Potential of Sawdust for the Decontamination of Lead from Aqueous Media

Abstract

Abstract The sorption of lead ions on sawdust has been exploited to evaluate its potential for the decontamination of lead ions from aqueous solutions. Various physico‐chemical parameters such as selection of appropriate electrolyte, equilibration time, amount of adsorbent, concentration of adsorbate, effect of diverse ions and temperature were studied in order to simulate the best conditions in which this material can be used as an adsorbent. Maximum adsorption was observed at 0.005 mol · L−1 acid solutions (HNO3, HCl, and HClO4) using 0.2 g of adsorbent for 4.83×10−5 mol · L−1 lead concentration in 10 min equilibration time. Studies show that the adsorption of lead decreases with the increase in the concentrations of all the acids. The adsorption data follows the Freundlich isotherm over the lead concentration range of 2.41×10−5 to 4.83×10−4 mol · L−1. The characteristic Freundlich constants, i.e., 1/n=0.49±0.02 and K=0.142±0.0038 m · mol · g−1 have been computed for the sorption system. The sorption mean free energy from the Dubinin‐Radushkevich isotherm is 11.26±0.31 kJ mol−1 indicating ion‐exchange mechanism of chemisorption. The uptake of lead decreases with the rise in temperature (293–323 K). Thermodynamic quantities, i.e., ΔG, ΔS, and ΔH have also been calculated for the system. The sorption process was found to be exothermic. The proposed procedure was applied for the removal of lead from battery water samples.