Mixed Surface Reaction and Diffusion-Controlled Kinetic Model for Adsorption at the Solid/Solution Interface

Abstract

The effects of diffusion and surface reaction mechanisms have been considered conjointly to investigate the kinetics of adsorption. A new model has been proposed for the modeling of adsorption kinetics at the solid/solution interface in batch systems. Based on generated data points (<i>t</i>, <i>q</i>) by using of the new model, it was found that there is a deviation from linearity as a downward curvature at initial times of adsorption in usual <i>t</i>/<i>q</i> vs time plot, when diffusion contributes to the rate-controlling step of adsorption. Moreover, results of nonlinear fitting to the different experimental data show that the mixed surface reaction and diffusion-controlled model can be useful for kinetics modeling of adsorption in which pure surface reaction or mixed surface reaction and diffusion contribute to the rate-controlling step of adsorption