CO2 Sorption to Subsingle Hydration Layer Montmorillonite Clay Studied by Excess Sorption and Neutron Diffraction Measurements

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• 作者：Gernot Rother ; Eugene S. Ilton ; Dirk Wallacher ; Thomas Hau尾 ; Herbert T. Schaef ; Odeta Qafoku ; Kevin M. Rosso ; Andrew R. Felmy ; Elizabeth G. Krukowski ; Andrew G. Stack ; Nico Grimm ; Robert J. Bodnar
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2013
• 出版时间：January 2, 2013
• 年：2013
• 卷：47
• 期：1
• 页码：205-211
• 全文大小：331K
• 年卷期：v.47,no.1(January 2, 2013)
• ISSN：1520-5851

文摘

Geologic storage of CO₂ requires that the caprock sealing the storage rock is highly impermeable to CO₂. Swelling clays, which are important components of caprocks, may interact with CO₂ leading to volume change and potentially impacting the seal quality. The interactions of supercritical (sc) CO₂ with Na saturated montmorillonite clay containing a subsingle 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 鈮?.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 脜. 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 the excess sorption maximum, increasing CO₂ sorption with decreasing temperature is observed while the high-pressure sorption properties exhibit weak temperature dependence.