African Journal of Biotechnology Vol. 4 (6), pp. 509-512, June 2005          
ISSN 1684–5315 © 2005 Academic Journals

Short Communication

Sorption kinetics and intraparticulate diffusivities of  Cd, Pb and Zn ions on maize cob

Abia, A. A.¹ and Igwe, J. C.²*

¹Department of Pure and Industrial Chemistry,University of PortHacourt, River State, Nigeria.

²Department of Industrial Chemistry,Abia State University,P. M. B. 2000 Uturu, Abia State Nigeria.

*Corresponding Author E-mail: jcigwe2001@yahoo.com.

Accepted February 2005

The kinetics of sorption and intraparticulate diffusivities of Zn, Cd and Pb using maize cob was studied. The amount of the metal ions adsorbed increased with time. The highest sorption rates of the three metal ions were 71% for Zn²⁺, 32% for Cd²⁺, and 30% for Pb²⁺. The fractional attainment of equilibrium showed that Zn²⁺ reached equilibrium before Pb²⁺ ion and then Cd²⁺ ion.  This study showed that the sorption of Zn²⁺, Cd²⁺ and Pb²⁺ ions on maize cob is particle diffusion controlled. The rate coefficients for particle diffusion were 0.07 min^-1 for Zn²⁺, 0.053min^-1 for Pb²⁺ and 0.081min^-1 for Cd²⁺.

Key words:  Adsorption, Kinetics, intraparticulate diffusivity, heavy metal, maize cob.