Using the Dubinin–Raduschkevich fitt

Using the Dubinin–Raduschkevich fitting of the equilibrium data, the isosteric heat of adsorption for both hydrocarbons was calculated with the Clausius–Clapeyron equation obtaining a heat of adsorption that depends on the amount adsorbed. This dependence is a decreasing function, which ranges from almost 40 to 10 kJ/mol in the case of propylene and from 35 to 10 kJ/mol for propane. Also,from the Henry constant determined by the dynamic method (breakthrough curves) via a Van’t Hoff relation we determined the isosteric heat of adsorption at zero cover age. The values obtained from these experiments are 18.4 and 23.7 kJ/mol for propane and propylene, respectively. The values obtained from the dynamic experiments are much smaller than the reported values on CMS 5A [9], which can be comparable only with the initial values,determined by the Clausius–Clapeyron equation using the Dubinin–Radushkevich model.