The interaction effects of cypress (Cupressus sempervirens), cinchona (Eucalyptus longifolia) and pine (Pinus halepensis) leaves on their efficiencies for lead removal from aqueous solutions

Batch and isotherm studies were carried out to compare the effectiveness of decaying leaves of cypress (Cupressus sempervirens), cinchona (Eucalyptus longifolia) and pine (Pinus halepensis) to adsorb lead from its aqueous solution and to study the leaf interaction effects. Lead removal increased with increasing concentrations of both lead ions and the plant leaves employed. Removal efficiency of leaves followed the decreasing order: pine > cypress > cinchona. While cinchona leaves showed an antagonistic effect on the removal efficiencies of cypress, pine, and a combination of cypress and pine leaves, the effect of cypress on the removal efficiency of pine leaves was additive. The adsorption of lead by cypress and cinchona leaves was well defined by both the Freundlich and Langmuir isotherms, but only the Freundlich isotherm was adopted for pine leaves. Desorption of lead from leaves upon standing in deionized water was minimal. (C) 2002 Elsevier Science Ltd. All rights reserved.