ON THE EQUIVALENT REDOX POTENTIAL OF AQUEOUS SOLUTIONS UNDER IONIZING RADIATION

A study of the electrochemical behavior of aqueous solutions irradiated by Co60γ- and 50–300-kv X-rays is being carried out. Results are presented which show that aqueous solutions of various electrolytes over a pH range of 0.0 to 14.0 attain a steady-state potential under irradiation.This steady-state potential, whose existence was postulated by Dainton and Collinson (who called it the equivalent redox potential), has been determined to be −0.85 v with respect to a hydrogen electrode in the same solution. This value is a property of water and is independent of pH, solute, temperature and radiation energy, and intensity within the ranges investigated.Electrodes under irradiation sometimes show potentials different from the potential of the bulk electrolyte. This is considered to be a result of selective adsorption of one or more primary or secondary radiation products. These transient phenomena depend upon source intensity and solute concentration and disappear when irradiation is stopped.