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51.
52.
Removal of manganese in batch and fluidized bed systems using beads of zeolite a as adsorbent
Mina Jovanovic, Iztok Arčon, Janez Kovač, Nataša Novak Tušar, Bojana Obradovic, Nevenka Rajić, 2016, original scientific article

Abstract: In this study the uptake capacity of Mn(II) ions by zeolite A beads was investigated for different initial Mn concentration (100e400 mg Mn dm^-3) in batch mode at 25e55 C. The obtained adsorption capacity varying from 30 to 50 mg Mn g^-1 demonstrated a high affinity of zeolite A towards Mn(II) present in solutions. Kinetic studies indicated the intra-particle diffusion as the rate limiting step up to 45 C with apparent diffusivities in the range (1.2e2.0) x 10^-13 m2 s^-1 and the activation energy of 21.9 kJ mol^-1, which implies strong interactions between the zeolite A and Mn ions. At 55 C ion-exchange became the rate limiting step. The adsorption isotherms were studied at 25 C showing that the Mn adsorption is the best described by the Langmuir model suggesting a homogenous zeolite surface. XPS analysis of the Mnloaded beads showed that there is no surface accumulation of Mn but an almost uniform Mn distribution inside zeolite A, whereas XANES and EXAFS suggested that the adsorption of Mn(II) was followed by the Mn(II) oxidation and oxide formation. Regeneration of the spent zeolite was examined in 8 adsorption/desorption cycles by a chelating Na2EDTA in a fluidized column. It has been found that zeolite A beads could be reused for at least 4 cycles with satisfactory Mn(II) adsorption efficiencies of about 70%.
Keywords: Zeolite A Manganese Adsorption kinetics EXAFS/XANES XPS
Published in RUNG: 01.04.2016; Views: 5368; Downloads: 0
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53.
Operando (micro) XAFS analysis
Iztok Arčon, Robert Dominko, Katarina Vogel-Mikuš, 2016, published scientific conference contribution abstract (invited lecture)

Abstract: In the talk the principles of XAS methods were presented with practical examples which illustrate the possibilities and advanced approaches for their use in structural analysis of different types of materials. The emphasis will be on to the use of XAS spectroscopy in operando mode and in combination with X-ray microscopy.
Keywords: X-ray absorption spectroscopy, X-ray microscopy, EXAFS, XANES, opearndo mode
Published in RUNG: 25.03.2016; Views: 6322; Downloads: 165
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54.
Development and characterization of improved materials for antifouling applications
Tihana Čižmar, Iztok Arčon, Urška Lavrenčič Štangar, 2015, published scientific conference contribution abstract

Keywords: sol-gel method, photocatalysis, hybrid materials, Cu K-edge XANES, photocatalytic activity
Published in RUNG: 15.02.2016; Views: 5250; Downloads: 0
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55.
X-ray absorption spectroscopy and related techniques
Iztok Arčon, Alojz Kodre, Jana Padežnik Gomilšek, 2004, original scientific article

Abstract: In the extensive field of X-ray diagnostic techniques, nowadays mostly implemented on synchrotron X-ray sources, the X-ray absorption methods offer a relatively simple tool for structural analysis of materials. The advantage of the methods is the sensitivity to chemical species and the insensitivity to the long-range order. An overview of various detection techniques is given together with the discussion of accuracy of the method with regard to the spatial resolution and the possible contamination by intra-atomic contributions, the multielectron photoexcitations.
Keywords: X-žarki, absorpcija, EXAFS, XANES
Published in RUNG: 10.07.2015; Views: 4854; Downloads: 26
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56.
Structural and magnetic properties of Fe-doped BaTiO [sub] 3 ceramics : dissertation
Iuliia Mikulska, 2014, doctoral dissertation

Keywords: barijev titanat, kisikova vrzel, Fe rob K EXAFS, XANES, disertacije
Published in RUNG: 22.01.2015; Views: 6122; Downloads: 371
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