MULTIPLE STAGE CROSS-CURRENT EXTRACTION USING VEGETABLE OIL IN THE REMEDIATION OF POLYCYCLIC AROMATIC HYDROCARBONS-CONTAMINATED SOIL

The present study aims to compare the efficiency of a single extraction and a 3-stage cross-current extraction of PAHs from both lowly contaminated (LC) and highly contaminated (HC) sands using palm kernel and soybean oils (PKO, SO). It is observed that 3-stage cross-current extractions increase the total efficiencies compared to single extractions by 18.7-22.7% and 27.2-30.6% for LC and HC sands, respectively. Maximum efficiencies of 94.3% and 98.4% are obtained for phenanthrene (PHEN) and fluoranthene (FLT), respectively using PKO at 70 degrees C in the 3-stage cross-current extraction. In HC soil, these efficiencies reduce by 11.6% and 9.2% for PHEN and FLT, respectively. An oil flotation process as a post treatment step for soil/oil slurry is demonstrated to successfully remove 88.8-90.0 % residue oil from treated sand and 70.5-75.7 % residue oil from treated soil. Finally, a conceptual process of the extraction of PAHs from contaminated soil using vegetable oil is proposed.