Promotion of Chemical Oxidation of Polycyclic Aromatic Hydrocarbons in Soil by a Sodium Persulfate/Sodium Percarbonate Double‐Oxidation System

In situ chemical oxidation (ISCO) is a highly effective remediation technique for the complete mineralization of organically contaminated soil. This study focused on the oxidative remediation of polycyclic aromatic hydrocarbons (PAHs) in contaminated soil using a composite oxidant system composed of monohydrated citric acid (CA) chelated with ferrous sulfate heptahydrate (FS) and activated sodium persulfate (PS) and sodium percarbonate (SPC). The effects of four individual factors-PS dosage, SPC dosage, FS addition, and CA addition-on PAH degradation were examined. Optimization of the test conditions using response surface methodology demonstrated that the dual oxidant system significantly increased the degradation rate of PAHs. The optimal process conditions were identified as follows: PS concentration of 52.66 g/kg, SPC concentration of 30.24 g/kg, FS concentration of 47.71 g/kg, CA concentration of 6.80 g/kg, a water-soil ratio of 1:1, a reaction time of 4 days, and a final total PAH removal rate of 69.65%. Another way to explain this is that a molar ratio of 6.3:5.5:4.9:1 for PS/SPC/FS/CA in this system can achieve maximum degradation efficiency. The dual-oxidant system investigated in this study exhibits significant potential for the remediation of PAHs in soil.