Thermal plasma potential to remediate soil contaminated with diesel.

Petroleum hydrocarbons (PHCs) are recognized as one of the major soil contaminants causing negative environmental impact. Thereby, PHCs remediation from the soil is essential. Hence, this experimental study aimed to assess the potential of thermal water vapor and air plasmas to remediate soil contaminated with habitually used PHCs - diesel. The impact of contaminant content in the soil on the remediation process also was estimated. The results of this research demonstrated that 99.9% contaminant removal efficiency was received proceeding diesel contaminated soil remediation in the environment of the thermal plasma in defiance of whether water vapor or air was employed as a plasma-forming gas. Moreover, the soil's contaminant content (80-160 g/kg) did not influence its' removal efficiency. The soil de-pollution process also caused the decomposition of the soils' natural carbon reserves since carbon content decreased from an initial 9.8 wt% in the clean soil to 3-6 wt% in the remediated soil. Furthermore, PHCs - diesel was decomposed into producer gas mainly consisting of H, CO (also known as synthesis gas) and CO. Thus, the thermal plasma offers a way not only to de-pollute the soil but also to reuse the PHCs present in the soil by breaking it down into gaseous products that can further be used to meet human needs.