Behavior of Some Predictive Isotherm Adsorption Models Describing the Multicomponent Equilibria of Phenol/o‐Cresol in a Reversed‐Phase Chromatographic System

Abstract

The suitability of different isotherm adsorption models to describe two‐component adsorption equilibria of phenol and o‐cresol on a RP‐18 column was studied in aqueous‐organic mobile phases with three different concentrations of methanol (10%, 20% and 30%). The isotherm models employed take into account homogeneous or heterogeneous adsorbent surfaces and lateral interactions of adsorbed solutes. The reliability of the predicted two‐component isotherm distribution data increases with increasing methanol concentration, both for models assuming homogeneous surface and lateral interactions between the adsorbed molecules and models considering both lateral interactions and surface heterogeneity. A modified Langmuir‐Freundlich model enables the best prediction of the two‐component equilibria from single‐component experimental distribution data, but other models such as Jovanovic Freundlich, Fowler Guggenheim‐Langmuir Freundlich, and Fowler Guggenheim‐Jovanovic Freundlich models also enable satisfactory predictions.