The use of floating sorbents
to retain and agglomerate oil or other pollutants in the event of an accident
is a technique often used on calm water bodies and in ports to recover small
spills. As a temporary measure, makeshift means can be used, such as straw
or sawdust. These substances can be a good choice if they do not come into
contact with water before or during the sorption process.
However, more suitable materials exist, in the form of low density products with the ability to prioritise
sorption of the oil (oleophilic property) rather than the water (hydrophobic property) and retain it in their pores.
These substances, known as sorbents, work due to two phenomena: adsorption
(whereby the pollutant accumulates on the surface of the sorbent) and absorption
(whereby the pollutant diffuses into the mass of the sorbent). They are
available in bulk, in the
form of powder, fibres, shavings, fine particles and conditioned, in the
form of mats, sheets, rolls, booms…
There is no lack of sorbents or agglomerating products, from natural pine bark to the most complex synthetic compounds. However, more often than not, they are not used in the conditions which would maximise their efficiency.