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Stengl V.,Academy of Sciences of the Czech Republic | Oplustil F.,Military Technical Institute of Protection Brno | Nemec T.,Military Technical Institute of Protection Brno
Photochemistry and Photobiology | Year: 2012

A novel In 3+-doped TiO 2 and TiO 2/In 2S 3 nanocomposites for photocatalytic degradation of environmental pollutants and stoichiometric degradation of warfare agents were prepared by a homogeneous hydrolysis with urea and thioacetamide, respectively. The prepared samples series TiInTAA were annealed at 600°C. The prepared samples were characterized by X-ray powder diffraction, IR spectroscopy, Raman spectroscopy, specific surface area (BET) and porosity determination. The method of UV-Vis diffuse reflectance spectroscopy was employed to estimate band-gap energies. The photocatalytic activity (PCA) was tested by degradation of Orange dye, whereas stoichiometric activity was studied by degradation of sulfur mustard. Incorporation of In 3+ into titania lattice increases PCA of TiO 2 in the visible light and increases stoichiometric decomposition of sulfur mustard against nondoped TiO 2 as well. PCA of TiO 2/In 2S 3 composite depends on the optimal ratio of TiO 2:In 2S 3 in composite, while the activity for stoichiometric decomposition of sulfur mustards depends on the content of In 2S 3 in nanocomposite. © 2011 The American Society of Photobiology. Source


Stengl V.,Academy of Sciences of the Czech Republic | Grygar T.M.,Academy of Sciences of the Czech Republic | Oplustil F.,Military Technical Institute of Protection Brno | Nemec T.,Military Technical Institute of Protection Brno
Journal of Hazardous Materials | Year: 2011

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. © 2011 Elsevier B.V. Source


Stengl V.,Academy of Sciences of the Czech Republic | Grygar T.M.,Academy of Sciences of the Czech Republic | Oplustil F.,Military Technical Institute of Protection Brno | Olsanska M.,Military Technical Institute of Protection Brno
Industrial and Engineering Chemistry Research | Year: 2013

We present a procedure for removal and detoxification of chemical warfare agents (CWA) from corrosion-sensitive components using their reactive sorption (adsorption and bond cleavage). The procedure consists of spraying a suspended sorbent over a contaminated surface followed by mechanical removal of the spent sorbent after liquid phase evaporation. The procedure was tested using a video graphics array (VGA computer card) VGA card, sulfur mustard (yperite, HD agent, bis(2-chloroethyl)sulfide), and Zr4+-doped TiO2 sorbent obtained by homogeneous hydrolysis. After 60 min of interaction with a suspension of the reactive sorbent with the contaminated VGA card, 99.3% of the sulfur mustard was removed, while the VGA card retained its functionality. The procedure does not require specialized instrumentation. This is feasible for electronic devices, as they do not need corrosive and electrically conducting agents or nonvolatile solvents that would harm electronic circuits. The method would be applicable to decontamination of a broad range of CWAs and pesticides. © 2013 American Chemical Society. Source


Stengl V.,Academy of Sciences of the Czech Republic | Grygar T.M.,Academy of Sciences of the Czech Republic | Oplustil F.,Military Technical Institute of Protection Brno | Nemec T.,Military Technical Institute of Protection Brno
Journal of Hazardous Materials | Year: 2012

Germanium doped TiO 2 was prepared by homogeneous hydrolysis of aqueous solutions of GeCl 4 and TiOSO 4 with urea. The synthesized samples were characterized by X-ray diffraction, scanning electron microscopy, EDS analysis, specific surface area (BET) and porosity determination (BJH). Ge 4+ doping increases surface area and content of amorphous phase in prepared samples. These oxides were used in an experimental evaluation of their reactivity with chemical warfare agent, sulphur mustard, soman and agent VX. Ge 4+ doping worsens sulphur mustard degradation and improves soman and agent VX degradation. The best degree of removal (degradation), 100% of soman, 99% of agent VX and 95% of sulphur mustard, is achieved with sample with 2wt.% of germanium. © 2012 Elsevier B.V.. Source


Stengl V.,Academy of Sciences of the Czech Republic | Kralova D.,Academy of Sciences of the Czech Republic | Kralova D.,Czech Institute of Macromolecular Chemical | Oplustil F.,Military Technical Institute of Protection Brno | Nemec T.,Military Technical Institute of Protection Brno
Microporous and Mesoporous Materials | Year: 2012

Manganese(IV) oxides were prepared by homogeneous hydrolysis of potassium permanganate with 2-chloroacetamide and direct reaction of potassium permanganate with manganese(II) sulfate in aqueous solutions. Synthesized manganese(IV) oxides were characterized using Brunauer-Emmett-Teller (BET) surface area and Barrett-Joiner-Halenda porosity (BJH), X-ray diffraction (XRD), infrared spectroscopy (IR), and scanning electron microscopy (SEM). These oxides were taken for an experimental evaluation of their reactivity with sulfur mustard (HD or bis(2-Chloroethyl)sulfide), soman (GD or (3,3′- dimethylbutan-2-yl)-) and VX agent (S-[-(diisopropylamino)ethyl]-O-ethyl- methylphosphonothionate). The degree of conversion for sulfur mustard and agent VX is very good for both samples and come up to 95% and 99%, respectively. In the contrast to sulfur mustard and agent VX, degradation of soman was only 56% of the cryptomelane-type MnO 2 and 18% of the birnessite-type MnO 2. © 2012 Elsevier Inc. All rights reserved. Source

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