Application of surfactant Tween 80 to enhance Fenton oxidation of polycyclic aromatic hydrocarbons (PAHs) in soil pre-treated with Fenton reagents

Successive Fenton oxidation (up to three times) was conducted to enhance the removal efficiency of nine USEPA priority PAHs in aged soil highly contaminated with PAHs. Results showed that PAHs concentrations decreased rapidly and the removal efficiency was relatively high during one-time Fenton oxidation. However, PAHs in soil exhibited a slow removal trend and decreased at an extremely slow rate during two- and three-times Fenton oxidation. Surfactant Tween 80 was used to increase the amount of PAHs available for hydroxyl radical (·OH) and enhance Fenton oxidation efficiency of PAHs in aged soil pre-treated with Fenton reagents in this study. Results showed that little effect of Tween 80 on desorption of nine USEPA priority PAHs was observed in treatment with low dose of Tween 80 (800 mg L−1). However, high dose of Tween 80 (6400 mg L−1) could improve desorption of 3- and 4-PAHs (10–18%) in soil pre-treated with Fenton reagents, therefore, Tween 80 could significantly improve degradation efficiency of 3- and 4-PAHs relative to control (13–22%). The results in this study offer a possible alternative to the removal of PAHs from soils.