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Remediating RDX‐Contaminated Water and Soil Using Zero‐Valent Iron
Author(s) -
Singh J.,
Comfort S. D.,
Shea P. J.
Publication year - 1998
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/jeq1998.00472425002700050032x
Subject(s) - zerovalent iron , environmental remediation , environmental chemistry , soil water , chemistry , contamination , soil contamination , microcosm , amendment , environmental science , adsorption , soil science , ecology , organic chemistry , political science , law , biology
Soil and water contaminated with RDX (hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine) pose a serious threat to the environment and human health. Our objective was to determine the potential for using zero‐valent iron (Fe 0 ) to remediate RDX‐contaminated water and soil. Mixing an aqueous solution of 32 mg RDX L −1 (spiked with 14 C‐labeled RDX) with 10 g Fe 0 L −1 resulted in complete RDX destruction within 72 h. Nitroso derivatives of RDX accounted for approximately 26% of the RDX transformed during the first 24 h; these intermediates disappeared within 96 h and the remaining 14 C products were water soluble and not strongly sorbed by iron surfaces. When RDX‐contaminated soil (30 mg RDX kg −1 spiked with 14 C‐RDX) was treated with a single amendment of Fe 0 (20 g kg −1 soil) in a static soil microcosm, more than 60% of the initial 14 C‐RDX was recovered as 14 CO 2 after 112 d. Treating surface and subsurface soils containing 3600 mg RDX kg −1 with 50 g Fe 0 kg −1 at a constant soil water content (0.35–0.40 kg H 2 O kg −1 soil) resulted in a 52% reduction in extractable RDX following 12 mo of static incubation. A second Fe 0 addition at 12 mo further reduced the initial extractable RDX by 71% after 15 mo. These results support the use of zero‐valent iron for in situ remediation of RDX‐contaminated soil.