Optimizing Graphene Oxide Interlayer Spacing for Zeolitic Imidazolate Framework-8 Growth Toward Enhanced Shale Oil Separation.

Hydrocarbons derived from petroleum typically undergo energy-intensive fractional distillations. Membrane separation technologies with high permeability and selectivity offer an energy-efficient alternative. However, traditional membranes frequently encounter issues, such as swelling, deformation and diminished flux. Herein, quaternary ammonium salts are utilized to precisely control the interlayer spacing of graphene oxide (GO), facilitating the in situ growth of zeolitic imidazolate framework (ZIF-8) to develop ZIF-8-GO membranes for shale oil separation. The ZIF-8 nanoparticles serve to cross-link the GO layers, effectively expanding the interlayer spacing and preventing swelling in organic solvents. The resultant ZIF-8-GO membrane achieves nearly complete rejection of n-docosane in n-hexane with a solvent permeance of 16.4 ± 0.8 L m h bar, which is 71 times higher than that of commercial membranes such as the PuraMem membrane (0.23 L m h bar), and surpasses previously reported membranes. The membrane is capable of concentrating hydrocarbons containing fewer than 20 carbon atoms and maintains its separation efficiency when transitioning from simple binary mixtures to more complex shale oil. This research opens a new avenue for the integration of MOF-GO membranes into petroleum fractionation and provides a practical framework for the precise separation of shale oil.