The efficacy of raw Malangali kaolin clay in the adsorptive removal of cadmium and cobalt ions from water

Abstract

The suitability of raw Malangali kaolin (RMK) clay for the removal of cadmium and cobalt ions from water was investigated using a batch technique whereas the characterization of adsorbent material was performed by XRD, XRF, ATR-FTIR and N₂ physisorption techniques. Various experimental parameters were tested for the effectiveness of RMK in removing heavy metals whereby quantitative determination of both Cd²⁺ and Co²⁺ ions has shown that, the factors such as adsorbent particle size, solution pH, contact time, adsorbent dose as well as initial metal ion concentration had significant effects on the adsorption processes. The equilibrium data described by Langmuir and Freundlich isotherms were used in this study. It was shown that Langmuir isotherm displayed a better fitting model than that of Freundlich because of its higher correlation coefficient, thus, demonstrating the occurrence of monolayer coverage of Cd²⁺ and Co²⁺ ions on the surface of RMK clay. The results obtained in this study, therefore, suggest that locally available RMK clay can be used as potential and effective adsorbent for removal of heavy metal ions from aqueous solutions.

Keywords: Clays, Malangali kaolin, Adsorption, Heavy metals