Elimination of lead using adsorption by pear peel

The aim of this study was to investigate the effects of pH, initial metal ions concentration and contact times in batch experiments to remove lead ion from aqueous solution by adsorption using pear peel (Pyrus pyrifolia) as a natural biosorbent.
For this purpose, four concentrations of 10, 50,100 and 250 mg/L, four times of 15, 30, 60 and 120 minutes and three pH values of 3, 4 and 5 were considered. Langmuir and Freundlich isotherm models, the critical factor determining the adsorption capacity of adsorbents and adsorption processes of design were evaluated in this study.
Findings: The optimal pH value for Pb adsorption onto the pear peel was found to be 5. Metal uptake capacity of Pb increased by increasing the initial metal ion concentrations,so that the maximum amount of lead was determined at a concentration of 250 mg/L. Maximum adsorption capacity for lead was estimated after 60 minutes. The equilibrium process was described well by the Langmuir isotherm model.