Citric acid-functionalized graphene oxide membranes with enhanced stability and permeability for high-efficiency separation

GO membranes face challenges in aqueous stability and water permeability due to narrow interlayer spacing. CCA was introduced as a multifunctional intercalator to construct expanded nanochannels between GO nanosheets. The resulting GC-2 membrane achieved a pure water flux of 130.1 L m^-2 h^-1, six times higher than pure GO, while maintaining >99% rejection of MG and high salt tolerance. The GC-2 membrane also enabled selective separation of dye mixtures, permitting MO permeation while retaining EBT. This work demonstrates a scalable strategy for designing high-flux, high-selectivity membranes applicable to dye recovery and complex wastewater treatment.