Active components in pharmaceuticals and
Ginger Camomile Marigold Thyme Spices and aromas for food Basil
Coriander Lovage root Vanilla Paprika
Odoriferous substances for perfumes
Angelica root Peach and orange leaves Vanilla Oil of spices Aromas for drink Angelica root Calamus Further applications
Separation of pesticides Refinement of raw extract material Separation of liquids Extraction of cholesterol cosmetics
Calmus Carrots Rosemary Salvia
Ginger Parsley seed Vetiver
Source: M. Saari, 1987. Prosessiteollisuuden Erotusmenetelmät, VTT Res. Note, and reference 730.
The advantage offered by supercritical extraction is that it combines the positive properties of both gases and liquids, i.e., low viscosity with high density, which results in good transport properties and high solvent capacity. Also, under critical conditions, changing the pressure and temperature varies the solvent characteristics over a range.
Figure 3.8.13 is a flow diagram of a typical supercritical extraction process using supercritical CO2. Mixing organic components into CO2 generally enhances their solvent power while inert gases (Ar, N2) reduce the solvent power. Supercritical extraction is developing rapidly and may become an alternative worth considering not only for fine chemical separation but also for bulk processes.
Reverse osmosis membranes have pores so small that they are in the range of the thermal motion of polymer chains, e.g., 5 to 20Â. Electrodialysis membranes separate ions from an aqueous solution under the driving force of an electrostatic potential difference.
The membrane is also used in pervaporization that permits the fractionation of liquid mixtures by partial vaporization through a membrane, one side of which is under reduced pressure or flushed by a gas stream. Currently, the only industrial application of pervaporation is the dehydration of organic solvents, particularly dehydration of 90% plus ethanol solutions.
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