Selective adsorption of heavy metals (Co 2+ , Ni 2+ , and Cr 3+ ) from aqueous solutions onto natural marne clay

Abstract

Natural marne clay (NMC) is a new clay that was used for the adsorption of heavy metal ions (Co (II), Ni (II), and Cr (III)) from aqueous solutions. Batch method was employed to study the influential parameters such as concentration of metal ions, pH, temperature, and mixing. The adsorption isotherms and kinetic studies were carried out in heavy metal systems. The Langmuir isotherm model fitted to the equilibrium data better than the Freundlich model, with the maximum adsorption capacities for Co 2+ , Ni 2+ , and Cr 3+ are 48.35, 20.64, and 76.62 mg/g, respectively. The thermodynamic data were indicative of the endothermic sorption process of heavy metal ions onto the NMC. The selectivity sequence of the adsorption was found as Co (II) > Cr (III) > Ni (II). The results showed that NMC was a good adsorbent, able to uptake uniquely large quantities of heavy metals from single and binary components, and demonstrate the practical and economic advantages of using NMC in the decontamination of wastewater.