Adsorption of zinc by a Tunisian Smectite through a filtration membrane

The metal adsorption by clays is widely studied. The classical method consists in mixing a volume of metal solution with a mass of clay and making a series of agitation and centrifugation. The supernatant is analyzed by an atomic absorption method to determine the concentration adsorbed by clay. But this method has several disadvantages as the extract may contain impurities which are suspensions that can yield wrong analysis results. This work aims at studying the influence of a new method that uses membrane filtration to determine the maximum amount of zinc adsorbed by clay. To prove the effectiveness of such method, several identification techniques are used. The local clay extracted from Oued Tfal south west Tunisia, has been characterized. The mineralogical and chemical compositions of the materials have been determined. Gives the adsorption of Zn(II) studies, experimental data demonstrated a high regression coefficients with the pseudo-second order kinetics. The equilibrium data showed the best most suitable model fit to Freundlich and Langmuir models. (c) 2013 Elsevier B.V. All rights reserved.