ION-SELECTIVITY IN HYDRATED IRON (II), (II. III), AND (III) OXIDE PRECIPITATE MEMBRANES.

The ion-selectivity of hydrated iron (II), (II. III) and (III) oxide precipitate membranes - artificially produced on a cellulose sheet - was investigated by measuring the membrane potential as a function of solution pH and ion-valency. The effect of adsorbed phosphate and molybdate anions on the ion-selectivity was also studied. Based on the ion-selective properties estimated in the precipitate membranes, the local corrosion of steels under the anion- and cation-selective precipitate films of hydrated iron oxides is discussed.