Effect of the basal spacing on CH4 diffusion in kaolinite

Abstract

The effect of the basal spacing on CH4 diffusion in kaolinite was first studied by molecular dynamics (MD) simulations. The results illustrated that the CH4 self-diffusion coefficient and transport diffusion coefficient increased exponentially with the basal spacing. Kaolinite swelling and the intensity of the interaction between CH4 and the kaolinite surface are two main parameters that can significantly determine the CH4 diffusion. The larger the basal spacing of kaolinite, the smaller the amount of CH4 adsorbed under unit volume conditions, resulting in an increase in the space for CH4 diffusion. The intensity of the interaction between CH4 and the kaolinite surface is weaker at higher basal spacing. The simulation results of our study also provide details of the correlation between adsorption and diffusion.