| With the rapid development of petroleum industry, the pollution of petroleumhas been a global environment problem, especially the oil contaminated soilthreatened the health of humans. In recent years, many researchers started toremediate soils contaminated with petroleum hydrocarbons, and a number oftechnologies have been developed, such as physical remediation, chemicalremediation and biological remediation. However, most of the research was based onthe ideal model. The influence of soil properties on the remediation was oftenneglected. Therefore, the results were so far from the real condition that it couldn’tguide the site remediation effectively. Solvent extraction is a promising technologyfor soils remediation. In this paper, solvent extraction was used to remediate the oilcontaminated soil. Technological condition was optimized. Meanwhile, the influenceof soil and oil properties on the removal of the petroleum hydrocarbons was evaluatedby multivariate data analysis in order to provide theoretical basis on the siteremediation.The petroleum contaminated soil samples were collected from six oil fields inChina. Analysis method of petroleum hydrocarbons was established by the means ofgas chromatography-mass spectrometry. After analysis, the oil content of the soilsamples were between4.18×104~2.86×105mg/kg.The removal efficiency of different solvents was studied. The results showed that,petroleum ether was proved to be of high efficiency and green solvent. The optimalconditions were room temperature,20min and liquid-solid ratio8:1of treatment.Under these conditions, the removals of petroleum hydrocarbons are between70%and90%. The removal of n-alkanes and PAHs are more than60%.How the extractability of petroleum hydrocarbons is influenced by soilcharacteristics (pH, oil content, organic matter content, moisture, cation exchangecapacity and soil particle) and physicochemical properties of petroleumhydrocarbons(octanol/water partition coefficient, soil organic carbon partitioncoefficient, water solubility, molecular weight, number of rings and number ofcarbon atoms) was investigated by multivariate data analysis. The results show that the removal of petroleum hydrocarbons is influenced by a combination of soilcharacteristics and physicochemical properties of petroleum hydrocarbons. Theorganic matter content, cation exchange capacity, moisture, pH and sand content ofsoil all had a positive impact on the removal efficiency, whereas the oil content, claycontent and silt content were correlated negatively with the removal of petroleumhydrocarbons. Parameters reflecting hydrophobicity such as water solubility,octanol/water partition coefficient, soil organic carbon partition coefficient andproperties reflecting molecular size such as molecular weight, number of rings andnumber of carbon atoms were all negatively correlated to the removal efficiency. Atthe same time, the correlation coefficients of soil and oil properties to oil removalefficiency were evaluated by partial least squares projections. According to the result,in the process of solvent extraction, the remediation effect of real contaminated soilwas different from that of man-made contaminated soil. The correlation coefficientsprovides a theoretical basis for site remediation. |
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