Batch experiments were conducted to examine the effects of ferrous iron source, soil salinity and temperature on degradation of long-chain petroleum hydrocarbons by Fenton-like processes. The results show that over 70%, 50% and 25% of aliphatic C16-C21, C21-C35 and C35-C40, respectively, was eliminated at a H2O2 dose of 1.5%. The decomposition rate of petroleum hydrocarbons was similar to each other for ferrous sulfate and magnetite while the capacity of pyrite to trigger Fenton-driven decomposition of long-chain aliphatic petroleum hydrocarbons was weaker, as compared to ferrous sulfate and magnetite. The decomposition rate of aromatic hydrocarbons decreased with increasing length of carbon chain in the ferrous sulfate and magnetite systems, but the opposite was observed in the pyrite system. The effect of Fenton-like process on degradation of long-chain petroleum hydrocarbons was enhanced by increased temperature. At a temperature of 60 °C, the enhancement of Fenton process outweighed the adverse effects from potential loss of H2O2 due to elevated temperature. The use of magnetite as a source of ferrous iron was likely to prevent consumption of Fe2+ by complexation with chloride ion from occurring and consequently effectively eliminated the inhibitory effect of salinity on Fenton reaction.
Keywords: Chemical degradation; Desert; Hydrogen peroxide; Hydroxyl radical; Oil contamination; Saline soil.
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