An X-ray investigation of the adsorption of methane, water, and their mixtures in carbon micropores

The adsorption of methane and water, and their coexisting state in carbon micropores were investigated by X-ray scattering measurements. The mechanisms of single-component adsorption of water and methane in the carbon micropores proceeded by cluster formation and micropore filling, respectively. The X-ray scattering of the coexisting state reveals that a mesoscopic phase separation occurred in the carbon micropores at 111 K because of the weak interaction between water and methane. At this low temperature, water molecules could not reform hydrogen bonds even with further adsorption of methane molecules. The X-ray scattering measurements provided detailed information on the coexisting state and can be used to study the temperature dependence of the phase behavior of the methane-water system during methane hydration formation in nanospaces.