Abstract
The surface of ice in contact with water contains sites that undergo
deprotonation 6 and protonation, and can act as adsorption sites for
aqueous ions. Therefore, an electrical double layer should form at this
interface, and existing models for describing the electrical double
layer at metal oxide-water interfaces should be able to be modified to
describe the surface charge, surface potential, and ionic occupancy at
the ice-water interface. I used a surface complexation model along with
literature measurements of zeta potential of ice in brines of various
strength and pH to constrain equilibrium constants. I then made
predictions of ion site occupancy, surface charge density, and
partitioning of counterions between the Stern and diffuse layers. The
equilibrium constant for cation adsorption is more than 5 orders of
magnitude larger than the others constants, indicating that this
reaction dominates even at low salinity. Deprotonated OH sites are
predicted to be slightly more abundant than dangling O sites, consistent
with previous work. Surface charge densities are on the order of ±0.001
C/m^2 and are always negative at the moderate pH values of interest
to atmospheric and geophysical applications (6-9). In this pH range,
over 99% of the counterions are contained in the Stern layer. This
suggests that diffuse layer polarization will not occur because the
ionic concentrations in the diffuse layer are nearly identical to those
in the bulk electrolyte, and that electrical conduction and polarization
in the Stern layer will be negligible due to reduced ion mobility.