Generation of Iodine by Galvanostatic Electrolysis

In the present study, generation of iodine by an electrolytic oxidation from solutions containing iodide ions was investigated in order to develop a recycling process of gold using iodine-iodide solutions. In an anodic polarization curve, the current began to rise at an anodic potential of around 0.5 V vs. SHE, and solution near anode surface became brown, which is comparable to the thermodynamic potential for I 3 − /I − of 0.536 V vs. SHE. In the initial stage of galvanostatic electrolysis, iodine concentration increased with time and iodide concentration decreased. The current efficiencies were more than 90% in this stage. In the further electrolysis, iodine concentration decreased with time and solid state iodine was formed on the anode. The highest concentration of iodine could be estimated by the relationship between its solubility and the initial concentrations of iodine and iodide.