Gibbs ensemble simulation of H2S/CH4 separation in single-walled carbon nanotubes and silicon nanotubes

This study employed the Gibbs ensemble simulation method to investigate the adsorption and separation behavior of H 2 S/CH 4 mixtures in single-walled carbon and silicon nanotubes . The results demonstrated that the selectivity of silicon nanotubes increased consistently with pressure. While the H 2 S adsorption capacity of both carbon and silicon nanotubes increased with radius, silicon nanotubes exhibited overall lower selectivity compared to carbon nanotubes with the same chirality . Molecular configuration and local density distribution analyses further confirmed the preferential selectivity for H 2 S within the nanotubes. Key factors such as nanotube radius, pore volume , density, and temperature significantly influenced the adsorption behavior of gas mixtures . For high-pressure conditions, larger-radius nanotubes are recommended for adsorption operations . Although H 2 S/CH 4 selectivity decreases in larger nanotubes, they offer higher H 2 S adsorption capacity while maintaining effective separation. Low-temperature operations enhance adsorption selectivity and maximize H 2 S adsorption. Additionally, increasing the H 2 S concentration in the gas phase improved both H 2 S selectivity and adsorption capacity, particularly at lower temperatures. • Carbon nanotubes show a maximum H 2 S/CH 4 selectivity of 28.6 at 0.1 MPa. • Silicon nanotubes adsorb over 20 mmol/g H 2 S at high concentrations. • Low temperatures enhance H 2 S selectivity and adsorption in nanotubes.