Adsorption and diffusion behavior of CO2/H-2 mixture in calcite slit pores: A molecular simulation study

XX Deng and QG Zhang and ZP Zhang and QB Li and XY Liu, JOURNAL OF MOLECULAR LIQUIDS, 346, 118306 (2022).

DOI: 10.1016/j.molliq.2021.118306

The adsorption and diffusion of gases in porous media are fundamental phenomena that find widespread application in the energy and chemical industries. In this study, we used Grand Canonical Monte Carlo and molecular dynamics simulation methods to evaluate the adsorption and diffusion properties of CO2 and H-2 in the calcite silt-like pores. We report the influence of pressure, pore size, and temperature on adsorption isotherms (i.e., total, absolute, and excess) and diffusion coefficients (i.e., self-diffusion, Fick transport diffusion, and Maxwell-Stefan diffusion). The results reveal a greater CO2 adsorption capacity compared to H-2 and the easy absorption of the oxygen atoms of CO2 onto the surface of calcite. The adsorption capacities of CO2 and H-2 increased together with the pressure, and the pore size had little effect on the absolute adsorption capacity and density distribution of the pure compounds. The interaction energy between calcite and CO2/H-2 showed that the calcite had greater affinity for CO2 than for H-2. The CO2 diffusion coefficients were smaller than those of H-2. The diffusion coefficients of CO2 and the mutual diffusion coefficients of the gas mixture increased with increasing pressure before stabilizing. In contrast, the diffusion coefficients of H-2 decreased with an increase in pressure. (C) 2021 Elsevier B.V. All rights reserved.

Return to Publications page