The Jovanović adsorption isotherm in water contaminant research: Unmasking spurious versions and spotlighting the real thing

Abstract

This study evaluates the capability of the Jovanović isotherm in correlating water contaminant adsorption data. Both incorrect and correct formulations of the isotherm are examined. Two flawed versions lead to negative adsorption equilibrium constants when fitting experimental data. These results are nonsensical and contradict the conventional definition of equilibrium constants. In contrast, the genuine Jovanović isotherm proves to be a valuable model for describing favorable or type I isotherm data. It serves as a practical alternative to the widely used Langmuir isotherm. Additionally, this research evaluates a rarely used version of the Jovanović isotherm specifically developed for multilayer adsorption. The findings reveal that a modified adaptation of the multilayer adsorption isotherm is superior to the original formulation, enabling an accurate representation of sigmoid or type II isotherm data. Moreover, this work demonstrates that by assuming Jovanović local behavior, global isotherms capable of representing adsorption on heterogeneous adsorbents can be obtained.