An adsorption diffusion model for removal of copper (II) from aqueous solution by pyrolytic tyre char

Kinetic and equilibrium adsorption experiments have been carried out in order to investigate the removal and diffusion mechanism of copper (II) ions onto pyrolytic tyre char obtained from an industrial plant. The experimental equilibrium data have been analyzed using Langmuir, Freundlich, and Redlich-Peterson isotherm models. The accuracy of the fit of the isotherm models to experimental equilibrium data was assessed using the sum of squares error (SSE) analysis. Modeling of the adsorption isotherm showed that Redlich-Peterson expression yields the best fit between experimental and predicted data. The batch kinetic data obtained at different concentrations of copper ions in the solution and also different masses of tyre char were analyzed using the intraparticle diffusion model. In the intraparticle diffusion model plots, three distinct linear sections were obtained for every batch operation. An intraparticle diffusion rate parameter, k is derived from the plots of copper adsorbed vs. the square root of time. The data indicated the potential of pyrolytic tyre char for the removal of copper from aquatic effluents and the adsorption mechanism of copper ions onto tyre char can be described by intraparticle diffusion model.