Kinetics of marine surfactant adsorption at an air-water interface. Baltic Sea studies

The paper contains the results of studies of natural surface film adsorption kinetics carried out in inland waters and in shallow offshore regions of the Baltic Sea during 2000–01 under calm sea conditions. The novel approach presented here for the adsorption dynamics is based on the mixed kinetic-diffusion model and analyses of the surface pressure-time plots at short (t → 0) and long (t→∞) adsorption time intervals. Values of the effective relative diffusion coefficient Deff/D (= 0.008 − 0.607) and energy barrier for adsorption Ea/RT (= 0.49 − 7.10) agree well with the data reported for model non-ionic surfactant solutions of pre-cmc concentrations. Wind speed is one of the factors affecting the adsorption barrier via the increased surface pressure of the natural film exposed to wind shear stress (∼ U10 2),a nd enters the relation Ea/RT = 1.70U10 1/3.