Application of silicone oil for removal of diesel oil from contaminated soil

초록

Diesel oil is one of major contaminants in soil contaminated from gas stations. Because diesel oil is composed of various components, it is difficult to select a feasible option for site remediation. A two-liquid-phase(TLP) system has been introduced as a new method for the remediation of diesel oil-contaminated soil. The TLP system can remove hydrophobic contaminants by mass transfer using water-immiscible liquid. Also, this system has the potential to increase biodegradation of contaminants by enhancing their bioavailability to microorganisms. The water-immiscible liquids used, for example, paraffine oil, silicone oil, and peanut oil, are typically non-toxic and biocompatible. In the present study, we have investigated the removal efficiency of diesel oil with the amount of silicone oil (20cs, Sigma, USA) in the TLP system. The soil, kaolinite-white O, was screened less than 150 μm and contaminated artificially with diesel oil from L gas station (Korea). Initial concentration of diesel oil was from 12,000 to 15,000 mg diesel oil/kg soil. Mixing speed was 300 rpm and the operating temperature was 30 ℃. As the amount of silicone oil increased from 2.5 % to 15 % (v/v), the removal efficiency of diesel oil was enhanced. Among the components of diesel oil, aromatics were transferred to silicone oil more than aliphatics because of their higher hydrophobicities. The maximum removal efficiency of diesel oil was over 90 % for the aromatics. Therefore, silicone oil can be applied to remediate effectively diesel oil-contaminated soil in the TLP system.