Humic colloid-borne migration of uranium in sand columns.

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Publication Details

Output type: Journal article

Author list: Artinger, Rabung, Kim, Sachs, Schmeide, Heise, Bernhard, Nitsche

Publisher: Elsevier

Publication year: 2002

Journal: Journal of Contaminant Hydrology (0169-7722)

Volume number: 58

Issue number: 1-2

Start page: 1

End page: 12

Number of pages: 12

ISSN: 0169-7722

eISSN: 1873-6009

Languages: English-Great Britain (EN-GB)

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Open access status: closed

Abstract

Column experiments were carried out to investigate the influence of humic colloids on subsurface uranium migration. The columns were packed with well-characterized aeolian quartz sand and equilibrated with groundwater rich in humic colloids (dissolved organic carbon (DOC): 30 mg dm(-3)). U migration was studied under an Ar/1% CO2 gas atmosphere as a function of the migration time, which was controlled by the flow velocity or the column length. In addition, the contact time of U with groundwater prior to introduction into a column was varied. U(VI) was found to be the dominant oxidation state in the spiked groundwater. The breakthrough curves indicate that U was transported as a humic colloid-borne species with a velocity up to 5% faster than the mean groundwater flow. The fraction of humic colloid-borne species increases with increasing prior contact time and also with decreasing migration time. The migration behavior was attributed to a kinetically controlled association/dissociation of U onto and from humic colloids and also a subsequent sorption of U onto the sediment surface. The column experiments provide an insight into humic colloid-mediated U migration in subsurface aquifers.

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