Induced polarization signatures of cations exhibiting differential sorption behaviors in saturated sands

Abstract

[1] Two sets of experiments were designed to understand the change in induced polarization associated with the sorption of copper and sodium, exhibiting distinct sorption behavior on a silica sand. A sand column experiment was first performed to see the change in the complex conductivity during the advective transport of a copper sulfate solution. A second set of experiments was done with the sand at equilibrium with various solutions of NaCl and CuSO 4 . In the first experiment, the copper sulfate solution replaced a sodium chloride solution, keeping the electrical conductivity of the solution nearly constant. During the passage of the copper sulfate solution, the apparent phase angle decreased from 3 6 0.2 to 0.5 6 0.2 mrad, while the magnitude of the conductivity of the sand remained nearly constant. A quantitative model is proposed to explain the change in the complex conductivity as a function of the chemistry assuming a polarization mechanism associated with the Stern layer (the inner part of the electrical double layer coating the water-mineral interface). The Stern layer polarization is combined with a complexation model describing the competitive sorption of copper and sodium at the pore water interface. The change of the phase lag is directly associated with the ion exchange between sodium and copper at the surface of the silica grains. The explanation of the observed phase differences between Na and Cu relies on their different complexation behaviors, with Na being loosely absorbed, while Cu forms relatively strong complexation with both inner (monodentate) and outer sphere (bidentate) complexes. The replacement of Cu 2þ by Na þ is less favorable; therefore, the kinetics of such a replacement is much slower than for the opposite replacement (Na þ by Cu 2þ ). We were able to reproduce the changes in the phase lags at thermodynamic equilibrium near the relaxation frequency and in the frequency domain. These measurements and modeling results open the door to the quantitative interpretation of spectral induced polarization data in the field in terms of quantification of the sorption processes.Citation: Vaudelet, P., A. Revil, M. Schmutz, M. Franceschi, and P. Bégassat (2011), Induced polarization signatures of cations exhibiting differential sorption behaviors in saturated sands, Water Resour. Res., 47, W02526,

Modeling the evolution of complex conductivity during calcite precipitation on glass beads

“…The parameters relative to the electrochemical properties of the mineral/water interface Q b , ϕ d and d i are computed using a BSM of the mineral/water interface Leroy et al 2008;Vaudelet et al 2011). The results of the BSM computations are showed in Section 3.…”

“…(10), the tangential mobility of the counterions in the Stern layer of the calcite/water interface, β b , remains unknown (Ricci et al 2013). Cations are assumed to be mostly adsorbed in the Stern layer of calcite as outer-sphere surface complexes because, similarly to the silica/water interface (Sverjensky 2001;Vaudelet et al 2011;Leroy et al 2013), the large hydration layer at the calcite surface repels hydrated cations from the surface (Stipp 1999;Heberling et al 2011Heberling et al , 2014. Nevertheless, as pointed out by Wolthers et al (2008) and Ricci et al (2013), some Na + and Ca 2+ counter-ions may also be adsorbed as inner-sphere surface complexes.…”

“…While the real part of complex conductivity is sensitive to electromigration processes in the pore space and at the mineral surface, its imaginary part is sensitive to polarization processes at the mineral surface (Weller et al 2013;Okay et al 2014). The magnitude of the imaginary conductivity is controlled by the electrochemical properties and the surface area of the mineral/water interface (Vaudelet et al 2011;Bucker & Hordt 2013;Okay et al 2014). The frequency behaviour of the imaginary conductivity is controlled by relaxation of ions in the EDL, which depends on the size, shape, surface roughness of the particles or pores, and on the ionic surface mobility at the mineral/water interface (Leroy et al 2008;Bucker & Hordt 2013).…”

The hydrogeologic information in cross-borehole complex conductivity data from an unconsolidated conglomeratic sedimentary aquifer

“…The dependence of σ 0 0 on the pore-normalized internal surface area S por (Börner, 1992;Weller et al, 2013) and grain size (Revil and Skold, 2011;Vaudelet et al, 2011) has encouraged many efforts to use complex conductivity measurements to predict K (Slater and Lesmes, 2002b;Revil and Florsch, 2010). Furthermore, the dependence of σ 0 0 on σ w is relatively weak.…”

Surface Geophysical Exploration - Compendium Document

“…al., 2010 , "An Experimental Study of the Diesel Biodegradation Effects on Soil Biogeophysical Parameters;" Ntarlagiannis, et. al., 2005, "Low-Frequency Electrical Response to Microbial Induced Sulfide Precipitation;" Vaudelet, et. al., 2010, "Induced Polarization Signatures of Cations Exhibiting Differential Sorption Behaviors in Saturated Sands;" and Vaudelet et.…”