title: Predicting helium and neon adsorption and separation on carbon nanotubes by Monte Carlo simulation.
abstract: The adsorption of helium and neon mixtures on single-walled carbon nanotubes (SWCNTs) was investigated at various temperatures (subcritical and supercritical) and pressures using canonical Monte Carlo (CMC) simulation. Adsorption isotherms were obtained at different temperatures (4, 40, 77 and 130 K) and pressures ranging from 1 to 16 MPa. Separation factors and isosteric enthalpies of adsorption were also calculated. Moreover, the adsorption isotherms were obtained at constant specific temperatures (4 and 40 K) and pressures (0.2 and 1.0 MPa) as a function of the amount adsorbed. All of the adsorption isotherms for an equimolar mixture of helium and neon have a Langmuir shape, indicating that no capillary condensation occurs. Both the helium and the neon adsorption isotherms exhibit similar behavior, and slightly more of the helium and neon mixture is adsorbed on the inner surfaces of the SWCNTs than on their outer surfaces. More neon is adsorbed than helium within the specified pressure range. The data obtained show that the isosteric enthalpies for the adsorption of neon are higher than those for helium under the same conditions, which means that adsorption of neon preferentially occurs by (15, 15) SWCNTs. Furthermore, the isosteric enthalpies of adsorption of both gases decrease with increasing temperature.
authors.affiliation: Department of Chemistry, Faculty of Science, Shahid Chamran University, Ahvaz, Iran. zb.nojini@gmail.com
authors.forename: Zabiollah
authors.initials: Z
authors.lastname: Bolboli Nojini
authors.forename: Amir
authors.initials: A
authors.lastname: Abbas Rafati
authors.forename: Seyed
authors.initials: S
authors.lastname: Majid Hashemianzadeh
authors.forename: Sepideh
authors.initials: S
authors.lastname: Samiee
mesh_terms: D000327:Adsorption; D000465:Algorithms; D003198:Computer Simulation; D006371:Helium / Q000737:chemistry*; D009010:Monte Carlo Method; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009356:Neon / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature
chemical_list: D037742:Nanotubes, Carbon; D006371:Helium; D009356:Neon