A Theoretical Study of H2S and CO2 Interaction with the Single-Walled Nitrogen Doped Carbon Nanotubes

The physical adsorption of hydrogen sulfide and carbon dioxide gases on the zigzag (5,0) carbon nanotubes doped with nitrogen was investigated through the application of B3LYP/6-31G* at the level of theory on Gaussian 03 software. A variety of stable and high abundance structures of nitrogen doped carbon nanotubes were considered in order to study the interaction between the mentioned gases in different situations by taking rotates of sour gas molecules in the inner and outer walls. Features such as correction of energy adsorption, energy gap, dipole moment, charge distribution, conductors and energy barrier as well as the main parameters such as the gas adsorption energy on the nanotubes were obtained. The results suggest that the nitrogen atom in the structure of carbon nanotubes causes to increase the adsorption of hydrogen sulfide and carbon dioxide gases. Adsorption of hydrogen sulfide on the nanotubes is more effective than carbon dioxide. Moreover, for both gases the adsorption processes are thermodynamically favorable. These nanotubes can be economically used to separate sour gases from natural gases and to recover the sulfur.