Separant

Separant is a term used in industrial chemistry to describe a substance that promotes the separation of two immiscible liquids or a dispersed phase from a continuous phase. It is used to break emulsions or to facilitate phase separation in processes such as liquid–liquid extraction, solvent recovery, and pretreatment of emulsified mixtures. The separant may act by reducing interfacial tension, altering the interfacial film that stabilizes droplets, or changing the relative solubilities of the components.

Common categories include demulsifiers, surfactants, salts, and polymeric additives. In crude oil production, separants (often called demulsifiers) are added to promote oil–water separation by coalescing water droplets and allowing free water to settle. Similar agents are used in solvent extraction to improve the separation between immiscible solvent layers, and in food and beverage processing to clarify emulsions or separate oil from aqueous phases.

Mechanistically, separants may work by weakening the droplet film, displacing stabilizing species at the interface, or by modifying surface properties to favor one phase over another. The choice of separant depends on the system, including temperature, pH, salinity, and the nature of the immiscible liquids.

Safety and handling depend on the specific chemical; separants can be irritants, corrosive, or hazardous. Proper storage and disposal follow relevant regulations and safety data sheets.

See also: demulsifier, phase separation, solvent extraction, emulsion.