SOIL CLEANING BY CARBON-DIOXIDE EXTRACTION - A REVIEW

Supercritical carbon dioxide is a solvent for non-polar solids and vol atile compounds. It dissolves hydrocarbons, polyaromatic hydrocarbons (PAH's), chlorinated hydrocarbons (such as PCB's and dioxins), phenols , chlorinated phenols and many pesticides and herbicides. Supercritica l carbon dioxide effectively extracts the non-polar compounds from all soil types. The extraction of more polar compounds, such as chlorophe nols and some pesticides requires that a polar compound, such as a sho rt chain alcohol is added to the carbon dioxide. Carbon dioxide extrac tion is usually quicker and in cases more complete than the standard a nalytical methods which use organic liquid solvents as extraction medi um. Supercritical carbon dioxide extraction is used by environmental a nalysis laboratories as a more efficient, occupationally more acceptab le method for analyzing contaminated soils. Plans to construct transpo rtable units for large scale soil cleaning have been published.