Remediation of heavily PAHs-contaminated soil with high mineral content from a coking plant using surfactant-enhanced soil washing

• Published in: The Science of the total environment 2024-01, Vol.909, p.168499-168499, Article 168499
• Main Authors: Zhang, Meng, Chen, Weixiao, Chuan, Xiuyun, Guo, Xiaoying, Shen, Xiaofang, Zhang, Haiyun, Wu, Fan, Hu, Jing, Wu, Zhipeng, Wang, Xilong
• Format: Article
• Language: English
• Subjects: Bioavailability; cationic surfactants; clay; environment; Extractability; mineral content; octoxynol; organic matter; PAHs; remediation; soil; Soil remediation; solubilization; Surfactant-enhanced washing
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.168499

This study investigated the effectiveness of various surfactants at different concentrations in removing high concentrations of polycyclic aromatic hydrocarbons (PAHs) from soil with high mineral content, focusing on the impact of surfactant treatment on the mobility of the residual PAHs in soil. The results revealed that the cationic surfactant (CTMAB) inhibited removal of PAHs in the whole tested concentration range of 0.1–8 g/L. In contrast, the non-ionic and anionic surfactants (Triton X-100 and SDBS) significantly enhanced removal of PAHs as their amendment concentrations reached 2 g/L and above. Triton X-100 exhibited steadily increased efficacy with increasing amendment concentrations and maintained favorable solubilization capability when continuously amended, making it the preferable choice for remediating PAHs-contaminated soil. Surfactant and water washing processes altered soil physicochemical properties by removing some clay minerals (e.g., faujasite) and organic matter that can bind or sequester PAHs, potentially increasing their extractability and bioavailability in the washed soil, thereby posing higher ecological risks compared to the original one. Although soil washing decreased retention of the remaining PAHs in soil, it did not significantly impact PAHs release from soil by flowing water. These findings provide insights into the long-term effectiveness and ecological impacts of surfactant-enhanced washing as a potential remediation technique for PAHs-contaminated soil. [Display omitted] •CTMAB inhibited removal of PAHs from soil within the concentration of 0.1–8 g/L.•Both Triton X-100 and SDBS enhanced PAHs removal, but Triton X-100 outweighed SDBS.•Surfactant or water washing promoted extractability of the remaining PAHs in soil.•Soil washing by surfactant may not alter the released amount of PAHs by water.