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Bioinorganic Chemistry and Applications
Volume 2009, Article ID 561091, 5 pages
Research Article

Divalent Cu, Cd, and Pb Biosorption in Mixed Solvents

Chemistry Department, King Saud University, P.O. Box 75318, Riyadh 11578, Saudi Arabia

Received 5 December 2008; Revised 3 May 2009; Accepted 5 June 2009

Academic Editor: Triantafillos Albanis

Copyright © 2009 M. H. Al-Qunaibit. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Dead dried Chlorella vulgaris was studied in terms of its performance in binding divalent copper, cadmium, and lead ions from their aqueous or 50% v/v methanol, ethanol, and acetone solutions. The percentage uptake of cadmium ions exhibited a general decrease with decrease in dielectric constant values, while that of copper and lead ions showed a general decrease with increase in donor numbers. Uptake percentage becomes less sensitive to solvent properties the larger the atomic radius of the biosorbed ion, and uptake of copper was the most affected. FT-IR analyses revealed stability of the biomass in mixed solvents and a shift in vibrations of amide(I) and (II), carboxylate, glucose ring, and metal oxygen upon metal binding in all media. values (59–69 ) confirmed bidentate metal coordination to carboxylate ligands. The value of increased slightly upon Cu, Cd, and Pb biosorption from aqueous solutions indicating lowering of symmetry, while a general decrease was noticed in mixed solvents pointing to the opposite. M–O stretching frequencies increased unexpectedly with increase in atomic mass as a result of solvent effect on the nature of binding sites. Lowering polarity of the solvent permits variations in metal-alga bonds strengths; the smaller the metal ion, the more affected.