Adsorption of Tetramethylthiourea in the Presence of Cationic Detergent at Interface Electrode/Aqueous Perchlorate Solutions

The mixed adsorption layers of tetramethylthiourea and a cationic detergent formed at electrode surface in NaClO(4) (1 mol dm(-3)) are described. The systems were characterized by the measurement of differential capacity, zero charge potential, and surface tension at this potential. The data were analyzed to obtain the surface pressure and relative surface excess of tetramethylthoiurea as a function of electrode charge at bulk concentration of studied compounds. It was stated that the adsorbing tetramethylthoiurea molecule pushed out the water molecule instead of the detergent molecule from the electrode surface. The constants of the Frumkin and corrected Flory-Huggins isotherm point to a decreased TMTU adsorption energy in the cationic detergents presence and stronger repulsive interaction. Electrostatic parameters of the inner layer were assigned. In the range of more negative potentials, mixed adsorption layers were described by investigating the kinetics of the Zn(2+) ions electroreduction as a piloting ion. (doi: 10.5562/cca1791)