Combination of Nonionic Surfactants with Thermal-activated Persulfate for Simultaneous Removal of Phenanthrene and Pyrene from Alluvial Soil: A Kinetic Study

Polycyclic aromatic hydrocarbons have adverse effects on the organisms, plants, and soil structure. Therefore, they should be removed by an appropriate and effective method. In this study, simultaneous removal of 500 mg/kg(soil) of phenanthrene and pyrene was investigated for the individual and combined application of Tween 80, Triton X-100, and sodium persulfate from the alluvial soil. The results revealed that the maximum removal efficiencies of phenanthrene (94.06 +/- 0.30%) and pyrene (90.07 +/- 0.19%) were observed in the presence of Triton X-100 + sodium persulfate (0.5 M) within 1 hour, respectively. Also, individual application of surfactants and sodium persulfate had efficiencies of less than 80%. It should be noted that the removal of phenanthrene and pyrene followed the first-order kinetic model. Economic evaluations of combined treatment demonstrated that the application of more proportion of Triton X-100 (10000 mg/L) + less proportion of sodium persulfate (0.3 M) is more cost-effective for the remediation of soil in the field study. Based on the results, the combined application of the washing process by Triton X-100 and persulfate oxidant can significantly improve the removal efficiencies and is a promising technique in the remediation of polycyclic aromatic hydrocarbons contaminated soil.