A molecular level-based parametric study on the capture of hydrogen sulfide and carbon oxides from flue gas mixtures using Au nanopores

Identifying a means of effectively separating and adsorbing the harmful constituents from flue gas emissions is always crucial for the protection of human health and the environment. All-atom molecular dynamics were employed to analyze the dynamic behaviour of flue gas molecules in Au nanopores. The influences of various system temperatures, gas concentrations, and pore sizes on the adsorption conformation, diffusion coefficient, average adsorption energy, and adsorption probability of the flue gases inside an Au nanopore were examined. Results showed that when the temperature rose to 300∼400 K, the gaseous H2S constituent in the flue gas was swiftly adsorbed to the nanopore walls due to the strong H2S-Au interactions, enabling an effective separation of H2S from the flue gas. In addition, increases in pore size (d ≥ 40 Å) reduced the adsorption probability of CO2 and CO on the nanopore surfaces, which also promoted constituent separations of H2S from the flue gas. When the concentration of flue gas exceeded 6.6 mol/L, hydrogen bonds of H2O clusters and their networks entangled, impeding molecular diffusion and thereby reducing the functionality of nanopore-trapping molecules. The results presented in this paper provide a valuable reference for filter material design for flue gas depuration.