Assessing the high frequency behavior of non-polarizable electrodes for spectral induced polarization measurements

Abstract

During the last decades, the usage of spectral induced polarization (SIP) measurements in hydrogeology and detecting environmental problems has been extensively increased. However, the physical mechanisms which are responsible for the induced polarization response over the usual frequency range (typically 1 mHz to 10-20 kHz) require better understanding. The phase shift observed at high frequencies is sometimes attributed to the so-called Maxwell-Wagner polarization which takes place when charges cross an interface. However, SIP measurements of tap water show a phase shift at frequencies higher than 1 kHz, where no Maxwell-Wagner polarization may occur. In this paper, we enlighten the possible origin of this phase shift and deduce its likely relationship with the types of the measuring electrodes. SIP Laboratory measurements of tap water using different types of measuring electrodes (polarizable and non-polarizable electrodes) are carried out to detect the origin of the phase shift at high frequencies and the influence of the measuring electrodes types on the observed complex resistivity. Sodium chloride is used to change the conductivity of the medium in order to quantify the solution conductivity role. The results of these measurements are clearly showing the impact of the measuring electrodes type on the measured phase spectrum while the influence on the amplitude spectrum is negligible. The phenomenon appearing on the phase spectrum at high frequency (N 1 kHz) whatever the electrode type is, the phase shows an increase compared to the theoretical response, and the discrepancy (at least in absolute value) increases with frequency, but it is less severe when medium conductivity is larger. Additionally, the frequency corner is shifted upward in frequency. The dependence of this phenomenon on the conductivity and the measuring electrodes type (electrode-electrolyte interface) seems to be due to some dielectric effects (as an electrical double layer of small relaxation time formed at the electrodes interface). Therefore, this dielectric response should be taken into account at high frequency to better analytically separate the medium own response from that linked to the measuring electrodes used. We modeled this effect by adding a capacitance connected in parallel with the traditional equivalent electric circuit used to describe the dielectric response of medium.

The Relative Importance of Saturated Silica Sand Interfacial and Pore Fluid Geochemistry on the Spectral Induced Polarization Response

“…Indeed, no significant differences, due to the electrodes and/or sample holder, are visible between the “water + resistance” and the water tests. The observed electrode behavior and SIP resolution agree with other recent studies where the same SIP setup (impedance meter and electrodes) was used (Abdulsamad et al, ; Kremer et al, ). Kremer et al (, their Figure 3) and Abdulsamad et al (, their Figure 5) also reported similar water test values.…”

“…(3) Upon measuring contact resistance in a tap‐water beaker, values were in the range 5 ± 1 k Ohm. Analogous tests on the electrode behavior were performed in Abdulsamad et al (, see their Figure 4) for specific data on the self‐potential and potential difference.…”

Tracking Magmatic Hydrogen Sulfur Circulations Using Electrical Impedance: Complex Electrical Properties of Core Samples at the Krafla Volcano, Iceland

“…If only dielectric absorption of water was causing the observed HF polarization, the phase angle should be only negative and much lower, considering a relative dieletric permittivity of water around r = 80 (Abdulsamad et al, 2016). A major contribution from the measuring electrodes is likely at these frequencies, as shown by previous studies (Abdulsamad et al, 2016;Lesmes & Frye, 2001;Volkmann & Klitzsch, 2015). Figure B1 compares the chemistry of the different sulfides and iron oxides for samples, analyzed by Electron Probe Micro-Analysis.…”

Predicting the Dielectric Response of Saturated Sandstones Using a 2-electrode Measuring System

“…Other authors [e.g., 30,36] found a pseudo-inductance by measuring electrolyte solutions using 4-electrode setups. Zimmermann et al [30] refers to this phenomenon as "contact impedance, " and attributed it to a phase error due to the inhomogeneous contact impedance of the current electrodes.…”