Evaluation of hydroxyapatite derived from flue gas desulphurization gypsum on simultaneous immobilization of lead and cadmium in contaminated soil

Yubo Yan; Qiao Li; Jianjun Yang; Shouyong Zhou; Lianjun Wang; Nanthi Bolan

doi:10.1016/j.jhazmat.2020.123038

Evaluation of hydroxyapatite derived from flue gas desulphurization gypsum on simultaneous immobilization of lead and cadmium in contaminated soil

J Hazard Mater. 2020 Dec 5:400:123038. doi: 10.1016/j.jhazmat.2020.123038. Epub 2020 Jun 15.

Authors

Yubo Yan¹, Qiao Li², Jianjun Yang³, Shouyong Zhou⁴, Lianjun Wang², Nanthi Bolan⁵

Affiliations

¹ Jiangsu Engineering Laboratory for Environment Functional Materials, Huaiyin Normal University, Huai'an, 223300, China; Institute of Environmental and Sustainable Development in Agriculture, Chinese Academy of Agricultural Science, Beijing, 100081, China.
² School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China.
³ Institute of Environmental and Sustainable Development in Agriculture, Chinese Academy of Agricultural Science, Beijing, 100081, China. Electronic address: yangjianjun@caas.cn.
⁴ Jiangsu Engineering Laboratory for Environment Functional Materials, Huaiyin Normal University, Huai'an, 223300, China.
⁵ Global Centre for Environmental Remediation, University of Newcastle, Callaghan Campus, NSW, 2308, Australia; Cooperative Research Centre for High Performance Soil (Soil CRC), Callaghan, NSW, 2308, Australia.

PMID: 32947730
DOI: 10.1016/j.jhazmat.2020.123038

Abstract

Flue gas desulphurization gypsum (FGD) is a major solid waste in coal-fired energy plants, and the appropriate reuse of this resources is still a major challenge. In this study, the feasibility of FGD as a calcium source to produce hydroxyapatite (FGD-HAP) for the immobilization of lead (Pb) and cadmium (Cd) in spiked soil was investigated. The effects of FGD and FGD-HAP on soil properties and redistribution, bioaccessibility and plant uptake of Pb and Cd were examined. Results showed that application of FGD and FGD-HAP could significantly improve the enzymes activities of contaminated soils, but the effectiveness was more pronounced with FGD-HAP. Addition of only 1% FGD-HAP could effectively reduce bioavailable Pb and Cd concentration in soil as measured by CaCl₂ extraction by 60.6% and 65.4%, respectively. On the other hand, plant available Pb and Cd could significantly decrease by 93.8% and 73.2% after amendment of 5% FGD-HAP. Significant changes in the micro-scale distribution of heavy metals before and after FGD-HAP treatment demonstrated that while heavy metals were predominantly associated with iron/manganese oxides in untreated soil, high correlation between heavy metals and phosphorus/sulfur was observed in FGD-HAP treated soil. In addition, results of the leaching tests showed that incorporation of FGD-HAP enhanced the retention capacity of heavy metals in soil, indicating that application of FGD-HAP could diminish the environmental risk of leachable heavy metals to groundwater. Overall, this study highlighted the potential value of FGD-HAP as a low-cost and high-efficient amendment for remediation of Pb and Cd contaminated soils.

Keywords: Flue gas desulphurization gypsum; hydroxyapatite; immobilization; lead and cadmium; soil remediation.

Publication types

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