Decontamination of Yperite using mesoporous mixed metal oxide nanocrystals

Efficient Decontamination of HD by an Electrophilic Iodine/Carboxylate Composite as an Active Sorbent

The development of new and efficient decontamination methods has become more relevant in recent years, especially with regard to solid-based decontamination and detoxification systems. The majority of powders used today are dealing with the physical adsorption of chemical warfare agents (CWAs) and their removal from sites without actively destroying them. In this work, we have designed and developed an active solid composite matrix combining organic carboxylate salts and N-iodosuccinimide (NIS) for HD decontamination via oxidation. All the reactions and mechanistic studies for the sorption and degradation of CWAs were conducted using direct polarization and cross polarization solid-state magic-angle spinning nuclear magnetic resonance techniques. Performance toward the sorption and detoxification of HD was tested, exhibiting oxidation within minutes in a mild and selective manner to the nontoxic sulfoxide derivative followed by visible formation of iodine. The results indicate that carboxylate moieties in the matrix are important for stabilizing the positively charged sulfonium ion intermediate and for supplying oxygen for hydrolysis in a water-deficient environment. The NaOBz/NIS composite was shown to be the most efficient in sorbing and converting the water-insoluble agent HD to its nontoxic, water-soluble sulfoxide, which could then be removed from the site with mere water, resulting in less environmental damage and quick remediation.

Ultrasensitive surface-enhanced Raman spectroscopy detection of gaseous sulfur-mustard simulant based on thin oxide-coated gold nanocone arrays

Surface Enhanced Raman Spectroscopy (SERS) could be a powerful technique for detecting trace gaseous sulfur-mustard, but it is still challenging due to the difficulty in efficiently capturing sulfur-mustard molecules by normal SERS substrates. Here, a chemically trapping strategy is presented for such detection via coating an ultrathin metal-oxide sensing layer on a SERS substrate. In the strategy, a SERS substrate Au-wrapped Si nanocone array is designed and fabricated by Si wafer-based organic template-etching and appropriate Au deposition, and coated with an ultrathin CuO for chemically capturing sulfur-mustard molecules. The validity of such strategy has been demonstrated via taking the gaseous 2-chloroethyl ethyl sulfide (a simulant of sulfur-mustard, or 2-CEES for short) as the target molecules. The response of the CuO-coated SERS substrate to the gaseous 2-CEES is detectable within 10 min, and the lowest detectable concentration is 10 ppb or less. Further experiments have shown that there exists an optimal CuO coating thickness which is about 6 nm. The CuO coating-based capture of 2-CEES molecules is attributed to the surface hydroxyl-induced specific adsorption, which is subject to the pseudo-second-order kinetics and Freundlich-typed model. This study presents the practical SERS chips and new route for the trace detection of gaseous sulfur-mustard.

Synthesis routes of CeO2 nanoparticles dedicated to organophosphorus degradation: a benchmark

Exposure to nerve agents, in military conflicts or terrorist acts, requires efficient decontamination systems. CeO₂ nanoparticles appear efficient against organophosphorus compounds, thus we performed a benchmark on the available synthesis routes.

Restrictions on the Use of Specimens Based on Magnesium and Titanium Nanocrystalline Oxides in Incidents Involving Uncontrolled Release of Hazardous Substances

Undertaking effective and prompt action during chemical events is an important measure in preventing the spread of contamination. Studies have shown that despite very high surface activity of nanocrystalline metal oxides, their use does not reduce the fire hazard for hydrocarbon spills and alcohols more effectively than commonly used sorbents during fire rescue operations. Other limitations of specimens containing nanocrystalline oxides have also been proven, such as the maximum absorption similar to commonly used specimens, as well as high costs of conducting the acid neutralization process without increasing the level of safety of operations. Results obtained allowed the determination of proposed principles of effective and economically appropriate application of nanocrystalline metal oxides in rescue units.

Rapid and complete degradation of sulfur mustard adsorbed on M/zeolite-13X supported (M = 5 wt% Mn, Fe, Co) metal oxide catalysts with ozone

Complete degradation of sulfur mustard adsorbed over M/zeolite-13X (M = 5 wt% Mn, Fe, Co) catalysts using ozone gas under ambient conditions.

Nanostructured Metal Oxides for Stoichiometric Degradation of Chemical Warfare Agents

Metal oxides have very important applications in many areas of chemistry, physics and materials science; their properties are dependent on the method of preparation, the morphology and texture. Nanostructured metal oxides can exhibit unique characteristics unlike those of the bulk form depending on their morphology, with a high density of edges, corners and defect surfaces. In recent years, methods have been developed for the preparation of metal oxide powders with tunable control of the primary particle size as well as of a secondary particle size: the size of agglomerates of crystallites. One of the many ways to take advantage of unique properties of nanostructured oxide materials is stoichiometric degradation of chemical warfare agents (CWAs) and volatile organic compounds (VOC) pollutants on their surfaces.

Self-assembled mesoporous γ-Al2O3 spherical nanoparticles and their efficiency for the removal of arsenic from water

We report a highly efficient synthetic strategy for self-assembled mesoporous γ-Al(2)O(3) materials using sodium salicylate as template. The mesoporous γ-Al(2)O(3) samples synthesized following this strategy have high surface areas (231-497 m(2)g(-1)), consist of crystalline tiny spherical nanoparticles of dimensions ca. 2-10nm and showed high affinity for the adsorption of arsenic from the contaminated aqueous solutions. Efficient synthesis strategy, exceptionally high surface area and high adsorption efficiency of these mesoporous γ-Al(2)O(3) materials for the dissolved arsenic from the contaminated aqueous solutions (in the form of oxyanions of arsenic) could find potential utility in the purification of polluted water.

Sulphur mustard degradation on zirconium doped Ti-Fe oxides

Zirconium doped mixed nanodispersive oxides of Ti and Fe were prepared by homogeneous hydrolysis of sulphate salts with urea in aqueous solutions. Synthesized nanodispersive metal oxide hydroxides were characterised as the Brunauer-Emmett-Teller (BET) surface area and Barrett-Joiner-Halenda porosity (BJH), X-ray diffraction (XRD), infrared (IR) spectroscopy, scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) microanalysis, and acid-base titration. These oxides were taken for an experimental evaluation of their reactivity with sulphur mustard (chemical warfare agent HD or bis(2-chloroethyl)sulphide). The presence of Zr(4+) dopant tends to increase both the surface area and the surface hydroxylation of the resulting doped oxides in such a manner that it can contribute to enabling the substrate adsorption at the oxide surface and thus accelerate the rate of degradation of warfare agents. The addition of Zr(4+) to the hydrolysis of ferric sulphate with urea shifts the reaction route and promotes formation of goethite at the expense of ferrihydrite. We discovered that Zr(4+) doped oxo-hydroxides of Ti and Fe exhibit a higher degradation activity towards sulphur mustard than any other yet reported reactive sorbents. The reaction rate constant of the slower parallel reaction of the most efficient reactive sorbents is increased with the increasing amount of surface base sites.