Iron-modified rice husk hydrochar and its immobilization effect for Pb and Sb in contaminated soil.

J Hazard Mater

College of Environmental Science and Engineering, Hunan University, Changsha, and Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.

Published: November 2020

Cationic and anionic heavy metal contamination sometimes co-exists in soil systems, such as mining areas and shooting ranges, seriously threatens human health and ecological stability. In this study, iron-modified rice husk hydrochar showed commendable ability to immobilize both heavy metal cation (Pb) and anion (Sb) simultaneously in soils. Iron-modified rice husk hydrochar (HC12.5-180) (5%) amendment reduced the bioavailability (EX- and CB-fraction) of Pb and Sb by 25 and 40%, respectively, which were 8 and 5 times higher than that of pristine rice husk hydrochar (HC0-180) (5%) amendment. The cation (Pb) immobilization mainly depends on cation exchange with mineral components (K, Ca, Na, Mg), precipitation with nonmetallic anions (Cl- and SO), and complexation. Meanwhile, the iron oxides (FeO, FeO, FeO), formed during hydrothermal process, can be easily combined with anion (Sb) to form geochemically stable minerals. In conclusion, this work offered a practical and cost-effective technology based on the iron modification rice husk hydrochar for the immobilization of both anionic and cationic heavy metal contaminants in soils.

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http://dx.doi.org/10.1016/j.jhazmat.2020.122977DOI Listing

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