Isosteric heats of adsorption are calculated for activated carbons prepared by chemical activation of macadamia nutshell. A commercial activated carbon is also used for comparison. The isosteric heat is calculated directly from the experimental isotherm data of hydrocarbons and CO_2 and indirectly from the three equilibrium models of Sips, Toth, and Unilan fitted to experimental data. The heat values resulted from a model of Do and Do (IHFL model), which takes into account the isosteric heat as a main source of heterogeneity of the solid, is also considered in the comparison. This investigation shows that although all equilibrium models fit the data well within the experimental error, the isosteric heat of these models do not agree and hence it can be used as additional criterion to choose the proper equilibrium model.
展开▼
