Adsorption of Lead from Aqueous Solution onto Untreated Orange Barks

Abstract

Waste materials with no further treatment such as orange barks from commercial oranges may act as adsorbent for the removal of Pb²⁺. Batch kinetic and equilibrium experiments were conducted to study theeffects of contact time, initial pH, adsorbent dose and initial concentration of lead. The results show that the equilibrium was achieved less than 30 min of contact time. Three adsorption isotherm models namely, Langmuir, Freundlich and Dubinin-Radushkevich were used to analyse the equilibrium data. The Langmuirisotherm which provided the best correlation for Pb²⁺ adsorption onto orange barks reveals that theadsorption was favourable and the maximum adsorption capacity found was equal to 112,36 mg.g^-1. The results of the present study suggest that orange barks will be used as an effective and economical adsorbent for Pb²⁺ removal.