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E-Journal of Chemistry
Volume 7, Issue 4, Pages 1491-1497

Effect of Ionic Charge on the Adsorption of Sodium-Palmitate and Sodium-Laurate onto Galena, Hematite and Cassiterite in Aqueous Solution

Millicent U. Ibezim-Ezeani and Alphonso C. I. Anusiem

Department of Pure and Industrial Chemistry, University of Port Harcourt, P.M.B. 5323, Choba, Port Harcourt, Nigeria

Received 12 November 2009; Accepted 7 January 2010

Copyright © 2010 Hindawi Publishing Corporation. 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.


The effect of ionic charge on the adsorption of sodium-palmitate and sodium-laurate onto galena, hematite and cassiterite surfaces in aqueous media was studied. The adsorption capacities were determined as a function of adsorbate concentration in the presence of various anions and cations at pH 7.31 and 29 °C. Positively charged ions depressed the adsorption capacity in the order: K+ > Ba2+ > Al3+, showing a reverse correlation with the charge to size ratio of these ions indicating a possible expansion of the double layer that results from predominant diffusion effect and electrostatic effect to some extent. The negatively charged ion enhanced adsorption capacity in the order: PO43- > SO42- > NO3-. This is attributed to the compression of the double layer through electrostatic interaction. In all the studies the adsorption capacities for the adsorbents were in the order: galena > hematite > cassiterite corresponding to the trend in the specific surface area of the adsorbents.