Quantification of the Fe3+ concentration in lead silicate glasses using X-band CW-EPR

Cnockaert, Vincent; Maes, Kwinten; Bellemans, Inge; Crivits, Tijl; Vrielinck, Henk; Blanpain, Bart; Verbeken, Kim

doi:10.1016/j.jnoncrysol.2020.120002

Cited by 13 publications

(17 citation statements)

References 47 publications

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“…As it is seen from Table , the linewidth and integral intensity of the EPR line at g ≈ 2.001 increase monotonically with concentration demonstrating that EPR may be used for the quantitative analysis of the Fe-doped synthetic apatites up to the highest iron content of 20%. The lineshape of this signal is Lorentzian for all iron concentrations giving a sign that the broadening is caused mainly by a homogeneous mechanism…”

Section: Resultsmentioning

confidence: 66%

“…It has been attributed by various authors to separate ferric oxide phases, variation of structural Fe 3+ species with overlapping signals, surface Fe oxide or oxyhydroxides, Fe•••O•••Fe clusters, and adsorbed Fe 3+ on HA. 69−71 As it is seen from Table 5, the linewidth and integral intensity of the EPR line at g ≈ 2.001 increase monotonically with concentration demonstrating that EPR may be used for the quantitative analysis of the Fe-doped synthetic apatites 72 up to the highest iron content of 20%. The lineshape of this signal is Lorentzian for all iron concentrations giving a sign that the broadening is caused mainly by a homogeneous mechanism.…”

Section: Resultsmentioning

confidence: 83%

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Iron-Doped Mesoporous Powders of Hydroxyapatite as Molybdenum-Impregnated Catalysts for Deep Oxidative Desulfurization of Model Fuel: Synthesis and Experimental and Theoretical Studies

et al. 2021

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Mesoporous iron-doped hydroxyapatite (HA) powders with a surface area up to 141 m 2 /g were synthesized and characterized by a variety of analytical and computational approaches, including X-ray diffraction (XRD) and X-ray fluorescence spectroscopy (XRF), atomic emission spectrometry with inductively coupled plasma (AES-ICP), Fourier transform infrared absorption (FTIR), nitrogen adsorption−desorption (BET), scanning and transmission electron microscopy (SEM and TEM), electron paramagnetic resonance (EPR), and density functional theory (DFT). Based on the data of TEM with mapping, the homogeneous distribution of Fe was evidenced. Fe 3+ ions were detected by EPR, and according to DFT, Fe 3+ occupied the Ca(2) position. The second part of the manuscript was dedicated to evaluating the catalytic properties of the developed HA powders for oxidative desulfurization, which is a promising alternative to hydrotreating for fuel purification. For this purpose, the molybdenum was impregnated on the HA, and iron-HA powders and the influence of its amount and the iron content were investigated. The optimal process parameters such as rotation speed, amount of H 2 O 2 , reaction time, temperature, and quantity of the catalyst were established and for the first time, to the authors' best knowledge, complete conversion of dibenzothiophene in the presence of an HA-based catalyst was achieved due to a combination of active sites of iron cations and molybdate anions.

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Section: Resultsmentioning

confidence: 66%

Section: Resultsmentioning

confidence: 83%

Iron-Doped Mesoporous Powders of Hydroxyapatite as Molybdenum-Impregnated Catalysts for Deep Oxidative Desulfurization of Model Fuel: Synthesis and Experimental and Theoretical Studies

et al. 2021

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“…A noticeable redistribution of the resonance intensities between the signals at g = 4.27 and g = 2.001 (starting at about 0.5–1 mol. % of the iron amount) can be attributed to the additional paramagnetic complex, probably in the form of the iron oxide (Fe 2 O 3 ) [ 66 , 67 ].…”

Section: Resultsmentioning

confidence: 99%

Mesoporous Iron(III)-Doped Hydroxyapatite Nanopowders Obtained via Iron Oxalate

et al. 2021

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Mesoporous hydroxyapatite (HA) and iron(III)-doped HA (Fe-HA) are attractive materials for biomedical, catalytic, and environmental applications. In the present study, the nanopowders of HA and Fe-HA with a specific surface area up to 194.5 m2/g were synthesized by a simple precipitation route using iron oxalate as a source of Fe3+ cations. The influence of Fe3+ amount on the phase composition, powders morphology, Brunauer–Emmett–Teller (BET) specific surface area (S), and pore size distribution were investigated, as well as electron paramagnetic resonance and Mössbauer spectroscopy analysis were performed. According to obtained data, the Fe3+ ions were incorporated in the HA lattice, and also amorphous Fe oxides were formed contributed to the gradual increase in the S and pore volume of the powders. The Density Functional Theory calculations supported these findings and revealed Fe3+ inclusion in the crystalline region with the hybridization among Fe-3d and O-2p orbitals and a partly covalent bond formation, whilst the inclusion of Fe oxides assumed crystallinity damage and rather occurred in amorphous regions of HA nanomaterial. In vitro tests based on the MG-63 cell line demonstrated that the introduction of Fe3+ does not cause cytotoxicity and led to the enhanced cytocompatibility of HA.

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“… Diffusion data: at the moment we used orders of magnitude for the diffusion coefficients, because there is not much diffusion data available for oxidic systems.  To investigate the influence of the partial pressure of oxygen, also more data on the ratios of Fe 3+ over Fe 2+ [58,59] are very relevant in various slag matrices.…”

Section: Discussionmentioning

confidence: 99%

Towards more realistic simulations of microstructural evolution in oxidic systems

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Vervliet

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et al. 2022

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Quantification of the Fe3+ concentration in lead silicate glasses using X-band CW-EPR

Cited by 13 publications

References 47 publications

Iron-Doped Mesoporous Powders of Hydroxyapatite as Molybdenum-Impregnated Catalysts for Deep Oxidative Desulfurization of Model Fuel: Synthesis and Experimental and Theoretical Studies

Iron-Doped Mesoporous Powders of Hydroxyapatite as Molybdenum-Impregnated Catalysts for Deep Oxidative Desulfurization of Model Fuel: Synthesis and Experimental and Theoretical Studies

Mesoporous Iron(III)-Doped Hydroxyapatite Nanopowders Obtained via Iron Oxalate

Towards more realistic simulations of microstructural evolution in oxidic systems

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