The application of persulfate (PS) for the remediation of petroleum hydrocarbon contamination is among the most widely employed in situ chemical oxidation (ISCO) techniques, and it has received widespread attention due to its limited impact on soil integrity. This study employed a FeSO4-activated PS oxidation method to investigate the feasibility of remediating soil contaminated with total petroleum hydrocarbons (TPHs). The factors tested included the TPH concentration, different PS:FeSO4 ratios, the reaction time for remediation, soil physical and chemical property changes before and after remediation, and the effect of soil before and after remediation on soybean growth. The TPH degradation rate in soil was highest for high-, medium-, and low-TPHs soils-81.5%, 81.4%, and 72.9%, respectively, with minimal disruption to the soil's physicochemical properties-when PS:FeSO4 = 1:1. The remediation verification results indicated that the condition of the soybeans was optimal when PS:FeSO4 = 1:1. Under this condition, the net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, and transpiration rate all remained high. Therefore, the best remediation effect was achieved with PS:FeSO4 = 1:1, which also minimized the damage to the soil and the effects on crop growth.

To investigate the efficacy and strength properties of Fe2+-activated persulfate remediation for 1,2-dichlorobenzene-contaminated soil with varying persulfate concentrations, we conducted degradation, microscopic, particle size, liquid-plastic limit, unconfined compressive strength (UCS), and undrained shear tests. The results indicate that adding 15.0% Fe2+-activated persulfate achieves a 92.59% removal rate of 1,2-dichlorobenzene. Furthermore, the reaction produces sodium sulfate, calcium sulfate, and ferric hydroxide. Small amounts of sodium sulfate and calcium sulfate fill the pores between soil particles, leading to a denser soil structure. However, the expansive effect of excessive sodium sulfate crystals weakens the inter-particle cohesion, leading to soil loosening. After remediation, the clay content increases, while the silt and sand content decreases. The liquid limit, the plastic capacity and the plastic index increase, while the plastic limit decreases with the increase of the persulfate dosage. The UCS and the maximum shear stress decrease with the increase of the persulfate dosage. The UCS of the soil treated by 10.0% persulfate is 310.75 kPa, 20.34% higher than the strength of untreated soil. The maximum deviator stress at shear failure is 142.73 kPa.