Novel reductive processes for the rapid and complete destruction of munition compounds in wastewater
Date
2025
Authors
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Publisher
University of Delaware
Abstract
The U.S. Army has been transitioning to insensitive munition formulations such as IMX-104, which contains the munition compounds (MC) 3-nitro-1,2,4-triazol-5-one (NTO), 2,4-dinitroanisole (DNAN), and 1,3,5-trinitro-1,3,5-triazine (RDX). These MC pose significant challenges for wastewater treatment. Conventional technologies such as biodegradation and granular activated carbon are ineffective at removing these MC, particularly NTO, whereas chemical methods such as nano-zero-valent iron and Fenton are expensive and require low pH. In this study, we evaluated two novel methods for their ability to reductively degrade the MC in a synthetic IMX-104 wastewater: one based on ferrous ion (Fe2+) and the other on dithionite as reductant. Micro-zero-valent iron (μZVI) was also evaluated for comparison. All three processes completely removed the three MC in seconds (Fe(II) and dithionite) to 60 minutes (μZVI). NTO and DNAN were reduced to their amino counterparts, ATO (44%-77%) and DAAN and 2-ANAN (16–72%), respectively. Dithionite was effective at all pH tested (2.8 - 11), and the final pH was close to neutral. Aqueous Fe2+, activated by either hematite or base (NaOH), degraded MC auto-catalytically under neutral to mildly alkaline conditions (8.0 – 10.0). pH control was necessary to sustain the reactivity of μZVI (< 3) and Fe2+ (> 7), but not of dithionite. The proposed methods are destructive, rapid, simple, inexpensive, and environmentally benign. They represent potentially superior options for the destruction of insensitive and legacy MC(e.g., TNT) in wastewater treatment and/or demilitarization efforts at DoD facilities.
Description
Keywords
Munition compounds, Wastewater, Ferrous, Micro-zero-valent iron