The sorption of toxic elements onto natural zeolite, synthetic goethite and modified powdered block carbon

Abstract

Inorganic elements analyses of Carapicuíba lake reveal that As, Cr, Pb and Mn are above the recom- mended drinking water standards. The mean total concentrations of toxic elements in surface water decrease in the order Mn > Cr > Pb > As. At elevated concentra- tions, toxic elements like Cr can accumulate in soils and enter the food chain, leading to serious health hazards and threatening the long-term sustainability of the local ecosystem. Absorbing materials has often been used to improve water quality. In this investigation three types of material were studied: the natural zeolite (mordenite); synthetic goethite and the powdered block carbon modified. The adsorption of Pb2+ and Mn2+ onto natural zeolite as a function of their concentrations was studied at 24 C by varying the metal concentration from 100 to 400 mg L-1 while keeping all other parameters constant. The low-cost zeolites removed Pb from water without any pretreatment at pH values <6. The maximum adsorption attained was as follows: Pb2+ 78.7% and Mn2+ 19.6%. The modified powdered block carbon effectively removed As(V) and Cr(VI) while goethite removed more chromate than arsenate in the pH range 5-6. Results of this study will be used to evaluate the application these materials for the treatment of the Carapicuíba lake's water. © The Author(s) 2009.