Effect of the ultrasound–Fenton oxidation process with the addition of a chelating agent on the removal of petroleum-based contaminants from soil

The effects of ultrasonic irradiation, the chelating agent modified Fenton reaction, and a combination of ultrasound and the Fenton method in removing petroleum contaminants from a soil were studied. The results showed that the contaminant removal rate of the Fenton treatment combined with an oxalic acid chelating agent was 55.6 % higher than that without a chelating agent. The average removal rate of the contaminants using the ultrasound–Fenton treatment was 59.0 % higher than that without ultrasonic treatment. A combination of ultrasound and an Fe(2+)/Fe(3+)-oxalate complex–modified Fenton reagent resulted in significantly higher removal rates of n-alkanes (C(n)H(2n+2), n < 28), isoprenoid hydrocarbons, aromatic hydrocarbons, and saturated polycyclic terpenes compared with the ultrasound treatment alone or the Fenton method. The Fenton reaction and the ultrasound–Fenton treatment can unselectively remove multiple components of residual hydrocarbons and a number of benzene rings in polycyclic aromatic hydrocarbons. The chemistry of the heterocyclic compounds and the position and number of substituents can affect the degradation process.