Simultaneous remediation of polycyclic aromatic hydrocarbons (PAHs) contaminated soil using integrated steam-assisted...

Polycyclic aromatic hydrocarbons (PAHs) are collectively known as a group of organic contaminants that pose a serious threat to the soil environment and also PAHs are very persistent in soil, which makes them very difficult to remove from the soil. Plasma technology has been used for the remediation of organic pollutants in recent years and shows great promise in soil remediation. The objective of this study is to optimize this technology by integrating water vapor and plasma to improve efficiency in the simultaneous remediation of mixed PAHs-contaminated soil. The impacts of several experimental settings, the role of radical species, and occurrence of gaseous products was assessed. The results of this study indicate that contaminant removal efficiency achieved 85.52-99.73 % with two main radical species (·OH and ·NO), which act as PAHs breaking agents and soil fertility enhancers, respectively. Afterwards, the gaseous products showed several PAHs with two to three rings that were almost completely degraded, as indicated by very low concentrations at retention times of 5 to 25 min, followed by complete mineralization that produced CO₂ and H₂O_(g) at retention times of 35 to 55 min in the total ion chromatogram (TIC) analysis. Furthermore, steam-assisted plasma offers not only to clean the soil from PAHs pollution but also to recycle those found in the soil by breaking them down into gas products that can be reused to meet human needs.