Organoclay modified with lignin as a new adsorbent for removal of Pb2+ and UO2 (2+)

Abstract

This study investigated a new adsorbent prepared from lignin modified organoclay for the removal of Pb2+ and UO2 (2+) from aqueous solutions. The characterization of new adsorbent was performed by FT-IR and XRD. Adsorption of Pb2+ and UO2 (2+) species in aqueous solution as a function of ion concentration, pH, temperature and time of adsorption was investigated in detail. The adsorption data were analyzed by using the Langmuir, Freundlich and Dubinin-Radushkevich models. The monolayer adsorption capacities of organoclay-lignin were 0.12 mol kg(-1) and 0.42 mol kg(-1) for Pb2+ and UO2 (2+), respectively. The experimental kinetic data were analyzed by using pseudo-second-order kinetic and intra-particle diffusion models. The proposed adsorption mechanism follows a pseudo-second-order kinetic and endothermic because of increasing disorderliness at adsorbate/adsorbent interface.