Mass transfer and adsorption kinetics during the adsorption of fluoride onto activated clays in agitated systems

Abstract

Much of the studies on the adsorption of fluoride by various adsorbents have focussed on the adsorbent capacity in the laboratory scale. The adsorption kinetics, diffusion and mass transfer studies have been largely neglected. In the present work, the adsorption kinetics was studied using an agitated batch reactor as a function of time, initial concentration, particle size and agitation rate. The equilibrium data were fitted the Langmuir model and model constants were determined. It was seen that the equilibrium data fitted very well to the model in the concentration range studied. Lagergren rate constants for different initial concentrations, different adsorbent concentrations and agitation rates were calculated. The rate constants of intraparticle diffusion were calculated. Mass transfer coefficients as a function of initial concentrations of fluoride, agitation rates and particle size were determined.