Interfacial Assembly of Graphene Oxide and UiO-66(OH)2 on Cellulose Acetate for Defect-Minimized, High-Flux Antifouling Separation of Oil Emulsions and Eriochrome Black T

Abstract

The membrane-based treatment of industrial wastewater streams containing surfactant-stabilized oil emulsions and synthetic dyes remains challenging, due to both membrane fouling and selectivity and the respective permeability–selectivity trade-offs. To that end, the application of metal–organic framework (MOF) modified membranes with continuous and defect-minimized structures is promising. Nevertheless, MOFs such as UiO-66 (with a high porosity and tunable chemistry) typically have poor processability and weak interfacial adhesion to the membrane’s polymer substrate. This study reports the development of a stable hybrid membrane in which graphene oxide (GO) regulates the deposition of hydroxyl-functionalized UiO-66(OH)2 MOF onto a commercial cellulose acetate membrane (GO-UiO-66(OH)2/CA). The oxygenated functional groups of GO that coordinate with the MOF’s Zr4+ nodes suppress the MOF particles’ aggregation, which in turn yields their uniform interfacial interaction with the polymer substrate. The developed GO-UiO-66(OH)2/CA membrane exhibited a high mechanical stability under bending, peeling, and hydraulic stress, along with increased porosity and enhanced hydrophilicity and underwater superoleophobicity. This resulted in more than 99% oil rejection while maintaining a high permeate flux. A similar trend was observed for the removal of aqueous Eriochrome Black T. Furthermore, the hybrid membrane architecture showed significantly reduced fouling while delivering >97% flux recovery even after repeated filtration cycles. The statistical analysis (ANOVA) indicated that the performance improvements were predominantly attributable to enhanced selectivity rather than to permeability loss, suggesting effective mitigation of the flux-selectivity trade-off. This work also demonstrates that GO-mediated interfacial regulation of MOF assembly is an effective strategy for constructing defect-minimized, antifouling hybrid CA membranes for multifunctional industrial wastewater treatment applications.