2017/06/19 by Daiane Damasceno Borges, Cristiano F. Woellner, Borges, Daiane Damasceno +5
Engineering · Environmental Science · Materials Science · #FOS: Physical sciences #Graphene research and applications #Membrane Separation Technologies #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Nanopore and Nanochannel Transport Studies #Soft Condensed Matter (cond-mat.soft)
paper · pdf · doi:10.48550/arxiv.1706.06213
openalex publication_date 2017/06/19 · openalex created_date 2022/10/03 · openalex updated_date 2026/07/28
Experimental evidences have shown that graphene oxide (GO) can be impermeable\nto liquids, vapors and gases, while it allows a fast permeation of water\nmolecules. The understanding of filtration mechanisms came mostly from studies\ndedicated to water desalination, while very few works have been dedicated to\ndistilling alcohols. In this work, we have investigated the molecular level\nmechanism underlying the alcohol/water separation inside GO membranes. A series\nof molecular dynamics and Grand-Canonical Monte Carlo simulations were carried\nout to probe the ethanol/water and methanol/water separation through GO\nmembranes composed of multiple layered graphene-based sheets with different\ninterlayer distance values and number of oxygen-containing functional groups.\nOur results show that the size exclusion and membrane affinities are not\nsufficient to explain the selectivity. Besides that, the favorable water\nmolecular arrangement inside GO 2D-channels forming a robust H-bond network and\nthe fast water diffusion are crucial for an effective separation mechanism. In\nother words, the separation phenomenon is not only governed by affinities with\nthe membrane (enthalpic mechanisms) but mainly by the geometry and size factors\n(entropic mechanisms). We verified that the 2D geometry channel with optimal\ninterlayer distance are key factors for designing more efficient alcohol-water\nseparation membranes. Our findings are consistent with the available\nexperimental data and contribute to clarify important aspects of the separation\nbehavior of confined alcohol/water in GO membranes.\n