Extraction | Supercritical fluid extraction

In this article, the fundamentals of supercritical fluids are provided and their main application as extracting media emphasized. Supercritical fluid extraction (SFE) at laboratory, pilot and processing scale is discussed, including some basics on equipment and operational conditions, together with some selected applications. SFE is discussed as an advanced and environmentally friendly alternative to conventional solid-liquid or liquid-liquid solvent extraction both for analytical sample preparation and for production scale applications, mainly when a clean solvent such as carbon dioxide is used instead of toxic organic solvents. The advantages of SFE are the possibility of tuning the solvent power of the fluid by changes in pressure and temperature, while modifying, at the same time other physico-chemical properties such as density, viscosity and diffusivity. In general, transport properties are favored under supercritical conditions and, therefore, extraction processes are faster and provide higher extraction yields. The main disadvantages are the requirement for more expensive equipment and more challenging process optimization. This article attempts to be a useful reference for researchers, students, technologists who are approaching for the first time the world of supercritical fluids.