ADSORPTION OF COPPER IN EXPANDED VERMICULITE: KINETICS AND EQUILIBRIUM

The aim of this work was to evaluate copper adsorption on expanded vermiculite through kinetic and equilibrium studies. The kinetics of adsorption of copper into vermiculite was assessed by kinetic phenomenological models of pseudofirst order, pseudo-second-order and intra-particle diffusion models as well as a mass transfer model in the external film. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were fitted to equilibrium data. The adsorption process follows kinetic External Film Mass Transfer and Intraparticle Diffusion models, and Freundlich model describes better the system in the equilibrium. It was also verified that the process is spontaneous, endothermic and favorable. D-R model indicated that the adsorption of copper on vermiculite is a physical process.