Removal of lead copper chromium and cobalt ions onto granular activated carbon in batch and fixed-bed adsorbers

Abstract

The adsorption of lead, copper, chromium and cobalt ions onto granular activated carbon (DARCO 20–40 mesh) in a single component system has been studied using fixed-bed adsorbers. A film-pore diffusion model has been utilized to predict the fixed-bed breakthrough curves for each of the four metal ions. This model considers both external and internal mass transfer resistances as well as axial dispersion with non-linear isotherm. The effects of flow rate, bed height and initial metal ion concentration on the breakthrough curves have been studied. The equilibrium isotherm data, the external mass transfer coefficient and pore diffusion coefficient were obtained from separate experiments in batch adsorber by fitting the experimental data with theoretical model. The pore diffusion coefficient was obtained using pore diffusion model for batch adsorber by matching between the experimental data and the model predicted data. The results show that the film-pore diffusion model used for fixed-bed adsorber provides a good description of adsorption process for Pb(II), Cu(II), Cr(III) and Co(II) onto activated carbon in fixed-bed adsorber.