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Supercritical fluid extraction of organic pollutants from soil combined with adsorption onto activated carbon
C. Erkey, , M. Orejuela, A. Akgerman
Published in
1993
Volume: 13
   
Issue: 5-7
Abstract
A novel process was developed on laboratory scale for remediation of soils contaminated with organic pollutants. In this process, the organics are continuously extracted using supercritical carbon dioxide (SCCO2) and then deposited onto activated carbon. Clean CO2 is circulated back to the extractor, and the cycle continues until the desired level of decontamination is achieved. In order to investigate the feasibility of the process, the adsorption isotherms of naphthalene, phenanthrene, hexachlorobenzene, and pentachlorophenol on standard EPA soil and on activated carbon were determined in the presence of SCCO2 using frontal analysis chromatography. All the adsorption isotherms were modelled based on the Freundlich isotherm. The amount of organic adsorbed on carbon was found to be dependent on the surface area rather than on the nature of the organic; whereas, the adsorbed amounts on soil were found to be strong function of the type of contaminant. The heats of adsorption of the organics were also extracted from the temperature dependency of the initial slopes of the isotherms. The desorptive behavior of these organics from soil using SCCO2 were also investigated, and the local equilibrium theory was found to predict the desorption profiles fairly accurately. An economical analysis indicates that the operational costs for the process compare favorably with existing technologies.
About the journal
JournalWaste Management
ISSN0956053X