Heavy Metal Adsorption Properties of the Basement Complex of Clay Deposit in Ire-EkitiSouthwestern Nigeria

Raw clay collected from Ire-Ekiti, Ekiti State, Nigeria, was used to adsorbsome heavy metals (Pb, Cr 3+ , Ni 2+ and Cu 2+ ) from aqueous solution of the metals.A laboratory batch adsorption study was performed to study the effect of concentration, pH, particle size, temperature and agitation time on adsorption characteristics of the adsorbates on the raw kaolinite clay. The experimental variables were found to have significant effect on metals sorption with an optimum pH of 5.0, 0.50g adsorbent dose, 200μm particle size and 50mL adsorbatesolutions. Equilibrium sorption was obtained for Pb 2+ , Cr 3+ , Cu 2+ and Ni 2+ at 40, 60, 60, and 70 min respectively. The effect of temperature showed that the adsorption process was exothermic for Pb 2+ while that of Cr 3+ , Ni 2+ and Cu 2+ showed endothermic.The adsorption capacity of the clay for the metal ions is as follow: Pb 2+ >Cu 2+ > Cr 3+ >Ni 2+ with percentage removal of 99.3, 80, 70.9 and 68.7 respectively. Efficiency of the raw clay showed possible suitability for removal of metals in their respective contaminated medium.