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Biochar Amendment for Reducing Leachability of Nitro Explosives and Metals from Contaminated Soils and Mine Tailings
Author(s) -
Oh SeokYoung,
Yoon HyunSu
Publication year - 2016
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2015.05.0222
Subject(s) - tailings , amendment , biochar , environmental science , soil water , waste management , explosive material , contamination , soil contamination , mining engineering , environmental chemistry , chemistry , geology , metallurgy , law , soil science , materials science , engineering , organic chemistry , pyrolysis , political science , biology , ecology
The mobility and bioavailability of nitro explosives (2,4‐dinitrotoluene [DNT], 2,4,6‐trinitrotoluene [TNT], and hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine [RDX]) in biochar‐amended soils and toxic metals (As, Cd, Cu, Pb, and Zn) in biochar‐amended mine tailings were investigated via various types of leaching procedures in laboratory‐scale batch experiments. The results from the toxicity characteristic leaching procedure (TCLP) and hydroxypropyl‐β‐cyclodextrin (HPCD) extraction showed that approximately 55 to 95% of the explosives were released from the contaminated soils and would thus be considered as mobile. With the addition of biochar, the extracted concentrations of explosives were reduced to less than 10% of the initial concentrations after 10 d. According to the results from a Korean waste leaching method, the TCLP method, and diethylenetriaminepentaacetic acid (DTPA) extraction, adding biochar to mine tailings reduced the extractability and bioavailability of metals. The chemical forms of the metals, types of extractants, pH, and curing period strongly affected the extractability of metals from mine tailings. The results suggest that biochar is a promising immobilizer of explosives and metals in contaminated soils and mine tailings under limited conditions. Core Ideas Immobilization of explosives in soil can be obtained by adding biochar. The curing period does not greatly affect the extractability of explosives in soil. Biochar amendment for mine tailings is applicable under limited conditions. Chemical forms of metals and types of extractants determine the metal leachability. pH and sorption mechanisms determine the immobilization of metals with biochar.