Modeling the mechanism, equilibrium and kinetics for the adsorption of Acid Orange 8 onto surfactant-modified clinoptilolite: The application of nonlinear regression analysis

Adsorption of Acid Orange 8 onto surfactant-modified clinoptilolite was studied conducting batch experiment system. Effect of pH, dye concentration and contact time on the adsorption was evaluated. Equilibrium adsorption data were analyzed by Langmuir, Freundlich, Redlich–Peterson and Koble–Corrigan isotherm equations using nonlinear regression analysis. The adsorption was analyzed using pseudo-first-order and pseudo-second-order kinetic models and pseudo-second-order model provided the best correlation of the experimental data. Adsorption process was found to be controlled by both surface and particle diffusions.