Collect. Czech. Chem. Commun. 1983, 48, 964-975

Electrocapillary measurements at low concentrations of surfactants: Adsorption of tetrabutylammonium cation

Ladislav Novotný, Ivan Smoler and Jaroslav Kůta

The J. Heyrovský Institute of Physical Chemistry and Electrochemistry, Czechoslovak Academy of Sciences, 118 40 Prague 1


Using drop-time technique with long drop-times achieved by means of a spindle-type capillary with the combination of a interrupted convection the surface tension data of tetrabutylammonium perchlorate in 0.1 mol l-1 NaClO4 in the concentration range 3 . 10-3 mol l-1 down to 10-7 mol l-1 could be measured. The corresponding adsorption parameters have been evaluated both from Langmuir (for Θ ⪬ 0.8) and Frumkin isotherm. The maximum energy of adsorption amounts to -48.1 kJ . mol-1. The dependence of E vs log c (Yesin-Markov plot) carried out in the concentration range 10-7 to 10-3 mol l-1 showed a S-shaped curve.