Performance evaluation of two-stage electrokinetic washing as soil remediation method for lead removal using different wash solutions

Yee Sern Ng, Bhaskar Sen Gupta  , Mohd Ali Hashim

    Research output: Contribution to journalArticlepeer-review

    18 Citations (Scopus)


    The study explores the application of a two-stage electrokinetic washing system on remediation of lead (Pb) contaminated soil. The process involved an initial soil washing, followed by an electrokinetic process. The use of electrokinetic process in soil washing not only provided additional driving force for transporting the desorbed Pb away from the soil but also reduced the high usage of wash solution. In this study, the effect of NaNO3, HNO3, citric acid and EDTA as wash solutions on two-stage electrokinetic washing system were evaluated. The results revealed that a two-stage electrokinetic washing process enhanced Pb removal efficiency by 2.52-9.08% and 4.98-20.45% in comparison to a normal electrokinetic process and normal washing process, respectively. Low pH and adequate current were the most important criteria in the removal process as they provided superior desorption and transport properties. The effect of chelating by EDTA was less dominant as it delayed the removal process by forming a transport loop in anode region between Pb ion and complexes. HNO3 was not suitable as wash solution in electrokinetic washing in spite of offering highest removal efficiency as it caused pH fluctuation in the cathode chamber, corroded graphite anode and showed high power consumption. In contrast, citric acid not only yielded high Pb removal efficiency with low power consumption but also maintained a low soil: solution ratio of 1 g: <1 mL, stable pH and electrode integrity. Possible transport mechanisms for Pb under each wash solution are also discussed in this work.
    Original languageEnglish
    Pages (from-to)9-18
    Number of pages10
    JournalElectrochimica Acta
    Publication statusPublished - 20 Nov 2014


    • Two-stage electrokinetic washing; soil treatment; lead; wash solutions; transport mechanisms


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