Textural properties of nickel, palladium and titanium oxides supported on MCM-41 materials and their application on oxidative desulfurization of dibenzothiophene

Franco, Regivânia L. M.; Oliveira, Thiago G.; Pedrosa, Anne Michelle Garrido; Naviciene, Sandro; Souza, M. J. B.

doi:10.1590/s1516-14392013005000161

Cited by 25 publications

(10 citation statements)

References 27 publications

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“…The additional mass loss is attributed to dehydroxylation of silanol nests in these temperature ranges. Mass loss through dehydroxylation of silanol nests has been observed by others over the same temperature ranges of 150–350°C and 500–800°C . TGA‐MS analysis confirms the formation of silanol nests during aqueous mineral carbonation reaction.…”

Section: Resultssupporting

confidence: 77%

“…We postulate that vicinal silanol group formation has occurred during the carbonation reaction as a result of the amorphous phase reacting with water. A new broad band in 3600-3100 cm −1 region is also observed, and this band has been attributed to the formation of silanol nests [25][26][27][28][29]. Silanol nests are formed through interaction of different silanol groups by extended hydrogen bonding.…”

Section: Observation Of the Formation Of Silanol Nests During Carbonamentioning

confidence: 99%

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ACEME: Direct Aqueous Mineral Carbonation of Dunite Rock

Rashid

Benhelal

Farhang

et al. 2018

Env Prog and Sustain Energy

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This research explores the use of serpentinized dunite (which is comprised of 61% lizardite) as a feedstock for aqueous mineral carbonation. In initial experiments, dunite was heat‐activated (630°C, 4 h), adopting a procedure which is similar to that used for serpentinite to enhance their carbonation reactivity. Heat‐activation converts crystalline lizardite mineral into an amorphous, reactive phase, and the carbonation of this heat‐activated material resulted in a magnesite yield of 55% compared to 27% obtained with raw dunite under the same reaction conditions. The formation of silanol nests occurred during carbonation of heat‐activated dunite as deduced through FTIR and TGA‐MS analyses. Samples of dunite were also heat‐transformed at high temperatures (800°C, 3 h) to convert lizardite into forsterite, and these samples were also studied as potential feedstocks for mineral carbonation. Heat‐activated dunite was found to engender much higher magnesite yields compared to heat‐transformed dunite (forsterite rich) and raw dunite. This study suggests that during heat‐activation of dunite, as it is for lizardite, conditions should be maintained to avoid forsterite formation. © 2018 American Institute of Chemical Engineers Environ Prog, 38:e13075, 2019

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Section: Resultssupporting

confidence: 77%

Section: Observation Of the Formation Of Silanol Nests During Carbonamentioning

confidence: 99%

ACEME: Direct Aqueous Mineral Carbonation of Dunite Rock

Rashid

Benhelal

Farhang

et al. 2018

Env Prog and Sustain Energy

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“…The initial mass loss is expected to be due to the release of water from decomposition of silanol groups in the carbonation product. Mass loss from silanol groups is expected to be continuous from 150 to 800 °C without any considerable changes in the rate. , The significant increase in the rate of mass loss for the TGA curve from 450 to 550 °C was due to decomposition of magnesite and release of CO 2 . , Above 550 °C (complete decomposition of magnesite), the rate of mass loss returned to the initial rate, and dehydroxylation of silanol groups continued. The rate of mass loss then slightly increased over temperature windows of 650–800 °C due to the onset and gradual dehydroxylation of unreacted lizardite remaining in the carbonation product.…”

Section: Resultsmentioning

confidence: 99%

“…Characterization of HAL7 and the carbonation product indicated, in addition to magnesite as the main carbonation product, that an amorphous silica/silica-rich phase(s) was precipitated, which is again consistent with the prediction of thermodynamic modeling. TGA of the carbonation product showed continuous mass loss due to the release of chemisorbed water in the temperature range of 200–800 °C, which is attributed to the dehydroxylation of silanol groups (surface silica). , FT-IR (Supporting Information S1) proved the presence of silanol nests (reflection at 3700–3000 cm –1 ), free silanol groups (reflection at 1110 cm –1 ), and siloxane (reflection at 900 cm –1 ) in the carbonation product …”

Section: Resultsmentioning

confidence: 99%

“…Mass loss from silanol groups is expected to be continuous from 150 to 800 °C without any considerable changes in the rate. 52,53 The significant increase in the rate of mass loss for the TGA curve from 450 to 550 °C was due to decomposition of magnesite and release of CO 2 . 23,54 Above 550 °C (complete decomposition of magnesite), the rate of mass loss returned to the initial rate, and dehydroxylation of silanol groups continued.…”

Section: Industrial and Engineering Chemistry Researchmentioning

confidence: 99%

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Structure of Silica Polymers and Reaction Mechanism for Formation of Silica-Rich Precipitated Phases in Direct Aqueous Carbon Mineralization

Benhelal

Oliver

Farhang

et al. 2019

Ind. Eng. Chem. Res.

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This research aims to provide insight into the structure and reaction mechanism of silica-rich phases formed as byproducts in direct aqueous carbonation of heat-activated lizardite. In undertaking this work, we employed analytical techniques such as thermogravimetric analysis (TGA), X-ray powder diffraction (XRPD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), 29Si solid-state nuclear magnetic resonance (29Si SS NMR), inductively coupled plasma-optical emission spectrometry (ICP-OES), and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) to characterize carbonation products and to understand the mechanism of formation and the structure of silica-rich byproducts. Thermodynamic analysis predicts the formation of magnesite and amorphous silica in the process of direct aqueous carbonation of heat-activated lizardite under the experimental conditions studied. Characterization of carbonation products disclosed the presence of magnesite, amorphous silica, and magnesium silicate phases. Analysis of supernatant solutions obtained from direct aqueous carbonation by MALDI spectroscopy showed the presence of silica polymers, which precipitate during the carbonation experiments. The precipitated amorphous silica on the surface of reacting particles was found to subsequently adsorb the dissolved magnesium (Mg) from the solution to form a magnesium silicate phase.

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Oxidative desulphurization of model fuel by in situ produced hydrogen peroxide on palladium/active carbon

Wang

2016

Can J Chem Eng

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Thiophenic compounds are considered one of the major obstacles in deep desulphurization of transportation gasoil. In this paper, a single‐stage reactor, in which the induction of hydrogen peroxide, oxidation of thiophenes, and adsorption of sulphones from model fuel was demonstrated in one single step at mild temperatures. In our proposed mechanism, the removal of thiophenes from model fuel undergoes three stages: 2‐propanol dehydrogenation and in situ generation of hydrogen peroxide, oxidative desulphurization, and the adsorption of sulphones on active carbon. Palladium/active carbon (Pd/C) was not only used to catalyze the production of hydrogen peroxide, but also guarantees efficiency in the adsorption of sulphones from the oil phase and aqueous phase owing to its large specific surface area and pore volume. Thus, the goal to get ultra‐low sulphur fuel was well achieved under optimal conditions after almost all the sulphones had entered into the pores of active carbon and stayed in the adsorbent. Accumulation of sulphur in active carbon inhibits further desulphurization operation. Washing with excessive anhydrous ethanol, the efficiency of Pd/C was almost fully recovered.

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Textural properties of nickel, palladium and titanium oxides supported on MCM-41 materials and their application on oxidative desulfurization of dibenzothiophene

Cited by 25 publications

References 27 publications

ACEME: Direct Aqueous Mineral Carbonation of Dunite Rock

ACEME: Direct Aqueous Mineral Carbonation of Dunite Rock

Structure of Silica Polymers and Reaction Mechanism for Formation of Silica-Rich Precipitated Phases in Direct Aqueous Carbon Mineralization

Oxidative desulphurization of model fuel by in situ produced hydrogen peroxide on palladium/active carbon

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