(713h) Tunable Interlayer Channels in Graphene Oxide Membranes for Molecular Separations

Two-dimensional (2D) lamellar membranes are highly advantageous in molecular separations. However, manipulation of the physical and chemical structure of interlayer channel to realize high-performance separation is challenging. In this presentation, we will show how the ions, molecules and nanoparticles work on channel-tuning to obtain highly efficient graphene oxide (GO) membranes for gas and liquid separations. 1) By intercalating ion cross-linker, borate ions, GO membranes with favorable physical, chemical and water microenvironment for CO₂ molecules are created, rendering ordered size-selective nanochannels, plenty of fixed facilitated transport carriers and moderate water content to implement efficient CO₂ transport. 2) By intercalating molecular cross-linker, poly(ethylene glycol) diamines (PEGDA), we report GO membranes containing CO₂-philic and non-CO₂-philic nanodomains in the interlayer channels. Owing to the orderly stacking of nanochannels as well as the distributed nanodomains with moderate CO₂ affinity, high performance of CO₂ separation membrane in the dry state was reported. 3) By the in-situ intercalating and cross-linking of SiO₂ nanoparticles in the GO interlayers, we design dual-spacing channel GO membranes, that give high permeance, high rejection and high stability in organic solvent nanofiltration. The hydrophilic nanoparticles locally widen the interlayer channels to enhance the solvent permeance. In the alternating nanoparticle-free areas, the GO layers simultaneously bend, and the Ï€-Ï€ interactions keep the narrow and hydrophobic channel, promoting a high solute rejection.

References:

1) S. Wang, M. D. Guiver*, Z. Jiang*, et al. Energ. Environ. Sci. 2016, 9, 3107.2) S. Wang, M. D. Guiver*, Z. Jiang*, et al. Angew. Chem. Int. Ed. 2017, 56, 14246.3) S. Wang, S. Nunes*, et al. J. Mater. Chem. A, (2019). DOI: 10.1039/C8TA10872B.