The pH dependence of spectral induced polarization of silica sands: Experiment and modeling
The pH dependence of spectral induced polarization of silica sands: Experiment and modeling
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硅砂光谱诱发极化的 pH 依赖性：实验和建模
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
P. Vaudelet
中科院分区：
文献类型：
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作者：
M. Skold;A. Revil;A. Revil;P. Vaudelet
在电解质饱和的沙子中，电荷在交变电场下的储存（称为“诱导极化”）是施加电流和产生的电场之间的相位滞后的原因。由于多孔材料中存在多种极化机制，激发极化的物理机制尚不清楚，现场数据难以定量解释。在不同pH值和盐度下的测量可用于在不存在电子导体的多孔介质中区分低频（1 mHz-1 kHz）下的不同竞争机制。新的实验数据指出，除了Stern层（覆盖在二氧化硅颗粒表面的双电层的内部部分）的极化之外，还有另一种极化机制可能与二氧化硅表面上质子的跳跃过程有关。我们建议，这样的过程可以遵循Grotthuss合作机制（如在冰），涉及结合水的二氧化硅表面。我们的数据还排除了基于漫射层的机制。新的极化机制可以应用于量化在酸性污染物羽流上收集的激发极化数据。
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.