Electrical signatures of ethanol–liquid mixtures: Implications for monitoring biofuels migration in the subsurface
| Autor: | Dimitrios Ntarlagiannis, Lee Slater, Zoltan Szabo, D. Dale Werkema, Yves Robert Personna |
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| Rok vydání: | 2013 |
| Předmět: |
Geological Phenomena
Ethanol Water Pollution Intermolecular force Electric Conductivity Analytical chemistry Water Models Theoretical Low frequency Conductivity Solutions Matrix (chemical analysis) chemistry.chemical_compound chemistry Electrical resistivity and conductivity Biofuels Environmental chemistry Environmental Chemistry Electrical measurements Polarization (electrochemistry) Groundwater Water Pollutants Chemical Environmental Monitoring Water Science and Technology |
| Zdroj: | Journal of Contaminant Hydrology. 144:99-107 |
| ISSN: | 0169-7722 |
| DOI: | 10.1016/j.jconhyd.2012.10.011 |
| Popis: | Ethanol (EtOH), an emerging contaminant with potential direct and indirect environmental effects, poses threats to water supplies when spilled in large volumes. A series of experiments was directed at understanding the electrical geophysical signatures arising from groundwater contamination by ethanol. Conductivity measurements were performed at the laboratory scale on EtOH-water mixtures (0 to 0.97 v/v EtOH) and EtOH-salt solution mixtures (0 to 0.99 v/v EtOH) with and without a sand matrix using a conductivity probe and a four-electrode electrical measurement over the low frequency range (1-1000 Hz). A Lichtenecker-Rother (L-R) type mixing model was used to simulate electrical conductivity as a function of EtOH concentration in the mixture. For all three experimental treatments increasing EtOH concentration resulted in a decrease in measured conductivity magnitude (|σ|). The applied L-R model fitted the experimental data at concentration ≤0.4v/v EtOH, presumably due to predominant and symmetric intermolecular (EtOH-water) interaction in the mixture. The deviation of the experimental |σ| data from the model prediction at higher EtOH concentrations may be associated with hydrophobic effects of EtOH-EtOH interactions in the mixture. The |σ| data presumably reflected changes in relative strength of the three types of interactions (water-water, EtOH-water, and EtOH-EtOH) occurring simultaneously in EtOH-water mixtures as the ratio of EtOH to water changed. No evidence of measurable polarization effects at the EtOH-water and EtOH-water-mineral interfaces over the investigated frequency range was found. Our results indicate the potential for using electrical measurements to characterize and monitor EtOH spills in the subsurface. |
| Databáze: | OpenAIRE |
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