Molecular Simulation of Capture of Sulfur-Containing Gases by Porous Aromatic Frameworks

Abstract

The adsorption of pure SO2 and H2S and their selective adsorption from various gas mixtures by porous aromatic frameworks (PAFs) are investigated using grand canonical Monte Carlo (GCMC) simulations and first-principles density functional theory calculations. The influence of functional groups including −CH3, −CN, −COOH, −COOCH3, −OH, −OCH3, −NH2, and −NO2 on the adsorption of pure SO2 and H2S as well as selective capture of SO2 and H2S from SO2/N2, SO2/CO2, H2S/CO2, and H2S/CH4 mixtures is explored. Our calculations indicate that PAFs exhibit high loadings for pure SO2 and H2S gas adsorption at 298 K up to 40 bar compare to other gases such as CH4 and CO2. Additional functional groups enhance gas uptake at low pressures because of stronger interaction with the gas molecules while reducing gas uptake at high pressures because of a decrease in pore volume. The contributions of electrostatic interactions to gas adsorption loadings are analyzed in GCMC simulations. Ideal adsorbed solution theory calculations...