Application of Dubinin–Radushkevich isotherm model at the solid/solution interface: A theoretical analysis

The Dubinin–Radushkevich (D–R) isotherm model was frequently applied in adsorption equilibrium studies. However, its mathematical characteristics with respect to the parameter β and the correct calculation of the adsorption potential ε have still not been discussed. In this work, attempts have been made to address these problems. This work indicated that the D–R isotherm model represented three types of the isotherm curves: S-, L- and H-shaped isotherm. The logarithmic term must be dimensionless in the formula of the adsorption potential. A misconception pertaining to the calculation of the adsorption potential in past publications was identified to avoid the repetition of this mistake in future publications. The author hopes that this work will help readers to better understand the D–R isotherm model.