produit dispersant

CONT: Produits émulsifiants ou dispersants. Ces produits [...] sont pratiquement tous des produits chimiques. Leur action [...] consiste à répartir une pollution de surface dans le volume de la mer, sous forme de fines particules. L'on espère, par ce procédé, favoriser l'action des bactéries et accélérer la biodégradation naturelle des hydrocarbures.

CONT: Oil slick dispersants. When oil ... is treated with a suitable surface active agent and agitation applied, the oil is broken up into particles ... so small that they constitute an oil-in-water emulsion ... Dispersants serve to increase the surface area of an oil spill and disperse oil globules throughout the layer volume water. This causes an accelerated degradation of oil by microbiological action.
OBS: The chemicals used to disperse the oil are emulsifiers. Although a chemist would never confuse the terms dispersant and emulsifier, the former designating a product which encourages the distribution of finely divided solids in a fluid, either liquid or gas, the latter referring to a product which encourages the colloidal dispersion of one liquid in another, the terms are synonymous in the field of oil pollution control. This is explained by the following sentence taken from ""The Control of oil pollution on the sea and inland waters"", edited by J. Wardley-Smith (source COCOB): ""It was found ... [that the product] when sprayed on to the oil, effectively softened and dispersed it by means of emulsification ..."" The dispersion is accomplished by products which emulsify the oil, i.e., emulsifiers. Dispersion is used in its general sense and hence dispersant simply means a product that causes spreading. Also dispersant is used more frequently than emulsifier.