Separation of gases from gas-water mixtures using carbon nanotubes

We investigate equilibrium transport of gas-water mixtures, such as CO ₂ -water, O₂ -water and H₂ -water mixtures, in carbon nanotubes using molecular dynamics simulations. Our results indicate that gases are selectively physisorbed in carbon nanotubes forming single-file gas chains. Once the single-file gas chains are formed, they prevent entry of water into the nanotube, suggesting that the presence of gas molecules can significantly affect the equilibrium transport of water in carbon nanotubes. The diffusion of single-file gas chains in nanotubes for gas-water mixtures is found to be lower compared to the single-file diffusion of gases in gas-only cases.