Objective The aim of this study is to explore the effect of soil physical and chemical properties on TPH-contaminated soil oxidative remediation so as to sought the efficient oxidation system.

Methods The purple soil in southwest China was selected to prepare TPH-contaminated soil with different soil organic matter contents, particle size, and cation exchange capacity. The CaO₂-like Fenton, activated Na₂S₂O₈ and CaO₂/Na₂S₂O₈ composite oxidation system were adopted to conduct oxidation experiments at room temperature of 25 ℃ under the optimal oxidation conditions respectively. The effects of soil physical and chemical properties on soil TPH loading capacity and oxidative remediation were investigated.

Results The results showed that when the TPH dosage was 15 000 mg/kg, the soil TPH loading capacity was positively correlated with soil organic matter content and cation exchange capacity, but negatively correlated with soil particle size. The influence degree was organic matter content > particle size > cation exchange capacity. The degradation rate of soil TPH was negatively correlated with soil organic matter content, cation exchange capacity, and particle size while the influence degree was particle size > organic matter content > cation exchange capacity.

Conclusion Under the optimal oxidation conditions, the effect of CaO₂/Na₂S₂O₈ composite oxidation system on soil TPH remediation was better than that of CaO₂-like Fenton and activated Na₂S₂O₈ single oxidation system.