Radioelectrochemistry. Review

Abstract

In part I of this report, we described chronocoulometric measurements of lead iodide and bromide adsorptions in which discontinuities in adsorption isotherms were related to surface solubility properties of the lead halide salts. While it is tempting to try to relate those abrupt changes in Fpb to the abrupt occurrences of inhibition observed in Part II, we believe this would be an error. We regard the two sets of observations as representing two different transitions for the adsorbed lead species. It is unfortunately not possible, for solubility (of Hg(II) halides) reasons, to conduct the inhibition tests in solutions of composition yielding adsorption isotherm discontinuities. We do know, however, from data in 1.0M I* and Br" obtained in this and a preceding report (3) that no large change in Pb occurs over the inhibition transition interval for Hg(II) reduction, and that Pb is furthermore close in value to the limiting plateau Pb of adsorption isotherm in Figures 1 and 2. The inhibition results appear to tell us that at least bits and traces of further lead halide adsorption can occur beyond formation of the two-dimensional PbX2 crystal at the adsorption isotherm, which is to say that the initially formed surface phase must not represent a "perfect crystal.'' The imperfections may be small boundary openings between patches of surface crystal, intruding adsorbed halide, or possibilities for structural reorganizations which can be eliminated or accomplished, by small amounts of additional lead halide. Whatever the reason, the rather readily penetrable surface crystal formed at the adsorption isotherm discontinuity is transformed into a surface phase exceedingly impenetrable from either the solution or electrode side by species other than the Pb(II) ion itself. In the case of Pb(II), actual penetration of intact surface phase is, of course, not required since Pb(II) can pass the surface lattice by simple exchange.

Application of radioisotope techniques for the study of phthalocyanine catalyzed electrochemical processes in fuel cells

“…In several studies, influence of the radiation of tracers on electrode processes has been reported. 7 As an example, the observation of a change in the mechanism of the oxygen reduction on platinum electrodes in alkaline solutions resulting from 60Co 7 radiation should be mentioned.37 Moreover, by the incorporation of radionuclides, such as 14C, 63Ni, or 60Co, in porous carbon electrodes, an improvement of current-voltage curves has been described. 38"40 Therefore, in order to be sure that any influence from the radiation of the 59Fe marker can be excluded, the electrochemical behavior of carbon-teflon electrodes with and without iron-59-containing polyphthalocyanines have been tested.…”

Evidence for a correlation between total lead concentrations in soils and the presence of geological faults

“…The analysis of all lead isotopes (total lead concentrations) in soil was realized by anodic stripping voltammetry (Model 797 VA, Metrohm). This method is a good method of analysis for a mixture of radioactive isotopes because it does not require the forehand knowledge to add an inactive carrier to the unknown solution as it does in most other radiochemical procedures (Katsanos et al 1966;Raaen 1974).…”