%0 Journal Article %T Induced polarization signatures of cations exhibiting differential sorption behaviors in saturated sands %+ Environnement, Géo-ingénierie et Développement (EGID) %+ Géophysique des volcans & géothermie %+ Agence de l'Environnement et de la Maîtrise de l'Energie (ADEME) %A Vaudelet, Pierre %A Revil, André %A Schmutz, Myriam %A Franceschi, Michel %A Bégassat, P. %Z The Office of Science (BER), U.S. Department of Energy, grant DE-FG02−08ER646559. %Z 21p. %< avec comité de lecture %@ 0043-1397 %J Water Resources Research %I American Geophysical Union %V 47 %P W02526 %8 2011 %D 2011 %R 10.1029/2010WR009310 %K induced polarization %K complex resistivity %K speciation %K silica %K copper %K hydrogeophysics %Z 1835 Hydrology: Hydrogeophysics; 1012 Geochemistry: Reactions and phase equilibria (3612, 8412); 3914 Mineral Physics: Electrical properties; 3947 Mineral Physics: Surfaces and interfaces. %Z Sciences of the Universe [physics]/Earth Sciences/GeomorphologyJournal articles %X 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 ± 0.2 to 0.5 ± 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 2+ by Na + is less favorable; therefore, the kinetics of such a replacement is much slower than for the opposite replacement (Na + by Cu 2+). 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. %G English %2 https://insu.hal.science/insu-00681789/document %2 https://insu.hal.science/insu-00681789/file/2010WR009310.pdf %L insu-00681789 %U https://insu.hal.science/insu-00681789 %~ IRD %~ INSU %~ UNIV-SAVOIE %~ UGA %~ CNRS %~ UNIV-GRENOBLE1 %~ ADEME %~ OSUG %~ GIP-BE %~ ISTERRE %~ USMB-COMUE