%0 Journal Article %T The pH dependence of spectral induced polarization of silica sands: Experiment and modeling %+ Department of Geophysics [Golden CO] %+ Géophysique des volcans & géothermie %+ Environnement, Géo-ingénierie et Développement (EGID) %A Skold, Magnus %A Revil, André %A Vaudelet, P. %Z The Office of Science (BER), US. Department of Energy, grant DE-FG02-08ER646559. %Z 6p. %< avec comité de lecture %@ 0094-8276 %J Geophysical Research Letters %I American Geophysical Union %V 38 %P L12304 %8 2011 %D 2011 %R 10.1029/2011GL047748 %K electrical double layer %K induced polarization %K pH %K silica %Z 3914 Mineral Physics: Electrical properties; 3947 Mineral Physics: Surfaces and interfaces; 3999 Mineral Physics: General or miscellaneous; 5109 Physical Properties of Rocks: Magnetic and electrical properties (0925); 5139 Physical Properties of Rocks. %Z Sciences of the Universe [physics]/Earth Sciences/GeomorphologyJournal articles %X In electrolyte-saturated sands, the storage of electrical charges under an alternating electrical field (called "induced polarization") is responsible for a phase lag between the applied current and the resulting electrical field. Because a variety of polarization mechanisms exists in porous materials, the underlying physics of induced polarization is somehow unclear and the field data difficult to interpret quantitatively. Measurements at various pHs and salinities can be used to discriminate between different competing mechanisms at low frequencies (1 mHz-1 kHz) in porous media in the absence of electronic conductors. New experimental data point out that, in addition to the polarization of the Stern layer (the inner part of the electrical double layer coating the surface of the silica grains), there is another polarization mechanism possibly associated with a hopping process of the protons on the silica surface. We propose that such a process could follow a Grotthuss cooperation mechanism (as in ice) involving the bound water of the silica surface. Our data also rule out a mechanism based on the diffuse layer. The new polarization mechanism may be applied to quantifying induced-polarization data collected over acidic contaminant plumes. %G English %2 https://insu.hal.science/insu-00681694/document %2 https://insu.hal.science/insu-00681694/file/2011GL047748.pdf %L insu-00681694 %U https://insu.hal.science/insu-00681694 %~ IRD %~ INSU %~ UNIV-SAVOIE %~ UGA %~ CNRS %~ UNIV-GRENOBLE1 %~ OSUG %~ GIP-BE %~ ISTERRE %~ USMB-COMUE