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Insensitive Munition (IM) formulations contain 3-nitro-1,2,4-trizole-5-one (NTO), an energetic compound with the highest aqueous solubility (16 g L-1) among all IM explosives, including 2, 4-dinitroanisole (DNAN) and 1-nitroguanidine (NQ); as a result wastewater streams from IM processing facilities can be highly contaminated and potentially toxic. The removal of energetic compounds from wastewater streams prior to their discharge in the environment is imperative, and new technology must be developed to efficiently treat high levels of NTO and other IM compounds in these streams. In this study, the treatment of NTO wastewater by a UV/H2O2 oxidation process under acidic conditions (pH =3.0±0.1) and a hydrogen peroxide concentration of at least 1500 mg L-1 resulted in successful removal of the energetic compound. The organic carbon from the NTO ring was completely converted to inorganic carbon (CO2), as confirmed through TOC measurements and GC-MS analysis on the reactor headspace. Nitrate and ammonium ions were the major nitrogen by-products, as indicated by mass spectrometry. The results obtained in this work demonstrate that the UV/H2O2 oxidation process can effectively mineralize high concentrations of NTO in wastewater streams leading to recovery of valuable nutrients that can be used for supporting algal biomass growth for biofuel/biogas generation.

A layer-by-layer (LbL) self-assembly strategy involving oppositely charged Ag nanoparticles was used to deposit a nanoshell of Ag nanoparticles on silica microspheres for trace chemical measurements in aqueous solutions by means of surface-enhanced Raman scattering (SERS). Positively charged Ag nanoparticles were produced by reduction of Ag nitrate in a solution mixture of branched polyethyleneimine (BPEI) and N-(2-hydroxyethyl)piperazine-N'-2-ethanesulfonic acid (HEPES) under UV irradiation whereas negatively charged Ag nanoparticles were synthesized by the conventional citrate reduction method. The density of Ag nanoparticles in the nanoshell exhibits a strong correlation with the layer number and the nanoparticle type. Thiocyanate (SCN-) and crystal violet and were used as model positively and negatively charged analytes respectively to assess the robustness of the resultant core-shell nanostructures for SERS measurements. High sensitivity, at ppt for crystal violet and ppb for SCN-, was obtained when the surface charge of the terminating Ag layer in the LbL self-assembled nanoshell was opposite to the ionic nature of the analyte of interest due to enhanced adsorption of the analyte to the Ag nanoparticles facilitated by strong electrostatic attraction. The microsphere-nanoshell structures were all individually SERS-active, making them excellent candidate platform for integration with microfluidic systems for in situ SERS-based sensing and measurements.

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