Equilibrium and kinetic data, and adsorption mechanism for adsorption of lead onto valonia tannin resin

The adsorption of lead onto valonia tannin resin studied using a batch adsorber. The aim of this study was to understand the mechanisms that govern lead removal and find a suitable equilibrium isotherm and kinetic model for the lead removal in a batch reactor. The experimental isotherm data were analyzed using the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich equations. The equilibrium data fit well the Langmuir isotherm. The experimental data were analyzed using four adsorption kinetic models - the pseudo first- and second-order equations, the Elovich equation and intraparticle diffusion equation - to determine the best fit equation for the adsorption of lead-ions onto valonia tannin resin. The characteristic parameters for each kinetic models have been determined and the correlation coefficients have been calculated in order to assess which model provides the best fit predicted data with experimental results. Also, predicted q(1) values from the kinetic equations were compared with the experimental data. Results show that the pseudo second-order equation provides the best correlation for the adsorption process. Adsorption mechanism was also proposed for the adsorption of lead-ions onto valonia tannin resin. (C) 2007 Elsevier B.V. All rights reserved.