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Remediating RDX‐Contaminated Ground Water with Permanganate
Author(s) -
Adam M. L.,
Comfort S. D.,
Morley M. C.,
Snow D. D.
Publication year - 2004
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/jeq2004.2165
Subject(s) - permanganate , chemistry , mineralization (soil science) , aqueous solution , potassium permanganate , environmental remediation , persulfate , environmental chemistry , contamination , nuclear chemistry , inorganic chemistry , organic chemistry , nitrogen , ecology , biology , catalysis
Ground water beneath the U.S. Department of Energy Pantex Plant is contaminated with the high explosive RDX (hexahydro‐1,3,5‐trinitro‐1,3,5 triazine). The USDOE Innovative Treatment and Remediation Demonstration (ITRD) program identified in situ oxidation by permanganate as a technology fit for further investigation. We evaluated the efficacy of KMnO 4 to transform and mineralize RDX by determining degradation kinetics and carbon mass balances using 14 C‐RDX. Aqueous RDX solutions (2–5 mg L −1 ) and RDX‐contaminated slurries (50% solids, w/v) were treated with KMnO 4 at 1000, 2000, 4000, and 20000 mg L −1 Treating an aqueous RDX solution of 2.8 mg L −1 with 20000 mg KMnO 4 L −1 decreased RDX to 0.1 mg L −1 within 11 d while cumulative mineralization proceeded for 14 d until 87% of the labeled carbon was trapped as 14 CO 2 Similar cumulative mineralization was obtained when Pantex aquifer material was included in the solution matrix. Other experiments using 4000 mg KMnO 4 L −1 showed that initial RDX concentrations (1.3–10.4 mg L −1 ) or initial pH (4–11) had little effect on reaction rates. Attempts to identify RDX degradates and reaction products showed that N 2 O was a product of permanganate oxidation and constituted 20 to 30% of the N balance. Time‐course measurements of a 14 C‐RDX solution treated with KMnO 4 revealed few 14 C‐labeled degradates but through liquid chromatography–mass spectrometry (LC–MS) analysis, we present evidence that 4‐nitro‐2,4‐diaza‐butanol is formed. Aquifer microcosm studies confirmed that the transformation products not mineralized by KMnO 4 were much more biodegradable than parent RDX. These results indicate permanganate can effectively transform and mineralize RDX in the presence of aquifer material and support its use as an in situ chemical oxidation treatment for the Pantex perched aquifer.