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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