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    Wyświetlanie 1-4 z 4
    Tytuł:
    Department of Mineralogy, Petrography and Geochemistry
    Autorzy:
    Matusik, J.
    Rzepa, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/184452.pdf
    Data publikacji:
    2016
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    chemistry
    rock
    origin
    Źródło:
    Geology, Geophysics and Environment; 2016, 42, 2; 218-222
    2299-8004
    2353-0790
    Pojawia się w:
    Geology, Geophysics and Environment
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Manganese oxides from Zalas, Kraków area, southern Poland
    Autorzy:
    Polak, M.
    Gołębiowska, B.
    Rzepa, G.
    Powiązania:
    https://bibliotekanauki.pl/articles/184692.pdf
    Data publikacji:
    2016
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    intrusion
    volcanic rock
    limestone
    Opis:
    The Zalas quarry is located in the southern, marginal part of the Silesian-Cracovian Monocline. Permian rhyodacite laccolith has been exploited here for over 70 years. The intrusion was formed about 260–280 Ma during the Early Permian transtensional, sinistral tectonic regime predominating in central Europe at that time (Nawrocki et al. 2005). Permian volcanic rocks are overlain by a Middle–Upper Jurassic sedimentary sequence, built from sands and sandstones, substituted with the passing of time by limestones and sandy limestones rich in fossils (Matyszkiewicz et al. 2006). Quarrying operations carried out approximately 10 years ago uncovered a fault zone cutting the Middle Jurassic sandy limestones. Exposed breccias was locally encrusted by a hydrothermal mineralization forming thin veinlets cutting the limestone, or surrounding the breccia clasts. Primary mineralization contained small relics of pyrite, chalcopyrite, chalcocite, galena, native bismuth and barite and was significantly replaced by supergene minerals e.g. Fe and Mn oxides, malachite, cuprite, Cu sulphates, iodargyrite, Bi oxychlorides and Na, K chlorides (Gołębiowska et al. 2006, 2010, 2015). The mineralization is most likely connected with rejuvenation of Early-Paleozoic fault zones during the Sava phase of the Alpine orogeny, and subsequent intensive weathering under semi-arid and arid climate in a period between the Oligocene and Middle Miocene (Gołębiowska et al. 2010). In the sandy limestone encrusted by the oxidized mineralization, very interesting Mn-oxides, enriched in numerous heavy metals were encountered. They filled small fractures and voids within the fault breccia. Among them, Tl-rich varieties have been recently reported. Extremely high thallium content, reaching 20.82 wt% Tl 2 O, makes the oxides unique on a world scale (Gołębiowska et al. 2015). In this paper we focused on the variable admixtures in Mn oxides from oxidation zone in Zalas; for this purpose, SEM-EDS and WDS analyses were carried out. Mn oxides in Zalas are accompanied by malachite, Fe oxides (goethite and hematite) and relics of primary mineralization (Matyszkiewicz et al. 2015). Mn and Fe oxides commonly form the yellowish to red-brownish or black tiny grains or cryptocrystalline aggregates with sizes up to a few millimetres across. Manganese oxides contain variable admixtures of Cu, Ca, Pb, Ba, Fe, Ni, Co and Tl. On the basis of chemical analyses, three major Mn oxide types have been distinguished: those enriched in (i) Ni and Co, (ii) Pb and (iii) Ba and Ca. Co-Ni-bearing Mn oxides, probably asbolane-type, contain 17.01–21.58 wt% CoO and 3.05–8.33 wt% NiO. These phases contain also admixtures of Cu (up to 10 wt% CuO) and Al (up to 7 wt% of Al 2 O 3 ), as well as traces of Fe, Ba, Zn, Mg and Tl (up to 0.5 wt%). Interestingly, in Mn oxides of this type, the admixtures of lead are absent. Pb-bearing Mn oxide, probably coronadite, contain up to 21.48 wt% PbO. In its composition various other elements were also noticed: up to 2 wt% CoO, 0.4 wt% NiO and very high concentrations of CuO up to 8 wt%, as well as up to 1 wt% BaO, FeO, CaO Tl 2 O, Al 2 O 3 and traces of Zn and Mg. Chemical mapping indicates that the Ba- or Ca-bearing Mn oxides occur only in marginal parts of zoned MnO 2 aggregates with almost pure MnO 2 in their cores. They contain 78–84 wt% MnO 2, 3–10 wt% BaO and 2.5–4.5 wt% CaO. High contents of Co, Ni, Pb, Cu and Tl in Mn oxides from Zalas indicate a direct link with the primary ore assemblage. High concentration of cobalt and nickel might suggest some connection with Co and Ni mineralization known from nearby Karniowice Travertine (Czerny 1992). Mineral association, as well as crystal morphologies and sizes could indicate hydrothermal origin of at least part of the Mn oxides. However, identification of the particular minerals as well as concluding on the details of their origin is quite difficult on this stage of research.
    Źródło:
    Geology, Geophysics and Environment; 2016, 42, 1; 120-121
    2299-8004
    2353-0790
    Pojawia się w:
    Geology, Geophysics and Environment
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Tlenki manganu z diabazów Niedźwiedziej Góry koło Krakowa
    Manganese oxides from the diabases of Niedźwiedzia Góra near Kraków
    Autorzy:
    Muszyński, M.
    Rzepa, G.
    Skowroński, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/183889.pdf
    Data publikacji:
    2009
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    dolny perm
    Niedźwiedzia Góra
    diabazy
    żyły epitermalne
    rancieit-takanelit
    Lower Permian
    diabases
    epithermal veins
    Opis:
    Czarne tlenki manganu z polimineralnych żył napotkanych w 1998 r. w tzw. diabazach z Niedźwiedziej Góry koło Krakowa zidentyfikowano (XRD, IR, DTA-TG, SEM/EDS, EPMA/WDS) jako człony pośrednie szeregu rancieit-takanelit. W porównaniu z opisanymi w literaturze minerałami tego szeregu charakteryzują się podwyższonymi koncentracjami żelaza i baru oraz stosunkowo niewielkimi udziałami wapnia. W przypuszczalnej sukcesji składników powyższych żył tlenki te zajmują przedostatnią pozycję: goethyt +/- saponit - tensja - baryt, kwarc pręcikowo-igłowy - ługowanie - tlenki Mn, kwarc słupkowy. Wykrystalizowały prawdopodobnie z wód descenzyjnych związanych z powierzchniowym wietrzeniem diabazów, które miało miejsce po zerodowaniu nadległych skał karbonu. Głównym źródłem manganu były zapewne wietrzejące diabazy.
    Black manganese oxides from the polymineral veins found in 1998 in the so-called diabases of Niedźwiedzia Góra near Kraków have been identified (XRD, IR, DTA-TG, SEM/EDS, EPMA/WDS) as intermediate members of the rancieite-takanelite series. In comparison with the minerals of this series described in the literature, they reveal elevated contents of iron and barium and relatively low contents of calcium. In the probable succession of components of the veins mentioned, the Mn oxides occupy the before last position: goethite +/- saponite - tension - barite, thin prismatic-acicular quartz - leaching - Mn oxides, prismatic quartz. They must have crystallized from descensive waters associated with surface weathering of the diabases, which took place when overlaying Carboniferous rocks had been eroded. The weathering diabases were a probable source of manganese.
    Źródło:
    Geologia / Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie; 2009, 35, 2; 135-151
    0138-0974
    Pojawia się w:
    Geologia / Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Arsenic interactions with bog iron ores – As(III) and As(V) adsorption-desorption study
    Autorzy:
    Tuchowska, M.
    Bajda, T.
    Rzepa, G.
    Dębiec, K.
    Drewniak, Ł.
    Powiązania:
    https://bibliotekanauki.pl/articles/184786.pdf
    Data publikacji:
    2016
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    environment
    ground water
    toxicology
    Opis:
    Arsenic is a toxic element, elevated concentration of which in the environment can result from both anthropogenic activity and natural geochemical processes. The contamination of water, especially groundwater, with As has been recognized as a major environmental problem (Choong et al. 2007). The mobility and toxicology of As is related to its valence state which can be (+III) or (+V), depending mainly on pH and redox conditions. Because even low As concentrations in drinking water causes severe health effects, the technologies of its effective removal are thought to be very important (Mohan & Pittman 2007). Among many methods developed for removing aqueous arsenic species, the adsorption onto iron oxyhydroxides or oxyhydroxide-rich sorbents is one of the most effective. Despite many studies, the factors affecting the adsorption processes, especially those related to the sorbent properties, are still far from being fully understood (e.g. Adra et al. 2016). In this work we investigated As(III) and As(V) adsorption and desorption by bog iron ores – natural ferruginous sediments which have been recently demonstrated to exhibit very good sorption properties. For this study four samples of bog iron ores, were collected at different sites in the Polish Lowlands: Kolechowice (KOL), Biadaszki (BD), Strzyżew (ST) and Dębe Małe (DM). They represent different bog iron ore types which, in spite of having diversified structures, mineral composition and, subsequently, physical and chemical properties, revealed good sorption affinities for trace elements in previous work (Rzepa et al. 2009). In batch experiments the influence of various factors on adsorption were studied, including initial As concentrations, initial pH values and competitive adsorption of As(III) and As(V). The effect of initial As concentrations was studied in the range of 0.01–20 mM As(III) or As(V) at pH 7.5. The influence of pH was evaluated by the adsorption of 5 mM As solution in the pH range of 2–12. The experiment of competitive adsorption of arsenite and arsenate was performed for various proportion of As(III) to As(V) in the range of initial concentrations 0.025–20 mM at pH 7.5. The bonding strength of As with bog iron ore surface was estimated on the basis of three-step desorption experiments, which were conducted for the samples previously treated with As(III) or As(V) at pH 7.5 and at constant 20 mM initial concentration of arsenic. Arsenic concentrations in filtered (filter with a 0.22 μm pore size) solutions after all the experiments were analyzed using AAS and UV-Vis spectrophotometry. The results showed that arsenic sorption depends on its oxidation state. All the bog iron ores bound more As(III) than As(V). The highest amount of As(III) was sorbed by ST sample (458 mmol/kg), lower by KOL (430 mmol/kg) and DM (427 mmol/kg), and the lowest by BD (333 mmol/kg). However, in the case of As(V), the order was different: the highest amount of As was sorbed by BD sample (264 mmol/kg), lower by ST (218 mmol/kg), and the lowest by DM (163 mmol/kg) and KOL (158 mmol/kg). The highest uptake (80–95%) of As(III) was noted at lower initial concentrations, while the highest uptake (60–70%) of As(V) was observed at higher initial concentrations. As(III) sorption effectiveness was >80% throughout the pH range of 4 to 9 and was almost independent on pH in that range. In contrast, the As(V) sorption was higher at slightly acidic pH and significantly decreased in alkaline conditions. At pH around 3, sorption efficiency of both As(III) and As(V) decreased, which is likely due to the increased solubility of iron oxyhydroxides (Zeng, 2004). The results of competitive sorption experiments revealed that at low concentrations of both As species reduction of sorption efficiency of As(III) occurred. Sorption of As(V) was also affected, but only if amount of As(III) was higher than As(V). On the contrary, at high As(V) and As(III) concentrations, As(V) did not influence As(III) sorption, but As(III) substantially increased sorption of As(V). Desorption of arsenic by foreign ligands resulted in extraction of more than 70% of absorbed As(III) and As(V). In the absence of the exchange ligand, i.e., in deionized water, desorption of As(V) and As(III) was considerably lower, but noticeable. This study shows that bog iron ores are very good arsenic sorbents. However, the extent of As removal seems to be affected by various factors including As species and the composition of the ores themselves. As(V) is immobilized less effectively than As(III), and the process is influenced by pH values. It is believed, that the uptake of As by bog ores is controlled primarily by iron oxyhydroxides, as main components of these rocks, but mechanisms predominant in As(III) and As(V) adsorption are different and affected by presence of e.g. phosphate and silicate ions (Ociński et al. 2011). There are no simple correlations between mineralogy and sorption capacity. Due to the variability in chemical and mineral composition of different types of bog iron ores, various levels of arsenic removal can be obtained. Such properties of the ores, combined with their ubiquity in many near-surface environments may be regarded as an incentive for the environmental protection practice.
    Źródło:
    Geology, Geophysics and Environment; 2016, 42, 1; 133-134
    2299-8004
    2353-0790
    Pojawia się w:
    Geology, Geophysics and Environment
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-4 z 4

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