Remediation of petroleum hydrocarbon contaminated soils by nZVI coupled with electrokinetic activation of persulfate

This paper explores the use of nanoscale zero-valent iron (nZVI) coupled with electrically activated persulfate (nZVI-EK/PS) for remediating petroleum hydrocarbon-contaminated soil. The effects of persulfate (PS) dosage, nZVI dosage, and soil organic matter content on the remediation of petroleum hydrocarbons were investigated. The study concludes that persulfate (PS) and nanoscale zero-valent iron (nZVI) are the primary factors influencing the remediation of petroleum hydrocarbons in the nZVI-EK/PS system. The optimal reaction conditions of PS = 170 mmol and nZVI = 17 mmol increased the efficiency of petroleum hydrocarbon treatment to 40.45%, with the highest removal efficiency of petroleum hydrocarbons observed at position S2, reaching 48.5%. With the addition of organic matter at 5%, the efficiency of petroleum hydrocarbon treatment reached 50.08%, representing a 9.68% enhancement in the nZVI-EK/PS system. Furthermore, potential mechanisms for the degradation of petroleum hydrocarbons by the nZVI-EK/PS system were identified using gas chromatography-mass spectrometry (GC-MS). The degradation order of different components was found to be esters < alkenes < alkanes < phenols.