Practical Colorimetry of 3‐Nitro‐1,2,4‐Triazol‐5‐One

Abstract

A field ready colorimetric method of quantifying the concentration of aqueous 3‐nitro‐1,2,4‐triazol‐5‐one (NTO), several orders of magnitude below its environmental toxicity level, has been developed. The test allows for the immediate evaluation of the level of contamination in aqueous solution without the need for analytical equipment such as high pressure liquid chromatography (HPLC). The observed colours have been explained by the different NTO species present over the range of pH; these observations are supported by modelling and experimental results.

A review of treatment methods for insensitive high explosive contaminated wastewater

“…Clarifiers, use the flow rate of the wastewater and the settling rate of the particles in suspension so promote settling onto inclined surfaces (tubes or plates) that collects and slides to the bottom of the container ( Hammer and Hammer, 2001 ). In the case of NTO, precipitation from solution could further be enhanced with a basic washout medium followed by neutralisation during separation as the solubility of NTO increases with pH ( Tennant et al., 2019 ).…”

“…NTO has a high LD 50 compared to other energetic materials is approximately 5000 mg.kg −1 in rats and studies of aquatic toxicity have produced similar results with toxicity levels so low that NTO could be classified as non-toxic ( Haley et al., 2009 ; London and Smith, 1985 ; O'Bryan and Ross, 1988 ). However, contamination of water sources with NTO leads to visual discolouration at concentrations over 100 mg.L −1 , which constitutes environmental degradation even if no ecotoxicological effect is observed ( Tennant et al., 2019 ).…”

“…For example, NTO lowers the pH of water when in solution and so could negatively affect the adsorption of other contaminants in solution. In addition, it was found that the solubility of NTO in solution was dramatically enhanced when the Ph was adjusted from 6 to 14 with the addition of KOH ( Tennant et al., 2019 ). For all of the contaminants of concern in this review, a higher initial concentration of contaminant in solution has led to a higher measured adsorptive capacity ( Fawcett-Hirst et al., 2020 ).…”

Quantitative Environmental Assessment of Explosive Residues from the Detonation of Insensitive High Explosive Filled 155 mm Artillery Shell

“…For example, many explosive test and impact areas are contaminated with lead, which is known to leach more rapidly in soils with pH lower than 4 [44]. In addition, NTO discolors water at low concentrations (10 ppm), which would be considered pollution under multiple UK and European regulations, even if there were no associated toxicity [46].…”

Adsorption behaviour of 1,3,5-trinitroperhydro-1,3,5-triazine, 2,4-dinitroanisole and 3-nitro-1,2,4-triazol-5-one on commercial activated carbons

“…NTO is a white crystalline energetic compound that was first used in explosive formulations in 1987 and in a proposed IHE in 1996 (Lamy et al, 1996;Lee and Coburn, 1988). NTO causes visible yellow discolouration in water and is a source of visible pollution (Tennant et al, 2019). NTO has been assessed by the US EPA as having a toxicity of greater than 5000 mg kg -1 , lower than that of table salt (Winstead, 2011).…”