TY  - JOUR
PB  - AMER CHEMICAL SOC
ID  - discovery10048644
N2  - In situ X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) experiments combined with molecular dynamics simulations using the grand canonical ensemble [grand canonical molecular dynamics (GCMD)] show that the cation size, charge, and solvation energy play critical roles in determining the interlayer expansion of smectite clay minerals when exposed to dry supercritical scCO2 (scCO2) under conditions relevant to petroleum reservoirs and geological CO2 sequestration conditions. The GCMD results show that the smectite mineral, hectorite, containing interlayer alkali and alkaline earth cations with small ionic radii and high solvation energies (e.g., Na+ and Ca2+) does not intercalate CO2 and that the fully collapsed interlayer structure is the most energetically stable configuration. With Cs+ and Ba2+, the monolayer structure is the stable configuration, and CO2 should spontaneously enter the interlayer. With Cs+, there is not even an energy barrier for CO2 intercalation, in agreement with the XRD and NMR results. 13C NMR and simulations show that the average orientation of the intercalated CO2 is with their O?C?O axes parallel to the basal clay surface and that they undergo a rapid rotation about an axis perpendicular to the main molecular axis. The simulations show that the strength of the interaction between the exchangeable cation and the clay structure dominates the intercalation energetics in dry scCO2.
KW  - Science & Technology
KW  -  Physical Sciences
KW  -  Technology
KW  -  Chemistry
KW  -  Physical
KW  -  Nanoscience & Nanotechnology
KW  -  Materials Science
KW  -  Multidisciplinary
KW  -  Chemistry
KW  -  Science & Technology - Other Topics
KW  -  Materials Science
KW  -  X-RAY-DIFFRACTION
KW  -  NUCLEAR-MAGNETIC-RESONANCE
KW  -  NATURAL ORGANIC-MATTER
KW  -  MOLECULAR-DYNAMICS
KW  -  IN-SITU
KW  -  SMECTITE CLAYS
KW  -  EXCHANGED MONTMORILLONITE
KW  -  NA-MONTMORILLONITE
KW  -  WATER-STRUCTURE
KW  -  LAYER CHARGE
EP  - 4402
AV  - public
Y1  - 2018/02/08/
TI  - Clay Swelling in Dry Supercritical Carbon Dioxide: Effects of Interlayer Cations on the Structure, Dynamics, and Energetics of CO2 Intercalation Probed by XRD, NMR, and GCMD Simulations
SN  - 1932-7447
UR  - https://doi.org/10.1021/acs.jpcc.7b12270
A1  - Loganathan, N
A1  - Bowers, GM
A1  - Yazaydin, AO
A1  - Schaef, HT
A1  - Loring, JS
A1  - Kalinichev, AG
A1  - Kirkpatrick, RJ
JF  - Journal of Physical Chemistry C
VL  - 122
SP  - 4391
N1  - This version is the author accepted manuscript. For information on re-use, please refer to the publisher?s terms and conditions.
IS  - 8
ER  -