Ionic liquids are being investigated in several labs as potential solvents for CO2 capture. These liquids can have high physical solubilities and selectivities for CO2. Moreover, chemical functionality can be added to the cation and/or anion to enhance the uptake of CO2 at low pressures via chemical complexation. In both situations, it is important to understand the physical solubility of CO2 and other species such as water and nitrogen in these liquids. In addition, the interfacial transport dynamics of how these gases cross from the gas phase to the liquid phase is important, as are other bulk thermodynamic and transport properties. We report results of Monte Carlo and molecular dynamics simulations directed at examining these questions. Specifically, we show how physical solubilities of gases are computed using rigorous free energy methods, and how the structure and composition of the ionic liquids affects these properties. Using large-scale interfacial molecular dynamics simulations, we compute the rates at which species cross the gas-liquid interface and deduce the equilibrium concentration profiles of different species across the interface. Finally, various bulk thermodynamic and transport properties such as heat capacities and viscosities are computed and results compared with available experimental data.

Solubility and interfacial transport of CO2 in ionic liquid systems

243rd National Meeting (2012)

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