Issue 29, 2015

Water–methanol separation with carbon nanotubes and electric fields


Methanol is used in various applications, such as fuel for transportation vehicles, fuel cells, and in chemical industrial processes. Conventionally, separation of methanol from aqueous solution is by distillation. However, this method consumes a large amount of energy; hence development of a new method is needed. In this work, molecular dynamics simulations are performed to investigate the effect of an electric field on water–methanol separation by carbon nanotubes (CNTs) with diameters of 0.81 to 4.07 nm. Without an electric field, methanol molecules fill the CNTs in preference to water molecules. The preference of methanol to occupy the CNTs over water results in a separation effect. This separation effect is strong for small CNT diameters and significantly decreases with increasing diameter. In contrast, under an electric field, water molecules strongly prefer to occupy the CNTs over methanol molecules, resulting in a separation effect for water. More interestingly, the separation effect for water does not decrease with increasing CNT diameter. Formation of water structures in CNTs induced by an electric field has an important role in the separation of water from methanol.

Graphical abstract: Water–methanol separation with carbon nanotubes and electric fields

Supplementary files

Article information

Article type
06 Apr 2015
17 Jun 2015
First published
19 Jun 2015
This article is Open Access
Creative Commons BY license

Nanoscale, 2015,7, 12659-12665

Author version available

Water–methanol separation with carbon nanotubes and electric fields

Winarto, D. Takaiwa, E. Yamamoto and K. Yasuoka, Nanoscale, 2015, 7, 12659 DOI: 10.1039/C5NR02182K

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