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The magnetic solid phase extraction as advanced and rapid method for isolation of hydrocarbons from water before analytical detection
Komárek, K. ; Kandelová, M. ; Šafaříková, Miroslava ; Šafařík, Ivo
For existing methods for isolation and pre-concentration of hydrocarbons from aqueous phase, new process based on the magnetic solid phase extraction (MSPE) was proposed. By this way the magnetic sorbent is added into the water sample and the suspension is mixed for some little time. The sorbent with hydrocarbons is separated from aqueous phase using magnetic field. Hydrocarbons from the separated sorbent are eluted by small amount of solvent. The magnetic sorbent is isolated using magnetic field and acquired extract is applied to gas-liquid chromatography analysis. The optimal conditions for each sorbents have to be found for the individual steps of MSPE. The study is focused on the mix of aliphatic hydrocarbons (C10 – C13) and avgas. Magnetically modified activated carbon Chezacarb B was used as sorbent.
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Dynamic Control of Hydrogenation Process in Trickle Bed Reactor
Hanika, Jiří
Periodic modulation of trickle bed reactor control parameters represents a new approach to the technology which enables higher reactor throughput and more safe operation of trickle bed reactor for exothermal reaction. Knowledge can be utilized for intensification of hydrogenation processes, e.g. hydrorefining of pyrolysis gasoline.
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Dynamics of Earth gases emissions in Czechia
Kroufek, J. ; Stejskal, M. ; Šebor, G. ; Mrlina, Jan ; Tesař, J. ; Suchý, V. ; Zeman, A.
A monitoring of the Earth gases emissions was carried out at selected sites in Cechia. Particularly, methan, CO2, SO2, Rn a H2S were investigated. It was proved that neither the chemical composition, nor the emissions themselves can be considered as permanent. They may be affected by geological processes including earthquakes, as well as by man-made activities.
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Problems with recycling of lithium from unusable batteries
Brožek, Vlastimil ; Dufek, V. ; Němečková-Hrnčířová, M.
The article describes critical stage of LIB recycling, that is, safe opening of the batteries to permit subsequent thermal treatment. LIB contain volatile, toxic and explosive components in hermetically sealed metallic or glassy containers. In LIB electrolytes such as Li-MH, Li /CF Li/SO2, Li-ion or Li-ion-polymer, and also Li-MnO2, Li-SOCl2, Li2FeS2 and Lipon (lithium and phosphorus oxide-nitride), the following compounds can be identified: polypropylen carbonate, ethylen carbonate, dimetoxyethane, various glykol esthers, lithium perchlorate or lithium fluoride-phosphate solutions. These can increase the risk of explosion when heated. Most of LIB producers do not disclose the composition; thus, every new type of battery is a specific item, from the cleanup point of view. The positive information about less flammable or non-toxic components of new LIB types, such as fluorated aryles, polyacryl-nitryl gels or phosphorus chelatocomplexes, do not make the recycling issues easier.
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Treatment of tungsten carbide in low temperature plasma
Brožek, Vlastimil ; Matějíček, Jiří ; Neufuss, Karel
Tungsten carbide powder was thermally processed in a water stabilized plasma, using the WSP plasma torch developed in the Institute of Plasma Physics, where the plasma temperatures can reach 30 000 K at the nozzle exit. Oxidation of the molten carbide was suppressed by a nitrogen atmosphere during deposition on substrates positioned immediately above liquid nitrogen level. Analyses of both the deposits and spheroidized particles in the 5 – 63 μm size range determined the W:W2C:WC ratios and mechanical properties.
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Photocatalytic aktivity of plasma treated titanium precursors
Brožek, Vlastimil ; Matějíček, Jiří ; Šrank, Z. ; Mastný, L. ; Janča, J.
Photoactive solid parts of chemical reactors could be produced via plasma deposition of boron carbide and titanium diboride using water-stabilized plasma torch WSP. Photocatalytic effectivity of TiC and TiB2 was measured, as well as those of their oxidation products gained at 450 and 1000°C on air as well as at 450°C in oxygen plasma. Photocatalytic effectivity of all studied substances was compared with those of plasma- treated TiO2 and Ti2O3, whose photocatalytic activity is known from plenty of practical applications.
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