Comments on the paper: a critical review of the applicability of Avrami fractional kinetic equation in adsorption-based water treatment studies

Abstract

This letter presents comments on the paper “Critical review on the applicability of Avrami fractional kinetic equation in adsorption-based water treatment studies” that was recently published in Desalination and Water Treatment by N.A. Oladoja. This author explained the misuse of Avrami-type kinetic equation in adsorption process at solid/solution interfaces and also mentioned few of the papers published in the literature that used the Avrami kinetic equation. We, therefore, decided to write this letter to make it clearer to the reader that there are no wrong or unfounded concepts in the papers cited in the review of N.A. Oladoja. We do believe that the mechanism of adsorption could only be established by several analytical techniques and a good sense of chemistry associated with the equilibrium and kinetic data. The mechanism cannot be directly assigned based on just simple kinetic experiments. In addition, the author was very selective in choosing some specific papers, which used this valuable kinetic adsorption equation, for his criticism. The kinetic equation presented at the end of Oladoja’s paper is worthless and may not be a feasible equation that can be applied to adsorption from solutions.