After reviewing the nature and importance of the environmental problems caused by oil spilled on seawater, several treatment possibilities have been listed based on STOKES Law.
The results recently obtained in three of these directions are discussed:
the increase of the drop-size (coalescence)
the increase in the differential density (flotation)
the use of a preferential wettability of some materials for recovering the' surface oil film.
In most cases, process efficiency of oil separation is the product of a collision probability between the oil drop and another drop (or bubble) and a collision efficiency characteristic of this kind of interaction.