Ethane/Ethylene adsorption on Carbon Nanotubes: temperature and size effect on separation capacity

ALBESA, ALBERTO; MIGONE, ALDO; VICENTE, JOSÉ; RAWAT, DINESH; RAFTI, MATÍAS

LANGMUIR

AMER CHEMICAL SOC

Lugar: Washington DC; Año: 2012 vol. 28 p. 1824 - 1832

0743-7463

We present the results of Monte Carlo simulations of the adsorption of single-componentethane and ethylene and of equimolar mixtures of these two gases on bundles of closed, single-walled carbon nanotubes. Two types of nanotube bundles were used in the simulations: homogeneous (i.e., those in which all the nanotubes have identical diameters) and heterogeneous (those in which nanotubes of different diameters are allowed). We found that at the same pressure and temperature more ethane than ethylene adsorbs on the bundles over the entire range of pressures and temperatures explored. The simulation results for the equimolar mixtures show that the pressure at which maximum separation is attained is a very sensitive function of the diameter of the nanotubes present in the bundles. Simulations using heterogeneous bundles yield better agreement with single-component experimental data for isotherms and isosteric heats than those obtained from simulations using homogeneous bundles. Possible applications of nanotubes to gas separation are discussed. We explored the effect of the diameter of the nanotubes on the separation ability of these sorbents, both for the internal as well as for the external sites. We found that substrate selectivity is a decreasing function of temperature.