Adsorption of lead and nickel from aqueous solution on natural sepiolite

Abstract

Heavy metals are a serious environmental problem due to their toxicity and abundance. The capacity of a natural clay (sepiolite) for heavy metals adsorption, Pb2+ and Ni2+, has been assessed using a batch method. The effect of mass of adsorbent on the process and the competitive adsorption between the two metals has been investigated. The adsorption of Pb2+ and Ni2+ increases with increasing dosage of natural sepiolite. The maximum removal of Pb2+ and Ni2+ by sepiolite, starting from a solution with both metals, was 98% and 59%, respectively. The experiments demonstrated that Pb2+ was adsorbed by natural sepiolite more efficiently than Ni2+. The conclusion of this study is that natural sepiolite can efficiently adsorb cationic species, which may have an interesting environmental application such as the removal of those species from polluted waters.