engleski

Investigation of different kinetic models of zinc ions uptake by natural zeolitic tuff

The kinetics of uptake of zinc ions from aqueous solutions by natural zeolitic tuff has been investigated. Batch experiments at constant temperature and hydrodynamic conditions have been performed. Decrease of initial zinc concentration in aqueous solutions prolongs the time needed for equilibrium. Various kinetic models including film diffusion model, surface diffusion model and heterogeneous diffusion model have been tested for the description of the experimental results of zinc concentration in the solution over time. Diffusion through the film and diffusion through the surface of the particle could be the rate limiting step at the initial reaction time. However, the heterogeneous diffusion model seems to be the best model providing a satisfactory fitting of the experimental results from the beginning to the equilibrium of the process, particularly at lower initial zinc concentrations.

zinc uptake; kinetic models; clinoptilolite; heterogeneous diffusion

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