Electrolytic H/D separation factors on cathode and diffusion sides of iron membranes in H2SO4

Abstract

The electrolytic hydrogen-deuterium separation factor has been measured, simultaneously for the first time, on both the cathode and the diffusion side of thin iron membranes in acid solution at room temperature as functions of time and current density. Both separation factors decreased with time and reached plateau values of 7.35±0.5 and 10.7±0.4, respectively; neither is a simple function of current density. Possible explanations for these observations are given. The separation factor on the diffusion side is always larger than that on the cathode side, the average ratio being 1.35–1.6 over the current density range 19.1–255 mA cm −2 . An estimate of the permeation rate of hydrogen was obtained and the variations in this quantity are accounted for in terms of the screened proton model.