CO2 Adsorption to Sub-Single Hydration Layer Montmorillonite Clay Studied by Excess Sorption and Neutron Diffraction

Journal Article · Tue Jan 01 04:00:00 EST 2013 · Environmental Science & Technology

DOI:https://doi.org/10.1021/es301382y· OSTI ID:1059710

Rother, Gernot ^[1]; Ilton, Eugene ^[2]; Wallacher, Dirk ^[3]; Hauss, Thomas ^[3]; Schaef, Herbert ^[2]; Qafoku, Odeta ^[2]; Rosso, Kevin M. ^[2]; Felmy, Andrew ^[2]; Krukowski, Elizabeth G ^[1]; Stack, Andrew G ^[1]; Bodnar, Robert J ^[1]

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1. ORNL
2. Pacific Northwest National Laboratory (PNNL)
3. Helmholtz-Zentrum Berlin

Geologic storage of CO2 requires that the caprock sealing the storage rock is highly impermeable by CO2. Swelling clays, which are important components of caprocks, may react with CO2 under volume change, potentially impacting the seal quality. The interactions of scCO2 with Na saturated montmorillonite clay containing a sub-single layer of water in the interlayer region have been studied by sorption and neutron diffraction techniques. The excess sorption isotherms show maxima at bulk CO2 densities of 0.15 g/cm3, followed by an approximately linear decrease of excess sorption to zero and negative values with increasing CO2 bulk density. Neutron diffraction experiments on the same clay sample measured interlayer spacing and composition. The results show that limited amounts of CO2 are sorbed into the interlayer region, leading to depression of the interlayer peak intensity and an increase of the d(001) spacing by ca. 0.5 . The density of CO2 in the clay pores is relatively stable over a wide range of CO2 pressures at a given temperature, indicating the formation of a clay-CO2 phase. At low pressure increasing CO2 adsorption with decreasing temperature is observed while the high-pressure sorption properties exhibit weak or no temperature dependence. Supercritical fluids, sorption phenomena, carbon dioxide, carbon sequestration, caprock integrity

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1059710
• Journal Information: Environmental Science & Technology, Journal Name: Environmental Science & Technology Journal Issue: 1 Vol. 47; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

Supercritical fluids
caprock integrity
carbon dioxide
carbon sequestration
sorption phenomena