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

Abstract

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 3,719 mg/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 0.9–1.0 mg/g, as it fitted Langmuir isotherm and followed pseudo-second-order kinetic model.

Keywords:

• Natural iron-rich sandy soil
• Lead
• Adsorption
• Adsorption kinetics
• Adsorption isotherm

Acknowledgements

This work was a part of a collaborative project between Queen’s University Belfast and University of Malaya and is financially supported by grant UM-QUB6A-2011 and PPP grant PG143-2012B, University of Malaya.