Modeling infinite dilution and Fickian diffusion coefficients of carbon dioxide in water

We propose a new model for calculating infinite dilution diffusion coefficients for carbon dioxide and water mixtures. The model takes into account temperature dependence of the dipole moment of water and polarizability of CO₂, and fits experimental CO₂? H₂O data at low and high pressures with an accuracy of 4.9%. Remarkably, the proposed model also accurately predicts infinite dilution diffusion coefficients for other binary water mixtures where solute polarizability is close to that of CO₂, such as CH₄, C₂H₆, C₃H₈, and H₂S. Moreover, we present—to the best of our knowledge—the first predictions of composition‐based Fickian diffusion coefficients for CO₂? H₂O mixtures over the temperature range 298.15–413.15 K, and pressures up to 50 MPa. © 2010 American Institute of Chemical Engineers AIChE J, 2011