Molecular simulation of penetration separation for ethanol/water mixtures using two-dimensional nanoweb graphynes

W Zhang and ZJ Xu and XN Yang, CHINESE JOURNAL OF CHEMICAL ENGINEERING, 27, 286-292 (2019).

DOI: 10.1016/j.cjche.2018.02.028

Graphyne is expected to be a new-class of highly-efficient sieving membranes due to its controllable uniform pore structure and ultrathin single-atom thickness. Herein, we computationally investigate the permeation performance of liquid ethanol-water mixtures across polyporous two-dimensional gamma-graphyne sheets. It was found that, in the mixture, ethanol with larger molecular diameter permeates faster through the graphyne pores than water. The simulations demonstrate that pristine graphynes could act as highly-efficient ethanol-pemiselective membranes for separation of ethanol-water mixtures, with ethanol permeability remarkably higher than conventional membranes. This separation mechanism is distinctly different from the molecular-size dependent sieving process. The stronger hydrophobic interfacial affinity between graphyne and ethanol makes ethanol molecules preferentially adsorb on graphyne surface and selectively penetrate through graphyne pores. This penetration mechanism provides new understanding of molecular transport through atomically thick two-dimensional nanoporous membranes and this work is expected to be valuable in the potential development of highly-efficient membranes for liquid-phase mixture separation. (C) 2018 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.

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