Thermodynamic study of krypton adsorbed on graphite using a statistical physics treatment

New theoretical expressions for the adsorption isotherm of krypton on exfoliated graphite at 77.3 K were established. The establishment of these new expressions is based on the statistical physics formalism and some working hypotheses. This method allowed the estimation of the physico-chemical parameters in the theoretical models. The parameters intervening in the adsorption process were deduced directly from the experimental adsorption isotherm by numerical simulation. Our objective in this modeling approach is to select an adequate model that presents a high correlation with the experimental curve. We introduce three parameters affecting the adsorption process, namely, the density of krypton receptor sites N-M, the number of molecules per site and the krypton adsorption energy. Then, we apply the appropriate model to calculate the thermodynamics functions, such as the entropy, the free enthalpy and the internal energy, that govern the adsorption mechanism. (C) 2013 Elsevier B.V. All rights reserved.