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Wyszukujesz frazę "Lanthanum" wg kryterium: Temat

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    Wyświetlanie 1-5 z 5
    Tytuł:
    Properties and activity of the cobalt catalysts for NH3 &enspsynthesis obtained by co-precipitation – the effect of lanthanum addition
    Autorzy:
    Zybert, M.
    Karasińska, M.
    Truszkiewicz, E.
    Mierzwa, B.
    Raróg-Pilecka, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/778653.pdf
    Data publikacji:
    2015
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    ammonia synthesis
    cobalt catalyst
    promoter
    lanthanum
    coprecipitation
    Opis:
    In modern research on catalysts for NH3&enspsynthesis a lot of attention is paid to cobalt. In this work the new catalytic systems based on cobalt are presented. Unsupported cobalt catalysts singly promoted (La or Ba) and doubly promoted (La and Ba) were prepared and tested in NH3&enspsynthesis reaction under commercial synthesis conditions. Characterization studies revealed that lanthanum plays a role of a structural promoter, which improves the surface of catalyst precursors and prevents from sintering during calcination. However, lanthanum has a negative effect on the reduction of cobalt oxide, but the addition of barium promoter (Co/La/Ba catalyst) diminishes the negative impact of La. The co-promotion of cobalt with lanthanum and barium results in the increasing of the active phase surface and improvement of its activity in NH3&enspsynthesis.
    Źródło:
    Polish Journal of Chemical Technology; 2015, 17, 1; 138-143
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Cobalt-lanthanum catalyst precursors for ammonia synthesis: determination of calcination temperature and storage conditions
    Autorzy:
    Zybert, M.
    Tarka, A.
    Mierzwa, B.
    Raróg-Pilecka, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/778044.pdf
    Data publikacji:
    2017
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    ammonia synthesis
    catalyst precursor
    cobalt
    lanthanum
    thermal analysis
    Opis:
    A thermal decomposition of a cobalt-lanthanum catalyst precursor containing a mixture of cobalt and lanthanum compounds obtained by co-precipitation were studied using thermal analysis coupled with mass spectrometry (TG-MS). Studies revealed that the calcination in air at 500°C is sufficient to transform the obtained cobalt precipitate into Co3 O4 , but it leads to only partial decomposition of lanthanum precipitate. In order to obtain Co/La catalyst precursor containing La2 O3  the calcination in air at the temperature about 800°C is required. However, it is unfavorable from the point of view of textural properties of the catalyst precursor. A strong effect of storage conditions on the phase composition of the studied cobalt-lanthanum catalyst precursor, caused by the formation of lanthanum hydroxide and lanthanum carbonates from La2 O3  when contacting with air, was observed.
    Źródło:
    Polish Journal of Chemical Technology; 2017, 19, 2; 61-66
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Lantan i cer w glebach Polski
    Autorzy:
    Kwecko, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/2074972.pdf
    Data publikacji:
    2012
    Wydawca:
    Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
    Tematy:
    lanthanum
    cerium
    REE
    soils
    Polska
    lantan
    cer
    gleby
    Polska
    Opis:
    The paper present basic spatial analysis lanthanum and cerium distribution in Poland soils. Attempted to determine geochemical background and range and intensity of enrichment and anomalies La and Ce content in top (0–0,2 m) and bottom (0,5–2 m) soils. These data are presented in the form two color maps of polygonal with basic statistic information. The text part describes the main areas of enrichment and attempts to indicate the source of these values.
    Źródło:
    Przegląd Geologiczny; 2012, 60, 9; 490--495
    0033-2151
    Pojawia się w:
    Przegląd Geologiczny
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Behavioral and Lethal Effects of La Salt and a Mixture of Cu and La Salt on Daphnia magna Straus
    Autorzy:
    Olkova, Anna Sergeewna
    Sysolyatina, Maria
    Powiązania:
    https://bibliotekanauki.pl/articles/2105282.pdf
    Data publikacji:
    2022
    Wydawca:
    Polskie Towarzystwo Inżynierii Ekologicznej
    Tematy:
    lanthanum
    copper
    bioassay
    Daphnia magna
    motor activity
    joint effect
    synergism
    potentiation
    Opis:
    The study of joint effects of REE and HM is relevant, since they are often satellite deposits, their areas of application are similar, and an increase in concentrations of elements of these groups in the areas that are not places of their extraction and enrichment is proven. The purpose of this work was to find out the pre-lethal and lethal effects of La, Cu and their equimolar mixtures in tests for Daphnia magna Straus. Bioassays of artificially polluted natural waters, initially free of toxic elements, was carried out. In bioassays on the mortality of D. magna in the space of 96 hours it was found that acute toxicity of copper sulfate solutions is observed at the calculated concentration of Cu2+ 0.1 mg/L (0.0016 mmol/L), and the acute toxicity of lanthanum sulfate is when the dose of La3+ is equal to 50 mg/L (0.36 mmol/L). In the solutions comprising mixtures of Cu and La salts (1:1 calculated using metals), the concentrations of which are equimolar to the investigated solutions of copper sulfate, the mortality of D. magna begins in the solution containing 10 times less toxic elements. It was found that 25% of individuals died in the variant “0.00016 mmol/L”, the mortality of 100% of individuals was at the total metal concentration of 0.0008 mmol/L. The solutions containing La (0.072–0.72 mmol/L) and Cu (0.00016–0.0016 mmol/L) naturally inhibit the motor activity of D. magna by 1.3–5.3 times and 1.2–1.9 times in 1 hour and 1.7–2.8 and 1.4–2.2 times in 24 hours, respectively. The solutions containing mixtures of Cu and La salts inhibited the motor activity of D. magna in the same way as copper sulfate solutions with the Cu2+ concentrations equimolar “Cu2+ + La3+”. Therefore, when testing the solutions with the same molar concentrations of Cu2+ and the mixture of “Cu2+ + La3+” it was shown that La potentiates the pre-lethal effect of Cu to the level of individual effects of Cu. The additions of La salt to the solutions containing pre-lethal doses of Cu lead to lethal effects of such mixtures for D. magna.
    Źródło:
    Journal of Ecological Engineering; 2022, 23, 6; 245--252
    2299-8993
    Pojawia się w:
    Journal of Ecological Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Comparison of Sensitivity of Autotrophic and Heterotrophic Microorganisms to the Pollution of Natural Water with Rare Earth Elements (Lanthanum and Cerium)
    Autorzy:
    Lozhkina, Roza A.
    Olkova, Anna S.
    Koval, Ekaterina V.
    Tomilina, Irina I.
    Sysolyatina, Maria A.
    Powiązania:
    https://bibliotekanauki.pl/articles/2086379.pdf
    Data publikacji:
    2022
    Wydawca:
    Polskie Towarzystwo Inżynierii Ekologicznej
    Tematy:
    rare earth elements
    lanthanum
    cerium
    bioassay
    Nostoc linckia
    Chlorella vulgaris
    Paramecium caudatum
    Escherichia coli
    Opis:
    The purpose of the work was to compare the sensitivity of autotrophic and heterotrophic organisms used in bioassay to lanthanum and cerium under the conditions of a model experiment with aqueous media. Using bioassay methods, the pre-lethal effects of La and Ce in heterotrophic Paramecium caudatum and Escherichia coli, as well as autotrophic Chlorella vulgaris and Nostoc linckia were determined. Model solutions of La2 (SO4)3∙8H2O and Ce2 (SO4)3∙8H2O were tested in the concentration range of 0.1–200 mg/l. As a result, it was shown that heterotrophic organisms are more sensitive to water pollution with La and Ce than autotrophic ones. According to the totality of experiments, cerium turned out to be more toxic than lanthanum. When planning the environmental studies of wastewater or reservoirs polluted with REE, it is recommended to focus on comparative sensitivity of bioassay methods, taking into account the test-functions used: bioassay for chemotaxis of P. caudatum > bioassay for changes in bioluminescence of E. coli (strain M-17) > bioassay for the content of chlorophyll а and intensity of lipid peroxidation in N. linckia > bioassay on the increase in the number of Cl. vulgaris.
    Źródło:
    Journal of Ecological Engineering; 2022, 23, 4; 58--63
    2299-8993
    Pojawia się w:
    Journal of Ecological Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-5 z 5

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