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Kang X, Power C, Kokkinaki A, Revil A, Wu J, Shi X, Deng Y. Characterization of DNAPL source zones in clay-sand media via joint inversion of DC resistivity, induced polarization and borehole data. JOURNAL OF CONTAMINANT HYDROLOGY 2023; 258:104240. [PMID: 37683375 DOI: 10.1016/j.jconhyd.2023.104240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 07/26/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023]
Abstract
Toxic organic contaminants in groundwater are pervasive at many industrial sites worldwide. These contaminants, such as chlorinated solvents, often appear as dense non-aqueous phase liquids (DNAPLs). To design efficient remediation strategies, detailed characterization of DNAPL Source Zone Architecture (SZA) is required. Since invasive borehole-based investigations suffer from limited spatial coverage, a non-intrusive geophysical method, direct current (DC) resistivity, has been applied to image the DNAPL distribution; however, in clay-sand environments, the ability of DC resistivity for DNAPLs imaging is limited since it cannot separate between DNAPLs and surrounding clay-sand soils. Moreover, the simplified parameterization of conventional inversion approaches cannot preserve physically realistic patterns of SZAs, and tends to smooth out any sharp spatial variations. In this paper, the induced polarization (IP) technique is combined with DC resistivity (DCIP) to provide plausible DNAPL characterization in clay-sand environments. Using petrophysical models, the DCIP data is utilized to provide tomograms of the DNAPL saturation (SN) and hydraulic conductivity (K). The DCIP-estimated K/SN tomograms are then integrated with borehole measurements in a deep learning-based joint inversion framework to accurately parameterize the highly irregular SZA and provide a refined DNAPL image. To evaluate the performance of the proposed approach, we conducted numerical experiments in a heterogeneous clay-sand aquifer with a complex SZA. Results demonstrate the standalone DC resistivity method fails to infer the DNAPL in complex clay-sand environments. In contrast, the combined DCIP technique provides the necessary information to reconstruct the large-scale features of K/SN fields, while integrating DCIP data with sparse but accurate borehole data results in a high resolution characterization of the SZA.
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Affiliation(s)
- Xueyuan Kang
- Key Laboratory of Surficial Geochemistry of Ministry of Education, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China
| | - Christopher Power
- Department of Civil and Environmental Engineering, Western University, London, Ontario N6A 5B9, Canada
| | - Amalia Kokkinaki
- Department of Environmental Science, University of San Francisco, San Francisco, CA 94117, USA
| | - André Revil
- Univ. Grenoble Alpes, Univ. Savoie Mont-Blanc, CNRS, UMR CNRS 5204, EDYTEM, 73370 Le Bourget du Lac, France
| | - Jichun Wu
- Key Laboratory of Surficial Geochemistry of Ministry of Education, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China.
| | - Xiaoqing Shi
- Key Laboratory of Surficial Geochemistry of Ministry of Education, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China.
| | - Yaping Deng
- School of Natural Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
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Hao N, You Y, Zhan LT, Bate B. Evaluation of aqueous Cd 2+ and Pb 2+ removal by natural loess using spectral induced polarization and microscopic characterization. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:50500-50514. [PMID: 35230635 DOI: 10.1007/s11356-022-19307-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 02/15/2022] [Indexed: 06/14/2023]
Abstract
Mining and landfill activities can cause serious soil and groundwater contamination with lead (Pb) and cadmium (Cd). Loess soils are common and have been reported as effective for the removal of heavy metals. The spectral induced polarization (SIP) technique has been approved for its nondestructive ability to characterize the contaminant transport process and surface geochemical properties in porous media. In the present study, SIP was applied to monitor Pb2+ and Cd2+ removal processes using loess through column flow-through experiments. The outflow aqueous geochemical analyses indicated a better retention capability of loess for Pb2+, which was through precipitation induced by calcite dissolution and aqueous pH increment, as confirmed by SEM-EDS and XRD results. Cd retention took place mainly through ion exchange with Ca2+ and Mg2+ on the loess surface. The SIP signals showed a continuous decrement on the magnitude of imaginary conductivity during both Pb2+ and Cd2+ flow-through, which was attributed to the total surface area and decrement of polarizable surface charges. The SIP signals differentiated the interactions between loess and Pb2+/Cd2+ by displaying a peak shift to a higher frequency on the imaginary conductivity spectra during Pb2+ flow-through, which was attributed to calcite dissolution and proved by the high correlation (R2 = 0.9366) between the estimated dissolved calcite mass and the peak of imaginary conductivity. The above results suggest that loess has a great potential for field heavy metal remediation applications, and the SIP technique displays a promising capability of monitoring the remediation performance.
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Affiliation(s)
- Na Hao
- MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, 310058, China.
| | - Yuqing You
- MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, 310058, China
| | - Liang-Tong Zhan
- MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, 310058, China
| | - Bate Bate
- MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, 310058, China
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3
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Hao N, Cao J, Ye J, Zhang C, Li C, Bate B. Content and morphology of lead remediated by activated carbon and biochar: A spectral induced polarization study. JOURNAL OF HAZARDOUS MATERIALS 2021; 411:124605. [PMID: 33465543 DOI: 10.1016/j.jhazmat.2020.124605] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 11/04/2020] [Accepted: 11/14/2020] [Indexed: 06/12/2023]
Abstract
Soil and groundwater contamination with lead (Pb) poses serious challenges for the environment. Activated carbon (AC) and biochar have huge potential application in the in-situ remediation processes through permeable reactive barriers (PRB). Spectral induced polarization (SIP) technique recently showed promises in nondestructively monitoring the spatio-temporal characteristics of physical, chemical and biological processes in porous media. In this study SIP technique was used for monitoring Pb remediation by AC and biochar in column scale. The calculated characteristic grain/pore size evolutions from SIP signals on AC, agreed well with the size of precipitates measured by SEM and mercury intrusion porosimetry (MIP) methods. The content increment process of the retained Pb on AC was also recorded via the magnitude increment of the imaginary conductivity. The mechanisms of Pb-AC and Pb-biochar interactions were investigated using SEM-EDS, TEM, FTIR, XRD, and XPS measurements. It showed that AC immobilizes through physical adsorption and precipitation, whereas complexation with functional groups is the remediation mechanism for biochar. Furthermore, the observed SIP responses of both AC and biochar are two orders of magnitude higher than those of typical natural soils or silica materials. This distinct difference is an additional advantage for the field application of SIP technique in PRB scenarios.
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Affiliation(s)
- Na Hao
- MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China
| | - Junnan Cao
- Department of Civil Engineering and Construction, Georgia Southern University, 1332 Southern Drive, Statesboro 30458, GA, USA
| | - Jianshe Ye
- MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China
| | - Chi Zhang
- Institut für Meteorologie und Geophysik (IMGW), University of Vienna, Vienna, Austria
| | - Chen Li
- Shandong Provincial Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266000, China
| | - Bate Bate
- MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China.
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4
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Mellage A, Holmes AB, Linley S, Vallée L, Rezanezhad F, Thomson N, Gu F, Van Cappellen P. Sensing Coated Iron-Oxide Nanoparticles with Spectral Induced Polarization (SIP): Experiments in Natural Sand Packed Flow-Through Columns. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:14256-14265. [PMID: 30485742 DOI: 10.1021/acs.est.8b03686] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The development of nanoparticle-based soil remediation techniques is hindered by the lack of accurate in situ nanoparticle (NP) monitoring and characterization methods. Spectral induced polarization (SIP), a noninvasive geophysical technique, offers a promising approach to detect and quantify NPs in porous media. However, its successful implementation as a monitoring tool requires an understanding of the polarization mechanisms, the governing NP-associated SIP responses and their dependence on the stabilizing coatings that are typically used for NPs deployed in environmental applications. Herein, we present SIP responses (0.1-10 000 Hz) measured during injection of a poloxamer-coated superparamagnetic iron-oxide nanoparticle (SPION) suspension in flow-through columns packed with natural sand from the Borden aquifer. An advective-dispersive transport model is fitted to outflow SPION concentration measurements to compute average concentrations over the SIP spatial response domain (within the columns). The average SPION concentrations are compared with the real and imaginary components of the complex conductivity. Excellent correspondence is found between the average SPION concentrations in the columns and the imaginary conductivity values, suggesting that NP-mediated polarization (that is, charge storage) increases proportionally with increasing SPION concentration. Our results support the possibility of SIP monitoring of spatial and temporal NP distributions, which can be immediately deployed in bench-scale studies with the prospect of future real-world field applications.
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Affiliation(s)
- Adrian Mellage
- Ecohydrology Research Group, Water Institute and Department of Earth and Environmental Sciences , University of Waterloo , 200 University Avenue West , Watterloo , Ontario N2L 3G1 , Canada
| | - Andrew B Holmes
- Waterloo Institute of Nanotechnology and Department of Chemical Engineering , University of Waterloo , 200 University Ave West , Watterloo , Ontario N2L 3G1 , Canada
| | - Stuart Linley
- Waterloo Institute of Nanotechnology and Department of Chemical Engineering , University of Waterloo , 200 University Ave West , Watterloo , Ontario N2L 3G1 , Canada
| | - Laureline Vallée
- Ecohydrology Research Group, Water Institute and Department of Earth and Environmental Sciences , University of Waterloo , 200 University Avenue West , Watterloo , Ontario N2L 3G1 , Canada
- Département de Chimie, UFR Sciences , Université d'Angers , 2 bd de Lavoisier , 49000 Angers , France
| | - Fereidoun Rezanezhad
- Ecohydrology Research Group, Water Institute and Department of Earth and Environmental Sciences , University of Waterloo , 200 University Avenue West , Watterloo , Ontario N2L 3G1 , Canada
| | - Neil Thomson
- Department of Civil and Environmental Engineering , University of Waterloo , 200 University Ave West , Watterloo , Ontario N2L 3G1 , Canada
| | - Frank Gu
- Waterloo Institute of Nanotechnology and Department of Chemical Engineering , University of Waterloo , 200 University Ave West , Watterloo , Ontario N2L 3G1 , Canada
| | - Philippe Van Cappellen
- Ecohydrology Research Group, Water Institute and Department of Earth and Environmental Sciences , University of Waterloo , 200 University Avenue West , Watterloo , Ontario N2L 3G1 , Canada
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Mellage A, Smeaton CM, Furman A, Atekwana EA, Rezanezhad F, Van Cappellen P. Linking Spectral Induced Polarization (SIP) and Subsurface Microbial Processes: Results from Sand Column Incubation Experiments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:2081-2090. [PMID: 29336556 DOI: 10.1021/acs.est.7b04420] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Geophysical techniques, such as spectral induced polarization (SIP), offer potentially powerful approaches for in situ monitoring of subsurface biogeochemistry. The successful implementation of these techniques as monitoring tools for reactive transport phenomena, however, requires the deconvolution of multiple contributions to measured signals. Here, we present SIP spectra and complementary biogeochemical data obtained in saturated columns packed with alternating layers of ferrihydrite-coated and pure quartz sand, and inoculated with Shewanella oneidensis supplemented with lactate and nitrate. A biomass-explicit diffusion-reaction model is fitted to the experimental biogeochemical data. Overall, the results highlight that (1) the temporal response of the measured imaginary conductivity peaks parallels the microbial growth and decay dynamics in the columns, and (2) SIP is sensitive to changes in microbial abundance and cell surface charging properties, even at relatively low cell densities (<108 cells mL-1). Relaxation times (τ) derived using the Cole-Cole model vary with the dominant electron accepting process, nitrate or ferric iron reduction. The observed range of τ values, 0.012-0.107 s, yields effective polarization diameters in the range 1-3 μm, that is, 2 orders of magnitude smaller than the smallest quartz grains in the columns, suggesting that polarization of the bacterial cells controls the observed chargeability and relaxation dynamics in the experiments.
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Affiliation(s)
- Adrian Mellage
- University of Waterloo , Water Institute and Department of Earth & Environmental Sciences, 200 University Ave. W, Waterloo, Ontario Canada N2L 3G1
| | - Christina M Smeaton
- University of Waterloo , Water Institute and Department of Earth & Environmental Sciences, 200 University Ave. W, Waterloo, Ontario Canada N2L 3G1
| | - Alex Furman
- Technion - Israel Institute of Technology , Civil and Environmental Engineering, Haifa 32000, Israel
| | - Estella A Atekwana
- Oklahoma State University , Boone Pickens School of Geology, 105 Noble Research Center, Stillwater, Oklahoma 74078, United States
- University of Delaware , Department of Geological Sciences, College of Earth, Ocean, and Environment, Newark, Delaware 19716, United States
| | - Fereidoun Rezanezhad
- University of Waterloo , Water Institute and Department of Earth & Environmental Sciences, 200 University Ave. W, Waterloo, Ontario Canada N2L 3G1
| | - Philippe Van Cappellen
- University of Waterloo , Water Institute and Department of Earth & Environmental Sciences, 200 University Ave. W, Waterloo, Ontario Canada N2L 3G1
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Hao N, Moysey SMJ, Powell BA, Ntarlagiannis D. Evaluation of Surface Sorption Processes Using Spectral Induced Polarization and a (22)Na Tracer. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:9866-9873. [PMID: 26191613 DOI: 10.1021/acs.est.5b01327] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We investigate mechanisms controlling the complex electrical conductivity of a porous media using noninvasive spectral induced polarization (SIP) measurements of a silica gel during a pH dependent surface adsorption experiment. Sorption of sodium on silica gel surfaces was monitored as the pH of a column was equilibrated at 5.0 and then successively raised to 6.5 and 8.0, but the composition of the 0.01 M NaCl solution was otherwise unchanged. SIP measurements show an increase in the imaginary conductivity of the sample (17.82 ± 0.07 μS/cm) in response to the pH change, interpreted as deprotonation of silanol groups on the silica gel surface followed by sorption of sodium cations. Independent measurements of Na(+) accumulation on grain surfaces performed using a radioactive (22)Na tracer support the interpretation of pH-dependent sorption as a dominant process controlling the electrical properties of the silica gel (R(2) = 0.99) and confirms the importance of grain polarization (versus membrane polarization) in influencing SIP measurements of silicate minerals. The number of surface sorption sites estimated by fitting a mechanistic, triple-layer model for the complex conductivity to the SIP data (13.22 × 10(16) sites/m(2)) was 2.8 times larger than that estimated directly by a (22)Na mass balance (5.13 × 10(16) sites/m(2)), suggesting additional contributions to polarization exist.
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Affiliation(s)
- Na Hao
- †Environmental Engineering and Earth Sciences, Clemson University, Clemson, South Carolina 29634, United States
| | - Stephen M J Moysey
- †Environmental Engineering and Earth Sciences, Clemson University, Clemson, South Carolina 29634, United States
| | - Brian A Powell
- †Environmental Engineering and Earth Sciences, Clemson University, Clemson, South Carolina 29634, United States
| | - Dimitrios Ntarlagiannis
- ‡Earth and Environmental Sciences, Rutgers University, Newark, New Jersey 07102, United States
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Malama B, Revil A. Modeling transient streaming potentials in falling-head permeameter tests. GROUND WATER 2014; 52:535-549. [PMID: 23782328 DOI: 10.1111/gwat.12081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We present transient streaming potential data collected during falling-head permeameter tests performed on samples of two sands with different physical and chemical properties. The objective of the work is to estimate hydraulic conductivity (K) and the electrokinetic coupling coefficient (Cl ) of the sand samples. A semi-empirical model based on the falling-head permeameter flow model and electrokinetic coupling is used to analyze the streaming potential data and to estimate K and Cl . The values of K estimated from head data are used to validate the streaming potential method. Estimates of K from streaming potential data closely match those obtained from the associated head data, with less than 10% deviation. The electrokinetic coupling coefficient was estimated from streaming potential vs. (1) time and (2) head data for both sands. The results indicate that, within limits of experimental error, the values of Cl estimated by the two methods are essentially the same. The results of this work demonstrate that a temporal record of the streaming potential response in falling-head permeameter tests can be used to estimate both K and Cl . They further indicate the potential for using transient streaming potential data as a proxy for hydraulic head in hydrogeology applications.
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Affiliation(s)
- Bwalya Malama
- Colorado School of Mines, Department of Geophysics, Golden, CO 80401
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Personna YR, Slater L, Ntarlagiannis D, Werkema D, Szabo Z. Complex resistivity signatures of ethanol in sand-clay mixtures. JOURNAL OF CONTAMINANT HYDROLOGY 2013; 149:76-87. [PMID: 23603518 DOI: 10.1016/j.jconhyd.2013.03.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 03/17/2013] [Accepted: 03/22/2013] [Indexed: 06/02/2023]
Abstract
We performed complex resistivity (CR) measurements on laboratory columns to investigate changes in electrical properties as a result of varying ethanol (EtOH) concentration (0% to 30% v/v) in a sand-clay (bentonite) matrix. We applied Debye decomposition, a phenomenological model commonly used to fit CR data, to determine model parameters (time constant: τ, chargeability: m, and normalized chargeability: mn). The CR data showed a significant (P≤0.001) time-dependent variation in the clay driven polarization response (~12 mrad) for 0% EtOH concentration. This temporal variation probably results from the clay-water reaction kinetics trending towards equilibrium in the sand-clay-water system. The clay polarization is significantly suppressed (P≤0.001) for both measured phase (ϕ) and imaginary conductivity (σ″) with increasing EtOH concentration. Normalized chargeability consistently decreases (by up to a factor of ~2) as EtOH concentration increases from 0% to 10% and 10 to 20%, respectively. We propose that such suppression effects are associated with alterations in the electrical double layer (EDL) at the clay-fluid interface due to (a) strong EtOH adsorption on clay, and (b) complex intermolecular EtOH-water interactions and subsequent changes in ionic mobility on the surface in the EDL. Changes in the CR data following a change of the saturating fluid from EtOH 20% to plain water indicate strong hysteresis effects in the electrical response, which we attribute to persistent EtOH adsorption on clay. Our results demonstrate high sensitivity of CR measurements to clay-EtOH interactions in porous media, indicating the potential application of this technique for characterization and monitoring of ethanol contamination in sediments containing clays.
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Affiliation(s)
- Yves Robert Personna
- Department of Earth and Environmental Sciences, Rutgers University, 101 Warren Street, Newark, NJ 07102, USA.
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Placencia-Gómez E, Slater L, Ntarlagiannis D, Binley A. Laboratory SIP signatures associated with oxidation of disseminated metal sulfides. JOURNAL OF CONTAMINANT HYDROLOGY 2013; 148:25-38. [PMID: 23531431 DOI: 10.1016/j.jconhyd.2013.02.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 01/05/2013] [Accepted: 02/17/2013] [Indexed: 06/02/2023]
Abstract
Oxidation of metal sulfide minerals is responsible for the generation of acidic waters rich in sulfate and metals. When associated with the oxidation of sulfide ore mine waste deposits the resulting pore water is called acid mine drainage (AMD); AMD is a known environmental problem that affects surface and ground waters. Characterization of oxidation processes in-situ is challenging, particularly at the field scale. Geophysical techniques, spectral induced polarization (SIP) in particular, may provide a means of such investigation. We performed laboratory experiments to assess the sensitivity of the SIP method to the oxidation mechanisms of common sulfide minerals found in mine waste deposits, i.e., pyrite and pyrrhotite, when the primary oxidant agent is dissolved oxygen. We found that SIP parameters, e.g., phase shift, the imaginary component of electrical conductivity and total chargeability, decrease as the time of exposure to oxidation and oxidation degree increase. This observation suggests that dissolution-depletion of the mineral surface reduces the capacitive properties and polarizability of the sulfide minerals. However, small increases in the phase shift and imaginary conductivity do occur during oxidation. These transient increases appear to correlate with increases of soluble oxidizing products, e.g., Fe(2+) and Fe(3+) in solution; precipitation of secondary minerals and the formation of a passivating layer to oxidation coating the mineral surface may also contribute to these increases. In contrast, the real component of electrical conductivity associated with electrolytic, electronic and interfacial conductance is sensitive to changes in the pore fluid chemistry as a result of the soluble oxidation products released (Fe(2+) and Fe(3+)), particularly for the case of pyrrhotite minerals.
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Affiliation(s)
- Edmundo Placencia-Gómez
- Aalto University School of Engineering, Department of Civil and Environmental Engineering, P.O. Box 16200, FI-00076 Aalto, Finland.
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Revil A. Effective conductivity and permittivity of unsaturated porous materials in the frequency range 1 mHz-1GHz. WATER RESOURCES RESEARCH 2013; 49:306-327. [PMID: 23576823 PMCID: PMC3618403 DOI: 10.1029/2012wr012700] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Revised: 11/26/2012] [Accepted: 11/29/2012] [Indexed: 05/31/2023]
Abstract
A model combining low-frequency complex conductivity and high-frequency permittivity is developed in the frequency range from 1 mHz to 1 GHz. The low-frequency conductivity depends on pore water and surface conductivities. Surface conductivity is controlled by the electrical diffuse layer, the outer component of the electrical double layer coating the surface of the minerals. The frequency dependence of the effective quadrature conductivity shows three domains. Below a critical frequency fp , which depends on the dynamic pore throat size Λ, the quadrature conductivity is frequency dependent. Between fp and a second critical frequency fd , the quadrature conductivity is generally well described by a plateau when clay minerals are present in the material. Clay-free porous materials with a narrow grain size distribution are described by a Cole-Cole model. The characteristic frequency fd controls the transition between double layer polarization and the effect of the high-frequency permittivity of the material. The Maxwell-Wagner polarization is found to be relatively negligible. For a broad range of frequencies below 1 MHz, the effective permittivity exhibits a strong dependence with the cation exchange capacity and the specific surface area. At high frequency, above the critical frequency fd , the effective permittivity reaches a high-frequency asymptotic limit that is controlled by the two Archie's exponents m and n like the low-frequency electrical conductivity. The unified model is compared with various data sets from the literature and is able to explain fairly well a broad number of observations with a very small number of textural and electrochemical parameters. It could be therefore used to interpret induced polarization, induction-based electromagnetic methods, and ground penetrating radar data to characterize the vadose zone.
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Affiliation(s)
- A Revil
- Department of Geophysics, Colorado School of Mines, Green Center Golden, Colorado, USA ; ISTerre, CNRS, UMR CNRS 5275, Université de Savoie Le Bourget du Lac, France
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Schwartz N, Furman A. Spectral induced polarization signature of soil contaminated by organic pollutant: Experiment and modeling. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012jb009543] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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