Polycyclic Aromatic Hydrocarbons (PAHs) that are generated by diverse anthropogenic sources, are classified by the U.S. Environmental Protection Agency (EPA) as Semivolatile Hazardous Compounds. PAHs are pollutants of great concern due to their toxicity and mobility in the environment; they can be found in air, water, and soil media. Supercritical Fluid Extraction (SFE) is currently an alternative technology for the removal of PAHs from solid matrices. Carbon dioxide, water and organic compounds, above their critical temperature and pressure conditions, have been used as supercritical fluids. This bench-scale study evaluates the influence of temperature and use of modifiers on the extraction efficiency of PAHs in a diesel-contaminated soil sample from the Miami International Airport (MIA). Carbon dioxide at supercritical conditions was used as extraction fluid in most of this research. Subcritical water, in vapor and liquid states, was also used in a preliminary testing as extraction fluids. A conceptual design of a supercritical carbon dioxide extraction plant is suggested.
