Compositional Changes of Hydrocarbons of Residual Oil in Contaminated Soil During Ozonation

摘要

abstract_textpOzonation is an effective method to remove recalcitrant weathered oil in contaminated soil. The purpose of this study was to characterize the compositional changes of hydrocarbons in residual oil during ozonation. A bioremediated soil containing residual oil was ozonated for up to 15 h. A total of 102 compounds in the residual oil were analyzed by GC/MS and 36 diagnostic ratios (DRs) were calculated based on quantitative or semi-quantitative results in order to evaluate the susceptibility of the residual oil compositions to ozonation and the effects of ozonation on the fingerprint profile of the residual oil. The total ozonation removal rates were in the following order: triaromatic steranes (TAS) steranes, polycyclic aromatic hydrocarbons, terpanes alkanes. Ozone kept the fingerprints of n-alkanes, C-27- to C-34-terpanes, steranes and TAS, separately. Branched alkanes (i.e., pristane and phytane) showed a higher removal rate than n-alkanes. Ozone reactivity of PAHs depended on the number of rings, presence of heteroatoms and level of alkylation. Four- to six-ring PAHs and PAHs with a high level of alkylation showed higher reactivity, while dibenzothiophene and alkylated dibenzothiophenes were found to be resistant to ozonation. Some of the biomarker source ratios remained stable and could still be used for source identification even after some of the biomarkers were removed by 90 by ozonation./p/abstract_text