Multiple stage cross-current extraction using vegetable oil in the remediation of polycyclic aromatic hydrocarbons-contaminated soil

Ee Von Lau1,2, Suyin Gan1, Hoon Kiat Ng3

1 The University of Nottingham Malaysia Campus, Department of Chemical and Environmental Engineering, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia
2 Monash University Malaysia, School of Engineering, Jalan Lagoon Selatan, 46150 Bandar Sunway, Selangor Darul Ehsan, Malaysia
3 The University of Nottingham Malaysia Campus, Department of Mechanical, Materials and Manufacturing Engineering, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia

Abstract


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 70oC 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.

Keywords


extraction; polycyclic aromatic hydrocarbons (PAHs); remediation; soil; vegetable oil

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