Microwave Heating Remediation of Light and Heavy Crude Oil-Contaminated Soil

The remediation of petroleum hydrocarbon-polluted soil with microwave irradiation is a promising technology due to its high decontamination efficiency and low energy consumption. The current study is to experimentally investigate the performance of microwave heating remediation of light and heavy crude oil-contaminated soil in a lab-scale apparatus. The results show that 98.95 and 96.39% of total petroleum hydrocarbons (TPHs) in light and heavy crude oil-contaminated soil can be removed in 15 and 20 min at 1000 W, while the residual TPHs constitute around 143.2 and 401.4 mg/kg, respectively. This indicates that the removal of light crude oil from soil is much more efficient and consumes less energy due to the difference in removing behaviors for different fractions. The major removal of C10–C16, C16–C22, and C22–C40 fractions at 200, 300, and 400 °C reveals that the removal of both small and large molecular fractions is promoted by microwave irradiation as it occurs at a temperature far below their boiling points. Moreover, soil organic matter (SOM) in light and heavy crude oil-contaminated soil is maintained at a moderate level (i.e., 19 and 21.7 g/kg at 400 °C) after microwave treatment, giving an opportunity for soil reusability.