Water Resources Research
Supporting Information for
Evaluating the Potential for Quantitative Monitoring of In Situ Chemical Oxidation
of Aqueous-Phase TCE Using In-Phase and Quadrature Electrical Conductivity
R. D. Hort1, A. Revil2, 3, J. Munakata-Marr1, and D. Mao2
(1) Colorado School of Mines, Dept of Civil and Environmental Engineering, Golden, CO, USA
(2) Colorado School of Mines, Dept of Geophysics, Golden, CO, USA
(3) ISTerre, CNRS, UMR 5275, Université de Savoie, Equipe Volcan, Le Bourget du Lac, France
Contents of this file
Figures S1 to S8 (aggregated into Data Sets 1 – 5)
Introduction
The eight following figures provide supplemental data to support the results discussed in
the parent document. The figures are organized into five datasets:
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Data Set 1 consists of Figure S1. This figure is a diagram of the two-dimensional
tank with electrode locations.
Data Set 2 consists of Figures S2 and S3. These figures compare quadrature
conductivity with and without the presence of dissolved TCE for clean sand (S2)
and for sand with 30% (v/v) smectite (S3). Data in Figure S2 were obtained
using the same instrumentation and sample holder as described in the methods
section of the parent document. Data in Figure S3predates the experiments
described in the parent document and were collected using a sealed glass bowl
with four silver-silver chloride electrodes inserted into the sample in a Wenner
array. An impedence spectrometer built by Forschungzentrum Jülich was used
to collect the complex resistivity data.
Data Set 3 consists of Figures S4 – S6. Figures S4 and S5 display the data
points that were used to calculate the formation factors presented in Table 2 of
the parent document for clean sand, 10% kaolinite, and 10% smectite with
artificial groundwater pore fluid (S4) and for clean sand with MnO2 precipitate
1
formed by the reaction of TCE with MnO4- (S5). Figure S6 shows the relationship
between formation factor in clean sand and the concentration of TCE that has
been oxidized.
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Data Set 4 consists of Figure S7. This figure compares electrical conductivity
and pH predictions based on stoichiometry and PHREEQC to observed values in
aqueous samples after complete oxidation of TCE by 10 mM KMnO4 in an
artificial groundwater with 2 mM HCO3-.
Data Set 5 consists of Figure S8. It contains bulk conductivity measurements for
porous media samples created by packing aqueous TCE oxidation samples with
clean sand, 10% kaolinite, or 10% smectite. The samples were packed after
reaction had completed. All aqueous samples originally had artificial
groundwater with 10 mM KMnO4 added, which resulted in complete
mineralization of the TCE present in all samples. Bulk conductivity was
measured two hours after packing. No flushing of any samples occurred after
packing.
2
Dataset 1
Figure S1. Diagram of the two-dimensional tank with resistivity electrode locations.
3
Dataset 2
Figure S2. Effect of TCE on quadrature conductivity in sand saturated with artificial
groundwater. Measurements were taken three hours after packing. Error bars
represent the range of duplicate samples.
Figure S3. Effect of 7.5 mM (1 g/L) dissolved TCE in tap water on quadrature
conductivity in a homogeneous saturated mixture of 30% smectite (by volume) in sand.
Error bars represent the standard deviation of triplicate samples.
Data Set 3
4
Figure S4. Formation factor (F) and surface conductivity (σs) after adding 10% kaolinite
or 10% smectite to clean sand. Varied conductivities were obtained by adding KCl or
NaCl to artificial groundwater. Error bars represent the 95% confidence interval for fluid
conductivity measurements. The formation factor and surface conductivity are given
plus or minus the 95% confidence interval for those calculations.
5
Figure S5. Formation factor (F) of saturated clean sand after precipitation of MnO2 from
oxidation of 2.1 to 7.5 mM TCE. Varied conductivities were obtained by adding KCl to
aqueous TCE oxidation samples prior to packing. Regression lines were forced through
the origin. Error bars represent 95% confidence intervals for pore fluid conductivity
measurements. Formation factor is reported plus or minus the 95% confidence interval.
6
Figure S6. Oxidized TCE concentration versus formation factor. Error bars represent
95% confidence intervals.
7
Data Set 4
Figure S7. Measured and predicted electrical conductivity and pH in aqueous samples
in which TCE was oxidized by 10 mM KMnO4 in artificial groundwater with 2 mM
NaHCO3. Predictions were based on Equation 5 using PHREEQC. Error bars represent
the standard deviation of at least three samples.
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Data Set 5
Figure S8. Observed bulk conductivity in porous media samples containing artificial
groundwater with 2 mM NaHCO3 and 10 KMnO4 in which various TCE concentrations
were oxidized. Error bars represent the standard deviation of at least two samples. The
lower bulk conductivity in kaolinite samples compared to clean sand reflects the higher
formation factor of 10% kaolinite. The effects of TCE oxidation and formation factor are
masked in the 10% smectite samples by the large concentration of ions present in the
smectite material used to create the samples.
9