EXTRACTION OF PETROLEUM-HYDROCARBONS FROM SOIL USING SUPERCRITICAL ARGON

The use of supercritical argon is described for the extraction of petr oleum hydrocarbons from soil samples, Argon is an attractive solvent b ecause it is inexpensive and inert, Additionally, it has a clear spect ral window in the infrared region which makes it useful for on-line (i ,e., directly coupled) experiments. Spiking studies conducted with gas oline, no. 1 fuel oil, and no, 5 fuel oil on sand, loam, and clay show that component recovery rates for argon supercritical fluid ex-tracti on (SFE) generally increase with increasing pressure and/or temperatur e, The highest recovery rates (and recoveries) were obtained for Ar SF E at 500 atm and 150 degrees C, Under these conditions, the components of the gasoline and no, 1 fuel oil spikes could be recovered in as li ttle as 12 min. However, the no. 5 fuel oil components could not be qu antitatively removed from the loam and clay matrixes even for extracti on times as long as 100 min, We also show in this work that;Zr SFE per forms similarly to CO2 SFE for petroleum hydrocarbon contamination in real-world soil samples under moderate pressure and temperature condit ions, Specifically, Ar SFE and CO2 SFE have similar recoveries and rep roducibilities, but Ar SFE requires a slightly longer extraction time.