Classical Density Functional Theory Coupled to the SAFT-VR Mie Equation of State: Extension to Associating Fluids

We have proposed a theoretical framework that enables the extension of the SAFT-VR Mie Equation of State to inhomogeneous associating fluids, on the basis of the weighted density formalism of classical density functional theory. A Helmholtz energy functional well established in the literature has been incorporated to represent the effect of associating interactions. For water confined in carbon slit-pores of few nanometers, the model predicts density profiles in good agreement with molecular simulations performed in the grand-canonical ensemble. Adsorption and desorption isotherms are obtained for different pore sizes, and capillary condensation and hysteresis are investigated by mapping the grand-potential. The results of our calculations indicate that the most stable curve generally matches one of the curves of GCMC, either adsorption or desorption. Further comparison with another theoretical approach available in the literature indicates similar performance of the models.