(754f) Confined Water Determines Transport Properties of Guest Molecules in Narrow Pores

We computed the transport of methane through 1-nm wide slit-shaped pores carved out of solid silica, magnesium oxide, alumina and muscovite. The pores were filled with water. The results show that the methane permeability through the hydrated pores is strongly dependent on the solid substrate, which determines local properties of confined water such as molecular structure, hydrogen bond network, and density fluctuations. The latter are found to be for the most part responsible for the pronounced differences observed. The simulations are extended to multi-component systems representative of natural gas, containing methane, ethane, and H₂S. A multi-scale approach, based on a Smoluchowski one-dimensional model, was then implemented to reproduce the molecular-level results for short pores. When verified by experiments, our simulations could have important implications in applications such as natural gas sweetening and predictions of methane migration through hydraulically fractured shale formations.