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Determination of bioavailable Fe redox fractions of sediment pore waters by DGT passive sampling and BDS detection
Hanna Budasheva, Dorota Korte, Arne Bratkič, Mladen Franko, 2019, objavljeni povzetek znanstvenega prispevka na konferenci

Opis: The bioavailability and toxicity of contaminants in sediments to benthic organisms depend on the speciation of the contaminant [1]. The level of iron supply to sediments creates contrasting chemical pathways, each producing distinctive mineral assemblag- es. Reliable measurement of Fe redox species (Fe2+ and Fe3+) in sediments is essential for studies of pollutants or trace-element cycling. This is, however, a difficult task, because the distribution of chemical species often changes during sampling and storage. In this work the Diffusive Gradients in Thin-films technique (DGT) is investigated as a passive sampling approach used in combination with photothermal beam deflection spectroscopy (BDS) as a detection method for determination of labile Fe-redox species in sediments and natural waters. DGT offers the advantage of pre-concentration of labile (i.e. bioavailable) Fe species from the total dissolved Fe pool in sediment pore waters [2]. The advantage of using BDS [3-4] is also in avoiding contamination by using additional steps as extraction or pre-concentration. Furthermore, combined DGT-BDS provides 2D information about distribution of Fe2+ and the total Fe content in the resin hydrogels [5]. The goal of this research is to show the repeatability of this technique for determining trace amounts of Fe redox species in environmental samples.
Ključne besede: beam deflection spectrometry, diffusive gradients in thin-films, iron species
Objavljeno v RUNG: 16.07.2019; Ogledov: 3512; Prenosov: 0
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Transparent titania-zirconia thin films for self-cleaning and photocatalytic application
Nives Vodišek, Kandalam Ramanujachary, Vlasta Brezová, Urška Lavrenčič Štangar, 2016, objavljeni povzetek znanstvenega prispevka na konferenci

Opis: Thin films were prepared by sol-gel process, where different amount of zirconia were added to titania. Photocatalytic activity of thin films was measured by two methods i) determination of degradation ration of methyl stearate with measuring the contact angle and ii) formation of hydroxyterephthalic acid was measured by spectrofluorometer. Prepared samples were characterized by UV-Vis spectrophotometer, SEM, XRD, FT-IR ATR, and BET. The result of measurements of photocatalytic activity shows that the highest activity has a sample without addition of zirconia, but mechanical stability of that sample is worse.
Ključne besede: photocatalysis, ZrO2/ TiO2, thin films, self-cleaning, low-temperature, sol-gel process
Objavljeno v RUNG: 14.03.2017; Ogledov: 5190; Prenosov: 203
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Transparent titania-zirconia-silica thin films for self-cleaning and photocatalytic applications
Nives Vodišek, Kandalam Ramanujachary, Vlasta Brezova, Urška Lavrenčič Štangar, 2017, objavljeni znanstveni prispevek na konferenci

Ključne besede: TiO2, ZrO2, thin films, photocatalysis, mechanical stability
Objavljeno v RUNG: 13.03.2017; Ogledov: 5139; Prenosov: 5
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Solar-driven photocatalytic treatment of diclofenac using immobilized TiO2-based zeolite composites
Marin Kovacic, Subhan Salaeh, Hrvoje Kušić, Andraz Suligoj, Marko Kete, Mattia Fanetti, Urška Lavrenčič Štangar, Dionysios D. Dionysiou, Ana Lončarić Božić, 2016, izvirni znanstveni članek

Opis: The study is aimed at evaluating the potential of immobilized TiO2-based zeolite composite for solar-driven photocatalytic water treatment. In that purpose, TiO2-iron-exchanged zeolite (FeZ) composite was prepared using commercial Aeroxide TiO2 P25 and iron-exchanged zeolite of ZSM5 type, FeZ. The activity of TiO2-FeZ, immobilized on glass support, was evaluated under solar irradiation for removal of diclofenac (DCF) in water. TiO2-FeZ immobilized in a form of thin film was characterized for its morphology, structure, and composition using scanning electron microscopy/energydispersive x-ray spectroscopy (SEM/EDX). Diffuse reflectance spectroscopy (DRS) was used to determine potential changes in band gaps of prepared TiO2-FeZ in comparison to pure TiO2. The influence of pH, concentration of hydrogen peroxide, FeZ wt% within the composite, and photocatalyst dosage on DCF removal and conversion efficiency by solar/ TiO2-FeZ/H2O2 process was investigated. TiO2-FeZ demonstrated higher photocatalytic activity than pure TiO2 under solar irradiation in acidic conditions and presence of H2O2.
Ključne besede: Photocatalysis, Thin films, TiO2-FeZ, Solar irradiation, Diclofenac, Water Treatment
Objavljeno v RUNG: 22.07.2016; Ogledov: 6227; Prenosov: 0
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