Adsorption and separation of binary mixtures of noble gases on single-walled carbon nanotube bundles

Adsorption and separation of binary mixtures of noble gases including Argon (Ar), Krypton (Kr), and Xenon (Xe) on (10,10) single-walled carbon nanotube (SWCNT) bundles is simulated by extensive equilibrium molecular dynamics (MD). Adsorption energies, diffusion coefficients, activation energies, and radial distribution functions (RDFs) were calculated to address the thermodynamics, transport and structural properties of adsorption process. The simulation results of exposing Ar–Kr, Ar–Xe, and Kr–Xe mixtures on (10,10) SWCNT bundles at temperatures of 75, 150, and 300 K, show that amount of adsorption is strongly influenced by the applied temperature. On the other hand, RDF plots show obviously that separation of binary gaseous mixture is occurred, where the heavier noble gas is adsorbed more than the lighter one in a selective manner by bundle. It is seen that the increase in the applied temperature results in more separation. These findings provide us a possible application of carbon nanotubes (CNTs) as efficient nanomaterials for separation and storage of gas mixtures.

Graphical abstractAdsorption sites of Ar–Kr mixture inside (10,10) SWCNT bundle at T=75 K.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► In a mixture of noble gases, heavier noble gas is adsorbed more than the lighter one in a selective manner by carbon nanotubes. ► Carbon nanotubes can be considered as efficient nanomaterials for separation and storage of gas mixtures. ► Increase in the temperature is accompanied with the reduction of gas adsorption.