Opposing behaviour of organic compounds at interfaces

Despite its extremely weak adsorption at the water/silica interface, carbofuran can, however, induce the coadsorption of metallic salts like lead nitrate, for example; by way of consequence its adsorption is enhanced. At the water/atmosphere interface, carbofuran adsorption is far more important than at the water–silica interface, whereas ionic adsorption remains smaller despite its enhancement by coadsorption. After comparison of the data obtained by a depletion method in the case of the solid/liquid interface and by tensiometry for the atmosphere/liquid interface, we tried to find a relationship between both from kinetic measurements of adsorbent desorption from a silica surface. Indeed, desorption from soil particles may feed surface adsorption, bubbling and entail the formation of polluted aerosols. In this study, the concentration conditions were close to the environmental ones. A model based on the Wagner–Onsager–Samarasʹ views of ionic interfaces positively accounts for the opposite behaviour of the systems according to the surface under study. This report shows that these facts have to be thoroughly considered in order to make a relevant assessment of environmental issues.