Abstract

Supercritical fluid extraction is two-step process, comprising of feed of fluid into extraction vessel at above its critical temperature and critical pressure and depressurization of fluid after extraction. Supercritical fluid has both gas like properties (diffusivity, viscosity and surface tension) and liquid like properties (density and solvating power), which are favorable for diffusion coefficient as well as mass transfer. Carbon dioxide is most useful supercritical fluid (Tc=31° and Pc=74 bars) as it is safe, inexpensive, non-toxic, non-inflammable, inert to materials and solvating strength is adjusted by modifier (methanol) as well as extraction parameters (time, temperature and pressure). Supercritical fluid extraction is useful in extraction, separation and refining, cleaning and disinfection, synthesis and processing, optimization of drug particles and environmental application such as soil remediation and treatment of municipal waste.