Graphene oxide-based organic framework composites for membrane separation: Advances in design, properties, and environmental applications

Graphene oxide (GO)-based organic framework composites, particularly those integrating metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), have emerged as a promising class of materials for membrane-based water treatment. These hybrid systems rationally combine the structural tunability and high porosity of MOFs/COFs with the mechanical strength, large surface area, and functional versatility of GO, enabling improved separation performance compared to individual components. This review provides a comprehensive examination of GO/MOF and GO/COF composite membranes, emphasizing recent advances in their rational design, synthesis strategies (in-situ vs. ex-situ assembly), and structure-property relationships relevant to desalination, dye removal, heavy-metal capture, and wastewater purification. Particular attention is given to overcoming critical limitations such as GO swelling, restricted water permeance, and framework brittleness and how hybridization enhances pore structure, interfacial compatibility, wettability, and long-term operational stability. The environmental applications of these composites are critically discussed, focusing on the efficient removal of dyes, heavy metals, salts, pharmaceuticals, and oils from aqueous streams. Finally, the review outlines current challenges, such as fabrication scalability, interfacial engineering, and antifouling durability, and presents future research directions toward practical and sustainable deployment of GO-based organic framework membranes for sustainable water treatment.