A Synergistic Nano‐Zerovalent Iron‐Hydrogen Peroxide Technology for Insensitive Munitions Wastewater Treatment

Abstract

The U.S. Army is phasing out legacy munitions compounds that are prone to accidental detonation and replacing them with insensitive munitions compounds (IMCs). The major IMCs, namely 3-nitro-1,2,4-triazol-5-one (NTO), 2,4-dinitroanisole (DNAN), and nitroguanidine (NQ), are not compatible with existing munitions wastewater treatment technologies such as granular activated carbon due to their high water solubilities. In this study, a two-stage process employing nanoscale zero-valent iron (nZVI) and hydrogen peroxide (H 2 O 2 ) was evaluated as a potential technology for the destructive treatment of IMC wastewater. In the first stage, nZVI rapidly and completely degraded all three IMCs and generated dissolved Fe(II). NTO and DNAN were de-graded via nitro reduction to 3-amino-1,2,4-triazol-5-one and 2,4-diaminoanisole, respectively. In the second stage, H 2 O 2 was added to oxidize the IMC reduction products through Fenton reaction utilizing the dissolved Fe(II) from the first stage. nZVI-treated NTO and DNAN samples showed 66 % and 63 % TOC removal after oxidation, respectively. In contrast, NQ reduction products exhibited negligible mineralization. The results with individual IMCs were confirmed by an experiment using synthetic wastewater containing all three IMCs. This study illustrates the potential feasibility of a synergistic and destructive nZVIÀ H 2 O 2 technology for treating IMC-laden wastewaters at military facilities.

Effective treatment of 2,4,6-trinitrotoluene from aqueous media using a sono–photo-Fenton-like process with a zero-valent iron nanoparticle (nZVI) catalyst

“…In the Fenton-like process, zerovalent nano iron can perform roles such as a reducing agent in direct reaction with nitro pollutants (-NO 2 ) and a renewable source of Fe 2+ ions for the Fenton reaction. 17,18 There are several research studies on TNT treatment using the Fenton or Fenton-like process combining ultrasonic, UV, and the nZVI catalyst. Li et al 19 investigated the treatment efficiency of 2,4,6-trinitrotoluene using different oxidation processes, observing that the sono-Fenton process achieved the highest treatment efficiency of 87% of TNT aer 30 min at pH 3, with a ratio of H 2 O 2 /Fe = 10 : 1, C 0 TNT = 30 mg L −1 , and C Fe = 0.5 mM.…”

Electron Transfer Energy and Hydrogen Atom Transfer Energy-Based Linear Free Energy Relationships for Predicting the Rate Constants of Munition Constituent Reduction by Hydroquinones

“…Many of these MCs are non-aromatic [e.g., nitroguanidine (NQ) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)] or negatively charged at pH 7 [e.g., NTO and 3,4-dinitropyrazole (DNP)] and therefore may react differently than NACs. Many of these MCs are also much more water-soluble and mobile in the environment than legacy MCs. − It is thus essential that we develop a better understanding of the kinetics and mechanism for the reduction of structurally diverse MCs.…”

Hydrothermal Synthesis of Mixed Oxide Compositions of Cobalt‐Zirconium and their Catalytic Activity in the Decomposition of Hydrogen Peroxide

“…On counterbalance to chlorine, the industrial safe oxidants for water and waste, wood pulp bleaching and chemical synthesis, are ozone (O 3 ) and hydrogen peroxide (H 2 O 2 ), because the main product of their recovery is non-toxic O 2 . [1][2][3][4][5][6][7] Ozone production is carried out by an electric discharge of purified gaseous stream of the oxygen with its subsequent dissolution in waste. Because the method is very expensive and requires both complex equipment and high energy consumption, the ozonation is not widely used for wastewater disinfection.…”

“…Existing methods of cleaning of drainsare divided into disinfection with reagents containing chlorine, ultraviolet radiation, ozonation and using of chlorine‐free reagents for small buildings or tanks. On counterbalance to chlorine, the industrial safe oxidants for water and waste, wood pulp bleaching and chemical synthesis, are ozone (O 3 ) and hydrogen peroxide (H 2 O 2 ), because the main product of their recovery is non‐toxic O 2 [1–7] . Ozone production is carried out by an electric discharge of purified gaseous stream of the oxygen with its subsequent dissolution in waste.…”