Extraction of Pollutant from Soils

Chlorinated phenolic compounds in air-dried sediments collected downstream of chlorine-bleaching mills were treated with acetic anhydride in the presence of triethylamine. The acetylated derivatives were removed from the matrix by supercritical fluid extraction (SEE) using carbon dioxide. The best overall recovery for the phenolics was obtained at 110°C and 37 MPa pressure. Two SEE steps had to be carried out on the same sample for quantitative recovery of the phenolics in weathered sediments. The SEE unit was coupled downstream with a GC for end analysis . Off-line SEE followed by capillary GC was applied in the determination of phenol in polymeric matrices . The sonication method recommended by EPA for extraction of pollutants from soil is inferior to both MAP and SEE techniques in the case of phenol, o-cresol, m-cresol and p-cresol spiked on soil containing various proportions of activated charcoal. MAP afforded the highest recoveries (>80%), except for o-cresol in a soil containing more than 5% of activated carbon. The SEE method was inefficient for the four phenols tested however, in situ derivatization of the analytes significantly improved the performance . 

Studies of the extraction of pollutants from soils, sediments, sludges and other matrices have been carried out extensively on a laboratory scale. In some cases degradation of the extracted compounds occurs during the process. In other studies, a degradation step, such as supercritical water oxidation, has been added in-Hne to... 

Extraction of Pollutant from Soils with Supercritical Carbon Dioxide and Other Supercritical Fluids... 

Supercritical fluids can be applied to remove polluting materials from the environment. Theory and practice of this technology is of increasing interest at the present time. In Supercritical fluids and reductions in environmental pollution by Koji Yamanaka and Hitoshi Ohtaki focus their attention to start with the thermodynamics and structure of supercritical fluids and then describe the supercritical water oxidation process, the extraction of pollutant from soils with supercritical carbon dioxide and other supercritical fluids, and recycle of used plastic bottles with supercritical methanol. Andrew I. Cooper et al. report on Supercritical carbon dioxide as a green solvent for... 

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See also in sourсe #XX -- [ ]

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