Interfacial Electrical Effects Observed during the Freezing of Dilute Electrolytes in Water

Abstract

Dilute solutions of about 50 typical salts, acids, and bases in the concentration range 10−6 to 10−3M were frozen at nonequilibrium rates. The freezing potential, charge separation across the phase boundary, and chemical composition of the phases were measured. The charge separation is a function of ionic species present in the solution, their concentration, and the freezing rate. It is caused by a differential transfer of ion constituents across the phase boundary. Hydrogen and hydroxyl ions neutralize the charge as the phase boundary advances. The solution pH greatly affects the charge separation, other conditions held constant.