Nanocellulose–Graphene Derivative Composite Membranes: Recent Advances, Functional Mechanisms, and Water Purification Applications

Nanocellulose-graphene derivative (NC-GD) composite membranes have attracted increasing attention as sustainable separation materials with high specific surface area, mechanical strength, and controllable interfacial chemistry. This review contextualizes the development of NC-GD composite membranes within advanced membrane technologies and summarizes recent progress in their structural design, interfacial mechanisms, and water purification applications. The synthesis and assembly of nanocellulose and graphene derivatives are analyzed, focusing on how surface functionalization regulates interfacial compatibility and transport pathways. Comparative evaluation of fabrication approaches-including vacuum filtration, layer-by-layer assembly, and solution casting-highlights their influence on structural uniformity and permeability. Key findings indicate that hydrogen bonding, electrostatic coupling, and π-π interactions govern the layer stability of composite membranes and the synergistic formation of nanochannels (by NC and GDs), thereby enabling efficient water permeation, selective separation, and fouling resistance. Overall, NC-GD membranes exhibit outstanding performance in heavy metal adsorption, dye removal, oil-water separation, and antibacterial treatment, representing a promising platform for next-generation sustainable water purification systems.