IN-SITU MEASUREMENTS ON SURFACTANT MINERAL INTERACTIONS BY POLAROGRAPHIC ADSORPTION-KINETICS

Adsorption of surfactants at the mercury/electrolyte interface causes changes in electrode capacity. This phenomenon can be used for surfact ant analysis in low and ultra-low concentration ranges. Tensammetry is carried out by alternating current or potential pulse techniques. Tim e-dependent concentration changes can be determined by adsorption kine tics at the mercury/electrolyte interface. As the interaction of surfa ctants with the mercury/electrolyte interface strongly depends on the potential of the electrode, repeated potential jumps can be used to ge nerate adsorption-desorption cycles. This permits rapid determination of constant or time-dependent concentration. The adsorption kinetics o f cationic and non-ionic surfactants on clay minerals were determined by Kalousek polarography. These two types of surfactant exhibit differ ent behaviour. Many other adsorption phenomena might also be investiga ted by using the method described here.