title: Modelling the extraction of soil contaminants with supercritical carbon dioxide.
abstract: Extractions of volatile organic compounds (VOC's) in contaminated soil from petroleum site were performed with supercritical carbon dioxide at different temperatures, pressures, extraction times, solvent flow rates, soil moisture contents and soil acidity. Three soil systems were investigated in order to compare the best parameters for extraction. A central composite rotatable design has been used to evaluate the influence of operation conditions on the extraction efficiency to generate model equations representing the types of soil. The results indicate that at least 70-80% of the initial amount of VOC's can be removed at moderate temperatures even at very high moisture content. Supercritical extraction is best suited to silt type soils which have a low adsorption capacity. VOC's recoveries from the artificial contaminated soil samples were higher in comparison with real contaminated soils. At moderate temperatures, the extraction efficiency for real soils is low because pollutants bind strongly to the soil.
authors.affiliation: School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK. m.n.baig@bham.ac.uk
authors.forename: M N
authors.initials: MN
authors.lastname: Baig
authors.forename: G A
authors.initials: GA
authors.lastname: Leeke
authors.forename: P J
authors.initials: PJ
authors.lastname: Hammond
authors.forename: R C D
authors.initials: RC
authors.lastname: Santos
mesh_terms: D002245:Carbon Dioxide / Q000032:analysis / Q000302:isolation & purification*; D025924:Chromatography, Supercritical Fluid / Q000379:methods*; D052918:Environmental Restoration and Remediation / Q000379:methods*; D008956:Models, Chemical; D012989:Soil Pollutants / Q000032:analysis / Q000302:isolation & purification*
chemical_list: D012989:Soil Pollutants; D002245:Carbon Dioxide