Remediation of heavy metal-contaminated soil by electrokinetic processing enhanced using a resonance phenomenon with electromagnetic wave-particles

PurposeThe removal performance of the existing electrokinetic (EK) processing technology for heavy metal contaminants has been improved by electrolyte conditioning. Nevertheless, limitations remain in the removal of strongly bound forms or contaminants, such as residual fractions. Therefore, an alternative method would be required to improve the overall performance of EK processing. In this study, we aimed to evaluate a novel method using a resonance phenomenon to enhance the EK processing for remediation of heavy metal-contaminated soils.MethodsWe evaluated whether the performance of EK processing could be improved using the resonance phenomenon and conditioning of the existing electrolyte solution. First, the electrolyte solution was conditioned using acidic solutions, such as nitric acid and EDTA, and then an electromagnetic wave (7.83 Hz)-particle-enhanced experiment was performed to apply the resonance phenomenon.ResultsWhen only cationic heavy metals were treated, nitric acid had a higher removal efficiency than EDTA; however, when anionic arsenic and complex heavy metals were treated, EDTA, which acts as a chelator, was observed to be more suitable than nitric acid. Further, in an experiment to remove Cd, Pb, and As simultaneously the removal rate of heavy metals in the resonance-applied soil was repeatedly observed to be higher for all the above-mentioned heavy metals and anionic arsenic.ConclusionThe study confirmed that the removal of arsenic and heavy metal contaminants through EK could be improved by the simultaneous application of electromagnetic wave-particles and conditioning of the electrolyte solution.