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Poster communications

Improvement in electrokinetic remediation of heavy metals and pahs from dredged marine sediment

Abstract : Sediments are dredged from harbors and channels to maintain navigational depths. However harbor sediments are generally contaminated by organic and inorganic contaminants. Little contaminated sediments are typically disposed of at sea but highly contaminated sediments are rather disposed of in lagoons, at land or in confined disposal facilities and reuse solutions can be proposed if they are treated before. Electrokinetic (EK) remediation can be a promising treatment for the removal of cationic heavy metals from low-permeable matrices such as sediments but is limited for PAHs which are nonionic and have a low aqueous solubility. In our study, electrokinetic experiments were conducted under a constant potential gradient (1 V.cm-1) with various processing fluids to improve the decontamination of artificially contaminated sediments with heavy metals (Cd, Cr, Cu, Pb, Zn) and five PAHs. Results revealed that adding a strong inorganic acid (nitric acid) into the aqueous fluid was more effective than adding a weak acid (citric acid) to remove heavy metals from the sediment, but the complexing citric acid was promising for longer treatments. Concerning PAHs, an anionic surfactant (sodium dodecyl sulfate SDS) and a nonionic surfactant (Tween 20) were tested to mobilize, solubilize and favor their EK migration. In all experiments, the low weight PAH (phenanthrene) was better extracted than the other PAHs. But using simultaneously SDS and citric acid or Tween 20 and citric acid improved the extraction of high weight PAHs, because the electro-osmotic flow was higher with the mixture surfactant + acid than when surfactant was used without acidification of the medium. Thus EK treatment with a combination of a surfactant and citric acid was the most effective to extract simultaneously PAHs and heavy metals. Consequently, this mixture was also tested on real dredged sediments from a Norman harbour disposal site. Treatment with a periodic voltage is required as a promising solution, to eliminate both PAHs and heavy metals in sediment.
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Poster communications
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https://hal-normandie-univ.archives-ouvertes.fr/hal-02557972
Contributor : Florence Koltalo <>
Submitted on : Wednesday, May 6, 2020 - 11:49:33 AM
Last modification on : Thursday, July 2, 2020 - 3:29:49 AM

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  • HAL Id : hal-02557972, version 1

Citation

M Ammami, Florence Portet-Koltalo, A. Benamar, H. Wang. Improvement in electrokinetic remediation of heavy metals and pahs from dredged marine sediment. International Symposium on Sediment Management (I2SM, 4, 2014), Sep 2014, Ferrare, Italy. ⟨hal-02557972⟩

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