Competitive sorption of CO2 and H2O in 2:1 layer phyllosilicates. (15th July 2015)

• Record Type: Journal Article
• Authors: Schaef, Herbert T.; Loring, John S.; Glezakou, Vassiliki-Alexandra; Miller, Quin R.S.; Chen, Jeffrey; Owen, Antoinette T.; Lee, Mal-Soon; Ilton, Eugene S.; Felmy, Andrew R.; McGrail, B. Pete; Thompson, Christopher J.
• Is Part Of: Geochimica et cosmochimica acta. Volume 161(2015:Jul. 15)
• Page Start: 248
• Page End: 257
• Publication Date: 2015-07-15
• Subjects: Geochemistry -- Periodicals; Meteorites -- Periodicals; Géochimie -- Périodiques; Météorites -- Périodiques; Geochemie; Astrochemie; Electronic journals; 551.905
• DOI: 10.1016/j.gca.2015.03.027
• Languages: English
• ISSNs: 0016-7037

Abstract

Graphical abstract: Abstract: Expandable clays such as montmorillonite have interlayer exchange sites whose hydration state can be systematically varied from near anhydrous to almost bulk-like water conditions. This phenomenon has new significance with the simultaneous implementation of geological sequestration and secondary utilization of CO2 to both mitigate climate warming and enhance extraction of methane from hydrated clay-rich formations. In this study, the partitioning of CO2 and H2 O between Na-, Ca-, and Mg-exchanged montmorillonite and variably hydrated supercritical CO2 (scCO2 ) was investigated using in situ X-ray diffraction (HXRD), infrared (IR) spectroscopic titrations, and quartz crystal microbalance (QCM) measurements. Density functional theory calculations provided mechanistic insights. Structural volumetric changes were correlated to quantified changes in sorbed H2 O and CO2 concentrations as a function of percent H2 O saturation in scCO2 . Intercalation of CO2 is inhibited when the clay is fully collapsed (dehydrated interlayer), peaks sharply with the introduction of some H2 O and partial expansion of the interlayer region, and then decreases systematically with further hydration of the clay. This behavior is discussed in the context of recent theoretical calculations of the montmorillonite H2 O–CO2 system.