. Modifying CNT with a series of polymers endowed the membranes with different surface charge and hydrophilicity. The compact hydration layer was formed at the interface of water/membrane by the water trapped in the hierarchical nanostructure to prevent oil from adhering on the membrane surface. Hence, the polymer@CNT nanohybrid membranes possessed underwater superoleophobicity and low oil adhesive force. Moreover, the antifouling properties of as-prepared membranes were evaluated through filtration of oil-in-water emulsions with different surface charges and the results demonstrated that synergetically regulating the surface charge and hydrophilicity could tune the interactions between the foulants and membrane surface, which can efficiently inhibit the irreversible fouling, leading to 100% flux recovery ratio (FRR). The fabrication process of the polymer@CNT nanohybrid membranes with high water permeation, high separation efficiency and excellent antifouling properties may enlighten the great prospects for CNT-based materials in water separation and purification.