Title: Acidification of harbor sediment and removal of heavy metals induced by water splitting in electrodialytic remediation 
Resource Type: document --> technical publication --> journal article 
Country: USA 
Year: 2005 
Availability: SEPARATION SCIENCE AND TECHNOLOGY 40 (11): 2245-2264 2005 Author (s): Nystroem GM, Ottosen LM, Villumsen A Year: 2005 Title: Acidification of harbor sediment and removal of heavy metals induced by water splitting in electrodialytic remediation Source detail: SEPARATION SCIENCE AND TECHNOLOGY 40 (11): 2245-2264 2005 Publisher: TAYLOR & FRANCIS INC Publishers detail: PHILADELPHIA USA ISSN/IDBN: 0149-6395/965MI 
Author 1/Producer: Nystroem GM, 
Other Authors/Producers: Ottosen LM, Villumsen A 
Author / Producer Type: University research group / research institute 
Publisher: TAYLOR & FRANCIS INC 
Publisher City: 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA 
ISSN: 0149-6395/965MI 
Article Weblink (=direct link): http://portal.isiknowledge.com/portal.cgi?DestApp=WOS&Func=F ...  
Format (e.g. PDF): HTML 
EUGRIS Keyword(s): Sediments
 
Short description: ION-EXCHANGE MEMBRANES; SOIL REMEDIATION; ELECTRIC-FIELD; ZN; PB; CU; DISSOCIATION; CADMIUM; CD 
Long description: Harbor sediments are often contaminated with heavy metals, which can be removed by electrodialytic remediation. Water splitting at the anion exchange membrane in contact with the contaminated material in electrodialytic remediation is highly important for the removal of heavy metals. Here it was investigated how acidification caused by water splitting at the anion exchange membrane during electrodialytic remediation of contaminated harbor sediment and hence the metal removal, was influenced by different experimental conditions. Two different experimental cells were tested, where the number of compartments and ion exchange membranes differed. Totally, 14 electrodialytic experiments were made, with varying remediation time, current densities, and liquid to solid ratio (L/S). pH in the sediment decreased slightly after 1 day of remediation, even if the sediment had a high buffering capacity, suggesting that water splitting at the anion exchange membrane started early in the remediation process. An increase in the voltage over the cell and a decrease in the electrical conductivity in the sediment suspension also indicated that the water splitting started within 1 day of remediation. When the sediment was acidified, the voltage decreased and electrical conductivity increased. After 5 days of remediation the sediment was acidified at the chosen current density (1 mA/cm(2)) and the main metal removal was observed shortly after. Thus it was crucial for the metal removal that the sediment was fully acidified. Lower metal removal was seen in an experimental cell with three compartments compared to five compartments, due to increased sensitivity of pH changes in the cell. Author Keywords: heavy metals; sediment; electrodialysis; water splitting; ion exchange membranes 
Submitted By: Dr Katalin Gruiz WhoDoesWhat?      Last update: 07/11/2005