An easy-to-use modification of the potential theory of adsorption and creation of an adsorbent data base

In this paper a modification of Dubinin's potential theory of adsorption is presented. The proposed method can be applied when the temperature invariance of the characteristic curve proposed by Dubinin is not satisfied e.g., in the case of adsorption of polar vapors on SAPO-18. The proposed method is easy to apply because only one additional fitting parameter is used. The new adsorption potential is discussed in terms of other previous modifications of the potential theory, and all thermodynamic potentials required for the design of technical adsorption processes are derived. In the second part of the paper a database with characteristic curves of 30 adsorbent-adsorptive pairs has been created using the new adsorption potential and adsorption equilibrium data from the literature. In 8 out of 21 cases studied, where sufficient experimental data are available, the new approach leads to a characteristic curve with a 42-61% better predictive accuracy than Dubinin's original method, according to the goodness of fit parameter used. Furthermore, a strategy is presented to construct characteristic curves also for complex curve trajectories of type IV and V isotherms according to the IUPAC classification.