Fully-continuous supercritical fluid extraction of PAHs from soil slurries

The research aimed to implement a functional slurry level control system into a fully-continuous laboratory scale supercritical fluid extraction system. In addition, the ability of the extraction system to remove PAHs (naphthalene and phenanthrene) from slurried soil was investigated. 1.5% spiked soil slurries were extracted with supercritical CO2 at pressures of up to 9.73 MPa and temperatures between 33.8°C and 43.8°C.; Major operational and mass transfer improvements were realised with the implementation of the level control system. The mass transfer coefficient for naphthalene was as high as 5.1 x 10-3 s-1. In addition, the system successfully extracted phenanthrene from the slurry with mass transfer coefficients of up to 4.9 x 10-4 s -1. Specific recommendations were made to improve laboratory system and to advance the technology of fully-continuous SCFE of soil slurries.