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Open Access Research

Kinetic modeling: a predictive tool for the adsorption of zinc ions onto calcium alginate beads

Morteza Hasanzadeh Kafshgari1, Mohsen Mansouri1, Mohammad Khorram2* and Shahab Rahimi Kashani3

Author Affiliations

1 Department of Chemical Engineering, University of Sistan and Baluchestan, PO Box 98164–161, Zahedan, Iran

2 School of Chemical, Petroleum and Gas Engineering, Shiraz University, Shiraz, Iran

3 Materials Science Centre, School of Materials, University of Manchester, Grosvenor Street, Manchester, M1 7HS, UK

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International Journal of Industrial Chemistry 2013, 4:5  doi:10.1186/2228-5547-4-5

Published: 16 January 2013

Abstract

Background

The main purpose of this study is to develop a nonlinear model of a batch adsorption and to evaluate the model's capability in the prediction of experimental adsorption data. Additionally, results of the nonlinear model were compared with data of pseudo first- and second-order models. Experimental data were extracted from the adsorption of zinc ions using calcium alginate beads prepared via electrospray method. In order to study the effects of biosorbent porosity and the initial concentration of the zinc solution on adsorption kinetics, calcium alginate beads were prepared with two different porosities and zinc concentrations.

Results

The results revealed that the nonlinear model offers a much more accurate prediction compared with other models as the average root mean square deviation of the nonlinear model was calculated to be only 2.66%, which was smaller at least four times than that of others. Furthermore, the nonlinear model showed that diffusive transport through beads was limited by pore diffusion.

Conclusions

The nonlinear model provided a good fit to the experimental data as the calculated equilibrium adsorptions were shown to be in good agreement with their experimental counterparts.

Keywords:
Nonlinear kinetic model; Pseudo-kinetic models; Zinc adsorption; Calcium alginate beads