International Research Journal of Plant Science

International Research Journal Plant Science Vol. 1(4), pp.107-117   October  2010         
Copyright © 2010 International Research Journals

 

Full Length Research Paper

A diffusion-chemisorption kinetic model for simulating biosorption using forest macro-fungus, fomes fasciatus

Clint Sutherland1*, Chintanapalli Venkobachar2

1*Project Management and Civil Infrastructure Systems, University of Trinidad and Tobago, Trinidad (WI)

2Formerly with Department of Civil and Environmental Engineering, University of the West Indies, St. Augustine, Trinidad (WI)

*Corresponding author. E-mail: clintsld@gmail.com ; Phone: 868 497 5744; Fax: 868 658 6356

Received 25 June, 2010; Accepted 12 August 2010

Abstract

Research into the development of cheaper technologies for the interception and treatment of heavy-metal-laden waste streams continues unabated. Biosorption using low-cost media provides an attractive alternative. The kinetic manner of a forest product, macro-fungus Fomes fasciatus, was analysed for the selection of an appropriate kinetic model. All experiments were conducted using Cu(II) as a model cation. The kinetic effect of initial Cu(II) concentration and sorbent size was studied in a batch laboratory-scale reactor. Fomes fasciatus exhibited an affinity to Cu(II) ions and approached maximum sorption efficiency as initial concentrations increased beyond 100 mg/l. The sorption process was more complex than that to be scripted by pseudo-first-order kinetics. Pseudo-second-order modelling produced a more defined simulation, however, the precision diminished as sorbent size increased. Intraparticle diffusion modelling showed an increasing conformity to increased sorbent size. The mechanisms of biosorption were found to be controlled by film diffusion or combined with surface adsorption during the initial stages. This was followed by a tangled combination of diffusion and chemisorption for the subsequent 98% of the reaction period. A diffusion-chemisorption model was successfully used to simulate the entire period of biosorption kinetics. Additionally, the model produced a good correlation to the reaction variables which not only advanced the development of predictive models involving Fomes fasciatus but can also improve the development of full-scale batch sorption systems.

Keywords: biosorption; kinetics; macro-fungus; heavy metal; chemisorption; copper (II); intraparticle diffusion

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