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Removal of Nitramine Explosives in Aqueous Solution by UV-Mediated Advanced Oxidation Process in Near-Neutral Conditions

Khue Do Ngoc, Bach Vu Quang, Binh Nguyen Thanh, Minh Do Binh, Nam Pham Thi, Loi Vu Duc, Nguyen Hoa Thanh

Journal of Ecological Engineering

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2021

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Vol. 22, nr 6

232--243

EN

Explosive compounds are hazardous to the environment, posing a serious risk to human and animal health and the ecosystem. The primary goal of research was to compare the efficiency of UV/H2O2, photo-Fenton, electro (EO)/ UV/H2O2 processes at near-neutral pH (pH=6) on the degradation of nitramine explosives (NAs), such as hexogen (RDX), octogen (HMX), and tetryl (TET), in an aqueous solution. The effect of operational conditions, likely pH of the solution, initial H2O2 concentration, initial Fe2+ concentration, and solution temperature, was observed. The removal kinetics fit with first-order kinetics and were in the order: photo-Fenton >EO/UV/ H2O2 > UV/ H2O2. The results showed higher rate constant values for TET, RDX and HMX removal by UV/ H2O2 (k = 0.07778, 0.03791 and 0.03786 min-1), EO/UV/ H2O2 (k = 0.16599, 0.1475 and 0.08674 min-1) and photo-Fenton (k = 0.18018, 0.1501 and 0.09336 min-1) processes. Furthermore, TET, RDX and HMX were mineralized at 59.7%, 45.1%, and 25.1 %, respectively, under optimum conditions after 60 min of the photo-Fenton process. From the economic perspective, photo-Fenton only requires 2.132–4.113 kWh m-3 to completely reduce NAs. Finally, acute toxicity towards Vibrio fischeri was defeated after usage of near-neutral photo-Fenton. Thus, photo-Fenton at circum-neutral is promising for low-cost, eco-friendly and efficient processes for treating nitramine explosives in aqueous solutions.

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UV-VIS and FTIR Investigations of Long-Term Aged Explosives. Part 1

Shishkov P., Nedkova M., Atanasova P.

Central European Journal of Energetic Materials

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2011

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Vol. 8, nr 4

293-301

EN

An investigation of TD-50 and tetryl samples obtained by dismantling of weapons, made in 1961 in Bulgaria, was carried out. The weapons were stored in non-heated military stores and the explosives were aged in this time (50 years). The results from UV-VIS and FTIR spectroscopy showed the formation of H-bonds in the solutions and in the investigated materials. The most available properties for determination of H-bond formation from UV-VIS spectra were: the shift, (Δ λ); ratio shift/dilution, (Δ λ /C1/Cn, nm, and Δ λ/Δ C, nm.ml/mg) in acetone solutions and only the shift, (Δ λ) in toluene solutions. The results from FTIR spectroscopy showed that the most available for determination of H-bond formation were: absorbances of some maxima for -NO2 groups, divided from maxima for -CH2 at 917 and 715 cm-1 like internal standards and some values of Δh*1/2.

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UV-VIS and FTIR Investigations of Long-Term Aged Explosives. Part 2

Shishkov P., Nedkova M., Atanasova P., Glavchev I.

Central European Journal of Energetic Materials

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2011

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Vol. 8, nr 4

303-310

EN

Samples of long-term aged TD-50 and tetryl were investigated by UV-VIS and FTIR spectroscopy and bands of products of ageing were obtained. A complicated maximum of nitro groups at 1537 cm-1 in the FTIR spectra of long-term aged explosives was obtained, like in the IR spectra of long-term aged single-based propellants. Ageing process was confirmed by the presence of several maxima in UV-VIS and FTIR spectra of aged products and determination of several characteristics of the investigated explosives (shifts Δ ν, differences in absorbances ΔA, differences in values of Δh*1/2). Ageing was connected with decrease of H-bond formation on the base of decrease of content of oxygen and nitro groups in TD-50 and tetryl.