Derivation of a General Adsorption Isotherm Model

According to the thermodynamics of adsorption, a general equation for the adsorption isotherm was derived and verified by the literature data. The constants involved in the proposed model are physically defined. It was shown that the Langmuir and Freundlich equations were special cases of the proposed adsorption isotherm model. The proposed model indeed provides a good insight into the thermodynamic mechanisms of adsorption.