To 2,4,6-trinitrotoluene Research Articles

Enhanced removal of warfare agent tri-nitro-toluene by a Methylophaga-dominated microbiome

Historical exposure of the marine environment to 2,4,6-trinitrotoluene (TNT) happened due to the dumping of left-over munitions. Despite significant research on TNT decontamination, the potential of marine microbiome for TNT degradation remains only little explored. In this study, TNT degradation experiments were conducted with sediment located near the World War I munition dumpsite – Paardenmarkt in the Belgian part of North Sea. A slow removal was observed using TNT as sole source of C and N, which could be enhanced by adding methanol. Degradation was reflected in nitro-reduced metabolites and microbial growth. 16S Illumina sequencing analysis revealed several enriched genera that used TNT as a sole source of C and N - Colwellia, Thalossospira, and Methylophaga. Addition of methanol resulted in increased abundance of Methylophaga, which corresponded to the rapid removal of TNT. Methanol enhanced the degradation by providing additional energy and establishing syntrophic association between methanol-utilizing and TNT-utilizing bacteria.

Rheological Behavior of DNP/HMX Melt-Cast Explosives with Bimodal and Trimodal Particle-Size Distributions

As a matrix for melt-cast explosives, 3,4-dinitropyrazole (DNP) is a promising alternative to 2,4,6-trinitrotoluene (TNT). However, the viscosity of molten DNP is considerably greater compared with that of TNT, thus, requiring the viscosity of DNP-based melt-cast explosive suspensions to be minimized. In this paper, the apparent viscosity of a DNP/HMX (cyclotetramethylenetetranitramine) melt-cast explosive suspension is measured using a Haake Mars III rheometer. Both bimodal and trimodal particle-size distributions are used to minimize the viscosity of this explosive suspension. First, the optimal diameter ratio and mass ratio (two crucial process parameters) between coarse and fine particles are obtained from the bimodal particle-size distribution. Second, based on the optimal diameter ratio and mass ratio, trimodal particle-size distributions are used to further minimize the apparent viscosity of the DNP/HMX melt-cast explosive suspension. Finally, for either the bimodal or trimodal particle-size distribution, if the original data between the apparent viscosity and solid content are normalized, the resultant plot of the relative viscosity versus reduced solid content collapses to a single curve, and the effect of the shear rate on this curve is further investigated.

Paper-Based Probes with Visual Response to Vapors from Nitroaromatic Explosives: Polyfluorenes and Tertiary Amines.

Although it is well-known that nitroaromatic compounds quench the fluorescence of different conjugated polymers and form colored Meisenheimer complexes with proper nucleophiles, the potential of paper as a substrate for those macromolecules can be further developed. This work undertakes this task, impregnating paper strips with a fluorene-phenylene copolymer with quaternary ammonium groups, a bisfluorene-based cationic polyelectrolyte, and poly(2-(dimethylamino)ethyl methacrylate) (polyDMAEMA). Cationic groups make the aforementioned polyfluorenes attachable to paper, whose surface possesses a slightly negative charge and avoid interference from cationic quenchers. While conjugated polymers had their fluorescence quenched with nitroaromatic vapors in a non-selective way, polyDMAEMA-coated papers had a visual response that was selective to 2,4,6-trinitrotoluene (TNT), and that could be easily identified, and even quantified, under natural light. Far from implying that polyfluorenes should be ruled out, it must be taken into account that TNT-filled mines emit vapors from 2,4-dinitrotoluene (DNT) and dinitrobenzene isomers, which are more volatile than TNT itself. Atmospheres with only 790 ppbv TNT or 277 ppbv DNT were enough to trigger a distinguishable response, although the requirement for certain exposure times is an important limitation.

Rapid Adsorption of 2,4,6-trinitrotoluene by hierarchically porous indole-based aerogel

A hybrid hierarchically porous indole-based aerogel (HINFA) was successfully fabricated and modified with hydroxyl groups. The HINFA with hierarchically porous exhibited satisfactorily adsorptive properties to 2,4,6-trinitrotoluene (TNT) in water in light of synergistic effect of hydrogen bonding and dipole-π interaction. Several factors such as pH, adsorbent dosage, contact time, initial TNT concentration and temperature were systematically discussed. Adsorption kinetics, isotherms and thermodynamic parameters had been calculated from experimental results. The HINFA demonstrated significantly fast equilibrium time (1.5 h) to TNT in particular. The maximum adsorption capacity was 117.5 mg g−1 calculated by Langmuir model at 293 K. The adsorption-desorption cyclic results revealed that HINFA could be effectively regenerated by acetone, and the regenerated HINFA could be employed for repeated use without significant deterioration after 7 cycles. The excellent adsorption performance of HINFA may be in virtue of the interweave meso- and macroporous structures which can enhance mass transport and easier accessibility for TNT to the adsorption sites. Therefore, the HINFA can be used potentially to remove TNT from water samples in practical applications for environmental remediation. Furthermore, the proposed synergy is expected to be a new rationale for design of TNT adsorbent materials.

Biodegradation and physiological response mechanism of a bacterial strain to 2,4,6-trinitrotoluene contamination

The aim of this study was to reveal the biodegradation characteristics and physiological response mechanism of a newly isolated bacterium to 2,4,6-trinitrotoluene (TNT) contamination. A Klebsiella variicola strain with high efficiency of TNT degradation was used as the test strain to analyze the changes in cell growth, morphology, and functional groups under different TNT concentrations (0, 100 mg⋅L−1) and the effects of TNT stress on the metabolic profile as revealed by non-targeted metabonomics. A TNT concentration of 100 mg L−1 caused a significant increase in the 5-day biochemical oxygen demand (BOD5) to 950 mg L−1, while the degradation rate of TNT reached 100% within 30 h after inoculation with Klebsiella variicola. Fourier transform infrared spectroscopy (FTIR) analysis showed changes in the characteristic peak of triamide by TNT treatment. Non-targeted metabonomics identified a total of 544 differentially produced metabolites under TNT treatment (252 upregulated and 292 downregulated), mainly lipids and lipid-like molecules. The metabolic pathways associated with amino acid biosynthesis and metabolism were the most significantly enriched pathways, and simultaneous detection showed that TNT was degraded to 4-amino-2,6-dinitrotoluene (DNT), 2-hydroxylamino-4,6-DNT, 2-amino-4,6-DNT, 2-amino-4-nitrotoluene, and 2,4-DNT. These results confirmed that Klebsiella variicola has a high tolerance to TNT and efficiently degrades it. The degradation mechanism involves TNT-induced accelerated amino acid biosynthesis, production of a protease to catalyze the TNT transformation, and the participation of the transformed TNT products in cell metabolism.

Synthesis of 2,4,6-Trinitrotoluene (TNT) Using Flow Chemistry.

This paper describes the nitration of 2,4-dinitrotoluene (DNT) and its conversion to 2,4,6-trinitrotoluene (TNT) at a gram scale with the use of a fully automated flow chemistry system. The conversion of DNT to TNT traditionally requires the use of highly hazardous reagents like fuming sulfuric acid (oleum), fuming nitric acid (90–100%), and elevated temperatures. Flow chemistry offers advantages compared to conventional syntheses including a high degree of safety and simpler multistep automation. The configuration and development of this automated process based on a commercially available flow chemistry system is described. A high conversion rate (>99%) was achieved. Unlike established synthetic methods, ordinary nitrating mixture (65% HNO3/98% H2SO4) and shorter reaction times (10–30 min) were applied. The viability of flow nitration as a means of safe and continuous synthesis of TNT was investigated. The method was optimized using an experimental design approach, and the resulting process is safer, faster, and more efficient than previously reported TNT synthesis procedures. We compared the flow chemistry and batch approaches, including a provisional cost calculation for laboratory-scale production (a thorough economic analysis is, however, beyond the scope of this article). The method is considered fit for purpose for the safe production of high-purity explosives standards at a gram scale, which are used to verify that the performance of explosive trace detection equipment complies with EU regulatory requirements.

Electrochromic and electrofluorochromic bifunctional materials for dual-mode devices based on ladder-like polysilsesquioxanes containing triarylamine

The display devices of the future will tend to be multifunctional, and the dual-mode device for emission and coloration satisfies the requirements of practical applications. We synthesized materials with electrochromic (EC) and electrofluorochromic (EFC) properties through the combination of triarylamine (TAA) and ladder-like polysilsesquioxanes (LPSQs). The ladder-like structure was confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and 29Si-NMR techniques. These polymers exhibit up to 37.3% fluorescence (PL) quantum efficiency (ФPL) and show strong solid-state fluorescence because TAA groups are effectively isolated in ladder-like backbone in LPSQs. The TAA-LPSQs films exhibit reversible change from colorless of bleached state to blue or green of oxidized state. Among them, the optical contrast of the MPA-LPSQ film synthesized from 1-(4-(bis(4-methoxyphenyl)amino)phenyl)-3-(3-(triethoxysilyl)propyl)urea is as high as 83.0% at 787 nm, which shows excellent cycle stability over 1000 s. Unique structure and good electrochemical activity of TAA-LPSQs make them promising materials for dual-mode device. The EC/EFC device (ECD/EFCD) was assembled using MPA-LPSQ as an active layer which showed good performance. In addition, TAA-LPSQs exhibit excellent sensitivity to 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (TNP) detection, so these materials can also be applied as highly sensitive chemosensor for explosives.

Two-dimensional molybdenum disulfide (MoS2) with gold nanoparticles for biosensing of explosives by optical spectroscopy

As one of the most important transition-metal dichalcogenides (TMDs) materials, molybdenum disulfide (MoS2) has gained extensive attention for its marvelous optoelectronic properties. In this study, nanocomposites of two-dimensional (2D) molybdenum disulfide (MoS2) with plasmonic noble metal nanoparticles were synthesized by a one-step green process. Under irradiation, 2D MoS2 in the nanocomposites absorbed photons and generated carriers in a wide spectrum. Then MoS2 coupled to gold nanoparticles and produced the enhanced electromagnetic field in the nanosturctures, leading to outstanding optical properties. In virtue of bio-compatibilities of the particles, the nanocomposites were chemically modified with specific peptides to construct an optical biosensor for explosive detection. When exposed to 2,4,6-trinitrotoluene (TNT), the biosensor showed significant absorption peak changes in visible spectra with a concentration-dependent behavior. The biosensor could detect TNT at the concentration as low as 2 × 10−7 M. For selectivity, the biosensor could differentiate TNT from other nitroaromatic explosives that have extremely similar structures to TNT, such as 4-nitrotoluene (4-NT) and 2,6-dinitrotoluene (DNT). All the results suggested that the biosensor based on the nanocomposites of 2D MoS2 coupling to plasmonic nanoparticles exhibited remarkable optical performance, which provided a promising approach to design versatile biosensors to detect biochemical molecules.

A computational study of ANTA and NTO derivatives.

This work is a study of 5-amino-3-nitro-1,2,4-triazole (ANTA), 3-nitro-1,2,4-triazol-5-one (NTO), and nitrated derivatives of ANTA and NTO. RDX and TNT were studied for comparison. ANTA and NTO are low-sensitive high explosives with detonation properties comparable to 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitroperhydro-1,3,5-triazine (RDX). We showed previously that nitrated NTO and ANTA compounds, when used in a glycidyl azide polymer (GAP) matrix in rocket propellants, could give impulses above 2600m/s and that the oxygen balance is positive. If used in aluminized explosives, the heat of detonation may be increased to a practical level significantly above RDX/aluminum compositions. Here, we use two different methods for sensitivity and two density functional theory functionals, B3LYP and M06-2X with the 6-31G(d) basis set, together with the complete basis set method CBS-4M. Calculations indicate that most of the nitrated derivatives have nearly equal sensitivity to RDX. Significantly different bond dissociation energies in the nitrimino functional group are predicted, although most models give much the same result.

Recent Developments for Prediction of Power of Aromatic and Non‐Aromatic Energetic Materials along with a Novel Computer Code for Prediction of Their Power

AbstractThe explosive power or strength of an energetic material shows its capacity for doing useful work. This work reviews recent developments for prediction of power of energetic compounds. A new user‐friendly computer code is also introduced to predict the relative power of a desired energetic compound as compared to 2,4,6‐trinitrotoluene (TNT). It is based on the best available methods, which can be used for different types of energetic compounds including nitroaromatics, nitroaliphatics, nitramines, and nitrate esters. The computed relative powers are consistent with the measured data for some new materials containing complex molecular structures.

제일인산칼륨과 벤토나이트 처리를 통한 토양 내 TNT와 중금속 이동성 및 인체위해도 저감 기술

Simultaneous mobility reduction of explosives and heavy metals in an operational range by monopotassium phosphate (MKP) and bentonite spreading technology was investigated. Potassium ion and phosphate ion in MKP act as explosives sorption enhancer and insoluble heavy metal phosphate formation, respectively, while bentonite acts as the explosives adsorbent. Then, the decrease in surface water concentration of the pollutants and resulting risk reduction for local residents of the operational range, by MKP/bentonite application was estimated. Under untreated scenario, the noncancer hazard index (HI) exceeded unity on February, July and August, mainly due to 2,4,6-trinitrotoluene (TNT); however, MKP/bentonite treatment was expected to lower the noncancer hazard index by decreasing the surface water concentration of explosives and heavy metals (especially TNT). For example, on July, estimated surface water concentration and HI of TNT were 0.01 mg/L and 1.1, respectively, meanwhile the sorption coefficient of TNT was 3.9 mg 1�n kg �1 L n . However, by MKP/bentonite treatment, the TNT sorption coefficient increased to 113.8 mg 1�n kg �1 L n and the surface water concentration and HI decreased to about 0.002 mg/L and 0.2, respectively. Based on the result, it can be concluded that MKP/bentonite spreading is a benign technology that can mitigate the risk posed by the pollutants migration from operational ranges.

Participation of metabolic activation of 2,4,6-trinitrotoluene to 4-hydroxylamino-2,6-dinitrotoluene in hematotoxicity.

Exposure to 2,4,6-trinitrotoluene (TNT) causes methemoglobin (metHb) formation, hemolysis and negative heme balance in vivo, but the mechanistic details are poorly understood. In the present study, we examined the participation of metabolic activation in TNT-mediated hematotoxicity. Exposure of rats with TNT (300 mg/kg, i.p.) for 4 days resulted in a decrease of hematocrit value coupled to an increase in metHb formation. The red blood cells treated with 4-hydroxylamino-2,6-dinitrotoluene (HADNT), a metabolite of TNT, underwent readily hemolysis in vitro, whereas such a phenomenon was not seen with TNT. Consistent with this, HADNT is active toward metHb formation and the decrease in thiol content of the globin moiety compared with TNT and its metabolites 4-amino-2,6-dinitrotoluene (ADNT) and 4-acetylamino-2,6-dinitrotoluene (AADNT). Furthermore, interaction of purified rat oxyhemoglobin (oxyHb) with HADNT, but not TNT, ADNT, and AADNT, caused a concentration-dependent production of H2O2 and ferrylhemoglobin (ferrylHb) which is a highly oxidizing state formed by reaction of oxyHb with H2O2. Notably, hemin was released during interaction of oxyHb with HADNT. Taken together, these findings suggest that HADNT is an active metabolite that mediates TNT-induced hematotoxicity via formation of prooxidants such as H2O2 and ferrylHb.

Near-infrared-light mediated ratiometric luminescent sensor for multimode visualized assays of explosives.

The development of a portable and easy-to-use device for the detection of explosives with high sensitivity and selectivity is in high demand for homeland security and public safety. In this study, we demonstrate miniaturized devices depending on the upconversion ratiometric luminescent probe for point-of-care (POC) assay of explosives with the naked-eye. When the PEI-coated upconversion nanoparticles (UCNPs) selectively bonded to 2,4,6-trinitrotoluene (TNT) explosives by the formation of Meisenheimer complex, the formed of UCNP-Meisenheimer complexes show turned visible multicolor upconversion luminescence (UCL) on account of TNT-modulating Förster resonance energy transfer process under near-infrared excitation. With UCL emission at 808 nm as internal standard and ratiometric UCL at 477 nm to that at 808 nm (I477/I808) as output signal, the probe can simultaneously meet the accuracy for TNT explosives quantitative analysis. In addition, this easy-to-use visual technique provides a powerful tool for convenient POC assay of rapid explosives identification.

Modification of Extended Open Frameworks with Fluorescent Tags for Sensing Explosives: Competition between Size Selectivity and Electron Deficiency

Three new electron-rich metal-organic frameworks (MOF-1-MOF-3) have been synthesized by employing ligands bearing aromatic tags. The key role of the chosen aromatic tags is to enhance the π-electron density of the luminescent MOFs. Single-crystal X-ray structures have revealed that these MOFs form three-dimensional porous networks with the aromatic tags projecting inwardly into the pores. These highly luminescent electron-rich MOFs have been successfully utilized for the detection of explosive nitroaromatic compounds (NACs) on the basis of fluorescence quenching. Although all of the prepared MOFs can serve as sensors for NACs, MOF-1 and MOF-2 exhibit superior sensitivity towards 4-nitrotoluene (4-NT) and 2,4-dinitrotoluene (DNT) compared to 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitrobenzene (TNB). MOF-3, on the other hand, shows an order of sensitivity in accordance with the electron deficiencies of the substrates. To understand such anomalous behavior, we have thoroughly analyzed both the steady-state and time-resolved fluorescence quenching associated with these interactions. Determination of static Stern-Volmer constants (KS) as well as collisional constants (KC) has revealed that MOF-1 and MOF-2 have higher KS values with 4-NT than with TNT, whereas for MOF-3 the reverse order is observed. This apparently anomalous phenomenon was well corroborated by theoretical calculations. Moreover, recyclability and sensitivity studies have revealed that these MOFs can be reused several times and that their sensitivities towards TNT solution are at the parts per billion (ppb) level.

New cyano functionalized silanes: aggregation‐induced emission enhancement properties and detection of 2,4,6‐trinitrotoluene

Two novel tetrahedral silicon‐centered cyano functionalized silanes, namely bis(4‐cyanophenylethynyl)dimethylsilane (CN-1) and bis(4‐cyanophenylethynyl) diphenylsilane (CN-2), have been synthesized and well characterized. They demonstrated unusual aggregation‐induced emission enhancement (AIEE) properties in the H‐type aggregation state with nanoparticle aggregate formation. Further study shows that the 4‐cyanophenylethynyl unit is the structure base to induce the AIEE phenomenon and the silicon core may enhance the AIEE effect. By single‐crystal analysis, the twisted tetrahedral conformation of silicon core and restricted intramolecular motions are speculated as the AIEE mechanism for these unusual H‐type aggregates of CN-1 and CN-2. Moreover, both CN-1 and CN-2 show an obvious fluorescent quenching response to 2,4,6‐trinitrotoluene (TNT) in THF solution, making them promising candidates in the application of explosive detection. Copyright © 2013 John Wiley & Sons, Ltd.

A novel fluorescent polymer brushes film as a device for ultrasensitive detection of TNT

In this work, we first report the application of fluorescent polymer brushes film as a device for ultrasensitive and selective detection of TNT. As positively charged fluorescent molecules of quaternary ammonium tetraphenylethylene derivatives (d-TPE) were self-assembled on the brushes of poly(acrylic acid) (PAA) by coulomb forces, we obtained a novel fluorescent polymer brushes film with excellent photoluminescent properties, and the emission could be quantitatively and sensitively responsive to 2,4,6-trinitrotoluene (TNT) due to the electron transfer between d-TPE and TNT. The limit of detection of TNT was established to be 0.1 ppb in water. The fluorescent device could also be used repeatedly for TNT detection, which indicated a promising application in trace explosive detection.

Templated Crosslinked Imidazolyl Acrylate for Electronic Detection of Nitroaromatic Explosives

AbstractA low‐voltage operable, highly sensitive, and selectively responsive polymer for the detection of nitroaromatic explosives is investigated. Resistive devices are fabricated by simple spin‐coating on flexible and transparent substrates in addition to silicon substrates and are stable under ambient temperature and oxygen levels before exposure to the nitroaromatics. After exposure to 2,4,6‐trinitrotoluene (TNT), the devices show increased conductance, even with picogram (pg) quantities of TNT, accompanied by a confirming color change from colorless to deep red. The relative conductance increase per unit exposure is the highest yet reported for TNT. Aromatic anion salts, on the other hand, do not induce any electronic responses. 1H NMR and microscopic analyses show chemical interactions and morphological changes correlated with the electronic responses, some of which are specific to TNT in relation to other nitroaromatics. The binding constant for the imidazole rings and TNT is on the order of tens of M−1. The materials are promising for rapid indication of exposure to nitroaromatic compounds.

Cholesterol modified OPE functionalized film: fabrication, fluorescence behavior and sensing performance

A novel oligo(p-phenyleneethynylene) with cholesterol on its side chains (CHOL-OPE) was designed and synthesized. Film 1 and Film 2 were fabricated by immobilizing, separately, the oligomer as prepared and its control, OPE, which contains no side chains, on glass plate surfaces via utilization of a self-assembled monolayer (SAMs) technique. Fluorescence studies revealed that the profile of the fluorescence emission spectrum of Film 1 is dependent upon the composition of a mixture of THF and water. In contrast, Film 2 shows no such effect. Sensing performance studies demonstrated that the fluorescence of Film 1 is super-sensitive to the presence of 2,4,6-trinitrophenol (picric acid, PA), and sensitive to 2,4,6-trinitrotoluene (TNT), 2,4-dinitrotoluene (DNT) and nitrobenzene (NB) in the aqueous phase, whereas the nitroaromatics (NACs) as studied show little effect on the fluorescence emission of Film 2. The results from fluorescence quenching studies and the fact that copper salts (copper nitrate and copper acetate) show no detectible effect on the fluorescence emission of Film 1 show that the oligomer and the short linker, connecting the oligomer and the substrate, of the CHOL-OPE functionalized film may adopt a compact structure. Interestingly, the sensing process is fully reversible and free of interference from commonly found compounds, including methanol, THF, toluene, dichloromethane, ammonia, HCl, NaOH, NaCl, copper salts and seawater, etc. Fluorescence lifetime measurements revealed the static nature of the quenching process. The superior sensing performance of Film 1 for the analytes in the aqueous phase guarantees that the film may have the potential to be developed into a sensor device for the detection of PA and other NACs in groundwater.

Highly fluorescent TPA-PBPV nanofibers with amplified sensory response to TNT

Well-aligned nanofibers were prepared from a conjugated polymer, poly(triphenylamine-alt-biphenylene vinylene) (TPA-PBPV), using a solution-assisted template wetting technique. TPA-PBPV was also coated on the surface of electrospun polyacrylonitrile (PAN) nanofiber nonwoven membrane. The extremely large surface area, highly porous fibrous structure, optical scattering and evanescent-wave guiding effect imparted these one-dimensional (1D) nanofibrous materials with highly improved sensory ability to 2,4,6-trinitrotoluene (TNT) vapors and higher quenching efficiency than that of the neat TPA-PBPV films. The results suggest that nanofibrous structures could be a promising strategy to improve the sensory efficiency of fluorescent chemosensors.

Expression of glutathione S-transferases in poplar trees ( Populus trichocarpa) exposed to 2,4,6-trinitrotoluene (TNT)

Twelve Populus genes were identified from Arabidopsis thaliana sequences previously shown to be induced by exposure to 2,4,6-trinitrotoluene (TNT). Using the resources of the Poplar Genome Project and National Center for Biotechnology Information databases, Populus conserved domains were identified and used to design gene specific primers. RNA extracted from root tissues of TNT-exposed hydroponic poplar plants was used to quantify the expression of genes by reverse-transcriptase real-time polymerase chain reaction. Cyclophilin and 18S ribosomal DNA genes were used as internal standards. Exposure to TNT resulted in a significant increase of gene expression of two glutathione S-transferases (GST), peaking at levels of 25.0 ± 13.1 and 10 ± 0.7 fold the expression level of non-exposed plants after 24 h for each of the GST genes, respectively. This paper demonstrates the use of functional genomics information from the model plant species, Arabidopsis, to identify genes which may be important in detoxification of TNT in the model phytoremediation species, Populus trichocarpa.