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We have studied the mechanism of intercalation and methane adsorption from a H2O/CH4/CO2mixture on a prototypical swelling shale component, Ca–montmorillonite. We employed ab initiomolecular dynamics simulations at 323 K and 90 bar to obtain molecular level information on adsorption energetics, speciation, and structural and thermodynamic properties. Interaction of CH4with surface Lewis acidic sites (Ca2+, surface OH) results in large induced dipoles (∼1 D) that lead to relatively strong adsorption energies compared to interactions of the normally apolar CH4that level off once a CH4layer is formed. Intercalated CH4, also exhibits large induced dipoles at lower hydration levels, when the interaction with Ca2+cations are less hindered. CO2displaces CH4in the coordination sphere of the cations (in the interlayer) or on the surface, thereby driving CH4extraction. Our simulations indicate that there is an optimal pressure range (∼70–90 bar) where scCO2-facilitated CH4extraction will be maximized.

Adsorption isotherms of pure gases present in flue gas including CO2, N2, SO2, NO, H2S, and water were studied using prussian blues of chemical formula M3[Co(CN)6]2·nH2O (M = Co, Zn) using an HPVA-100 volumetric gas analyzer and other spectroscopic methods. All the samples were characterized, and the microporous nature of the samples was studied using the BET isotherm. These materials adsorbed 8−10 wt % of CO2at room temperature and 1 bar of pressure with heats of adsorption ranging from 200 to 300 Btu/lb of CO2, which is lower than monoethanolamine (750 Btu/lb of CO2) at the same mass loading. At high pressures (30 bar and 298 K), these materials adsorbed approximately 20−30 wt % of CO2, which corresponds to 3 to 5 molecules of CO2per formula unit. Similar gas adsorption isotherms for SO2, H2S, and NO were collected using a specially constructed volumetric gas analyzer. At close to 1 bar of equilibrium pressure, these materials sorb around 2.5, 2.7, and 1.2 mmol/g of SO2, H2S, and NO. In particular, the uptake of SO2and H2S in Co3[Co(CN)6]2is quite significant since it sorbs around 10 and 4.5 wt % at 0.1 bar of pressure. The stability of prussian blues before and after trace gases was studied using a powder X-ray diffraction instrument, which confirms these materials do not decompose after exposure to trace gases.