Citric Acid-Enhanced Electroremediation of Toxic Metal-Contaminated Dredged Sediments： Effect of Open/Closed Orifice Condition, Electric Potential and Surfactant  

作　　者：Yue SONG Ahmed BENAMAR Salim MEZAZIGH Huaqing WANG 

机构地区：[1]Laboratoire Ondes et Milieux Complexes, UMR CNRS 6294, Universite du Havre, 76600 Le Havre ,France [2]Laboratoire Morphodynamique Continentale et Cotiere, UMR CNRS 6143, Universite de Caen, 14000 Caen ,France

出　　处：《Pedosphere》2018年第1期35-43,共9页土壤圈（英文版）

基　　金：financially supported by the Project SEDEVAR of the Research Network SCALE provided by the Normandy Region, France

摘　　要：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.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.

关 键 词：electric potential electrokinetic remediation electro-migration electro-osmotic flow electro-osmotic permeability metal-citrate complex 

分 类 号：X55[环境科学与工程—环境工程]