Why is carbon dioxide used in supercritical fluid extraction method?

SFE is a separation technology that uses supercritical fluid solvent for extraction. Carbon dioxide is the most commonly used supercritical fluid, with other choices including ethanol. It eliminates the use of organic solvents, which reduces the problems of their storage, disposal, and environmental concerns.

Why does co2 need to be a supercritical fluid for the process of decaffeination?

Supercritical CO2 has been used in industry to extract caffeine from coffee beans since the 1970s. Caffeine has a low solubility in supercritical carbon dioxide and, for this reason, a co-solvent (either water or ethanol) is used which triples the caffeine solubility, hence accelerating the extraction.

Why is the use of supercritical carbon dioxide gaining popularity for commercial and medical uses?

As a non-toxic and environmentally benign green solvent, it has been widely used in the food and pharmaceutical industries for extraction. However, scCO2 also has many unique properties and thus has great potential for advanced, green materials processing.

What is the main advantage of using supercritical fluids over regular fluids for extraction processes?

The advantages of using SFE [89,101,102] when compared to conventional methods are several: (1) higher selectivity because the solvation power of the fluid can be adjusted by changing temperature and pressure; (2) lower viscosity and higher diffusivity of supercritical fluids allow faster mass transfer of solutes from …

How does supercritical fluid extraction work?

The liquid is pumped to a heating zone, where it is heated to supercritical conditions. It then passes into the extraction vessel, where it rapidly diffuses into the solid matrix and dissolves the material to be extracted.

What is the critical temperature of carbon dioxide in supercritical fluid extraction?

Supercritical carbon dioxide (sCO. 2 More specifically, it behaves as a supercritical fluid above its critical temperature (304.13 K, 31.0 °C, 87.8 °F) and critical pressure (7.3773 MPa, 72.8 atm, 1,070 psi, 73.8 bar), expanding to fill its container like a gas but with a density like that of a liquid.

What is the critical temperature of CO2?

31.1oC
Critical temperature for carbon dioxide and methane are 31.1oC and −81.9oC respectively.

How does CO2 decaffeination work?

In the carbon dioxide decaffeination process, green coffee beans are soaked in highly compressed CO2, which extracts the caffeine. The caffeine is then removed from the CO2 using activated carbon filters, which are then reused to extract caffeine from the coffee again.

Why does CO2 dissolve caffeine?

Supercritical Carbon Dioxide Processing Water is more polar than caffeine is, so supercritical carbon dioxide, in the presence of a co-solvent like water, will dissolve the more non-polar substance, in this case, caffeine.

What is the critical temperature of carbon dioxide?

What is the critical temperature of carbon dioxide in degrees Celsius?

31.1^∘C
Critical temperature for carbon dioxide and methane are 31.1^∘C and – 81.9^∘C respectively.