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

Meng Zhang; Weixiao Chen; Xiuyun Chuan; Xiaoying Guo; Xiaofang Shen; Haiyun Zhang; Fan Wu; Jing Hu; Zhipeng Wu; Xilong Wang

doi:10.1016/j.scitotenv.2023.168499

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

Sci Total Environ. 2024 Jan 20:909:168499. doi: 10.1016/j.scitotenv.2023.168499. Epub 2023 Nov 15.

Authors

Meng Zhang¹, Weixiao Chen², Xiuyun Chuan³, Xiaoying Guo², Xiaofang Shen², Haiyun Zhang², Fan Wu², Jing Hu², Zhipeng Wu², Xilong Wang⁴

Affiliations

¹ Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China; Co-Innovation Center for Sustainable Forestry in Southern China, College of Ecology and Environment, Nanjing Forestry University, Nanjing 210037, China.
² Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
³ School of Earth and Space Sciences, Peking University, Beijing 100871, China.
⁴ Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China. Electronic address: xilong@pku.edu.cn.

PMID: 37977369
DOI: 10.1016/j.scitotenv.2023.168499

Abstract

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.

Keywords: Bioavailability; Extractability; PAHs; Soil remediation; Surfactant-enhanced washing.