Title
Adsorption of heavy metals on charcoal from lignin
Authors
B. BERRIMA W. MAATAR G. MORTHA S. BOUFI L. EL ALOUI and M. N. BELGACEM

Published Volume 50 Issue 5-6 May-June
Keywords lignin, charcoal, heavy metals, adsorption

Abstract
Lignin precipitated from black liquor was carbonized at a temperature of 600 °C and the resulting charcoal was used as adsorbent for the removal of heavy metals from aqueous solutions (Pb2+, Cd2+, Hg2+ and Ni2+). The particle diameters and the morphology of the prepared coal were investigated. The adsorption properties of charcoal from lignin were explored under batch conditions and the results were compared to a commercial homologue used in water treatment. The kinetic study of the investigated adsorbent (lignin-based coal, CL), as well as that of the commercial (CC) substrate, was also performed. Then, the regeneration of the charcoal was achieved using diluted ethylene diamine tetra-acetic acid (EDTA) and nitric acid (HNO3) as desorbing solution. Finally, the thermodynamic parameters, free energy of adsorption ∆G˚, entropy ∆S˚ and enthalpy ∆H˚ for the adsorption process were determined and the mechanism of the adsorption was studied by zeta potential measurement. It was concluded that the charcoal from lignin may be used as a high capacity and reusable sorbent material in heavy-metal removing processes.