Supercritical fluid extraction of mixed wastes

Abstract

This study assesses the feasibility of extraction and separation of uranium and PCBs from contaminated soil samples using a sequential supercritical CO₂ extraction method. The contaminated soil was first extracted with neat supercritical CO₂ at 150 °C and 200 atm to remove PCBs. Subsequently, complexing agents, tri-n-butylphosphate (TBP) and thenoyltrifluoroacetylacetone (HTTA), were added to remove uranium from the contaminated soils. Using this method, nearly all PCBs were removed, and up to 75% of the uranium in the soil could be removed after multiple extractions. This sequential supercritical fluid extraction method may have a wide range of applications for treating various mixed wastes.