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Resistivity imaging of electrokinetic transport in soil.

West, L. J. and Stewart, D. I. and Binley, Andrew M. and Shaw, B. (1999) Resistivity imaging of electrokinetic transport in soil. Engineering Geology, 53 (2). pp. 205-219. ISSN 0013-7952

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Abstract

Electrical resistance imaging of soil specimens during electrokinetic treatment is reported. Column experiments were carried out on Speswhite kaolinite contaminated with lead nitrate to levels both above and below its cation exchange capacity (CEC). Post test chemical analyses of the specimens and their pore fluids show that resistivity variations correlate with changes in pore fluid chemistry but do not show the extent of decontamination. Regions of high resistivity correspond with precipitation zones within the specimens whereas regions of low resistivity correspond with regions of high pore fluid ionic strength. Where the contamination level is below the CEC, decontamination is slow as lead ions are mostly sorbed to the clay so most of the current is carried by electrolysis products and clay dissolution products. A broad resistive zone forms over the cathode half where hydroxyl and HCO−3 ions formed in the cathode reservoir precipitate clay with dissolution products and other ions. Where the contamination level is above the CEC, lead ions are initially major charge carriers and decontamination over the bulk of the specimen is rapid. However, lead still precipitates immediately adjacent to the cathode reservoir to form a narrow resistive region.

Item Type: Article
Journal or Publication Title: Engineering Geology
Uncontrolled Keywords: Clays ; Contaminated land ; Electrokinetics ; Environmental geotechnics ; Pollution migration/control ; Resistivity surveys
Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
Departments: Faculty of Science and Technology > Lancaster Environment Centre
ID Code: 21768
Deposited By: ep_ss_importer
Deposited On: 05 Feb 2009 13:48
Refereed?: Yes
Published?: Published
Last Modified: 26 Jul 2012 15:51
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/21768

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