Monte Carlo simulations of simple gases adsorbed onto graphite and molecular models of activated carbon
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Monte Carlo simulations of simple gases adsorbed onto graphite and molecular models of activated carbon M. E. Farías Hermosilla1 · A. G. Albesa1 Received: 1 April 2020 / Revised: 6 August 2020 / Accepted: 11 August 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract We had performed GCMC simulations to study the adsorption isotherms, the isosteric heats of argon, methane, nitrogen, carbon dioxide, methanol and water adsorption on molecular models of activated carbons at their boiling points in order to understand the contributions of the different functional groups of the adsorbent sites in the adsorption process. We had found that the values obtained from the simulations are in excellent agreement with those obtained in experiments on real activated carbons, which shows the validity of the model proposed here. In this way we can conclude that this type of model is very useful for studying adsorption mechanisms at the microscopic level. It was also observed that the mechanism of adsorption of polar and non-polar species is very different since solid–fluid and fluid–fluid interactions differ markedly. Keywords Activated carbon · Adsorption · Surface structure · Monte Carlo Simulation
1 Introduction Adsorption isotherms measurements have been used for a long time to determine specific surface areas in solid substrates and, if the solid is porous, the pore volume and pore size distribution (Sing 2001; Thommes et al. 2015; Mastalerz et al. 2017). It is very common to characterize the physical and textural properties of porous materials through the physical adsorption of non-polar gases, because there are no electrostatic interactions. (Bahamon et al. 2019). The characterization of the surface chemistry is usually made with polar fluids, such as water and methanol, since these molecules have strong interactions with oxygenated functional groups (Sarkisov et al. 2017). Another very important factor when studying adsorption phenomena is the study of isosteric heat of adsorption. Its value is very important since it is able to provide information about adsorption mechanisms. The Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10450-020-00254-z) contains supplementary material, which is available to authorized users. * A. G. Albesa [email protected] 1
INIFTA (Depto. de Qumica, Fac. Cs. Exactas, UNLP, CONICET), Casilla de Correo 16, Sucursal 4, B1904DPI La Plata, RA, Argentina
interaction that exists between the adsorbed molecules and the adsorbent can delay the adsorption process (Klomkliang et al. 2016; Moon et al. 2017; Gallaba et al. 2016, 2019). Among the materials that currently exist as adsorbents in applications such as: air separation to obtain nitrogen and oxygen, separations used to reduce industrial pollution, energy storage, support in catalysts, etc., microporous coals are found, such as activated carbons. As its cost is relatively low, there is great interest in understanding the adsorption processes in these mate
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