ABSTRACT
Aphrons are globules of phases encapsulated in a soapy film. A soap bubble is a giant gas aphron; colloidal gas aphrons comprise gas bubbles that are of micrometer size, and colloidal liquid aphrons have the gas replaced by a liquid that is immiscible in water and can be submicrometer in size. Presenting an enormous interfacial surface area, these systems have potential in separation processes. The properties of these systems are discussed in this chapter. Ion flotation, which uses small gas bubbles and surfactants for buoying ions to the surface, is improved by using colloidal gas aphrons as in precipitate flotation. These can also be used to float finely divided solids that are too small to be collected by conventional flotation as well as fine oil droplets. The bubbles are so small that they can be entrained in flocs conferring buoyancy (bubble-entrained floc flotation). Predispersed solvent extraction uses oil core aphrons, eliminating the need for a mixer-settler unit.
