11. Solid carriers of potentially toxic elements and their fate in stream sediments in the area affected by iron ore mining and processingSaša Kos, Nina Zupančič, Mateja Gosar, Miloš Miler, 2022, izvirni znanstveni članek Povzetek: The potential environmental impact of historical mining and ore processing on stream sediments and water was studied in a small siderite iron ore deposit with diverse sulfide mineral paragenesis. The main aim was to characterize solid carriers of potentially toxic elements (PTEs) in stream sediments and mine waste, to understand their fate in fluvial systems. General mineralogy (X-ray powder diffraction) and individual solid PTE carriers (scanning electron microscopy/energy dispersive spectroscopy) were correlated with the geochemical composition of stream sediments, mine waste, and stream waters (inductively coupled plasma mass spectrometry). Primary solid PTE carriers were pyrite, chalcopyrite, sphalerite, Hg-bearing sphalerite, galena, and siderite. Slightly alkaline and oxidizing conditions in stream water promoted the transformation of primary phases into secondary PTE carriers. Fe(Mn)-oxide/oxyhydroxides were major sinks for Pb, Zn, and As. Compared to background levels, Co (14.6 ± 2.1 mg/kg), Cu (30 ± 2.9 mg/kg), Ni (32.1 ± 2.9 mg/kg), Pb (64.5 ± 16.4 mg/kg), Zn (175.3 ± 22.5 mg/kg), As (81.1 ± 63.7 mg/kg), and Hg (2 ± 0.8 mg/kg) were elevated in mining area. Mine waste contained similar PTE carriers as stream sediments, but much higher PTE contents. Prevailingly low PTE concentrations in streams, with the exception of As (1.97 ± 2.4 µg/L) and Zn (4.5 ± 5.7 µg/L), indicate the stability of PTE carriers. Environmental effects were not significant, and additional monitoring is recommended.
Ključne besede: environmental mineralogy, environmental geochemistry, potentially toxic elements, stream sediments, solid phases, iron ore deposit, SEM/EDS
Objavljeno v DiRROS: 16.11.2022; Ogledov: 538; Prenosov: 175
 Celotno besedilo (8,07 MB) |
12. Characterization of atmospheric deposition as the only mineral matter input to ombrotrophic bogValentina Pezdir, Martin Gaberšek, Mateja Gosar, 2022, izvirni znanstveni članek Povzetek: Ombrotrophic peatlands contain a very small percentage of mineral matter that they receive exclusively from atmospheric deposition. Mineral matter deposited on the Šijec bog was characterized using scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS). We collected solid atmospheric deposition from snow, rainwater, and using passive samplers. Samples were collected at average atmospheric conditions and after two dust events. Size, morphology, and chemical composition of individual particles were determined. We distinguished four main particle groups: silicates, carbonates, organic particles, and Fe-oxyhydroxides. Silicate particles are further divided into quartz and aluminosilicates. Proportions of these groups vary between samples and between sample types. In all samples, silicate particles predominate. Samples affected by dust events are richer in solid particles. This is well observed in passive deposition samples. Carbonates and organic particles represent smaller fractions and are probably of local origin. Iron-oxyhydroxides make up a smaller, but significant part of particles and are, according to their shape and chemical composition, of both geogenic and anthropogenic origin. Estimated quantity and percentage of main groups vary throughout the year and are highly dependent on weather conditions. Dust events represent periods of increased deposition and contribute significantly to mineral matter input to peatlands.
Ključne besede: atmospheric deposition, SEM/EDS, mineral matter, peatland
Objavljeno v DiRROS: 08.09.2022; Ogledov: 548; Prenosov: 258
Celotno besedilo (3,51 MB)
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13. Unravelling the tribological behaviour of mercerized coconut inflorescence fiber fortified unsaturated polyester compositesKarthik Soundarrajan, Nitish Kaushik, C. Shanthi, Joshua Gnana Sekaran, 2022, izvirni znanstveni članek Ključne besede: coconut inflorescence fibre, unsaturated polyester resin, mercerization, wear, friction coefficient, SEM analysis
Objavljeno v DiRROS: 22.06.2022; Ogledov: 466; Prenosov: 153
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14. Celostna obravnava geokemije trdnih anorganskih delcev v urbanem okoljuMartin Gaberšek, 2020, doktorska disertacija Povzetek: Biogeokemično kroženje elementov je v urbanih okoljih zaradi velikega števila prebivalcev in njihovih različnih dejavnosti precej drugačno kot v naravnih. Zaradi kompleksnosti urbanih okolij, je pri geokemičnih raziskavah treba uporabiti celosten pristop. To pomeni, da s kombinacijo različnih metod preučujemo vsebnosti in pojavljanje potencialno strupenih elementov (PSE) v več urbanih materialih. V okviru doktorske disertacije smo na urbanem območju Maribora raziskovali tla, podstrešni, stanovanjski in cestni prah ter trdne delce nakopičene v snegu in delce v zraku. Opredelili smo lastnosti obravnavanih materialov in geokemične značilnosti Maribora ter vpeljali analizo trdnih delcev v zraku s SEM/EDS. Prevladujoč mineral v tleh je kremen (geogen vpliv), v cestnem prahu dolomit (zimsko posipanje cest) in v podstrešnem prahu sadra, ki je najverjetneje sekundarnega nastanka. Analiza vsebnosti 65 elementov v tleh in vseh treh tipih prahov je pokazala, da se ti materiali po kemični sestavi medsebojno močno razlikujejo. Prevladujoč antropogen izvor smo v vseh materialih, z izjemo stanovanjskega prahu, pripisali Cd, Cu, Pb, Sb, Sn in Zn. Dodatno so v posameznih materialih pretežno antropogenega izvora še nekateri drugi PSE. Na dveh industrijskih območjih (Melje in Tezno) so vsebnosti PSE običajno najvišje, zato predvidevamo, da so večinoma posledica pretekle in sedanje kovinske industrije. V primerjavi s tlemi, so vsebnosti PSE višje v prahovih, kar je deloma posledica razlik v njihovem nastanku in v fizikalno-kemičnih lastnostih, vpliva antropogenih virov ter različnega zadrževalnega časa materialov. Podstrešni prah odraža zgodovinske vplive, cestni prah predvsem današnje vplive industrije in prometa ter stanovanjski prah vplive znotraj stanovanj. Z analizo prahov in delcev v snegu ter zraku s SEM/EDS smo ugotovili, da izmed delcev s PSE v vseh materialih prevladujejo oglati Fe-oksidi. Samo na industrijskem območju Melje se pojavljajo Cu-Zn ostružki, ki najverjetneje izvirajo iz livarne in Fe-Cr (Cu, Mn, Ni) ostružki, najverjetneje iz tovarne kovinskega pohištva ter livarne. Za Tezno so značilni predvsem visoki deleži Fe-oksidov in kroglastih Fe-oksidov, pogosto z nizkimi vsebnostmi Mn in drugih PSE. Glede na rezultate, kemična sestava stanovanjskega prahu odraža predvsem vire znotraj stanovanj in manj zunanje vplive. Izmed notranjih virov smo najbolj jasno prepoznali uporabo vžigalnikov v stanovanjih v katerih stanovalci kadijo, kar se odraža v visokih vsebnostih Ce, Fe in La ter pojavljanju Fe-Ce-La-O kroglic. Biodostopni deleži (BAF) PSE se močno razlikujejo med različnimi elementi, vzorci in materiali. V tleh, cestnem in podstrešnem prahu so večinoma večji v želodčni fazi kot v želodčno-črevesni. Za stanovanjski prah velja obratno. Med najbolj biodostopnimi PSE v želodčni fazi so Cd, Cu, Pb in Zn, katerih povprečni BAF je pogosto nad 40 %, ter v želodčno-črevesni As, Cd, Cu in Ni.
Ključne besede: urbana geokemija, trdni delci, potencialno strupeni elementi, biodostopnost, tla, podstrešni prah, stanovanjski prah, cestni prah, SEM/EDS
Objavljeno v DiRROS: 03.03.2022; Ogledov: 1070; Prenosov: 359
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15. Towards a holistic approach to the geochemistry of solid inorganicparticles in the urban environmentMartin Gaberšek, Mateja Gosar, 2021, izvirni znanstveni članek Povzetek: Airborne particulate matter (PM) has a major impact on the biogeochemical cycles of chemical elements in theurban environment. Anthropogenic-derived PM emissions are the cause of some of the most severe environmen-tal and health problems. The presented study aims to improve our knowledge of PM dynamics by introducing amulti-media, multi-analytical and multi-elemental holistic approach to geochemical studies of inorganic PM inthe urban environment. The importance of the holistic approach is highlighted and its application in a casestudy of Maribor (Slovenia) is presented. The chemical composition and individual particulate characteristicsof street, attic and household dust were determined and compared with the characteristics of airborne PM,and PM deposited in snow, together with the chemical composition of the soil. We found that the mineralogicaland chemical composition and the individual solid particle characteristics of the studied media differ consider-ably. Nevertheless, minerals of geogenic origin are present in all media. The highest levels of potentially toxic el-ements (PTEs) in all media, except household dust, are typical for industrial areas. Street dust primarily reflectsthe influence of winter road maintenance and industrial activities, while characteristics of household dust arepredominantly influenced by indoor activities and properties of dwellings. The comparison of the chemical com-position of attic and street dust indicates that emissions of As, Cd, Pb, S and Zn were higher in the past. The char-acterisation of airborne PM and PM deposited in snow is essential for the identification of the mostrecentsourcesof PTE-bearing particles. Several industrial sources and the fate of some particle types in the environment havebeen determined based on thefindings of the SEM/EDS analyses. This study confirms that various environmentalmedia are carriers of diverse geochemical information and highlights the importance of a holistic approach ingeochemistry of PM in urban areas.
Ključne besede: Street dust, attic dust, household dust, airborne particulate matter, potentially toxic elements, SEM/EDS
Objavljeno v DiRROS: 06.01.2021; Ogledov: 1703; Prenosov: 840
Celotno besedilo (2,91 MB) |
16. Effects of a mixed O/F ligand in the Tavorite-type LiVPO[sub]4O structureSorour Semsari Parapari, Jean-Marcel Ateba Mba, Elena Tchernychova, Gregor Mali, Iztok Arčon, Gregor Kapun, Mehmet Ali Gülgün, Robert Dominko, 2020, izvirni znanstveni članek Ključne besede: XRD, SEM, V XANES, Tavorite-type, electrochemical properties
Objavljeno v DiRROS: 25.11.2020; Ogledov: 1614; Prenosov: 893
Celotno besedilo (3,10 MB)
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17. Synthesis and advanced electrochemical characterization of multifunctional electrocatalytic composite for unitized regenerative fuel cellLeonard Moriau, Marjan Bele, Alen Vižintin, Francisco Ruiz-Zepeda, Urša Petek, Primož Jovanovič, Martin Šala, Miran Gaberšček, Nejc Hodnik, 2019, izvirni znanstveni članek Ključne besede: electrocatalysis, bifunctional electrocatalysts, oxygen evolution reaction, oxygen reduction reaction, IL-TEM, IL-SEM, EFC-ICP-MS
Objavljeno v DiRROS: 24.11.2020; Ogledov: 1449; Prenosov: 984
Celotno besedilo (3,51 MB)
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