Interfacial tension and adsorption in the binary system ethanol and carbon dioxide: Experiments, molecular simulation and density gradient theory

Abstract

Data on the interfacial tension and adsorption are reported for the binary mixture of ethanol + carbon dioxide (CO2) as well as for pure ethanol. The data are obtained from experiments, molecular dynamics (MD) simulations, and density gradient theory in combination with the PC–SAFT equation of state (DGT + PC–SAFT). Experimental data of the interfacial tension are reported for 8 temperatures between 303 K and 373 K and pressures up to 6 MPa. The experimental data are compared to results from MD simulations and from DGT + PC–SAFT for which pressures up to 12 MPa are considered. From the experimental data, the relative adsorption of CO2 is obtained via the Gibbs adsorption equation using the PC–SAFT equation of state. Data on the relative adsorption of CO2 is also determined both from MD and DGT + PC–SAFT. The three data sets show good agreement. There is a substantial enrichment of CO2 at the interface. This is consistently predicted both by MD and DGT + PC–SAFT. The work shows that both MD and DGT + PC–SAFT are well suited for detailed studies of interfacial properties and that the independent methods yield similar predictions for those interfacial properties which cannot be studied experimentally.