Adsorption of Lead from Industrial Effluents using Rice Husk

Rice husk a very low cost material has been utilized as adsorbent for the removal of lead from industrial effluents. Adsorption studies have been carried out at 28°Cand the effect of initial lead concentrations (100-1000) mg/l, adsorbent dosage (0.05-1) g, pH (2-10) and contact time (10-180) min on lead uptake to establish a mathematical model description percentage removal of Pb (II). The influence of four parameterson the percentage removal of Pb(II) was examined using a response surface methodological approach. BoxWilson design of experiments was adopted to find a useful relationship betweenthese parameters andthe removal efficiency. The experiment data collected by this method successfully fitted to a second order polynomial mathematical model. The optimum operating conditions of initial Pb (II) concentrations, adsorbent dose, pH and contact time were 325 mg/l, 0.7625 g, 4 and 137 min, respectively with high value of correlation coefficients (R= 0.9877). At these conditions, the maximum percentage removal of Pb(II) was 95.55% and lead uptake was 102.97 mg/g.The experimental data were analyzed using Langmuir and Freundlich isotherm models were applied in the adsorption studies. Langmuir model is found very well represent the equilibrium data with correlation factor is close to unity than the Freundlich model. Keywords— Adsorption, Removal, Lead, Rice husk, Isotherms.