In this study, we applied coconut fiber-derived biochar (CFB) to a lead (Pb)-contaminated soil (at 600 mg kg−1) at 2% and 4% (w/w), in order to explore the efficacy and mechanism of CFB to immobilize Pb in soil during a 150-day incubation experiment. Our approach integrated various techniques namely micro-X-ray fluorescence, sequential extraction, X-ray absorption fine structure, scanning electron microscopy combined with energy dispersive X-ray spectroscopy to evaluate the Pb immobilization. Results indicated that the distribution of Pb in the studied soil was significantly affected by CFB application. The Pb content in organic matter bound fraction of the studied soil increased by 29.5% and 33.5% with 2% and 4% CFB, respectively, compared to control soil after 150-day of incubation. Lead-loaded humic acid (HA) and Pb3(PO4)2 were higher in the biochar-amended soil (2% CFB) as compared with the control soil. The CFB particles possibly offer more binding sites of PO4 3− and carboxylic functional groups than the binding sites of –FeO(OH), SiO3 2−, −Al2O3 and organic functional groups provided by the original soil particles alone (no biochar) for Pb. Overall, this study highlights that CFB can be a potential candidate to immobilize Pb for the restoration and remediation of Pb-contaminated soils.
Bibliographical noteFunding Information:
This work was financially supported by the National Key Research and Development Program of China ( 2017YFD0202101 , 2018YFD0800703 ), the Natural Science Foundation of China ( 21866013 , 21577131 , 21467007 , 21876027 ), the Natural Science Foundation of Guangdong Province , China ( 2017A030311019 ), the Hainan Provincial Natural Science Foundation of China ( 418QN208 ), the Postgraduate Innovation Project of Hainan Province ( Hyb2017-20 ), the Ecology Discipline Construction Funding of Hainan University , and the Crop Science Postgraduate Innovation Project of Hainan University Tropical Agriculture and Forestry College ( ZWCX2018013 ).
- Binding site
- Heavy metal
- Synchrotron radiation
ASJC Scopus subject areas
- Soil Science