Green synthesized hydroxyapatite for efficient immobilization of cadmium in weakly alkaline environment

Yubo Yan; Meng Du; Liquan Jing; Xiaoxin Zhang; Qiao Li; Jianjun Yang

doi:10.1016/j.envres.2023.115445

Green synthesized hydroxyapatite for efficient immobilization of cadmium in weakly alkaline environment

Environ Res. 2023 Apr 15:223:115445. doi: 10.1016/j.envres.2023.115445. Epub 2023 Feb 8.

Authors

Yubo Yan¹, Meng Du², Liquan Jing³, Xiaoxin Zhang⁴, Qiao Li⁴, Jianjun Yang⁵

Affiliations

¹ Institute of Environmental and Sustainable Development in Agriculture, Chinese Academy of Agricultural Science, Beijing, 100081, China; Jiangsu Engineering Laboratory for Environment Functional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huaian, 223300, China; Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Drive, NW, Calgary, Alberta, T2N1N4, Canada.
² Jiangsu Engineering Laboratory for Environment Functional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huaian, 223300, China; College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, Gansu, 730070, China.
³ Department of Chemical and Petroleum Engineering, University of Calgary, 2500 University Drive, NW, Calgary, Alberta, T2N1N4, Canada.
⁴ Jiangsu Engineering Laboratory for Environment Functional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huaian, 223300, China; Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Huaiyin Normal University, Huaian, 223300, China.
⁵ Institute of Environmental and Sustainable Development in Agriculture, Chinese Academy of Agricultural Science, Beijing, 100081, China; Key Laboratory of Low-carbon Green Agriculture in North China, Ministry of Agriculture and Rural Affairs, PR China. Electronic address: yangjianjun@caas.cn.

PMID: 36758915
DOI: 10.1016/j.envres.2023.115445

Abstract

The development of cost-effective passivators for the remediation of heavy metal-contaminated soils has been a research hotspot and an unsolved challenge. Herein, a novel hydroxyapatite (GSCH) was synthesized by co-precipitating distiller effluent-derived Ca with (NH₄)₂HPO₄ using straw-derived dissolved organic matter (S-DOM) as the dispersant. Batch adsorption experiments and soil incubation tests were performed to assess the immobilization efficiency of GSCH for Cd in weakly alkaline environments. As a result, GSCH showed an excellent adsorption efficiency to Cd with a maximum adsorption amount of ∼222 mg g^-1, which was fairly competitive compared to other similar previously materials reported. The kinetic data indicated that the adsorption of Cd on GSCH was a chemical and irreversible process, while the thermodynamic data revealed a spontaneous (ΔG° < 0) and endothermic (ΔH° > 0) adsorption process. Based on mechanism analysis, both physisorption (e.g., electrostatic attraction and pore filling) and chemisorption (e.g., ion exchange and complexation) were responsible for Cd adsorption on GSCH. Particularly, the incorporated S-DOM and hydroxyapatite phase in GSCH acted synergistically in the adsorption process. The incubation results showed that GSCH application could significantly reduce the bioavailability, phytoavailability and bioaccessibility of Cd in soil by 48.4%-57.8%, 20.4%-28.6% and 12.6%-24.0%, respectively. Moreover, GSCH application also improved soil bacterial communities and enhanced soil nutrient availability. Overall, this is the first study to demonstrate the potential application value of GSCH in Cd immobilization, providing promising insights into the development of green and cost-effective hydroxyapatite-based passivators for the remediation of heavy metal-contaminated soils.

Keywords: Adsorption mechanism; Cd; Green synthesized hydroxyapatite; Soil immobilization.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adsorption
Cadmium / analysis
Durapatite
Metals, Heavy* / analysis
Soil
Soil Pollutants* / analysis

Substances

Cadmium
Durapatite
Soil Pollutants
Soil
Metals, Heavy