Adsorption and diffusion of sulfur dioxide and nitrogen in single-wall carbon nanotubes.

SO2 is a kind of harmful gas produced in the process of many industries. Carbon nanotubes is a widely used adsorbent material. The adsorption and diffusion behavior of equimolar ratio of SO2/N2 mixture gas in single-walled carbon nanotubes is studied by the way of molecular simulation. The results show that at a given temperature, SO2 adsorption capacity increases with the carbon nanotubes' diameter. On the other hand, the N2 adsorption capacity reduces with the diameter increase. For a given diameter, both of the SO2 and N2 adsorption amount reduced with the increase of temperature. The isosteric heat of SO2 in the nanotubes decreases with adsorption capacity rise. The self-diffusion coefficients of SO2 increase with the increasing of temperature. We also find that the gas molecular port migration frequency follows an increasing function with the temperature and the nanotube diameter, and SO2 port migration frequency is always higher than that of N2. The results may provide some theoretical guidance for SO2 adsorption and separation.