Modelling adsorption using an augmented two-dimensional statistical associating fluid theory: 2D-SAFT-VR Mie

Abstract

We present an extension of the SAFT-VR Mie approach to model adsorption of molecular fluids based on a two-dimensional (2D) approximation to describe the adsorbed fluid. Analytical results are provided for the first- and second-order perturbation terms of the free energy for the 2D system. The adsorption model is based on the assumption that the particle pair interactions in the adsorbed and bulk phases are described with the same Mie potential exponents ${\lambda }_{\mathrm{a}}$ and ${\lambda }_{\mathrm{r}}$, in contrast with the square-well version of the 2D-SAFT-VR approach in which it is considered necessary to modify the attractive ranges of the SW interactions. This important difference between the two approaches leads to a reduction in the number of molecular parameters to be determined. In order to demonstrate the performance of the 2D-SAFT-VR Mie approach, we present results for the the modelling of carbon dioxide (CO₂) and methane (CH₄) adsorbed onto dry coal.

GRAPHICAL ABSTRACT

Keywords:

• SAFT-VR-Mie
• adsorption
• 2D fluids

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was carried out in part as an activity of the Qatar Carbonates and Carbon Storage Research Centre (QCCSRC). We gratefully acknowledge funding from QCCSRC provided jointly by Qatar Petroleum, Shell, and the Qatar Science and Technology Park. We thank the Universidad de Guanajuato (México) for financial support via DAIP-UG projects CIIC 1143/2016 and CIIC 292/2018. GCV is also thankful to the University of Guanajuato for a students mobility grant for a research visit to Imperial College London. We are also grateful to the Engineering and Physical Sciences Research Council (EPSRC) of the UK for support to the Molecular Systems Engineering group at Imperial College London through Grants EP/EP016340 and EP/J014958.