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1.
Validacija metode za določanje bisfenola A v izcedni vodi s tekočinsko kromatografijo visoke zmogljivosti
Nina Plantan, 2012, diplomsko delo

Najdeno v: osebi
Ključne besede: bisfenol A, tekočinska kromatografija, HPLC, izcedne vode, diplomske naloge
Objavljeno: 15.10.2013; Ogledov: 2968; Prenosov: 647
URL Polno besedilo (0,00 KB)
Gradivo ima več datotek! Več...

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Strupenost in estrogenost bisfenola A pred in po mokri oksidaciji
Jana Krautberger, 2011, diplomsko delo

Najdeno v: osebi
Ključne besede: bisfenol A, mokra oksidacija, heterogena kataliza, strupenost, estrogenost, diplomske naloge
Objavljeno: 15.10.2013; Ogledov: 2700; Prenosov: 316
URL Polno besedilo (0,00 KB)
Gradivo ima več datotek! Več...

4.
Hidrotermalna sinteza in strukturna karakterizacija svežih ter toplotno obdelanih titanatnih nanocevk
Veronika Rihar, 2014, diplomsko delo

Najdeno v: osebi
Ključne besede: struktura snovi, nanostrukture, sdsorbcija, materiali, sinteza, eksperimentalne metode, analize, diplomske naloge
Objavljeno: 19.02.2015; Ogledov: 1879; Prenosov: 216
.pdf Polno besedilo (2,01 MB)
Gradivo ima več datotek! Več...

5.
HETEROGENEOUS PHOTOCATALYTIC OXIDATION FOR THE REMOVAL OF BISPHENOL A FROM AQUEOUS SOLUTION OVER TiO2/GRAPHENE OXIDE (GO) BASED NANOCOMPOSITES
Ana Veternik, 2017, magistrsko delo

Opis: Since water is an essential substance for all life on earth, it is therefore vital to prevent its pollution and to improve wastewater purification processes. There is a vast number of pollutants which can contaminate water, of which bisphenol A (known as an endocrine disruptor) is the pollutant studied herein. In this study, several TiO2/GO based nanocomposites with various GO loadings (2, 4, 10, 20 and 40%) and differently shaped nanocrystalline TiO2 phases (titanate nanotubes (TNTs) and calcined titanate nanotubes (TNTs_500)) were synthesised. All of the nanocomposites were characterised through SEM, UV-vis-DR, TGA, BET, FT-IR and CHNS analyses and were used in the heterogeneous photocatalytic degradation of bisphenol A and compared to the activity of pure TNTs and TNT_500 photocatalysts. All TiO2/GO nanocomposites exhibit much better activity than pure TNTs and TNTs_500 catalysts. The conversion of the BPA was analysed using HPLC and the mineralisation was analysed using a TOC analysis. The best experiment was performed with TNTs_500 + 10% GO composite, which can be attributed to the TiO2 crystalline structure obtained. According to the results obtained, TiO2 + 10% GO was found to exhibit the best degradation ratio, which can be ascribed to the fact that excessive GO can act as a charge carrier recombination centre and promotes the recombination of electron-hole pairs in reduced GO.
Najdeno v: osebi
Ključne besede: heterogeneous photocatalysis, titanium dioxide, graphene oxide, bisphenol A
Objavljeno: 23.02.2017; Ogledov: 1892; Prenosov: 185
.pdf Polno besedilo (2,96 MB)

6.
Operando XAS analysis of CuO/SiO2 and CuO/CeO2 catalysts
Albin Pintar, Maxim Zabilsky, Petar Djinović, Janvit Teržan, Iztok Arčon, 2018, objavljeni povzetek znanstvenega prispevka na konferenci

Opis: The possibilities of the operando XAS analysis of catalysts will be presented on two case studies of promising new catalytic materials: alkali doped nano-dispersed copper oxide clusters on ordered mesoporous SiO2, which is highly active and selective towards propylene epoxidation [1], and nanoshaped CuO/CeO2 catalysts used in N2O decomposition reaction [2]. Operando Cu K-edge and Ce L3-edge XANES and EXAFS analysis was performed during catalytic reactions under controlled reaction conditions in a tubular reactor filled with protective He atmosphere at 1 bar. The spectra were measured before the reaction at RT, then during heating, and during catalytic reaction at 400 °C under controlled atmosphere. Operando XANES analysis is used to monitor the changes in valence states and local symmetries of Cu and Ce cations in the catalysts. A partial reduction of Cu2+ to Cu+ and Cu0 and Ce4+ to Ce3+ species was detected during catalyst activation, and re-oxidation during catalytic reaction. Different dynamics of reaching a quasi-steady oxidation state were revealed as the tested catalysts approached the quasi-steady state after 300 min of reaction. Operando EXAFS spectra are used to precisely determine local structure of Cu and Ce cations, to identify structural characteristics and changes of Cu and Ce species during the catalytic reactions. In this way, the active site in the catalytic reactions can be identified and the mechanism of the reaction clarified. The results of operando XAS analyses are crucial to guide further material modification, to obtain more effective catalyst, and material which is more resistant to inhibiting effects that cause catalyst deactivation during catalytic reaction.
Najdeno v: osebi
Ključne besede: katalizatorji, Cu XANES, EXAFS
Objavljeno: 12.09.2018; Ogledov: 506; Prenosov: 0
.pdf Polno besedilo (62,04 KB)

7.
In-situ XAS analysis of nanoshaped CuO/CeO2 catalysts used for N2O decomposition
Albin Pintar, Petar Djinović, Maxim Zabilsky, Iztok Arčon, 2018, objavljeni povzetek znanstvenega prispevka na konferenci

Opis: The goal of this research is to establish the working state and correlations between atomic structure and catalytic activity of nanoshaped CuO/CeO2 catalysts used in N2O decomposition reaction. The catalysts contained CuO nanoclusters dispersed over different CeO2 morphologies: nano-rods and nano-cubes. N2O is a side product of nitric and adipic acid production and a very potent greenhouse gas that is formed in amounts estimated at about 400 Mt/a of CO2 equivalent. Consequently, the development of robust, active and selective catalysts for N2O decomposition is of a great environmental and economical interest. CeO2-based materials promoted by CuO represent a new class of catalysts that exhibit considerable activity in N2O decomposition reaction between 300 and 500 °C [1-3], and are significantly cheaper and more efficient than Pt, Pd or Rh based catalysts. In order to maximize the efficiency of the catalyst, the active site in this reaction needs to be identified and the mechanism clarified. In-situ Cu K-edge and Ce L3-edge XANES and EXAFS analysis was done on a set of CuO/CeO2 catalysts with different ceria morphology (nano-cubes, nano-rods) and Cu loadings between 2 to 8 wt. %, during N2O decomposition reaction, under controlled reaction conditions at 400 °C. The XAS spectra were measured in-situ, in a tubular reactor, filled with protective He atmosphere at 1 bar, first at RT, then during heating, and at final temperature of 400 °C, during catalytic reaction, when the catalyst was exposed to a small amount (0.2 vol%) of N2O mixed with He. The Cu K-edge and Ce L3-edge XANES and EXAFS analysis reveals changes in valence and local structure of Cu and Ce in the CuO/CeO2 catalysts. In the initial state (in He at RT), copper is present in the form of CuO nanoparticles attached to the CeO2 surface. After heating in He to 400 °C, partial (10%) reduction of Ce [Ce(IV)→Ce(III)] is detected, significant part of Cu(II) is reduced to Cu(I) and Cu(0) species, and direct Cu-Cu bonds are formed. During catalytic N2O decomposition at 400°C, all Ce(III) is oxidized back to Ce(VI), and a major part of Cu is oxidized back to Cu(II), with about 5% of Cu(I) remaining in equilibrium state. Observed structural and valence changes of copper strongly depend on its loading and CeO2 morphology. With systematic In-situ XAS analysis of different nanoshaped CuO/CeO2 catalysts, we identified the structural characteristics and changes of Cu and Ce phases during catalytic N2O decomposition reaction, which could lead to identification of the active catalytic site during the reaction and further improve the performance of these promising catalytic materials.
Najdeno v: osebi
Ključne besede: EXAFS, CuO/CeO2 catalyst, N2O decomposition
Objavljeno: 12.09.2018; Ogledov: 557; Prenosov: 0
.pdf Polno besedilo (281,07 KB)

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