Use of XPS in the determination of chemical environment and oxidation state of iron and sulfur samples: constitution of a data basis in binding energies for Fe and S reference compounds and applications to the evidence of surface species of an oxidized pyrite in a carbonate medium

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Alkaline preparation conditions engendered the zeolite with mesoporosity;Rubidium deposition enhanced allyl alcohol yield and decreased acrolein yield;Alkali post synthesis modification reduced the concentration of acid sites. AbstractUnder most reaction conditions studied, acrolein is reported as the primary product in the conversion of glycerol over zeolites. In such processes, acrolein forms at relatively high yields, with negligible allyl alcohol selectivity. In this contribution, we report the development of ZSM5-supported iron catalysts, modified by rubidium deposition, as stable materials for production of allyl alcohol from glycerol. Our results demonstrate a reduced rate of formation of acrolein over modified catalysts. Both unmodified and modified catalysts were analysed by inductively coupled plasma optical emission spectrometry, nitrogen adsorption, scanning electron microscope, X-ray diffraction, ammonia temperature programmed desorption, X-ray photoelectron spectroscopy and ultraviolet-visible spectroscopy. These techniques revealed that differences in product distribution and catalyst performance are due to the combined effects of iron loading, catalyst acidity and changes in the porosity of the catalyst.2

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“…[49][50][51]. The peak at 533.1 eV, present in all cases, has been attributed as reported elsewhere [52,53] to ZSM5 lattice oxygen.…”

Section: +supporting

confidence: 68%

Zeolite-supported iron catalysts for allyl alcohol synthesis from glycerol

Sánchez

Dlugogorski

Kennedy

et al. 2016

Applied Catalysis A: General

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“…This result also supported by iron(III) sulfate peak at 713.25 eV 38) that can be seen only on untreated pyrite. Natural oxidation of untreated pyrite might cause the following oxidation reaction to produce iron sulfate.…”

Section: Effect Of Treatment Time Of Silicate Coating On Pyrite Oxidasupporting

confidence: 64%

Silicate Covering Layer on Pyrite Surface in the Presence of Silicon–Catechol Complex for Acid Mine Drainage Prevention

et al. 2015

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In this paper, prevention of pyrite oxidation by carrier microencapsulation (CME) was investigated. A possible layer structure was suggested following analysis with electrochemical and surface analysis techniques. Electrochemical study of treated pyrite samples showed that treatment with siliconcatechol (Si-Cat) for 6 h at an initial pH of 9.5 gave the best barrier properties and suppression of the samples. Scanning electron microscopy with energy-dispersive X-ray, and Fourier transform infrared (FTIR) analyses confirmed the presence of a silicate layer on the surface of treated pyrite. X-ray photoelectron spectroscopy indicated that the coating layers on the treated pyrite samples consisted of a network of Fe-O-Si and Si-O-Si units bonded to the surface of pyrite. The Si-O-C asymmetric stretching mode was also observed in FTIR spectra. Detailed spectroscopic analyses confirmed the formation of a silicate polymer on a silicaquinone layer, which resulted in the effective suppression effect shown by Si-Cat-treated pyrite at increasing pH.

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“…The most interesting feature for the GO-H-E sample is the shift in the S2p peak from 168.1 eV to 168.4 eV which we link to the oxidation of all SO 3 (from sulfonic groups) into SO 4 (from sulfates) after exposure to ammonia. 46 Formation of sulfates is further supported by analyzing the filtrate of a GO-H-was stirred overnight, and then filtrated. .…”

Section: Resultsmentioning

confidence: 99%

Revisiting the chemistry of graphite oxides and its effect on ammonia adsorption

2009

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Graphical content entryThe mechanism of ammonia adsorption on graphite oxide (GO) is strongly related to the GO preparation and chemical features, especially to the sulfur-containing groups present on its surface. SummaryGraphite oxide (GO) was synthesized using two different methods: one with sulfuric acid as part of the oxidizing mixture (Hummers-Offeman method), and another one without the sulfurcontaining compound involved in the oxidation process (Brodie method). They were both tested for ammonia adsorption in dynamic conditions, at ambient temperature, and characterized before 2 and after exposure to ammonia by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, potentiometric titration, energy-dispersive X-ray (EDX) spectroscopy, X-ray photoelectron spectroscopy (XPS) and elemental analysis. Analyses of the initial materials showed that besides epoxy, hydroxyl and carboxylic groups, a significant amount of sulfur is incorporated as sulfonic group for GO prepared by the Hummers-Offeman method. The process of ammonia adsorption seems to be strongly related to the type of GO. For GO prepared by the Brodie method, ammonia is mainly retained via intercalation in the interlayer space of GO and by reaction with the carboxylic groups present at the edges of the graphene layers. On the contrary, when GO prepared by the Hummers method is used, ways of retention are different: not only does the intercalation of ammonia is observed but also its reaction with the epoxy, carboxylic and sulfonic groups present. In particular, during the ammonia adsorption process, sulfonic groups are converted to sulfates in presence of superoxide anions O 2 -* . These sulfates can then react with ammonia to form ammonium sulfates. For both GOs, an incorporation of a significant part of the ammonia adsorbed as amines in their structure is observed as a result of reactive adsorption.

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Use of XPS in the determination of chemical environment and oxidation state of iron and sulfur samples: constitution of a data basis in binding energies for Fe and S reference compounds and applications to the evidence of surface species of an oxidized pyrite in a carbonate medium

Cited by 683 publications

References 32 publications

Zeolite-supported iron catalysts for allyl alcohol synthesis from glycerol

Zeolite-supported iron catalysts for allyl alcohol synthesis from glycerol

Silicate Covering Layer on Pyrite Surface in the Presence of Silicon–Catechol Complex for Acid Mine Drainage Prevention

Revisiting the chemistry of graphite oxides and its effect on ammonia adsorption

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Use of XPS in the determination of chemical environment and oxidation state of iron and sulfur samples: constitution of a data basis in binding energies for Fe and S reference compounds and applications to the evidence of surface species of an oxidized pyrite in a carbonate medium

Cited by 683 publications

References 32 publications

Zeolite-supported iron catalysts for allyl alcohol synthesis from glycerol

Zeolite-supported iron catalysts for allyl alcohol synthesis from glycerol

Silicate Covering Layer on Pyrite Surface in the Presence of Silicon&ndash;Catechol Complex for Acid Mine Drainage Prevention

Revisiting the chemistry of graphite oxides and its effect on ammonia adsorption

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Product

Resources

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Silicate Covering Layer on Pyrite Surface in the Presence of Silicon–Catechol Complex for Acid Mine Drainage Prevention