Humic substances-enhanced electroremediation of heavy metals contaminated soil

•Using humic acids and fulvic acids as chelating agents to improve EK efficiency.•HSs-enhanced EK efficiency was about 2–3 times greater than that in unenhanced EK.•Fulvic acids provided higher HMs removal than humic acids.•Results indicate the suitability of HSs-enhanced EK in real HMs contaminated...

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Bibliographic Details
Published in:Journal of hazardous materials 2016-07, Vol.312, p.307-318
Main Authors: Bahemmat, Mahdi, Farahbakhsh, Mohsen, Kianirad, Mehran
Format: Article
Language:English
Subjects:
Catholytes
Cations
Charging
Conditioning
Contamination
Electrokinetic remediation
Fulvic acids
Heavy metals
Humic acids
Remediation
Soil (material)
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Summary:•Using humic acids and fulvic acids as chelating agents to improve EK efficiency.•HSs-enhanced EK efficiency was about 2–3 times greater than that in unenhanced EK.•Fulvic acids provided higher HMs removal than humic acids.•Results indicate the suitability of HSs-enhanced EK in real HMs contaminated soil. The effects of catholyte conditioning and the use of humic acids (HAs) and fulvic acids (FAs) as chelating agents to improve electrokinetic (EK) remediation efficiency were investigated using a real and highly contaminated soil. By applying a constant voltage (2.0V/cm) to the soil, pH and current changes and heavy metals (HMs) concentration were investigated through a range of durations and positions. The observations demonstrated that both catholyte conditioning with 0.1N HNO3 and using humic substances (HSs) enhance remediation efficiency. After 20 days of EK treatment, the removal efficiency of HMs in HS-enhanced EK remediation was about 2.0–3.0 times greater than when unenhanced. The quantity of HMs moving toward the cathode exceeded the anode, from which it could be reasonably inferred that most negatively charged HM-HS complexes were moved by electroosmotic forces. Further, free HM cations and positively charged complexed HMs migrated to the catholyte compartment by electromigration. The results obtained in this study, demonstrate the suitability of HS-enhanced EK remediation in HMs contaminated soil.
ISSN:0304-3894
1873-3336
DOI:10.1016/j.jhazmat.2016.03.038