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Title: FT-IR study of CO 2 interaction with Na-rich montmorillonite

Here, carbon capture, utilization and storage (CCUS) in saline reservoirs in sedimentary formations has the potential to reduce the impact of fossil fuel combustion on climate change by reducing CO 2 emissions to the atmosphere and storing the CO 2 in geologic formations in perpetuity. At pressure and temperature (PT) conditions relevant to CCUS, CO 2 is less dense than the pre-existing brine in the formation, and the more buoyant CO 2 will migrate to the top of the formation where it will be in contact with cap rock. Interactions between clay-rich shale cap rocks and CO 2 are poorly understood at PT conditions appropriate for CCUS in saline formations. In this study, the interaction of CO 2 with clay minerals in the cap rock overlying a saline formation has been examined using Na + exchanged montmorillonite (Mt) (Na +-STx-1) (Na + Mt) as an analog for clay-rich shale. Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) was used to discern mechanistic information for CO 2 interaction with hydrated (both one- and two-water layers) and relatively dehydrated (both dehydrated layers and one-water layers) Na+-STx-1 at 35 °C and 50 C and CO 2 pressure from 0 5.9 MPa. CO 2-induced perturbationsmore » associated with the water layer and Na+-STx-1 vibrational modes such as AlAlOH and AlMgOH were examined. Data indicate that CO 2 is preferentially incorporated into the interlayer space, with relatively dehydrated Na +-STx-1 capable of incorporating more CO 2 compared to hydrated Na +-STx-1. Spectroscopic data provide no evidence of formation of carbonate minerals or the interaction of CO 2 with sodium cations in the Na +-STx-1 structure.« less
 [1] ;  [2] ;  [3] ;  [4] ;  [2] ;  [1]
  1. National Energy Technology Lab.-Regional Univ. Alliance (NETL-RUA) (United States); Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
  2. National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Applied Clay Science
Additional Journal Information:
Journal Volume: 114; Journal ID: ISSN 0169-1317
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
58 GEOSCIENCES; clay; CO2; FT-IR; carbon storage; caprock; global warming; infrared spectroscopyl carbon dioxide; montmorillonite
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1251756