Resumo

PONS-JIMENEZ, M; GUERRERO-PENA, A; ZAVALA-CRUZ, J  e  ALARCON, A. Removal of oil and petroleum compounds from soils with different physical and chemical characteristics. Universidad y ciencia [online]. 2011, vol.27, n.1, pp.1-15. ISSN 0186-2979.

Among the techniques most used in the analysis of hydrocarbons of the heavy fraction petroleum in soils, is the method published in the Official Mexican Standard NMX-AA-134-SCFI-2006, that establishes an extraction time without taking into account the physical and chemical properties of the soil. This study aimed to optimise the extraction time of petroleum compounds in a Soxhlet system, in three soils polluted by crude oil and with different physical and chemical characteristics. The variables studied in the experiment were soil, extraction time and solvent, with a 3 x 4 x 3 factorial arrangement respectively, in a completely randomised design, with three replicates per treatment. The soils used were Anthrosol, Gleysol and Histosol, and 4 times of extraction (4, 8, 12 and 16 h) and 3 solvents (methanol, hexane and dichloromethane) were evaluated. The treatments with methanol provided the greatest recoveries of compounds in the Gleysol soil, whereas the treatments with this solvent presented the lowest recoveries in the Histosol soil. The treatments with hexane resulted in low recoveries in the Gleysol and Anthrosol soils, and high recoveries in the Histosol soil. The extraction capacity of dichloromethane was evident mainly in the Histosol and Anthrosol soils. The interaction soil, solvent and time generated significant positive effects (Tukey p < 0.05). It is concluded that the extraction time of compounds derived from petroleum in a Soxhlet system is a direct function of the type of soil and the solvent.

Palavras-chave : Chemical analysis; soil; contamination; crude oil.