2004

Štengl, V.; Bakardjieva, S.; Maříková, M.; Šubrt, J.; Opluštil, F.; Olšanská, M., Aerogel nanoscale magnesium oxides as a destructive sorbent for toxic chemical agents. Central European Journal of Chemistry 2004, 2 (1), 16-33

Abstract: An autoclave hypercritical drying procedure has been used to prepare precursors of MgO from Mg(OCH3)2. This material was prepared with a specific surface area of 1200 m2g-1. The dehydrated materials consisted of much smaller crystallites than conventionally prepared MgO and were free of OCH3 groups. The precursors and samples of magnesium oxide were taken for experimental evaluation of their reactivity with mustard. The largest percentage of the conversion mustard into non-toxic products after the elapse of the reaction was 77%. Link

Štengl, V.; Šubrt, J., Power ultrasound and its applications. Chemicke Listy 2004, 98 (6), 324-327

Abstract: The power ultrasonic device described consists of an electric power ultrasound source (generator) and an electroacoustic transducer with a mechanical transformer (sonicator). The generator operates at the frequency 25 kHz and enables transfer of power up to 300 kW into a piezoelectric transducer. The changes in acoustic loading of the medium into which the sonicator emits are compensated by feedback. The device can be used in applications utilizing the cavitation process in liquids, e.g. degassing of liquids, water treatment (sterilization) in swimming pools, laboratory preparation of sonogels, initiation and acceleration of organic reactions. In modifications of technologies, the device can be used for delamination of tabular minerals (mica, specularite), for dispersing of pigments in a solvent and, after impedance adjustment, for milling of powdery materials. Link

Krýsa, J.; Keppert, M.; Jirkovský, J.; Štengl, V.; Šubrt, J., The effect of thermal treatment on the properties of TiO2 photocatalyst. Materials Chemistry and Physics 2004, 86 (2-3), 333-339.

Abstract: Two new types of TiO2 photocatalysts were synthesised by precipitation from titanylsulphate solution by urea and compared with the commercial photocatalyst TiO2 P25 (Degussa). The photocatalysts were thermally treated at 300, 600 and 900 °C and characterised by X-ray diffraction, specific surface area and pore distribution analyses, and scanning electron microscopy. New photocatalysts exhibit a rather large surface area (300 m3 g−1) and small particle size (3–4 nm), and consist of round agglomerates (1–2 μm). Their photoactivity (degradation of oxalic acid and 4-chlorophenol) reached only about 60% of that of TiO2 P25 although they had a six times higher specific surface area. The possible reason could be a more efficient charge recombination in smaller TiO2 particles. Link

Kalenda, P.; Kalendova, A.; Štengl, V.; Antoš, P.; Šubrt, J.; Kváča, Z.; Bakardjieva, S., Properties of surface-treated mica in anticorrosive coatings. Progress in Organic Coatings 2004, 49 (2), 137-145.

Abstract: The paper deals with using lamellar mica pigments for anticorrosive barrier coatings. By depositing a ferric oxide layer on a muscovite particle a novel pigment is obtained. The use of these pigments in coatings improves the mechanical properties and the resistance to UV radiation. The pigment acts as an active barrier. Link

Bakardjieva, S.; Šubrt, J.; Štengl, V.; Opluštil, F.; Olšanská, M., Magnesium oxide nanoparticles as destructive sorbent for toxic agents. Microscopy and Microanalysis 2004, 10 (Supplement 2), 476-477.