Engineering Research Seminar Series 9_2011: Remediation of Polycyclic Aromatic Hydrocarbons (PAHs) Contaminated Soil with Vegetable Oil

Ms Ee Von Lau, Agilent Technologies

Date: 2011-03-29
Time: 13:00 to 14:00
Venue: Classroom 6-3-06


The occurrence of polycyclic aromatic hydrocarbons (PAHs) in soils has drawn increasing public health and environmental concerns because of their mutagenic and carcinogenic properties. Characterized by their palpable hydrophobic nature, these toxic pollutants are highly resistant to environmental degradation. As such, significant research efforts are currently invested into the remediation of PAH-contaminated soils. This study aims to treat PAH-spiked sand using vegetable oil, a non-toxic and biodegradable alternative to organic solvents or surfactants commonly employed in the solvent extraction or soil washing method. Batch extraction experiments were carried out to compare the extraction efficiency using a highly saturated palm kernel oil (PKO) and a highly unsaturated soybean oil (SO) to remove phenanthrene (PHEN) and fluoranthene (FLT) spiked into sand at concentrations of 1000 ppm each at temperatures of 30°C and 70°C. Experimental data of PAH desorption from soil were fitted to an empirical first order kinetic model to attain the equilibrium concentration, Ce and mass transfer coefficient, k. Results showed maximum extraction efficiencies of 59.0 % and 63.6 % for PHEN and FLT respectively were achieved using PKO at 70oC. This study then included a multiple batch extraction of the PAH-contaminated sand. In this improved solvent extraction process, it was seen that almost complete PAH removal were attained, with maximum extraction efficiencies of 94.3 % and 98.4 % for PHEN and FLT respectively using PKO at 70oC. Finally, the potential performance of vegetable oil in the treatment of PAH-contaminated soil was studied using native soil. Results showed that a significant drop of 11.6 % and 9.2 % for PHEN and FLT respectively was mainly attributed to the dominant effects of organic matter in soil. This study thus highlights the potential of using vegetable oil in solvent extraction of PAH-contaminated soils as a replacement for more toxic and costly solvents and surfactants.

About the Speaker

Ee Von is a 1st Class Honours Mechanical Engineer graduate from The University of Melbourne, Australia. Upon graduation, she has since worked with Agilent Technologies in Penang as an NPI Materials Engineer and Process Mechanical Engineer for 1.5 years. Given the opportunity to further her studies, Ee Von then joined The University of Nottingham, Malaysia Campus as a Research Assistant to pursue her PhD degree in Chemical and Environmental Engineering under the supervision of Dr Gan Suyin and Dr Ng Hoon Kiat.