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NISCAIR PUBLICATIONS >
Research Journals >
Indian Journal of Chemical Technology (IJCT) >
IJCT Vol.18 [2011] >
IJCT Vol.18(2) [March 2011] >
| Title: | Kinetics and thermodynamics study of copper ions removal by natural clinoptilolite |
| Authors: | Ćurković, Lidija
Trgo, Marina
Rožić, Mirela
Medvidović, Nediljka Vukojević |
| Keywords: | Clinoptilolite
Copper
Diffusion
Kinetic models
Thermodynamic parameters |
| Issue Date: | Mar-2011 |
| Publisher: | NISCAIR-CSIR, India |
| Abstract: | The process
of removal of copper ions by means of clinoptilolite type natural zeolite has
been studied as a function of the particle size and temperature. Results
indicate that increase in temperature and decrease of particle size improves
the removal of copper from aqueous solutions. The parabolic diffusion model is
well described process in all examined range of time and it shows that the
calculated diffusion coefficient increases with temperature. This increase is
more visible at higher particle sizes what assume diffusion through zeolite
particle as main mass transfer mechanism. The film diffusion model provides
calculation of initial sorption rate (k´)
and dimensionless parameter proportional to the diffusion film thickness (xi), in relation of particle
size and temperature. Diffusion from the surface of zeolite particles through
the micro and macro pores is well described with homogenous diffusion model,
where change of the calculated overall rate constant is observed at »60
min of the process. This indicates the change of mass transfer rate through
porous zeolite particle.
The activation energy (Ea), activation enthalpy ( H), activation entropy (S) and free energy of activation (G) have been calculated based on kinetic
data. These thermodynamic parameters characterize process as diffusion
dependent, weakly endothermic and nonspontaneous, where structural changes in
structure of natural zeolite particle are not observed. |
| Page(s): | 137-144 |
| CC License: |  CC Attribution-Noncommercial-No Derivative Works 2.5 India |
| ISSN: | 0975-0991 (Online); 0971-457X (Print) |
| Source: | IJCT Vol.18(2) [March 2011]
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