Factorial design analysis for adsorption of Indigo Carmine onto Montmorillonite-Evaluation of the kinetics and equilibrium data

In this study, the potential of montmorillonite for Indigo Carmine (IC) adsorption from aqueous solutions was evaluated. The equilibrium adsorption results for montmorillonite can be successfully modeled by the Langmuir, Freundlich, and Temkin, isotherms. The pseudo- first order and pseudo-second order models were used to describe the kinetic data and rate constants were evaluated. In order to reduce the number of experiments to achieve better IC removal efficiency, two independent sets of full 23 factorial design experiments were carried out. The variables were montmorillonite of 1.25 and 5.00 g/L, IC concentrations of 20 and 200 mg/L and pH of 3 and 7. (C) 2016 Elsevier B.V. All rights reserved.