Competitive adsorption of Zn (II), Cd (II) AND Pb (II) ions from aqueous and non- aqueous solution by maize cob and husk

Abstract

Heavy metals rank as major environmental pollutants. Industrial wastewater effluents carry admixtures of these heavy metals. The competitive adsorption of Zn2+, Cd2+ and Pb2+ metal ions from aqueous and non-aqueous solutions by unmodified and modified maize cob and husk was investigated. The results showed that maximum adsorption occurred at 495.9 mg/g for Zn2+ ion, 456.7 mg/g for Pb2+ ion and 493.7mg/g for Cd2+ ion without modification. The adsorption in a mixture of the metal ions caused a leveling effect on the adsorption capacity of the maize cob and husk. The adsorption efficiency of each metal ion was influenced by the presence of other metal ions, presence of non-aqueous solvent and modification by carboxymethylation. The study significantly reveals the presence of other heavy metals and chemicals as design parameter in the treatment and management of heavy metal pollutants using cellulosic materials. Key words: Competitive adsorption, mixed metal ions, aqueous and non-aqueous solution, maize cob and husk.