Sorption of caffeine onto low cost sorbent: Application of two and three-parameter isotherm models

Abstract

The retention capacity of caffeine onto the zizyphus mauritiana seeds as adsorbent is investigated. The experimental data were fitted to the Langmuir, Freundlich, Temkin, Sips, Redlich – Peterson and Toth isotherms. The correlation coefficient R² between the calculated and the experimental data by nonlinear regressive analysis were used. For two-parameter isotherms, the Langmuir model showed higher correlation coefficient R² compared to Freundlich and Temkin isotherms for the sorption of caffeine onto zizyphus mauritiana seeds sorbent. From three parameter isotherms, Sips model was found to be the best representative for caffeine adsorption on the studied material. The Zizyphus mauritiana seeds can be used as low-cost and environmentally friendly sorbent.