Superheated Water - Extraction

Extraction

Extraction using superheated water tends to be fast because diffusion rates increase with temperature. Organic materials tend to increase in solubility with temperature, but not all at the same rate. For example, in extraction of essential oils from rosemary and coriander, the more valuable oxygenated terpenes were extracted much faster than the hydrocarbons. Therefore, extraction with superheated water can be both selective and rapid, and has been used to fractionate diesel and woodsmoke particulates. Superheated water is being used commercially to extract starch material from marsh mallow root for skincare applications and to remove low levels of metals from a high-temperature resistant polymer.

For analytical purposes, superheated water can replace organic solvents in many applications, for example extraction of PAH’s from soils and can also be used on a large scale to remediate contaminated soils, by either extraction alone or extraction linked to supercritical or wet oxidation.