Remediation of Sb-Contaminated Soil by Low Molecular Weight Organic Acids Washing: Efficiencies and Mechanisms

Sicheng Li, Weibin Pan (), Lizhi Tong, Yuanyuan Hu, Yulin Zou and Xiaojia Huang
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Sicheng Li: School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
Weibin Pan: School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
Lizhi Tong: South China Institute of Environmental Sciences, Ministry of Ecology and Environment, 7 West 12 Street, Guangzhou 510655, China
Yuanyuan Hu: School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
Yulin Zou: School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
Xiaojia Huang: School of Environment and Energy, South China University of Technology, Guangzhou 510006, China

Sustainability, 2023, vol. 15, issue 5, 1-18

Abstract: Low molecular weight organic acids (LMWOAs) are promising agents in the remediation of heavy metal contaminated soil with strong complexing ability and less environmental impact. However, the application of LMWOAs for washing the Sb-contaminated soil still faces great challenges, such as the selection of suitable washing agents, optimal washing parameters, and the unclear Sb removal mechanism. In this study, five suitable LMWOAs were screened from ten common washing agents and their optimum washing parameters were determined. The results showed that oxalic acid (OA) and HEDP were the top two outstanding agents, and the removal efficiencies of Sb were 68.79% and 49.73%, respectively, under optimal parameters (OA at 0.5 mol/L, HEDP at 0.2 mol/L, washing for 480 min, and the liquid-to-solid ratio of 15). The soil was analyzed for chemical speciation, morphology, functional groups, and mineralogy before and after washing. The results indicated that Fe/Al minerals in the soil are the main reason for the adsorption of Sb, and the possible mechanisms of Sb removal by LMWOAs included the dissolution of minerals, complexation reaction, and ligand exchange. Our findings highlight the potential application of LMWOAs as efficient washing agents to remove Sb from contaminated soils.

Keywords: soil washing; antimony; organic acid; oxalic acid; HEDP; desorption (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2023
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