文摘
Characterisation and remediation of contaminated soils are crucial issues in environmental control. Extraction of pollutants with supercritical fluids is a competitive and viable technique on a laboratory scale and is of great interest for the treatment of contaminated soils in the future. Extraction by supercritical fluids (CO2 or modified CO2) has been carried out on a standard soil (EUROSOIL 1), artificially polluted by organochloride compounds, i.e. pyralene and aldrin. A commercialised extraction apparatus has been used in order to determine the optimal operating conditions for quantitative extraction. A systematic extraction study has been developed and interpreted according to the optimal design method. Several parameters influencing extraction have been identified and studied: pressure, temperature, extraction flow-rate, type of extracting fluid, water content of soil. The percentage recovery has been determined for each experiment. Linear regression of the resulting data has allowed the construction of a recovery response surface, which indicates that high recovery can be obtained over a wide range of extraction conditions.
