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

摘要: [1] Two sets of experiments were designed to understand the change in induced polarization associated with sorption copper and sodium, exhibiting distinct behavior on a silica sand. A sand column experiment was first performed see complex conductivity during advective transport sulfate solution. second set done at equilibrium various solutions NaCl CuSO4. In experiment, solution replaced sodium chloride solution, keeping electrical nearly constant. During passage apparent phase angle decreased from 3 ± 0.2 0.5 mrad, while magnitude remained quantitative model is proposed explain as function chemistry assuming mechanism Stern layer (the inner part double coating water-mineral interface). The combined complexation describing competitive pore water interface. lag directly ion exchange between surface grains. explanation observed differences Na Cu relies their different behaviors, being loosely absorbed, forms relatively strong both (monodentate) outer sphere (bidentate) complexes. replacement Cu2+ by Na+ less favorable; therefore, kinetics such much slower than for opposite (Na+ Cu2+). We able reproduce changes lags thermodynamic near relaxation frequency domain. These measurements modeling results open door interpretation spectral data field terms quantification processes.