REMOVAL OF LEAD IONS FROM AQUEOUS SOLUTION USING MAGNESITE TAILING

The present work deals with the application of magnesite tailing in the removal of lead from aqueous solution. The effects of pH, contact time, adsorbent dosage, initial solution concentration and temperature on lead removal were studied. The Langmuir and Freundlich isotherms were employed and the equilibrium adsorption data were found to fit the Langmuir isotherm model. The pseudo first order kinetics model, the pseudo second order kinetics model and the intraparticle diffusion model were used to evaluate the adsorption kinetics. The pseudo second order kinetics model was determined to correlate well to the experimental data. Thermodynamic parameters such as the changes of free energy, enthalpy and entropy were calculated. The thermodynamic studies showed the spontaneous and endothermic nature of the lead adsorption. An optimum lead removal of about 100% was obtained at a pH value of 5.0, an adsorbent dosage of 0.5 g of magnesite tailing/50 mL of lead solution and an initial lead concentration of 500 mg/L. The results of this study will be useful for using magnesite tailing as a low-cost adsorbent for the removal of lead from aqueous solutions.