Performance evaluation of natural iron-rich sandy soil as a low-cost adsorbent for removal of lead from water

Technical feasibility of natural iron-rich sandy soil as a low-cost adsorbent for removal of lead from water was investigated . The soil, which had an iron content of 3,719mg/kg, was collected from Hulu Langat, Malaysia, and was used for adsorption studies without any surface modification through chemical treatment. The effects of pH, solution: soil ratio and initial lead concentration on the adsorption efficiency were studied using response surface methodology based on Box-Behnken experimental design. The results showed that pH of the solution had the highest impact on the adsorption efficiency whereby adsorption efficiency of 97% could be achieved at pH 3.5-5. The experimental data were also checked for compliance with different kinetic models and adsorption isotherms. The adsorption process was found to be rapid monolayer chemisorption with adsorption capacity of 0.9-1.0mg/g, as it fitted Langmuir isotherm and followed pseudo-second-order kinetic model.