Persulfate oxidation for the remediation of petroleum hydrocarbon-contaminated soils

Abstract

The feasibility of total petroleum hydrocarbon-contaminated (TPH) soil remediation was studied using persulfate oxidation. Factors tested included type of activator, persulfate concentration, number of persulfate applications, and reaction time. Probe chemicals were used to study efficiency of the persulfate oxidation mechanism. The best activation method used Fe2+, which achieved 40.8% TPH degradation at 24 h with an initial TPH concentration of 14,432.5 mg/kg. For alkaline (high pH) and hydrogen peroxide activation treatments, TPH degradation efficiencies were 35.2% and 21%, respectively. Thermal activation efficiency was relatively low (15.6%). Kinetic experiments demonstrated that the oxidation reaction was substantially completed within 60 min. A one-time addition of persulfate was superior to multiple applications. The addition of probe compounds produced sulfate radicals, hydroxyl radicals, and reductants. The results indicate that activated persulfate is reasonably effective for remediation of TPH-contaminated soils.