SUPERCRITICAL EXTRACTION OF ORGANIC CONTAMINANTS FROM SOIL COMBINED WITH ADSORPTION ONTO ACTIVATED CARBON

A novel process is proposed for remediation of soils contaminated with heavy molecular weight organic compounds. In this process, the organi cs are continuously extracted using supercritical carbon dioxide and t hen deposited on activated carbon. The feasibility of this process is investigated on a laboratory scale for remediation of soils contaminat ed with naphthalene, phenanthrene, hexachlorobenzene, and pentachlorop henol. The desorption profiles of the organics from soil and the adsor ption isotherms of these organics on activated carbon were determined in presence of supercritical carbon dioxide using an experimental tech nique based on frontal analysis chromatography. The desorption profile s from soil indicated that the organics can be completely extracted fr om soil in a short time. The adsorption isotherms of the organics on c arbon indicated that the adsorptive capacity of carbon was very high a nd approached monolayer coverage. An economic analysis using these res ults indicated that the proposed process is feasible for soils contami nated with low levels of these organics.