Atomically detailed simulations were used to examine the adsorption and transport diffusion of CO2 and N2 in single-walled C nanotubes at room temperature, as a function of nanotube diameter. Linear and spherical models for CO2 were compared, showing that representing this species as being spherical had only a slight effect upon the computed diffusion coefficients. The results supported previous predictions that the transport diffusivities of molecules within C nanotubes were extremely rapid when compared with other porous materials. By examining C nanotubes as large as the (40,40) nanotube, it were possible to compare the transport rates predicted by the present calculations with experimental measurements. The predicted transport rates were in reasonable agreement with experiment.

Adsorption and Diffusion of Carbon Dioxide and Nitrogen through Single-Walled Carbon Nanotube Membranes. A.I.Skoulidas, D.S.Sholl, J.K.Johnson: Journal of Chemical Physics, 2006, 124[5], 054708 (7pp)