Metal-Organic Framework-Intercalated Graphene Oxide Membranes for Highly Efficient Oil/Water Separation

Graphene oxide (GO) has drawn extensive research interest in the fabrication of high-performance membranes. However, the original narrow interlayer distance of the GO membrane restrains the permeation flux. Herein, a metal-organic framework (MOF)@GO nanocomposite was synthesized by growing UiO-66-NH2 (N-UiO-66), a water-stable MOF, on the GO nanosheet followed by modification with poly(acrylic acid) (PAA). MOF-intercalated GO membranes were fabricated by intercalating N-UiO-66@GO-PAA nanocomposites into adjacent GO nanosheets through the vacuum-assisted self-assembly process. Because of low membrane thickness and enlarged interlayer distance, the membranes showed significantly increased water permeance (5067 L m(-2) h(-1) bar(-1) under optimum conditions) as well as high rejections for oil/water emulsion (>99.9%). Moreover, due to the hydrophilic chemical structures and typical micronano-topological structures, the MOF-intercalated GO membranes exhibited underwater superoleophobicity and antifouling property with a flux recovery ratio (FRR) above 80% after the three-cycle oil/water emulsion filtration test. Owing to the existence of multiple interactions, including electrostatic interactions and covalent and hydrogen bonds, the membranes exhibited satisfying operational and structural stability.