The combined effects of surfactant solubilization and chemical oxidation on the removal of polycyclic aromatic hydrocarbon from soil

Abstract

A method for the remediation of polycyclic aromatic hydrocarbons (PAHs) contaminated soils was proposed involving a combination of surfactant-aided soil washing and chemical oxidation by activated persulfate (SP). In this study, Triton X-100 (TX-100) and SP was applied to the soil, either concurrently or sequentially. Results indicated that surfactant followed by amendment with a solution of SP, TX-100 + SP(l), was most effective in decreasing PAHs concentrations in a sandy loam soil (SS) and a silty clay soil (NS) from 1220 mg/kg and 2730 mg·kg−1 to 414 mg·kg−1 and 180 mg·kg−1, respectively. Compared with extraction alone and oxidation alone, TX-100 + SP(l) increased the removal of PAHs by 10–20%. TX-100 improved the degradation of 3–4 ring PAHs (M-PAHs) and 5–6 ring PAHs (H-PAHs) in SS, by approximately 8%–11%. The oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs) including furans and xanthene exhibited greater reductions in soil when amended with the TX-100 and SP, than under TX-100 extraction or SP oxidation alone. Overall, increased removal of PAHs in contaminated soil can occur through simultaneous application of TX-100 and SP, relative to the sole use of TX-100 or SP. The sequential combination of surfactant and oxidant was most effective for the elimination of PAHs, especially for M-PAHs and H-PAHs in sandy loam contaminated soil.