Molecular Dynamics Simulation of Carbon Dioxide in Single-Walled Carbon Nanotubes in the Presence of Water: Structure and Diffusion Studies

0445899 - ÚCHP 2016 RIV GB eng J - Journal Article
Svoboda, Martin - Brennan, J. K. - Lísal, Martin
Molecular Dynamics Simulation of Carbon Dioxide in Single-Walled Carbon Nanotubes in the Presence of Water: Structure and Diffusion Studies.
Molecular Physics. Roč. 113, 9-10 (2015), s. 1124-1136. ISSN 0026-8976. E-ISSN 1362-3028
R&D Projects: GA ČR(CZ) GA13-02938S
Institutional support: RVO:67985858
Keywords : carbon dioxide separation * density profiles * self-diffusion coefficients
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 1.837, year: 2015

We present a molecular dynamics study on the structure and diffusion of carbon dioxide in single-walled carbon nanotubes (SWCNTs) in the presence of water. We consider (10,10) and (15,15) SWCNTs of nanotube diameter 13.6 and 20.3 angstrom, respectively, with amounts of pre-adsorbed water equal to 0, 0.025, 0.1, and 0.2 g/cm(3). The density of the carbon dioxide in the SWCNTs corresponds to the maximum amount adsorbed at 300 K and 37.6 bar, as previously determined by grand canonical Monte Carlo simulation. We determine the structure of the confined fluids by calculating density distributions in the nanotube axial and radial directions, along with a second-order Legendre polynomial to elucidate their molecular orientations. The diffusion of the confined molecules is then analysed via both the overall time-dependent and space-dependent mean-square displacements in the nanotube axial direction. We find that the systems display distinct axial regions comprised of either pure carbon dioxide or water clusters that have been penetrated by CO2 molecules. The confined molecules form layered structures that strongly depend on the nanotube diameter.
Permanent Link: http://hdl.handle.net/11104/0247939