Remediation of petroleum contaminated soil with Na₂S₂O₈ activated by different iron-based catalysts

Objective In the treatment of petroleum contaminated soil by activated persulfate system, different forms of iron-based materials were used as catalysts to remove petroleum hydrocarbons.

Methods Sodium persulfate (Na₂S₂O₈) activated by three iron-based catalysts (ferrous citrate, zero valent iron and ferroferric oxide) were compared to treat petroleum contaminated soil through indoor simulation experiments. The persistence of oxidant, the effectiveness of pollutant removal, the change of soluble carbon and nitrogen content and pH value were investigated.

Results The addition of zero valent iron significantly promoted the removal of total petroleum hydrocarbons (TPH) from petroleum contaminated soil. After 10 days of reaction, the removal rate of TPH was 53.39%, which is 15.3% higher than that of the control group. The addition of iron-based catalyst showed significant impact on the content of dissolved organic carbon and total nitrogen. If microbial remediation is used in the follow-up, additional nutrients were needed to add to adjust the carbon nitrogen phosphorus ratio for microbial growth.

Conclusions The addition of zero valent iron can increase the effective utilization of Na₂S₂O₈, and then improve the sustainability and effectiveness of TPH removal. The results have a certain reference value for the treatment of organic contaminated soil by using persulfate technology activated by more types of iron-based materials.