Degradation Of Trinitrotoluene Research Articles

Characterization of industrial TNT in ammunition shells: An in-depth study of artificial aging effects using Fourier-Transform infrared spectroscopy and gas chromatography–mass spectrometry

In this study, we comprehensively investigated the degradation of industrial trinitrotoluene (TNT), focusing on the effects of aging and direct contact with steel surfaces, mirroring real-world usage conditions. While practical knowledge exists regarding this degradation, the existing literature lacks in-depth insights into the underlying processes. To address this gap, we conducted experiments using small steel samples, representative of military ammunition casings, which were coated with TNT and subjected to 30 days of heating at 75 °C under vacuum conditions. A subset of these samples was coated with a protective red alkyd paint. After the aging process, the TNT was carefully removed from the metal surfaces and subjected to a comprehensive analysis encompassing scanning electron microscopy, Fourier-transform infrared spectroscopy, and gas chromatography-mass spectrometry. Our results reveal a remarkable preservation of the chemical integrity of industrial TNT, even in the presence of thermal stress and direct steel contact. Although superficial changes were observed in the TNT's appearance, all analytical data consistently demonstrated the maintenance of its chemical composition. Notably, the sole change in composition was attributed to the presence of degradation products associated with the alkyd paint coating, rather than intrinsic TNT degradation. These findings underscore the negligible impact of degradation processes on TNT in scenarios involving the solid-phase thermal stress of TNT in direct contact with metal, significantly enhancing our understanding of TNT safety when packaged within steel artifacts—a common context in military ammunition.

Microecological characteristics of water bodies/sediments and microbial remediation strategies after 50 years of pollution exposure in ammunition destruction sites in China

The effects of long-term ammunition pollution on microecological characteristics were analyzed to formulate microbial remediation strategies. Specifically, the response of enzyme systems, N/O stable isotopes, ion networks, and microbial community structure/function levels were analyzed in long-term (50 years) ammunition-contaminated water/sediments from a contamination site, and a compound bacterial agent capable of efficiently degrading trinitrotoluene (TNT) while tolerating many heavy metals was selected to remediate the ammunition-contaminated soil. The basic physical and chemical properties of the water/sediment (pH (up: 0.57–0.64), nitrate (up: 1.31–4.28 times), nitrite (up: 1.51–5.03 times), and ammonium (up: 7.06–70.93 times)) were changed significantly, and the significant differences in stable isotope ratios of N and O (nitrate nitrogen) confirmed the degradability of TNT by indigenous microorganisms exposed to long-term pollution. Heavy metals, such as Pb, Zn, Cu, Cd, Cs, and Sb, have synergistic toxic effects in ammunition-contaminated sites, and significantly decreased the microbial diversity and richness in the core pollution area. However, long-term exposure in the edge pollution area induced microorganisms to use TNT as a carbon and nitrogen sources for life activities and growth and development. The Bacteroidales microbial group was significantly inhibited by ammunition contamination, whereas microorganisms such as Proteobacteria, Acidobacteriota, and Comamonadaceae gradually adapted to this environmental stress by regulating their development and stress responses. Ammunition pollution significantly affected DNA replication and gene regulation in the microecological genetic networks and increased the risk to human health. Mg and K were significantly involved in the internal mechanism of microbial transport, enrichment, and metabolism of TNT. Nine strains of TNT-utilizing microbes were screened for efficient TNT degradation and tolerance to typical heavy metals (copper, zinc and lead) found in contaminated sites, and a compound bacterial agent prepared for effective repair of ammunition-contaminated soil significantly improved the soil ecological environment.

The characteristics and metabolic potentials of the soil bacterial community of two typical military demolition ranges in China

The response mechanism of soil microbiota in military polluted sites can effectively indicate the biotoxicity of ammunition. In this study, two military demolition ranges polluted soils of grenades and bullet were collected. According to high-throughput sequencing, after grenade explosion, the dominant bacteria in Site 1 (S1) are Proteobacteria (97.29 %) and Actinobacteria (1.05 %). The dominant bacterium in Site 2 (S2) is Proteobacteria (32.95 %), followed by Actinobacteria (31.17 %). After the military exercise, the soil bacterial diversity index declined significantly, and the bacterial communities interacted more closely. The indigenous bacteria in S1 were influenced more compared to those in S2. According to the environmental factor analysis, the bacteria composition can easily be influenced by heavy metals and organic pollutants, including Cu, Pb, Cr and Trinitrotoluene (TNT). About 269 metabolic pathways annotated in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database were detected in bacterial communities, including nutrition metabolism (C, 4.09 %; N, 1.14 %; S, 0.82 %), external pollutant metabolism (2.52 %) and heavy metal detoxication (2.12 %), respectively. The explosion of ammunition changes the basic metabolism of indigenous bacteria, and heavy metal stress inhibits the TNT degradation ability of bacterial communities. The pollution degree and community structure influence the metal detoxication strategy at the contaminated sites together. Heavy metal ions in S1 are mainly discharged through membrane transporters, while heavy metal ions in S2 are mainly degraded through lipid metabolism and biosynthesis of secondary metabolites. The results obtained in this study can provide deep insight into the response mechanism of the soil bacterial community in military demolition ranges with composite pollutions of heavy metals and organic substances. CapsuleHeavy metal stress changed the composition, interaction and metabolism of indigenous communities in military demolition ranges, especially the TNT degradation process.

Excellent photocatalytic performance and dual-band degradation of organic pollutants through Z-scheme photocatalysts

Organic pollutants, particularly nitrogen-rich explosives and carbon-rich dyes are generally degraded by different photocatalysts under either visible or ultraviolet light, leading to substantial waste and cost. Three photocatalysts with Z-scheme structures, Ag@AgBr/Cu2O-1, Ag@AgBr/Cu2O-2, and Ag@AgBr/Cu2O-3, are designed and synthesized employing a simple solvothermal and photoreduction technique to develop advanced photocatalyst materials that can degrade nitro substances under ultraviolet (UV) irradiation and organic dyes under visible-light irradiation. The structural characterization of Ag@AgBr/Cu2O-2 as determined through various spectroscopic techniques (e.g. XPS, XRD and TEM) reveal that the Z-scheme photocatalysts are composed of Ag, Cu2O and AgBr nanospheres with particle size less than 100 ​nm, while nano-Ag and nano-AgBr coupled to the surface of the Cu2O microspheres. Further investigations demonstrate that these photocatalysts exhibit a good UV–visible absorption range (200–800 ​nm) and outstanding photocatalytic degradation activity for two typical organic pollutants. Among them, Ag@AgBr/Cu2O-2 achieve a 100% degradation of trinitrotoluene (a common explosive) in 30 ​min under UV radiation, and a 99.2% degradation of rhodamine B (a typical dye) in 60 ​min under visible-light irradiation in the absence of UV light, demonstrating remarkable dual-band adaptability. Moreover, Ag@AgBr/Cu2O-2 displays superior stability, with a degradation rate of up to 85% after four cycles. The putative photocatalytic reaction mechanism is proposed based on the radical trapping experiment.

Optimization and evaluation of the efficiency of sono-Fenton and photo-Fenton processes in the removal of 2, 4, 6 trinitrotoluene (TNT) from aqueous solutions

The adverse health effects of trinitrotoluene (TNT) include allergies, liver and blood damage, and carcinogenesis. The present study aimed to optimize the sono-Fenton and photo-Fenton processes for the removal of TNT from aqueous solutions. TNT removal was evaluated at various pH (acidic, neutral, and alkaline), pollutant concentrations (10, 30, 50, 100, and 120 mg/l), H2O2 concentration (10-80 mM), and ferrous ions (0.5-4 Mm). After the optimization of the parameters, the appropriate UV irradiation time and optimal time of ultrasonic waves were determined for the removal of this compound. TNT concentration was measured using high-performance liquid chromatography. Increased hydrogen peroxide from 10 to 40 mMole/l led to higher TNT degradation (45.3% to 88.4% and 40 to 80 mMole/l), while the removal rate decreased from 88.4% to 79%. At the optimal H2O2 concentration, increased pH (3±0.2 to 11±0.2) decreased TNT decomposition from 88.4% to 23.5%. In addition, increased time (5 to 60 minutes) led to the higher photo-Fenton process efficiency (68.6% to 89%). The maximum photo-Fenton efficiency was achieved in optimal conditions at the TNT concentration of 10 mg/L (97%) and 60 minutes, while the efficiency of the sono-Fenton process in optimal conditions was 100% at 20 minutes. Therefore, it was concluded that the sono-Fenton process was effective in the removal of TNT.

Application of response surface methodology to optimize degradation of TNT using nano Fe0‐assisted fenton process

This work aims to investigate the degradation of 2,4,6 trinitrotoluene (TNT) as a model typical nitro‐aromatic compound. The degradation process was carried out by hydroxyl radical that was produced via hydrogen peroxide activated by nano zero‐valent iron (Fe0). The nanoparticles as a source of ferrous ions were synthesized by precipitation method using a starch coating as a stabilizer. The transmission electron microscope analysis revealed that the size of the Fe0 particles is about 40 nm. The operating parameters were optimized using central composite design as a kind of response surface methodology. The degradation efficiency of 91% during 10 minutes and mineralization efficiency of 83% during 40 minutes were obtained under the experimental conditions of 30 mg/L TNT, 104.8 mg/L Fe0, 675 mg/L H2O2, and pH of 3.5. Finally, redwater treatment as real nitro‐aromatic wastewater was evaluated by this process, and 63% removal efficiency was attained after 40 minutes in the optimum condition. © 2018 American Institute of Chemical Engineers Environ Prog, 38: 477–482, 2019

Degradation of trinitrotoluene by transgenic nitroreductase in Arabidopsis plants

The explosive 2,4,6-trinitrotoluene (TNT) is a highly toxic and persistent environmental pollutant. TNT is toxic to many organisms, it is known to be a potential human carcinogen, and is persistent in the environment. This study presents a system of phytoremediation by Arabidopsis plants developed on the basis of overexpression of NAD(P)H-flavin nitroreductase (NFSB) from the Sulfurimonas denitrificans DSM1251. The resulting transgenic Arabidopsis plants demonstrated significantly enhanced TNT tolerance and a strikingly higher capacity to remove TNT from their media. The highest specific rate constant of TNT disappearance rate was 1.219 and 2.297 mL/g fresh weight/h for wild type and transgenic plants, respectively. Meanwhile, the nitroreductase activity in transgenic plant was higher than wild type plant. All this indicates that transgenic plants show significantly enhanced tolerances to TNT; transgenic plants also exhibit strikingly higher capabilities of removing TNT from their media and high efficiencies of transformation.

Preliminary investigation on ultrasound frequency determination in TNT, RDX and HMX degradation

The wastewater of the munitions industry varies in terms of the recalcitrant compounds depending on the products and the manufacturing process. The most commonly encountered energetic nitro-aromatic compounds in ammunition wastewater are trinitrotoluene (TNT), nitro-heterocyclic hexahydro-trinitrotriazine (RDX), and cyclotetramethylene-tetranitramine (HMX). These compounds are known to be very toxic and resistant to biodegradation. The aim of this study was to determine the appropriate ultrasound frequency to assist the anaerobic biodegradation of TNT, RDX, and HMX Therefore, the optimum ultrasound frequencies were investigated to degrade TNT, RDX, and HMX without destroying anaerobic microorganisms. The results showed that ultrasound irradiation was effective for the degradation of all the explosive compounds used. However, the maximum removal efficiencies and minimum microorganism lysis were achieved by the frequencies of 20 and 800 kHz.

Improved removal of Trinitrotoluene (TNT) from contaminated soil by inducing aerobic process: kinetic and chemical byproducts

This study describes the biological degradation of TNT by using induced aeration. Three plastic reactors were used. In each reactor 3 kg of soil were used. In order to increase the porosity of the soil, sawdust was added to soil. Textile wastewater treatment plant sludge was also added to soil. TNT at the concentrations of 1000 mg/kg of soil was added thereafter. Rhamnolipid biosurfactant at the concentration of 60 mg/L was added to related reactors. Aeration interval was at every 3 to 5 days. Every two weeks, sampling of soil were done to analyze the explosives. Samples were analyzed by HPLC. The results showed that at the end of 120 days, TNT removal efficiency in induced aeration in reactors containing sludge and biosurfactant was 98 percent. COD removal efficiency in induced aeration in reactors amended by rhamnolipid was 58 percent and in reactors to which rhamnolipid was not added was 41 percent. Follow-up kinetic studies revealed that explosives removal follow the pseudo first order reaction. The pseudo first-order rate constants of rhamnolipid amended experiments were at least 3.89 orders of magnitude higher for TNT than those found for experiments without rhamnolipid. Application of Rhamnolipid biosurfactant could have a protective effect against the toxicity of explosives for bacteria. Textile sludge from wastewater treatment plant can decrease the time needed for explosive removal. Growth of bacteria and degradation of explosives showed that explosives have been used as a nitrogen source.

Biodegradation of trinitrotoluene (TNT) by indigenous microorganisms from TNT-contaminated soil, and their application in TNT bioremediation

ABSTRACTSoil and groundwater contaminated by munitions compounds is a crucial issue in environmental protection. Trinitrotoluene (TNT) is highly toxic and carcinogenic; therefore, the control and remediation of TNT contamination is a critical environmental issue. In this study, the authors characterized the indigenous microbial isolates from a TNT-contaminated site and evaluated their activity in TNT biodegradation. The bacteria Achromobacter sp. BC09 and Citrobacter sp. YC4 isolated from TNT-contaminated soil by enrichment culture with TNT as the sole carbon and nitrogen source (strain BC09) and as the sole nitrogen but not carbon source (strain YC4) were studied for their use in TNT bioremediation. The efficacy of degradation of TNT by indigenous microorganisms in contaminated soil without any modification was insufficient in the laboratory-scale pilot experiments. The addition of strains BC09 and YC4 to the contaminated soil did not significantly accelerate the degradation rate. However, the addition of an additional carbon source (e.g., 0.25% sucrose) could significantly increase the bioremediation efficiency (ca. decrease of 200 ppm for 10 days). Overall, the results suggested that biostimulation was more efficient as compared with bioaugmentation. Nevertheless, the combination of biostimulation and bioaugmentation using these indigenous isolates is still a feasible approach for the development of bioremediation of TNT pollution.

Biodegradation of 2, 4, 6- Trinitrotoluene (TNT) in Contaminated Soil and Microbial Remediation Options for Treatment

This review paper provides a critical examination on current microbial biodegradation of 2, 4, 6-Trinitrotoluene (TNT) and its metabolites in soil, with focus on: (i) extent of biological degradation of TNT and its metabolites in soil, (ii) factors affecting the TNT transformations, and (iii) microbial bioremediation technologies , and related challenges. This was carried out through an extensive examination of relevant published literature on the topic. The review paper found that the detoxification of TNT contaminated sites by microorganisms based- technologies have been employed but TNT has been proven to resist biological mineralization and undergo biotransformations, leading to immobilization of toxic and unstable transformation products. TNT mineralization is however achievable, but scientific studies are far away from attaining the best desired in situ bioremediation practices and much remains to be delineated. We provide future research directions to design effective bioremediation technologies for solving the problems of TNT and minimize environmental impacts.

Palladium 촉매와 포름산을 활용한 액상 trinitrotoluene 분해 특성 연구

Various methods to degrade explosives efficiently in natural soil and water that include trinitrotoluene (TNT) have been studied. In this study, TNT in water was degraded by reduction with palladium (Pd) catalyst impregnated onto alumina (henceforth Pd-Al catalyst) and formic acid. The degradation of TNT was faster when the temperature of water was high, and the initial TNT concentration, pH, and ion concentration in water were low. The amounts of Pd-Al catalyst and formic acid were also important for TNT degradation in water. According to the experimental results, the degradation constant of TNT with unit mass of Pd-Al catalyst was . The degradation constant of TNT was higher than the results of previous studies which used zero valent iron. 2,6-diamino-4-nitrotoluene and 2-amino-4,6-dinitrotoluene were detected as by-products of TNT degradation showing that TNT was reduced. The by-products of TNT were also completely degraded after reaction when both Pd-Al catalyst and formic acid existed. Even though there are several challenges of Pd-Al catalyst (e.g., deactivation, poisoning, leaching, etc.), the results of this study show that TNT degradation by Pd-Al catalyst and formic acid is a promising technique to remediate explosive contaminated water and soil.

Quantifying the degradation of TNT and RDX in a saline environment with and without UV-exposure

Terrorist attacks in a maritime setting, such as the bombing of the USS Cole in 2000, or the detection of underwater mines, require the development of proper protocols to collect and analyse explosive material from a marine environment. In addition to proper analysis of the explosive material, protocols must also consider the exposure of the material to potentially deleterious elements, such as UV light and salinity, time spent in the environment, and time between storage and analysis. To understand how traditional explosives would be affected by such conditions, saline solutions of explosives were exposed to natural and artificial sunlight. Degradation of the explosives over time was then quantified using negative chemical ionization gas chromatography mass spectrometry (GC/NCI-MS). Two explosives, trinitrotoluene (TNT) and cyclotrimethylenetrinitramine (RDX), were exposed to different aqueous environments and light exposures with salinities ranging from freshwater to twice the salinity of ocean water. Solutions were then aged for up to 6 months to simulate different conditions the explosives may be recovered from. Salinity was found to have a negligible impact on the degradation of both RDX and TNT. RDX was stable in solutions of all salinities while TNT solutions degraded regardless of salinity. Solutions of varying salinities were also exposed to UV light, where accelerated degradation was seen for both explosives. Potential degradation products of TNT were identified using electrospray ionization mass spectrometry (ESI-MS), and correspond to proposed degradation products discussed in previously published works [1].

MICROBIAL COMMUNITY CHANGES IN TNT SPIKED SOIL BIOREMEDIATION TRIAL USING BIOSTIMULATION, PHYTOREMEDIATION AND BIOAUGMENTATION

Trinitrotoluene (TNT), a commonly used explosive for military and industrial applications, can cause serious environmental pollution. 28-day laboratory pot experiment was carried out applying bioaugmentation using laboratory selected bacterial strains as inoculum, biostimulation with molasses and cabbage leaf extract, and phytoremediation using rye and blue fenugreek to study the effect of these treatments on TNT removal and changes in soil microbial community responsible for contaminant degradation. Chemical analyses revealed significant decreases in TNT concentrations, including reduction of some of the TNT to its amino derivates during the 28-day tests. The combination of bioaugmentation-biostimulation approach coupled with rye cultivation had the most profound effect on TNT degradation. Although plants enhanced the total microbial community abundance, blue fenugreek cultivation did not significantly affect the TNT degradation rate. The results from molecular analyses suggested the survival and elevation of the introduced bacterial strains throughout the experiment.

Analysis of redox responses during TNT transformation by Clostridium acetobutylicum ATCC 824 and mutants exhibiting altered metabolism

The transformation of trinitrotoluene (TNT) by several mutant strains of Clostridium acetobutylicum has been examined to analyze the maximal rate of initial transformation, determine the effects of metabolic mutations of the host on transformation rate, and to assess the cell metabolic changes brought about during TNT transformation. Little difference in the maximal rate of TNT degradation in early acid phase cultures was found between the parental ATCC 824 strain and strains altered in the acid forming pathways (phosphotransacetylase, or butyrate kinase) or in a high-solvent-producing strain (mutant B). This result is in agreement with the previous findings of a similar degradation rate in a degenerate strain (M5) that had lost the ability to produce solvent. A series of antisense constructs were made that reduced the expression of hydA, encoding the Fe-hydrogenase, or hydE and hydF, genes encoding hydrogenase maturating proteins. While the antisense hydA strain had only ∼30 % of the activity of wild type, the antisense hydE strain exhibited a TNT degradation rate around 70 % that of the parent. Overexpression of hydA modestly increased the TNT degradation rate in acid phase cells, suggesting the amount of reductant flowing into hydrogenase rather than the hydrogenase level itself was a limiting factor in many situations. The redox potential, hydrogen evolution, and organic acid metabolites produced during rapid TNT transformation in early log phase cultures were measured. The redox potential of the acid-producing culture decreased from -370 to -200 mV immediately after addition of TNT and the hydrogen evolution rate decreased, lowering the hydrogen to carbon dioxide ratio from 1.4 to around 1.1 for 15 min. During the time of TNT transformation, the treated acidogenic cells produced less acetate and more butyrate. The results show that during TNT transformation, the cells shift metabolism away from hydrogen formation to reduction of TNT and the resulting effects on cell redox cofactors generate a higher proportion of butyrate.

Sustainable remediation – The application of bioremediated soil for use in the degradation of TNT chips

Environmental contamination by TNT (2,4,6 trinitrotoluene), historically used in civilian industries and the military as an explosive is of great concern due to its toxicity. Scientific studies have however shown that TNT is susceptible to microbial transformation. The aim of this study was to assess the potential of a previously bioremediated hydrocarbon contaminated soil (PBR) to increase TNT degradation rates. This was investigated by adding TNT chips to PBR and uncontaminated soils (PNC) in laboratory based studies (up to 16 weeks). Residual TNT chip analysis showed greater TNT degradation in PBR soils (70%) and significantly higher metabolic rates (4.5 fold increase in cumulative CO2 levels) than in PNC soils (30%). Molecular analysis (PCR-DGGE-cluster analysis) showed substantial shifts in soil microbial communities associated with TNT contamination between day 0 and week 4 especially in PBR soils. Bacterial communities appeared to be more sensitive to TNT contamination than fungal communities in both soils. Quantitative PCR analysis showed ∼3 fold increase in the abundance of nitroreductase genes (pnrA) in PBR soils with a gradual reduction in community evenness (Pareto-Lorenz curves) in contrast to PNC soils. These results suggest that microbial response to TNT contamination was dependent on the history of soil use. The results also confirm that the microbial potential of waste soils such as PBR soil (usually disposed of via landfill) can be successfully used for accelerated TNT chip degradation. This promotes sustainable re-use of waste soils extending the life span of landfill sites.

Nanotechnology: the next revolution for wastewater treatment (TNT contaminate)

Abstract Trinitrotoluene (TNT), a nitroaromatic explosive, is encountered groundwater contaminant that can pose a human health risk, even at very low aqueous concentrations. In this study, a series of catalytic degradation of dissolved TNT have been investigated using iron nanocatalysts (zero valent and its oxide) and Fe2O3 bentonite nanocomposite. The prepared nano catalysts were characterized via XRD, BET and TEM. The degradation of TNT by Fe-PILC, is almost complete after 30 min, whereas 65, 100 min on using the Fe-zero valent and Fe-oxide, respectively. These results indicate that the reaction rate is a strong function of the number of iron surface active sites, and therefore the Fe-catalysts an important reaction variable.

Detoxification of high concentrations of trinitrotoluene by bacteria

The ability of the strains-destructors of various aromatic compounds to utilize trinitrotoluene (TNT) up to concentration of 70 mg/1 was shown. An increase in the TNT concentration from 100 to 150 mg/1 did not inhibit its conversion rate by the Kocuria palustris RS32 strain. The Acinetobacter sp. VT 11 strain utilized TNT as a sole substrate for growth; 3,5-dinitro-4-methyl anilide acetate and 2,6-dinitro-4-aminotoluene were identified as intermediates of TNT degradation by active strains of Pseudomonas sp. VT-7W and Kocuria rosea RS51. At the same time, 4-methyl-3,5-dinitroformamide was discovered for the first time upon the TNT destruction by the bacteria strains of Rhodococcus opacus 1G and Rhodococcus sp. VT-7. The active bacterial strains achieved an 82-90% destruction of TNT when they were introduced into the soil.

Photo catalytic oxidation of TNT using TiO2-SiO2 nano-composite aerogel catalyst prepared using sol–gel process

The degradation of nitro aromatics like trinitrotoluene (TNT) released in the waste water from explosive process plants is the serious problem due to toxic and explosive nature of TNT. The poor response of TNT to biodegradation enhanced the gravity of the problem. We have demonstrated that high specific surface area TiO2–SiO2 nano-composite aerogel is promising photo catalyst in successful treating of TNT contaminated aqueous solution. The TiO2–SiO2 composite aerogel with nominal content of 20 and 50% TiO2, used as catalyst, were prepared by co-precursor sol–gel method using titanium isopropaxide and tetramethylorthosilicate as source of titania and silica, respectively. The XRD studies confirmed formation of anatase phase of crystalline TiO2 with nano sized crystallites. The TiO2–SiO2 aerogel showed specific surface area of 1,107 and 485 m2/g for the aerogels containing 20 and 50% TiO2, respectively. The 100 ppm TNT solution was treated, in 700 ml capacity reaction vessel, using H2O2 oxidizer and TiO2–SiO2 aerogel catalyst in presence of UV light (8 W UV lamp). Using TiO2–SiO2 (50/50) aerogel with surface area of 485 m2/g, we succeeded to reduce the TOC to 1 ppm within 3.5 h where as using TiO2/SiO2 (20/80) aerogel with surface area of 1,107 m2/g, the TOC was reduced to about only 7 ppm in the same time. It revealed that the combination of high TiO2 content and high specific surface area is an important factor to achieve effective and faster degradation of TNT for complete mineralization.

Energetics and Vibronics Analyses of the Enzymatic Coupled Electron–Proton Transfer From NfsA Nitroreductase to Trinitrotoluene

We analyze the coupled electron-proton transfer from the NfsA nitroreductase enzyme to the trinitrotoluene (TNT) explosive as a possible reaction mechanism for nitrocompounds sensing. Based on earlier experiments, we have chosen as active site a group of amino acids around the flavin mononucleotide cofactor. In this site, we evaluate charge transfer, leading to a first step in the enzymatic TNT degradation that is enough for its detection. Our analysis suggests that light absorption and vibrations around the active site induce charge transfer for the enzymatic reaction with TNT.