Kinetics and thermodynamics study of copper ions removal by natural clinoptilolite

Ćurković, Lidija and Trgo, Marina and Rožić, Mirela and Vukojević Medvidović, Nediljka (2011) Kinetics and thermodynamics study of copper ions removal by natural clinoptilolite. = Kinetics and thermodynamics study of copper ions removal by natural clinoptilolite. Indian Journal of Chemical Technology, 18 (2). pp. 137-144. ISSN 0971-457X. Vrsta rada: Original scientific paper. Kvartili JCR: Q3 (2011). .

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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 (x i), 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 (E a), activation enthalpy (ΔH), activation entropy (ΔS) and free energy of activation (ΔG) 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.

Item Type:	Article (Original scientific paper)
Keywords (Croatian):	Clinoptilolite; Copper; Diffusion; Kinetic models; Thermodynamic parameters
Subjects:	TECHNICAL SCIENCE
Divisions:	1000 Department of Materials > 1010 Chair of Materials and Tribology
Indexed in Web of Science:	Yes
Indexed in Current Contents:	Yes
Citations JCR:	2 (21.4.2015.)
Quartiles:	Q3 (2011)
Citations SCOPUS:	3 (21.4.2015.)
Date Deposited:	21 Apr 2015 11:39
Last Modified:	21 Apr 2015 11:39
URI:	http://repozitorij.fsb.hr/id/eprint/3830

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