Sorptive Removal of Copper and Lead From Aqueous Solution by An Fe-Mn Binary Oxide

Abstract: Heavy metals sorption onto the surfaces of Fe-Mn binary oxides may play an important role in the mobilization and transformation of heavy metal because of the common occurrence of these oxides in the environment. However, the study of sorption behaviors of heavy metals on Fe-Mn binary oxides is less reported. Therefore, this study investigated systematically the sorption kinetics, edges and isotherms of Cu²⁺ and Pb²⁺ on a synthesized Fe-Mn binary oxide using a simultaneous oxidation and coprecipitation method. Additionally, the influences of coexisting Ca²⁺, Mg²⁺ and humic acid on their sorption were also examined. The sorption of Cu²⁺ and Pb²⁺ on the Fe-Mn binary oxide was fast and was almost completed within two hours. The prepared Fe-Mn binary oxide had high sorption capacity towards Cu²⁺ and Pb²⁺, especially the latter. The maximal sorption capacities are 0.96 and 1.42 mmol/g, respectively. The sorption of Cu²⁺ and Pb²⁺ was obviously pH-dependent and high pH value favored their sorption. The presence of Ca²⁺, Mg²⁺ and humic acid had no great effect on Cu²⁺ and Pb²⁺ sorption. The Fe-Mn binary oxide has also the potentials to be used as a scavenger for heavy metals from water, due to its high sorption capacity and low cost.