Molecular simulation of the solubility of carbon dioxide in aqueous solutions of sodium chloride

The solubility of carbon dioxide in aqueous solutions of sodium chloride is studied by NVT- and NpT-Gibbs Ensemble Monte Carlo Simulations at 373, 393 and 433 K at pressures up to 10 MPa. The intermolecular forces are approximated by effective pair potentials (SPC and TIP4P models for water, the EPM2 potential model for carbon dioxide and several pair potentials for sodium chloride). Unlike interactions are estimated applying common combining rules. The simulation results are compared with experimental data. The experimentally observed “salting-out effect” is predicted by the simulation, but the decrease of the solubility of carbon dioxide caused by the presence of salt is overestimated. An improvement is achieved by introducing binary interaction parameters into unlike pair potentials. In some simulations the amount of dissolved sodium chloride was above the solubility limit. In these simulations crystal-like structures were observed in the liquid phase.