LAUSR

Molecular dynamics simulation was used to study the role of water in the intercalation of CO2 with a model Mg–Al–Cl-hydrotalcite mineral at ambient pressure and temperature. The ClayFF force field was used along with a model Mg–Al–Cl-hydrotalcite containing different amounts of water (H2O) and carbon dioxide (CO2) molecules in its interlayer spacing. It was observed that high CO2 content, say 3.85 mmol g–1, could be achieved at low water concentrations or even without the presence of water. However, high water concentrations (e.g., 2 H2O molecules/hydrotalcite unit cell, the maximum allowed water concentration observed experimentally) could also yield similar CO2 content, but in this case, the presence of water led to a significant interlayer spacing expansion (from 23.0 A (no water) to 28.5 A). The expansion was likely due to the change in the orientation distribution of the CO2 molecules. Analyzing the orientation of CO2 molecules revealed that they preferred to orientate parallel to the mineral surface...