Stabilization of arsenic and antimony Co-contaminated soil with an iron-based stabilizer: Assessment of strength, leaching and hydraulic properties and immobilization mechanisms

Shiji Zhou; Yanjun Du; Yasong Feng; Huiyan Sun; Weiyi Xia; Hang Yuan

doi:10.1016/j.chemosphere.2022.134644

Stabilization of arsenic and antimony Co-contaminated soil with an iron-based stabilizer: Assessment of strength, leaching and hydraulic properties and immobilization mechanisms

Chemosphere. 2022 Aug:301:134644. doi: 10.1016/j.chemosphere.2022.134644. Epub 2022 Apr 19.

Authors

Shiji Zhou¹, Yanjun Du², Yasong Feng³, Huiyan Sun⁴, Weiyi Xia⁵, Hang Yuan⁶

Affiliations

¹ Jiangsu Key Laboratory of Urban Underground Engineering & Environmental Safety, Institute of Geotechnical Engineering, Southeast University, Nanjing, 210096, China; Jiangsu Key Laboratory of Urban Underground Engineering and Environmental Safety, Institute of Geotechnical Engineering, Southeast University, Nanjing, 211189, China. Electronic address: shijizhou@seu.edu.cn.
² Jiangsu Key Laboratory of Urban Underground Engineering & Environmental Safety, Institute of Geotechnical Engineering, Southeast University, Nanjing, 210096, China; Jiangsu Key Laboratory of Urban Underground Engineering and Environmental Safety, Institute of Geotechnical Engineering, Southeast University, Nanjing, 211189, China. Electronic address: duyanjun@seu.edu.cn.
³ Jiangsu Key Laboratory of Urban Underground Engineering & Environmental Safety, Institute of Geotechnical Engineering, Southeast University, Nanjing, 210096, China; Jiangsu Key Laboratory of Urban Underground Engineering and Environmental Safety, Institute of Geotechnical Engineering, Southeast University, Nanjing, 211189, China; Jiangsu Province Key Laboratory of Environmental Engineering, Jiangsu Provincial Academy of Environmental Science, Nanjing, 210036, China. Electronic address: fengyasong@seu.edu.cn.
⁴ Jiangsu Key Laboratory of Urban Underground Engineering & Environmental Safety, Institute of Geotechnical Engineering, Southeast University, Nanjing, 210096, China; Jiangsu Key Laboratory of Urban Underground Engineering and Environmental Safety, Institute of Geotechnical Engineering, Southeast University, Nanjing, 211189, China. Electronic address: 220193200@seu.edu.cn.
⁵ Jiangsu Environmental Engineering Technology Co., Ltd., Jiangsu Environmental Protection Group Co., Ltd., Nanjing, 210019, China. Electronic address: duguosj@163.com.
⁶ Jiangsu Key Laboratory of Urban Underground Engineering & Environmental Safety, Institute of Geotechnical Engineering, Southeast University, Nanjing, 210096, China; Jiangsu Key Laboratory of Urban Underground Engineering and Environmental Safety, Institute of Geotechnical Engineering, Southeast University, Nanjing, 211189, China. Electronic address: 220194497@seu.edu.cn.

PMID: 35452641
DOI: 10.1016/j.chemosphere.2022.134644

Abstract

Soils with relatively high concentrations of arsenic (As) and antimony (Sb) in mining areas would impose significant risks to human health and ecosystem. A new stabilizer PFSC composed of polymerized ferric sulfate (PFS) and calcium hydroxide (Ca(OH)₂) is proposed to stabilize the soil with co-existed As and Sb sampled at an abandoned arsenic factory site. The effects of stabilizer dosage on the properties of the stabilized soil including leached concentrations of As and Sb, unconfined compressive strength (UCS), and hydraulic conductivity (k_w) were investigated. The mechanisms of As and Sb immobilization in the soils were interpreted by Tessier's sequential extraction procedure (SEP), scanning electron microscope (SEM), and X-ray diffraction (XRD) results. The results showed increasing PFSC dosage was effective for reducing leached concentrations of As and Sb. When the PFSC dosage increased from 2% to 10%, the UCS and k_w increased from 84 to 206 kPa and decreased from 6.48 × 10^-8 to 6.33 × 10^-9 m s^-1, respectively. Tessier's SEP results showed that the leachable As and Sb fractions decreased from 12% to 5.6% and 7.5% to 3.8%, while the Fe-Mn oxides bound fractions increased from 22.3% to 29.4% and 13.2% to 19.5%. The SEM images and XRD patterns of untreated and PFSC stabilized contaminated soils indicated that hematite and calcite (CaCO₃) were the main products of PFSC stabilization processes. Adsorption on ferrihydrite, entrapment in hematite lattices, and co-precipitate with calcite might were the main mechanisms of As and Sb immobilization.

Keywords: Arsenic and antimony co-contaminated soil; Hydraulic conductivity; Immobilization mechanism; Leached concentration; Stabilization; Unconfined compressive strength.

MeSH terms

Antimony / analysis
Arsenic* / analysis
Calcium Carbonate
Ecosystem
Humans
Iron
Soil
Soil Pollutants* / analysis

Substances

Soil
Soil Pollutants
Antimony
Iron
Calcium Carbonate
Arsenic