Batch leaching of Pb-contaminated shooting range soil using citric acid-modified washing solution and electrochemical reduction

  • E. U. EtimEmail author
Original Paper


This study examines the removal efficiency of lead from contaminated shooting range soils by different citric acid concentrations modified with potassium chloride. Concentrations of 0.01, 0.1 and 0.5 M citric acid were subjected to sequential single-batch washing experiment on 3, 6, 9, 12, 15 and 18% soil pulp density for 2, 4, 6, 8 and 10 h. Furthermore, 1 and 2 M potassium chloride-modified 0.01 M citric acid was subjected to similar washing experiment. The optimum washing conditions for the single-batch washing experiment were found to be 3% soil pulp density at 4 h. Under these conditions, lead removal efficiency was 25.1 ± 1.1, 80.9 ± 1.9 and 90.3 ± 2.6% for 0.01, 0.1 and 0.5 M citric acid solutions, respectively. Modification of low efficient 0.01 M citric acid solution using 1 and 2 M potassium chloride increases removal efficiency of lead by about a factor of two. Using 0.01 M citric acid mixed with 1 M potassium chloride, 77.6 ± 3.4% of lead was removed and 69.8 ± 1.9% by 0.01 M citric acid mixed with 2 M potassium chloride. Single-batch washing using potassium chloride-modified 0.01 M citric acid solution enhanced lead extraction from contaminated soils. Thus, low concentration biodegradable 0.01 M citric acid modified with potassium chloride is ecologically ideal for soil washing with little or no environmental concerns.


Contaminated soil Heavy metal Organic acid Potassium chloride Soil washing 



I gratefully acknowledge Akeju, Kemisola Ruth and Olanrewaju, Oladimeji Fiponmile for their assistance in setting up the laboratory scale washing experiment and chemical analysis of samples.

Compliance with ethical standards

Conflict of interest

There is no conflict of interest for this manuscript.


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Copyright information

© Islamic Azad University (IAU) 2018

Authors and Affiliations

  1. 1.Department of ChemistryUniversity of IbadanIbadanNigeria

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