Removal of Cu2+, Zn2+ and Pb2+ by adsorption onto fly ash and fly ash/lime mixing

Disposal of a growing amount of fly ash creates environmental problems due to the leachability of their heavy metal content. Elsewhere, desulfurization treatment in power plants induces pollution by their heavy metals. In this paper, removal of Cu, Zn and Pb by fly ash and fly ash/lime mixing was studied. In the first part of the study, isotherms at different pH were carried out at room temperature. Results show increasing removal with increasing pH. In the second part, experimental design methodology was used. The objectives were to determine the influential parameters among the seven studied for adsorption of copper, zinc and lead, then to study their interactions. Results indicate greater removal by using 100 g.l(-1) of adsorbent with 20% mass of lime at pH 5. However, the preparation of the adsorbent must be modified to increase the role of lime in the removal mechanism. (C) 1999 IAWQ Published by Elsevier Science Ltd. All rights reserved.