Adsorption of Lead (II) Ions by Activated Carbon Prepared From Different Parts of Jatropha Curcas Plant

Abstract

Activated carbon samples prepared from the stem, root and seed coat of Jatropha curcas plant by activation using orthophosphoric acid was used for the removal of Pb (II) from aqueous solution. The samples were labeled ACS, ACR and ACC for activated stem, root and seed coat respectively. The effects of initial Pb(II) ion concentration, adsorbent dose, contact time, pH and ionic strength were studied to optimize the conditions required for maximum adsorption. At suitable condition (pH 8, contact time of 180, adsorbent dose of 1.4g, initial Pb(II) concentration of 40gL^-1), the adsorption capacities observed were 72.80% for ACR, 75.50% for ACS and 74.96% for ACC respectively. The mechanisms of the rate of adsorption were analyzed using pseudo 1^st and 2^nd order models. It was found that the adsorption mechanisms in the lead/adsorbents system follow the pseudo first order kinetics. The adsorption data were modeled by using both Langmuir and Freundlich isotherms. Freundlich isotherm was found to fit better fit in the experimental data than Langmuir isotherm. The result shows that ACS, ACR and ACC could be an effective adsorbents for Pb(II) removal.