Naslov
A comparative study of ion exchange kinetics in zinc/lead - natural zeolite clinoptilolite systems

Autori
Perić, Jelena ; Trgo, Marina ; Vukojević Medvidović, Nediljka

Izvornik
Journal of hazardous materials (0304-3894) 136 (2006), 3; 938-945

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
zinc; lead; ion exchange; diffusion models; clinoptilolite

Sažetak
The kinetics of zinc and lead ions removal by natural zeolite clinoptilolite has been investigated. The rate of the ion exchange process for lead ions is faster than for zinc ions, as well as the time needed to reach the equilibrium. The ion exchange capacity of zeolite of lead ions is doubly higher than that of zinc ions. Diffusion models according to the Vermeulen˘s approximation, the parabolic diffusion model and the homogeneous diffusion model have been tested with the experimental data of ion exchange for zinc and lead. For both systems examined, the best fit of the models proposed with the experimental data was shown by the Vermeulen˘s approximation and the homogeneous diffusion model with t-t∞ . The diffusion coefficients are calculated from kinetic models and for suspension of lead ions they are of the order of 10^-6 cm^2/min, constant for all examined initial concentrations and not dependent on time. The diffusion coefficients in the system of zinc ions is of the order of 10^-8 cm^2/min, also independent of initial concentrations, but decreasing with time from the beginning of ion exchange to the equilibrium.

Izvorni jezik
Engleski

Znanstvena područja
Kemijsko inženjerstvo

POVEZANOST RADA