engleski

Surface potential at ice/water interface

Ice surface in water is charged due to exchange of protons between surface and bulk water molecules: ≡ OH2 + H3O+ → ≡ OH3+ + H2O ; Kp ≡ OH2 + H2O → ≡ OH– + H3O+ ; Kd Another possible reaction is transfer of hydronium and hydroxide ions from the bulk phase to the interface: H3O+ → ≡ OH3+ ; KH OH– → ≡ OH– ; KOH Electrokinetic measurements1 resulted in the isoelectric point of ice at pHiep ≈ 3, while potentiometric experiments1, 2 showed that surface potential Ψ 0 is lower than the Nernstian potential. The pHiep values of numerous inert materials in aqueous environment, such as oil, teflon and air, were found to be low, i.e. between 2.5 and 3.5, so that it was concluded that the similar charging mechanism takes place3. Electrokinetic and potentiometric data for ice/water are presented. Evaluation of parameters characterizing the equilibrium at aqueous solid/liquid interface is described.

ice; surface potential; water; interface; electrical interfacial layer

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