Immobilization of Cd by mercapto-palygorskite in typical calcareous and acidic soil aggregates: Performance and differences

Yale Wang; Yingming Xu; Liping Li; Yongqiang Yang; Chunhong Xu; Yichao Luo; Yali Wang; Xuefeng Liang; Jingjie Sun

doi:10.1016/j.chemosphere.2023.138223

Immobilization of Cd by mercapto-palygorskite in typical calcareous and acidic soil aggregates: Performance and differences

Chemosphere. 2023 May:323:138223. doi: 10.1016/j.chemosphere.2023.138223. Epub 2023 Feb 28.

Authors

Yale Wang¹, Yingming Xu², Liping Li¹, Yongqiang Yang¹, Chunhong Xu¹, Yichao Luo³, Yali Wang⁴, Xuefeng Liang⁵, Jingjie Sun³

Affiliations

¹ School of Environmental Engineering, Henan University of Technology, Zhengzhou, Henan, 450001, China; Henan International Joint Laboratory of Environmental Pollution, Remediation and Grain Quality Security, Zhengzhou, Henan, 450001, China; Institute for Carbon Neutrality, Henan University of Technology, Zhengzhou, Henan, 450001, China.
² Innovation Team of Remediation of Heavy Metal Contaminated Farmlands, Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, China.
³ School of Environmental Engineering, Henan University of Technology, Zhengzhou, Henan, 450001, China.
⁴ School of Environmental Engineering, Henan University of Technology, Zhengzhou, Henan, 450001, China; Henan International Joint Laboratory of Environmental Pollution, Remediation and Grain Quality Security, Zhengzhou, Henan, 450001, China; Institute for Carbon Neutrality, Henan University of Technology, Zhengzhou, Henan, 450001, China. Electronic address: wangyl@haut.edu.cn.
⁵ Innovation Team of Remediation of Heavy Metal Contaminated Farmlands, Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, China. Electronic address: liangxuefeng@caas.cn.

PMID: 36863623
DOI: 10.1016/j.chemosphere.2023.138223

Abstract

The microscale spatial heterogeneity and complexity of soil aggregates affect the properties and distribution of heavy metals (HMs). It has been confirmed that amendments can alter the distribution of Cd in soil aggregates. However, whether the Cd immobilization effect of amendments varies across soil aggregate levels remains unknown. In this study, soil classification and culture experiments were combined to explore the effects of mercapto-palygorskite (MEP) on Cd immobilization in soil aggregates of different particle sizes. The results showed that a 0.05-0.2% MEP application decreased soil available Cd by 53.8-71.62% and 23.49-36.71% in calcareous and acidic soils, respectively. The Cd immobilization efficiency of MEP in calcareous soil aggregates was in the following order: micro-aggregates (66.42-80.19%) > bulk soil (53.78-71.62%) > macro-aggregates (44.00-67.51%), while the efficiency in acidic soil aggregates was inconsistent. In MEP-treated calcareous soil, the percentage change in Cd speciation in micro-aggregates were higher than that in macro-aggregates, whereas there was no significant difference in Cd speciation between the four acidic soil aggregates. Mercapto-palygorskite addition in micro-aggregates of calcareous soil increased the available Fe and Mn concentrations by 20.98-47.10% and 17.98-32.66%, respectively. Mercapto-palygorskite had no effect on soil pH, EC, CEC, and DOC values, while the difference in soil properties between the four particle sizes was the main influencing factor of MEP treatments on Cd in calcareous soil. The effects of MEP on HMs varied across soil aggregates and soil types, but had strong specificity and selectivity for Cd immobilization. This study illustrates the influence of soil aggregates on Cd immobilization using MEP, which can be used to guide the remediation of Cd-contaminated calcareous and acidic soils.

Keywords: Cd-contaminated soil; Immobilization; Mercapto-palygorskite; Soil aggregates.

MeSH terms

Cadmium / analysis
Metals, Heavy* / analysis
Soil / chemistry
Soil Pollutants* / analysis

Substances

Soil
Cadmium
attapulgite
Soil Pollutants
Metals, Heavy