Publications by authors named "Martin Stastny"

The surface of nanocrystalline cerium oxide (CeO) was treated with various chemical agents by a simple postmodification method at 25 °C and atmospheric pressure. Hydrogen peroxide, ammonium persulfate, deionized water, ascorbic acid, and ortho-phosphoric acid were used in order to study and evaluate their effect on surface materials, such as surface area, crystallite size, number of surface hydroxyl groups, particle morphology, and Ce/Ce ratio. Paraoxon-methyl (PO) decomposition and inorganic phosphate adsorption were used to evaluate the effect of surface treatment on catalytic and adsorption properties.

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Ammonia is one of the most widely produced chemicals worldwide, which is consumed in the fertilizer industry and is also considered an interesting alternative in energy storage. However, common ammonia production is energy-demanding and leads to high CO emissions. Thus, the development of alternative ammonia production methods based on available raw materials (air, for example) and renewable energy sources is highly demanding.

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Two types of CeO nanoparticles (CeNPs) prepared by low-temperature (<100 °C) precipitation methods in water were successfully immobilized in a matrix of electrospun PA6 nanofibers. The colloidal solutions of CeNPs in AcOH were directly mixed with the polymer solution before the needle electrospinning process, thereby achieving their good dispersion in the nanofibers. CeNPs embedded in the structure and on the surface of nanofibers exposing their reactive surfaces showed robust dephosphorylation catalytic activity, as demonstrated by monitoring the hydrolytic cleavage of three phosphodiester molecules (-NP-TMP, -NPPC, BNPP) in water by the HPLC method.

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Nanoscale cerium-bismuth oxides/oxynitrates were prepared by a scalable low-temperature method at ambient pressure using water as the sole solvent. Solid solutions were formed up to a 1:1 Ce/Bi molar ratio, while at higher doping levels, bismuth oxynitrate photocatalysts with a pronounced layered structure were formed. Bismuth caused significant changes in the structure and surface properties of nanoceria, such as the formation of defects, oxygen-containing surface groups, and Lewis and Brønsted acid sites.

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The determination of secondary volatile degradation products in drying oil extracts is substantial to prevent formation of undesirable metal formates in paintings and/or other artefacts. This study develops a simple, cost-effective, and reliable, high-performance liquid chromatography with diode array detector (HPLC-DAD) method to determine three secondary volatile degradation products (methanol, formaldehyde, and formic acid) in drying oils, including linseed, poppy-seed, and walnut oil. Extraction of analytes was performed using QuEChERS-based procedure followed by metal oxide-based dispersive solid-phase extraction (d-SPE) clean-up and presented a good performance for all of the volatile analytes of interest with recoveries in the range of 90-120% after application of the nanostructured cerium oxide-based (CeO) and zirconia-based (ZrO) sorbents prepared by favorable and ecological-friendly methods.

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Surface catalyzed reactions can be a convenient way to deactivate toxic chemical warfare agents (CWAs) and remove them from the contaminated environment. In this study, pure titanium oxide, magnesium hydroxide, and their composites TiO/Mg(OH) were prepared by thermal decomposition and precipitation of the titanium peroxo-complex and/or magnesium nitrate in an aqueous solution. The as-prepared composites were examined by XRD, XPS, HRTEM, and nitrogen physisorption.

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A simple low-temperature water-based and one-pot synthesis was developed for the preparation of nanocrystalline CeO that was used for degradation of the toxic organophosphate pesticide parathion methyl. By changing the reaction temperature in the range from 5 °C to 95 °C, several properties (, crystallinity, grain size and surface area) of nanoceria can be easily controlled. The catalytic decomposition of parathion methyl to its degradation product 4-nitrophenol was highly dependent on the CeO preparation temperature.

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Lead carboxylates are an extensive group of compounds studied for their promising industrial applications and for their risky behavior when they are formed in oil paintings as corrosion products of lead-based pigments, leading to serious deterioration of paintings. Although the processes leading to the formation of aggregates, protrusions or inclusions, affecting undesirably the appearance of paintings, are assumed to be long term, neo-formed lead carboxylates are detectable in the early stage of paint drying. To uncover the chemical changes in lead pigments during the drying of oil paint films, model systems consisting of minium (Pb3O4) and four common drying oils were studied by X-ray powder diffraction (XRPD), 13C and 207Pb solid state NMR (ssNMR) spectroscopy and Fourier-transformed infrared spectroscopy (FTIR).

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Anthracyclines are a class of pharmaceuticals used in cancer treatment have the potential to negatively impact the environment. To study the possibilities of anthracyclines (represented by pirarubicin and valrubicin) removal, chemical inactivation using NaOH (0.01 M) and NaClO (5%) as decontamination agents and adsorption to powdered nanocrystalline titanium dioxide (TiO2) were compared.

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Cerium oxide nanoparticles were prepared by calcination of basic cerous carbonate (as a precursor) obtained by precipitation from an aqueous solution. Prepared samples were characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR), high resolution scanning electron microscopy (HRSEM), BET (Brunauer-Emmett-Teller) surface area and porosity measurement. Prepared cerium oxide was applied as a destructive sorbent for the fast and safe degradation of organophosphorus flame retardant triphenyl phosphate (TPP).

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Introduction: Macrocrystalline oxides of alkaline earth metals (Mg and Ca) or light metals (Al and Ti) can respond to standard warfare agents such as sulfur mustard, soman, or agent VX. In this paper, we compared the decontamination ability of sodium hydroxide (NaOH) and sodium hypochlorite (NaClO) for nitrogen mustards (cyclophosphamide [CP] and ifosfamide [IFOS]) with a new procedure using a destructive sorbent based on nanocrystalline and nanodispersive titanium dioxide (TiO) as a new efficient and cheap material for complete decontamination of surfaces.

Methods: Titanium (IV) dioxide nanoparticles were prepared by the homogeneous hydrolysis of titanium(IV) oxysulfate (TiOSO) with urea.

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Nanostructured titanium(IV) oxide was used for the destructive adsorption and photocatalytic degradation of mitoxantrone (MTX), a cytostatic drug from the group of anthracycline antibiotics. During adsorption on a titania dioxide surface, four degradation products of MTX, mitoxantrone dicarboxylic acid, 1,4-dihydroxy-5-((2-((2-hydroxyethyl)amino)ethyl)amino)-8-((2-(methylamino)ethyl)amino)anthracene-9,10-dione, 1,4-dihydroxy-5,8-diiminoanthracene-9,10(5H,8H)-dione and 1,4-dihydroxy-5-imino-8-(methyleneamino)anthracene-9,10(5H,8H)-dione, were identified. In the case of photocatalytic degradation, only one degradation product after 15 min at m/z 472 was identified.

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