Abstract

In this paper, adsorption of lead and zinc on Curcuma longa leaf powder from solutions with environmentally
relevant concentrations of metals was studied. The kinetics of adsorption of metal ions was analyzed. Optimum
pH values for maximum metal ion adsorption were determined. Adsorption isotherms were expressed by
Langmuir and Freundlich models. Langmuir adsorption model fits the experimental data reasonably well than
Freundlich model. The thermodynamic parameters - such as standard Gibb’s free energy change (∆G°), standard
enthalpy change (∆H°), and standard entropy change (∆S°) - were evaluated, which indicated that this system
was spontaneous and endothermic. The studies showed that this low-cost material could be used as an efficient
adsorbent for the removal of lead and zinc from aqueous solutions.