Large-pore-size (150 nm) polystyrene (PSt) microspheres were carboxylated with phthalic anhydride (PA) through Friedel-Crafts acetylation to study the adsorption of 2,4,6-trinitrotoluene (TNT) on this material from aqueous solution. The scanning electron microscope (SEM) images and mercury porosimetry measurements (MPM) of the microspheres showed that the pore structure was unchanged during the reaction. High adsorption capacity (11.2 mg g−1 of suction-dried adsorbent) and adsorption rate (33.9 mg g−1 h−1) for TNT were observed during the study. As shown by the adsorption isotherm, the adsorption of TNT on PA-PSt can be described by the Freundlich adsorption equation, indicating heterogeneous adsorption process. On-column adsorption of TNT on PA-PSt and elution indicated that TNT can be completely removed from aqueous solution and condensed into acetone. 相似文献
A detailed chemical kinetic mechanism for gas phase combustion of 2,4,6-tri-nitrotoluene (TNT) has been developed to explore problems of explosive performance and of soot formation during the destruction of munitions. Thermodynamic properties of intermediate and radical species are estimated by group additivity. Reactions for the decomposition and oxidation of TNT and its intermediate products are assembled, based on information from the literature and from analogous reactions where the rate constants are available. The resulting detailed reaction mechanism for TNT is added to existing reaction mechanisms for RDX and for hydrocarbons which can be produced from TNT and RDX. Properties of the reaction mechanism are demonstrated by examining problems of soot formation during open burning of TNT and mixtures of TNT and RDX. Computed results show how addition of oxygen to TNT can reduce the amounts of soot formed in its combustion and why RDX and most mixtures of RDX and TNT do not produce soot during their combustion or incineration. 相似文献
The monolayer dispersion of MoO3 supported on the surface of titanate nanotubes (TNT) were prepared by heating mechanical mixture of molybdate (HMA) and TNT. The result shows that MoO3 can disperse spontaneously onto the surface of TNT, and the dispersion capacity is ca. 27 mg MoO3/g TNT by X-ray diffraction (XRD). On the basis of thermogravimetric (TG) and X-ray photoelectron spectroscopy (XPS) analysis, it was found that the HMA as precursor could not decompose completely into MoO3 crystal on the surface of TNT around the threshold above decomposed temperature due to the strong interaction between HMA and the surface of TNT. 相似文献
NQR detection of materials, such as TNT, is hindered by the low signal-to-noise ratio at low NQR frequencies. Sweeping small (0-26 mT) magnetic fields to shift the (1)H NMR frequency relative to the (14)N NQR frequencies can provide a significant increase of the (14)N NQR signal-to-noise ratio. Three effects of (1)H-(14)N level crossing are demonstrated in diglycine hydrochloride and TNT. These effects are (1) transferring (1)H polarization to one or more of the (14)N transitions, including the use of an adiabatic flip of the (1)H polarization during the field sweep, (2) shortening the effective (14)N T(1) by the interaction of (1)H with the (14)N transitions, (3) "level transfer" effect where the third (14)N (spin 1) energy level or other (14)N sites with different NQR frequency are used as a reservoir of polarization which is transferred to the measured (14)N transition by the (1)H. The (14)N NQR signal-to-noise ratio can be increased by a factor of 2.5 for one (14)N site in diglycine hydrochloride (and 2.2 in TNT), even though the maximum (1)H frequency used in this work, 111 6 kHz, is only 30% larger than the measured (14)N frequencies (834 kHz for diglycine hydrochloride and 843 kHz for TNT). 相似文献
The off-resonance dependence of the amplitudes of the six dominant 14N nuclear quadrupole resonance (NQR) lines in commercial polymorphic trinitrotoluene (TNT) sample were experimentally determined for a wide range of experimental parameters when irradiated with the spin-lock spin-echo (SLSE) pulse sequence. We find that the amplitudes off-resonance dependence follows a sinc-like function with an additional modulation due to the spacing between the RF pulses. This dependence can be very well modeled with expressions we have derived for a single site 14N NQR in paranitrotoluene (PNT). The results can be immediately used for the reduction of the number of free parameters used in the robust signal processing models for the TNT NQR detectors. 相似文献
The results of experimental studies of the nonideal detonation of high-density, high-energy aluminum-ammonium perchlorate-organic
fuel-HE compositions and of the blast waves it generates in a channel filled with air are presented. Aluminum-enriched compositions
have high densities (up to 2 g/cm3) and high heats of explosion, nearly twice that for TNT. The studies were performed to work out scientific fundamentals of
controlling nonideal detonation and to explore the possibility of creating new high-energy high-density formulations with
an enhanced fugacity effect. The factors that enable controlling the nonideal detonation of such charges were determined.
It was demonstrated that, at RDX contents above 15%, the detonation velocity increases linearly with the charge density while
the critical detonation diameter decreases. Adjusting the density, HE content, ratio of the components makes it possible to
vary the detonation velocity in high-density charges over a wide range, from 4 to 7 km/s. The experimental data were compared
to the thermodynamically calculated velocity of ideal detonation. For the compositions under study, the pressure- time histories
of the blast wave generated in a cylindrical tube by the expanding detonation products at different distances from the charge
were measured. The results were compared to analogous data obtained under the same conditions for the detonation of the same
mass of TNT (100 g). The parameters of blast waves generated by the test compositions are markedly superior to those characteristic
of TNT: the pressure at the leading front of the wave and pressure impulse at a given distance from the charge were found
to be 1.5–2.0 (or even more) times those observed for TNT. The TNT equivalency at pressures 30–60 atm has similar values.
The TNT equivalencies in pressure and pressure impulse depend nonmonotonically on the distance from the charge, so far unclear
why. It was established that the interaction between excess fuel and air oxygen during the expansion of detonation products
contributes little to supporting the blast wave. 相似文献
Rapid and onsite detection of nitroaromatic explosive 2,4,6-trinitrotoluene (TNT) is very crucial for the safety and security of human life as well as for the environment. In this present work, we demonstrate the feasibility for employing Folic Acid (FA) as a fluorescent as well as a colorimetric probe for the detection of TNT. This probe was synthesized by a simple one-step process. The developed probe shows an emission maximum at 490 nm upon excitation at 420 nm. On adding TNT, the fluorescence of the FA probe is quenched. Also, it shows a good selectivity towards TNT over other similar organic compounds such as 4-nitrophenol (4-NP), 2,4-dinitrophenol (2,4-DNP) and picric acid (PA). The limit of detection (LoD) of TNT was found to be 1.9398 µM. Colorimetric detection was conducted and paper strip assay was developed for the practical applications.
For application as an anode material in lithium batteries, composite anodes consisting of TiO2 nanotubes (TNT) and Li4Ti5O12 (LTO) nanocrystalline particles are prepared by hydrothermal reaction of rutile TiO2 particles, physical blending with LTO, and subsequent heat treatment at 300 °C. The TNT-LTO composites with varying the composition are characterized by electron microscopy, X-ray diffraction, potentiostatic cyclic voltammetry, and galvanostatic charge-discharge tests at various current rates. With higher LTO content, short TNTs with the average tube diameter of 10 nm are distributed among the potato-shaped LTO particles with the average diameter of 200 nm. At higher content of TNT, however, the LTO particles are sparsely distributed in the fibrillar aggregates of TNT with more lengthened image. As a result, the samples of TNT:LTO = 2:8 and 4:6 show superior cycle performance and high-rate capability, mainly due to their higher electrode densities to yield nanotubular TNT distributed on and supported by potato-shaped LTO nanoparticles. 相似文献