Table 2.

Comparisons between conventional organic solvents extraction and CO₂-based solvents extraction approaches.

Items	Organic solvent	scCO2	lCO2
Heavy metal contamination	Unavoidable	Free of heavy metals	Free of heavy metals
Inorganic salt content	Difficult to avoid	Free of inorganic salts	Free of inorganic salts
Selectivity	Poor selectivity	Highly selective	Highly selective
Extracted compounds	Polar and nonpolar compounds	Nonpolar compounds	Nonpolar compounds
Safety	Flammable and/or toxic	Nontoxic and nonflammable	Nontoxic and nonflammable
Operation condition	Regular temperature and pressure	High temperature and pressure	Lower temperature and pressure than scCO2
Recycling	Solvent recovery is expensive	CO2 could be recycled and reused	CO2 could be recycled and reused
Operation cost	High power consumption (in solvent recovery)	High power consumption	Lower than scCO2
Extraction time	Time-consuming	Shorter than solvent extraction	Shorter than solvent extraction