Characterization and Adsorption Mechanism of Pb (II) Removal by Insolubilized Humic Acid in Polluted Water

Abstract

The removal of Pb2+ in the aqueous solutions by adsorption onto insolubilized humic acid (IHA) is investigated. The equilibrium isotherms were determined at pH 3.5 under constant ionic strength and at different temperatures. At the same time, the paper has also analyzed the adsorption experimental data by using three different isotherm models: Langmuir, Frendlich and Linear isotherm. As the result, it has obtained the optimal correlation for Frendlich isotherm equations. In addition, the paper has calculated the thermodynamic quantities ΔH in accordance with the Clausius-Claperyon,s theory. It means that the type of adsorption of Pb2+ onto IHA is physisorption, rather than by chemical bonding. And finally, the adsorption equilibrium gained around 12 hours and a high and stable removal of heavy metals on insoluble humic acid has been obtained almost under the neutral conditions.