On the nature of the adsorbed species and mechanism of adsorption of In(III) from iodide solutions at the dme

The reduction of In(III) in solutions containing 0.05, 0.1 and 0.25 M of NaI and with an ionic strength of 1.00 maintained with sodium perchlorate, has been studied by means of interfacial admittance measurements at different frequencies and dc potentials of the dropping mercury electrode.

Our results demonstrate that the process takes place with specific adsorption of electroactive species. The adsorption parameters and their dependence with potential have been determined. From the analysis of our results, together with those obtained in a previous study at higher concentrations of I^?, it can be deduced than InI⁺₂ is the species preferentially adsorbed, this adsorption taking place via a bridge-like mechanism, through I^? ions previously adsorbed.