Physico-chemical remediation of polycyclic aromatic hydrocarbons contaminated soil

This study exploited the solvent extraction and mechanical agitation techniques for the remediation of soils contaminated with polycyclic aromatic hydrocarbons (PAHs). The removal of pollutants from diesel contaminated site through ethanol, hexane, and ethanol-hexane mixtures was evaluated. 50 g dried contaminated soil was placed in a Soxhlet extractor and 250 ml solvent (ethanol, or hexane, or ethanol-hexane mixture) was added with extraction occurring at different temperatures of 30, 35, 45, 50, and 60 degrees C for 16 h. Mechanically agitated method was carried out by weighing out an equal amount of 50 g of the contaminated soil, thoroughly washing with 250 ml of ethanol, hexane, and equal ratio of ethanol to hexane. Qualitative analysis recovered PAHs was done by Agilent series gas chromatography equipped with flame ionization detector. The chromatographic evaluations of the solvent extraction of the contaminated soil showed that more of the polluted compounds were removed when hexane was the solvent. The maximum yield of extracted diesel by the solvent hexane was 11.84% at 60 degrees C. Extracted diesel removal was also directly proportional to periods of extraction.