Adsorption of iodide ions on liquid (Ga + In) electrode from mixed solutions with constant ionic strength in dimethylsulfoxide

The adsorption of iodide ions on a liquid (Ga + In) electrode of an eutectic composition (14.2 at % In) from mixed electrolyte (xc M NaJ + (1 − x)c M NaClO4) solutions in dimethylsulfoxide containing surface inactive ions ClO4− with the constant ionic strength of 0.1 M is studied by measuring differential capacitance curves at 305 K. The analysis of experimental data for the studied interval of iodide ion concentration shows that the charge of specifically adsorbed ions on the liquid electrode surface is much lower as compared with the charge found for their adsorption from aqueous solutions of the same electrolyte. The applicability of various adsorption isotherms for the description of experimental data is analyzed. The virial isotherm with the linear dependence of the adsorption free energy on the electrode charge provides the best description. The obtained data on adsorbability of iodide ions are compared with available literature data in aqueous and dimethylsulfoxide solutions on various electrodes.