Removal and preconcentration of lead (II) and other heavy metals from water by alumina adsorbents developed by surface-adsorbed-dithizone

This paper presents the removal and preconcentration of Pb(II) from drinking tap water and wastewater samples via applications of newly modified three alumina-physically loaded-dithizone adsorbents. The synthesized acidic, neutral and basic alumina adsorbents (I), (II) and (III), respectively are characterized by a strong stability toward acid leaching and thermal decomposition. Sorption of Pb(II) was investigated as a function of the solution pH and contact time. The incorporated selectivity characteristics into alumina adsorbents were studied and the results of metal sorption capacity showed the strong affinity toward Pb(II), Cr(III) and Cu(II). Determination of the distribution coefficient and separation factors indicated that these alumina adsorbents are highly selective for Pb(II). Selective removal of Pb(II) from wastewater samples was accomplished with percentage recovery values of 94-99 +/- 1-2%, while the results collected from the selective preconcentration of Pb(II) from drinking tap water proved excellent percentage recovery values of 96-99 +/- 2-3% and 94-99 +/- 2-4% for the two studied concentration values 1.212 ng ml(-1) and 4.800 ng ml(-1) respectively. (c) 2009 Elsevier B.V. All rights reserved.