The separation of an equimolar SF6-N-2 fluid mixture in a three-dimension porous carbon nanotube network has been investigated by means of classical molecular dynamics simulations at ambient conditions. The calculations performed have shown that the SF6 molecules are preferentially adsorbed over the nitrogen ones, yielding a high selectivity for sulfur hexafluoride. The adsorbed mixture is much denser than the bulk supercritical fluid, exhibiting a liquid-like behavior, which is reflected on the static structural, transport and dynamic properties of the confined mixture. (C) 2016 Elsevier B.V. All rights reserved.