Molecular Thermodynamics of Adsorption using Discrete-Potential Systems

Abstract

Résumé -Thermodynamique moléculaire de l'adsorption à l'aide de systèmes à potentiels discrets -Un modèle thermodynamique de fluide basé sur des potentiels discrets a été développé pour décrire l'adsorption sur une surface solide. À l'aide de théories de la perturbation, comme la théorie SAFT (Statistical Associating Fluid Theory), et la théorie DPT (Discrete Potential Theory), en combinaison avec la simulation moléculaire, nous avons formulé une approche bi-dimensionnelle qui permet de décrire des systèmes qui intéressent l'industrie pétrolière, tels les isothermes d'adsorption du CO 2 ou des asphaltènes. Abstract -Molecular Thermodynamics of Adsorption using Discrete-Potential Systems

2D-SAFT-VR approach to study of the adsorption isotherms for binary mixtures

“…The correspond mixture is nitrogen 40 %-carbon dioxide 60 % a specific application to model adsorption of three different mixture systems: CH 4 -N 2 , CH 4 -CO 2 and CO 2 -N 2 . Adsorption isotherms for these systems are well reproduced when compared to experimental data (Sudibandriyo et al 2003), using pure-compound parameters studied previously elsewhere (Martínez et al 2007 andJiménez et al 2008), and for high bulk-pressure values. Although the thermodynamic approach followed here, based on the use of Eq.…”

“…Absolute adsorption of N 2 on dry activated carbon at 318.2 K. Solid lines and symbols correspond to the SAFT-VR prediction and experimental data(Sudibandriyo et al 2003), respectively et al 2007and Jiménez et al 2008, the particle-wall potential parameters were chosen in order to reproduce the theoretical limit that determines the adsorption of a monolayer (λ w = 0.8165) and the reproduction of the experimental adsorption isotherms ( w ).Our results are obtained from Eq. (6), getting only absolute adsorption.…”

Molecular thermodynamics of biodiesel fuel compounds

“…A very good agreement between theory and experiment reference data is obtained in all the cases, with the expected theoretical deviation around the critical point. Since the obtained model parameters are the best values attainable with the SAFT-VR method using SW potentials, it is worthwhile to consider if the selection of a different potential model could improve these results, based on the fact that the SAFT-VR approach allows the use of different non-conformal potentials, such as the Yukawa model [35], the Mie potential of variable repulsive and attractive ranges [36], or a general discrete potential [27,37,38].…”

“…In particular, we have explored the use of discrete potentials (DP), that have been used successfully in the modeling of 2D and 3D substances [27,[39][40][41]. Combining a perturbation theory for discrete potentials [37] with the SAFT-VR approach, it is possible to model different type of associating-chain-molecules models, depending on the form and shape of the discrete potential chosen to model a substance [38].…”

“…Further developments have extended the theory in order to take into account explicit contributions from electrostatic interactions. This approach has been able to model a wide range of complex-fluid systems, such as electrolytes [21][22][23], cloud curves and solubility of gases in polyethylene [24], light and heavy esters [25], non-associating [26] and associating [27] adsorbed phases of molecular fluids, bulk asphaltenes [28], confined asphaltenes in porous rocks [29] and second derivative properties of alcohols [30], just to mention some applications.…”