Kinetic, Equilibrium and Thermodynamics Study of the Adsorption of Pb(Ii), Cu(Ii) and Ni(Ii) from Aqueous Solution using <i>Mangiferaindica</i> Leaves

Abstract

The kinetics, equilibrium and thermodynamic study of the adsorption of Ni2+, Pb2+ and Cu2+ions from aqueous solution by the leaf of Mangiferaindica were investigated at different experimental conditions. Optimum conditions of initial metal ion concentration, pH, adsorbent dose, contact time and temperature were determined. The kinetics studies indicate that the adsorption process of the metals ions followed the pseudo second-order model with R2 value of 0.9938, 1.00 and 1.00 respectively. Equilibrium studies showed that the adsorption of Ni2+, Pb2+ and Cu2+ ions are well represented by both Langmuir and Freundlich isotherm but the Langmuir model gave a better fit for Pb2+ ions with R2 value of 0.9950 and Langmuir constant KL of 4.3383 while Freundlich isotherm model best fit the experimental data of lead(II) and nickel(II) with a R2 value of 0.976 and 0.9973 and Freundlich constant KF value of 4.2677 and 0.0874. The calculated thermodynamics parameters of Ni2+, Pb2+ and Cu2+ ions are ( ΔGo -1182.49,-5479.1 and 613.48 KJ/mol) showed that the adsorption of Ni2+ and Pb2+are spontaneous while Cu2+ non-spontaneous. The findings indicate that the leaf of Mangiferaindica could be used for the adsorption of Ni2+, Pb2+ and Cu2+ ions from industrial effluents.