Enhanced infiltration of fuel-contaminated hydrophobic unsaturated soil by hydrogen peroxide using surfactant, potassium dihydrogen phosphate, and phytate

Purpose Fuel-contaminated soil can be remediated via oxidation using hydrogen peroxide (H2O2). However, it is difficult for H2O2 to infiltrate deep soil due to its vigorous reaction in shallow soil. The inability of H2O2 to infiltrate contaminated soil affects the remediation of deep soil. Methods In this study, hydrophobic and fuel contaminated soil was pretreated (pre-soaked) with sodium alpha-olefin sulfonate (AOS; 1% w/v), potassium dihydrogen phosphate (KH2PO4; 1% w/v), and sodium phytate (1% w/v) as a chelator. After the soil was pretreated, H2O2 (1.5%) infiltration was recorded for 100 min. The removal of total petroleum hydrocarbon (TPH) from the soil after H2O2 infiltration was determined using gas chromatography equipped with mass spectroscopy (GC-MS). Result and discussion After pretreatment, the 100-min cumulative infiltration of 1.5% H2O2 was 17.45 cm. No infiltration (0 cm) was observed without pretreatment. The addition of AOS for pretreatment reduced the hydrophobicity of the soil, and KH2PO4 and phytate improved the stability of H2O2 in the soil. Significant removal of diesel oil from the pretreated soil was also achieved after the infiltration of H2O2. The initial soil total petroleum hydrocarbon (TPH) content of 14,784 mg/kg was reduced to 2,821 mg/kg (80.24% removal efficiency), and the removal of TPH from the soil was uniform throughout the soil column (top, middle, and bottom; 80.82%, 79.96%, and 79.94% removal efficiency, respectively) when compared to the control (16.17%, 4.61%, and 0.83%, respectively). Conclusion H2O2 infiltration after pretreatment can provide effective contact between the fuel oil and H2O2 for oxidation in the soil. The findings of this study can provide useful insights into the soil remediation process via chemical oxidation after natural H2O2 infiltration.

Automated summary

The study investigated the use of pretreatment with chelators to improve the stability of H2O2 in hydrophobic and fuel contaminated soil. The findings showed that pretreatment facilitated H2O2 infiltration and resulted in effective removal of diesel oil from the soil. This study provides valuable insights into the remediation process of soil through chemical oxidation after natural H2O2 infiltration.