Modeling the mass-transport processes in the sorption of metal ions onto bone char.

摘要

This research focuses on the adsorption of cadmium, copper and zinc ions onto bone char. The first part of this research studies the sorption equilibrium of each system. The Langmuir, Langmuir Freundlich, and binary Langmuir equations are used to correlate the experimental data. The Langmuir and the Langmuir-Freundlich equations are used to incorporate the Ideal Adsorbed Solution Theory to predict the multicomponent data.;The sorption kinetics of metal ions onto bone char was studied using a batch agitation method. Novel film-pore and film-pore-surface diffusion models derived by incorporating a Langmuir-type isotherm equation, shrinking core model and mass balance equation, were used to correlate the experimental data for single component systems. These new diffusion models were applied to different sorption systems to model the effect of initial concentration and mass of sorbent on uptake. The results obtained from these models were comparable to those obtained from the analytical film-pore diffusion model but provide better agreement with the experimental data. The temperature effect was analyzed to verify that the pore diffusion is the primary mass transport mechanism of metal ions.;As the film-pore diffusion model was successfully used to correlate the single component systems, it was extended to incorporate the empirical method or the IAST in the diffusion model to correlate the multicomponent systems. Finally, the IAST-film-pore diffusion is recommended for use in kinetic study for the multicomponent systems.