AN INTERSTITIAL MODEL OF THE INTERFACIAL ELECTRIC POTENTIAL OF FREEZING of AQUEOUS SOLUTIONS
A.V. Shavlov, A.A. Yakovenko, E.S. Yakovenko
Tyumen Research Centre, Siberian branch of the Russian Academy of Sciences, Earth Cryosphere Institute, Tyumen, Russia
Keywords: ice, Workman-Reynolds potential, crystallization rate, proton, interstitial, acceptor
Abstract
A new model of pure water freezing potential (Workman-Reynolds potential) explained the positive electric charge of ice relative to water during crystallization by the fact that protons were captured faster than hydroxide ions by numerous traps of charge in ice - interstitials. In the present article, additions have been made to this model to extend its application from pure water to aqueous solutions with an impurity concentration in the parent solution of 10-4 mol/L or more. The additions take into account the ability of impurity anions and cations to act as acceptors for protons and hydroxide ions in ice. As a result of capture by acceptors, the equilibrium concentrations of protons and hydroxide ions can shift significantly in favor of the former or the latter. This shift should radically affect the kinetics of filling the charge traps (interstitials) with protons or hydroxide ions and the sign of the electric charge of ice relative to the solution. In particular, the model explains the negative ice charge during crystallization of 10-4 mol/L KCl solutions.
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