Pedosphere 28(1): 35--43, 2018
ISSN 1002-0160/CN 32-1315/P
©2018 Soil Science Society of China
Published by Elsevier B.V. and Science Press
Citric Acid-Enhanced Electroremediation of Toxic Metal-Contaminated Dredged Sediments: Effect of Open/Closed Orifice Condition, Electric Potential and Surfactant
Yue SONG1,2, Ahmed BENAMAR1, Salim MEZAZIGH2, Huaqing WANG1
1Laboratoire Ondes et Milieux Complexes, UMR CNRS 6294, Université du Havre, 76600 Le Havre (France)
2Laboratoire Morphodynamique Continentale et Côtière, UMR CNRS 6143, Université de Caen, 14000 Caen (France)
Corresponding Author:Yue SONG
ABSTRACT
      Citric acid (CA), a widely used eco-friendly electrolyte, can be employed as an agent for enhancing toxic metal (TM) removal from contaminated dredged sediment using electrokinetic (EK) technology. In this study, dredged harbor sediments co-contaminated by TMs were subjected to enhanced EK treatment using a mixture of chelating agent (CA) and surfactant as an additive in the processing fluids. Several control conditions that may influence the efficiency of TM removal were tested, including open/closed sediment chamber orifices, electric potential gradients (0.5, 1.0, and 1.5 V cm-1), and electrolyte surfactant. Tween 20 (4 mmol L-1) was used as a surfactant within the electrolyte to investigate the extent of TM removal in sediment with high organic matter content. The results showed that an open orifice led to a greater electro-osmotic flow (EOF) with moderate TM removal. In contrast, a closed orifice with a nonionic surfactant electrolyte allowed the highest removal of TMs from the matrix. Moreover, increasing the electric potential gradient led to a higher EOF under the open orifice condition, but no significant increase in TM removal was observed owing to a higher accumulation of TMs in the middle of the matrix, caused by the opposite direction of EOF and electro-migration of metal-citrate complexes.
Key Words:  electric potential,electrokinetic remediation,electro-migration,electro-osmotic flow,electro-osmotic permeability,metal-citrate complex
Citation: Song Y, Benamar A, Mezazigh S, Wang H Q. 2018. Citric acid-enhanced electroremediation of toxic metal-contaminated dredged sediments:Effect of open/closed orifice condition, electric potential and surfactant. Pedosphere. 28(1):35-43.
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