Removal of Lead from Aqueous Solution by an Efficient Low Cost Biosorbent

Removal of Pb(II) ion from aqueous solution on modified sawdust obtained from Morus alba was investigated. The sample was characterized by BET surface area, EDX, FTIR and Zeta potential technique. The surface contains carbonyl and hydroxyl functional groups which act as binding sites for Pb(II) ion. Adsorption kinetics of Pb(II) on sawdust was tested by pseudo first order, Elovich and parabolic diffusion kinetic equations. The adsorption data were found to fit to Freundlich, Langmuir and Tempkin isotherms. The rate of adsorption was high at high temperature. Thermodynamic parameters like Delta H, Delta S and Delta G were calculated from the kinetic data. The positive values of AS reflect some structural exchange among the active site of the adsorbent and metal ion. The negative values of Gibbs free energy (Delta G) show the spontaneous nature of the process.