Katsuya Kawamoto

Dept. of Architectural Environmental Engineering, Faculty of Engineering, Kanto Gakuin University
(4834 Mutsuura, Kanazawa-ku, Yokohama 236 Japan)

Abstract

The supercritical fluid extraction method using carbon dioxide was investigated from the viewpoint of the relationship between the recovery of organic pollutants in the model waste sample and extraction parameters. Chlorobenzenes were selected as target compounds because they are considered to be priority pollutants. Extraction was almost completed within 30min under the flowrate of ca. 1ml/min on model sample. The pressure which determines the density of fluid under the constant temperature essentially affects extraction efficiency with increased recovery in the region of high pressure. However, extraction recovery does not simply depend on the increase of pressure, the effect of temperature is also observed. It is expected that the volatilization effect contributes to achieving high extraction efficiency for volatile and thermally stable compounds. Though the addition of a polar modifier increases extraction efficiency, the effect is influenced by interaction between the analyte-matrix complex and the bulk of supercritical fluid. The application of supercritical fluid extraction to real fly ash sample demonstrates that this method is not sufficient for accomplishing quantitative extraction. Further problems were also discussed.

Key words: solid waste, fly ash, hazardous organics, supercritical fluid extraction, chlorobenzenes