Deep oxidation of 1,2-dichlorobenzene over Ti-doped iron oxide

Catalytic effects of metal oxides on combustion characteristics of inferior coal, sludge, and their mixture were investigated by thermogravimetric analysis. Combustion and thermal dynamic characteristics including ignition temperatures, apparent activation energy, and frequency factors of inferior coal, sludge, and their mixture were observed. The catalytic effects and mechanism of combustion were discussed. Results showed that thermal gravity analysis (TG) and derivative thermogravimetric analysis (DTG) curves of coal and sludge shifted to lower temperature side, the weight losses increased, and the ignition performance was improved with the addition of metal oxides CaO, Al2O3, and K2O. The combustion dynamics analysis showed that the apparent activation energy of cocombustion of coal blending sludge decreased by 11–20% and the frequency factors increased by 20–30%. The minimum apparent activation energy and the maximum frequency factors were obtained in the presence of K2O, indicating that the catalytic effect of K2O was most significant.

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Solid-State Kinetic Investigations of Nonisothermal Reduction of Iron Species Supported on SBA-15

Journal of Analytical Methods in Chemistry ◽

10.1155/2017/6205297 ◽

2017 ◽

Vol 2017 ◽

pp. 1-13 ◽

Cited By ~ 3

Author(s):

N. S. Genz ◽

D. Baabe ◽

T. Ressler

Keyword(s):

Activation Energy ◽

Iron Oxide ◽

Solid State ◽

Apparent Activation Energy ◽

Reduction Process ◽

Kissinger Method ◽

Iron Loading ◽

Iron Species ◽

Vis Spectroscopy ◽

Model Independent

Iron oxide catalysts supported on nanostructured silica SBA-15 were synthesized with various iron loadings using two different precursors. Structural characterization of the as-prepared FexOy/SBA-15 samples was performed by nitrogen physisorption, X-ray diffraction, DR-UV-Vis spectroscopy, and Mössbauer spectroscopy. An increasing size of the resulting iron species correlated with an increasing iron loading. Significantly smaller iron species were obtained from (Fe(III), NH4)-citrate precursors compared to Fe(III)-nitrate precursors. Moreover, smaller iron species resulted in a smoother surface of the support material. Temperature-programmed reduction (TPR) of the FexOy/SBA-15 samples with H2 revealed better reducibility of the samples originating from Fe(III)-nitrate precursors. Varying the iron loading led to a change in reduction mechanism. TPR traces were analyzed by model-independent Kissinger method, Ozawa, Flynn, and Wall (OFW) method, and model-dependent Coats-Redfern method. JMAK kinetic analysis afforded a one-dimensional reduction process for the FexOy/SBA-15 samples. The Kissinger method yielded the lowest apparent activation energy for the lowest loaded citrate sample (Ea ≈ 39 kJ/mol). Conversely, the lowest loaded nitrate sample possessed the highest apparent activation energy (Ea ≈ 88 kJ/mol). For samples obtained from Fe(III)-nitrate precursors, Ea decreased with increasing iron loading. Apparent activation energies from model-independent analysis methods agreed well with those from model-dependent methods. Nucleation as rate-determining step in the reduction of the iron oxide species was consistent with the Mampel solid-state reaction model.

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Thermal analysis on potential risk of cosmetic materials by DSC

MATEC Web of Conferences ◽

10.1051/matecconf/201816901009 ◽

2018 ◽

Vol 169 ◽

pp. 01009

Author(s):

Yi-Feng Chen ◽

An-Chi Huang ◽

Chung-Fu Huang ◽

Chi-Min Shu

Keyword(s):

Activation Energy ◽

Thermal Analysis ◽

Differential Scanning Calorimetry ◽

Iron Oxide ◽

Silicon Dioxide ◽

Copper Oxide ◽

Apparent Activation Energy ◽

Potential Risk ◽

Potential Hazard ◽

Scanning Calorimetry

To explore the potential risk of usage on daily chemicals, the product which most contact for human directly, cosmetics, were selected as study object. In this study, common cosmetic materials, such as propylene glycol, ethanolamine, silicon dioxide, iron oxide, and copper oxide were discussed for potential hazard. According to results of differential scanning calorimetry experiments, the apparent activation energy and SADT were calculated out as 779.22 kJ mol-1 and 45°C, respectively.

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Influence of Cerium on the Reduction Behaviour of Iron Oxide by Using Carbon Monoxide: TPR and Kinetic Studies

Malaysian Journal of Science Health & Technology ◽

10.33102/mjosht.v4i.81 ◽

2019 ◽

Author(s):

Tengku Shafazila Tengku Saharuddin ◽

Nurul Syahira Ezzaty Nor Azman ◽

Fairous Salleh ◽

Alinda Samsuri ◽

Rizafizah Othaman ◽

...

Keyword(s):

Activation Energy ◽

Carbon Monoxide ◽

Iron Oxide ◽

Reduction Process ◽

Kinetic Studies ◽

Xrd Analysis ◽

Oxide Reduction ◽

Iron Oxide Reduction ◽

Reduction Behaviour ◽

Lower Temperature

Reduction of iron oxide is one of the most studied topics owing to the importance of iron/steel industry and also has been used as a precursor and active component in a number of important chemical processes. The interaction between iron oxide and other metal additive have gained interest in the past two decades due to the ability on enhancing the reduction performance of the iron oxide. Therefore, this study was undertaken to investigate the influence of cerium on the reduction behaviours of iron oxide by (10%, v/v) carbon monoxide in nitrogen. The cerium doped (Ce-Fe2O3) and non-doped iron oxide reduction behaviour and the kinetic studies have been studied by temperature programmed reduction (TPR) and the phases formed of partially and completely reduced samples were characterized by X-ray diffraction spectroscopy (XRD) while the activation energy values were calculated from Arrhenius equation using Wimmer’s method. TPR results indicate that the reduction of doped and undoped iron oxide proceeds in three steps reduction (Fe2O3 ? Fe3O4 ? FeO ? Fe), while doped iron oxide showed a large shifted towards lower temperature especially in the transition steps of FeO ? Fe. Furthermore, TPR results also suggested that by adding Ce metal into iron oxide the reduction of metal iron completed at lower temperature (700 ?C) compared to non-doped iron oxide (900 ?C). Meanwhile, XRD analysis indicated that doped iron oxide composed of Fe2O3 and a small amount of FeCe2O4. The increase in the rates of iron oxide reduction may relate to the presence of cerium species in the formed of FeCe2O4 and was confirmed by the decrease in the activation energy regarding to all transition phases (Fe2O3 ? Fe3O4 ? FeO ? Fe) during the reduction process

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The Hydrothermal Stability and the Properties of Non- and Strongly-Interacting Rh Species over Rh/γ, θ-Al2O3 Catalysts

Catalysts ◽

10.3390/catal11010099 ◽

2021 ◽

Vol 11 (1) ◽

pp. 99

Author(s):

Guanghao Cheng ◽

Gurong Shen ◽

Jun Wang ◽

Yunhao Wang ◽

Weibo Zhang ◽

...

Keyword(s):

Activation Energy ◽

Apparent Activation Energy ◽

Aging Time ◽

Reaction Path ◽

Aging Treatment ◽

Hydrothermal Stability ◽

Hydrothermal Aging ◽

Strongly Interacting

The present work reports the effects of γ-, θ-phase of alumina on the hydrothermal stability and the properties of non- and strongly-interacting Rh species of the Rh/Al2O3 catalysts. Comparing to γ-Al2O3, θ-Al2O3 can not only reduce the amount of occluded Rh but also better stabilize Rh during hydrothermal aging treatment. When the aging time was prolonged to 70 h, all the non-interacting Rh was transformed into strongly-interacting Rh and occluded Rh. The XPS results indicated that non- and strongly-interacting Rh might exist in the form of Rh/Rh3+ and Rh4+, respectively. CO-NO reaction was chosen as a probe reaction to research more information about non- and strongly-interacting Rh. The two Rh species had similar apparent activation energy (Eapp) of 170 kJ/mol, which indicated that non- and strongly-interacting Rh follow the same reaction path. The non-interacting Rh was removed from aged samples by the acid-treated method, and obtained results showed that only 2.5% and 4.0% non-interacting Rh was maintained in aged Rh/γ-Al2O3 and Rh/θ-Al2O3.

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The activation energy U(T,B) in high temperature superconductor

The European Physical Journal Applied Physics ◽

10.1051/epjap/2020200223 ◽

2020 ◽

Vol 92 (2) ◽

pp. 20601

Author(s):

Abdelaziz Labrag ◽

Mustapha Bghour ◽

Ahmed Abou El Hassan ◽

Habiba El Hamidi ◽

Ahmed Taoufik ◽

...

Keyword(s):

Magnetic Field ◽

Activation Energy ◽

Phase Diagram ◽

High Temperature ◽

Apparent Activation Energy ◽

High Temperature Superconductor ◽

Flux Flow ◽

Resistivity Measurements ◽

Vortex Phase ◽

The Magnetic Field

It is reported in this paper on the thermally assisted flux flow in epitaxial YBa2Cu3O7-δ deposited by Laser ablation method on the SrTiO3 substrate. The resistivity measurements ρ (T, B) of the sample under various values of the magnetic field up to 14T in directions B∥ab-plane and B∥c-axis with a dc weak transport current density were investigated in order to determine the activation energy and then understand the vortex dynamic phenomena and therefore deduce the vortex phase diagram of this material. The apparent activation energy U0 (B) calculated using an Arrhenius relation. The measured results of the resistivity were then adjusted to the modified thermally assisted flux flow model in order to account for the temperature-field dependence of the activation energy U (T, B). The obtained values from the thermally assisted activation energy, exhibit a behavior similar to the one showed with the Arrhenius model, albeit larger than the apparent activation energy with ∼1.5 order on magnitude for both cases of the magnetic field directions. The vortex glass model was also used to obtain the vortex-glass transition temperature from the linear fitting of [d ln ρ/dT ] −1 plots. In the course of this work thanks to the resistivity measurements the upper critical magnetic field Hc2 (T), the irreversibility line Hirr (T) and the crossover field HCrossOver (T) were located. These three parameters allowed us to establish a phase diagram of the studied material where limits of each vortex phase are sketched in order to optimize its applicability as a practical high temperature superconductor used for diverse purposes.

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Effect of CaO on catalytic combustion of semi-coke

Green Processing and Synthesis ◽

10.1515/gps-2021-0002 ◽

2021 ◽

Vol 10 (1) ◽

pp. 011-020

Author(s):

Luyao Kou ◽

Junjing Tang ◽

Tu Hu ◽

Baocheng Zhou ◽

Li Yang

Keyword(s):

Activation Energy ◽

Apparent Activation Energy ◽

Combustion Rate ◽

Activation Energies ◽

Combustion Reaction ◽

Tg Analysis ◽

Conversion Rates ◽

Apparent Activation Energies ◽

Ozawa Integral Method ◽

Addition Amount

Abstract Generally, adding a certain amount of an additive to pulverized coal can promote its combustion performance. In this paper, the effect of CaO on the combustion characteristics and kinetic behavior of semi-coke was studied by thermogravimetric (TG) analysis. The results show that adding proper amount of CaO can reduce the ignition temperature of semi-coke and increase the combustion rate of semi-coke; with the increase in CaO content, the combustion rate of semi-coke increases first and then decreases, and the results of TG analysis showed that optimal addition amount of CaO is 2 wt%. The apparent activation energy of CaO with different addition amounts of CaO was calculated by Coats–Redfern integration method. The apparent activation energy of semi-coke in the combustion reaction increases first and then decreases with the increase in CaO addition. The apparent activation energies of different samples at different conversion rates were calculated by Flynn–Wall–Ozawa integral method. It was found that the apparent activation energies of semi-coke during combustion reaction decreased with the increase in conversion.

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Synthesis of iron oxide nanoflakes at lower temperature by air oxidation of iron foils

Japanese Journal of Applied Physics ◽

10.7567/jjap.53.11re04 ◽

2014 ◽

Vol 53 (11S) ◽

pp. 11RE04 ◽

Cited By ~ 2

Author(s):

Norhana Mohamed Rashid ◽

Xuyang Li ◽

Naoki Kishi ◽

Tetsuo Soga

Keyword(s):

Iron Oxide ◽

Air Oxidation ◽

Lower Temperature

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Discovery of Fe7O9: a new iron oxide with a complex monoclinic structure

Scientific Reports ◽

10.1038/srep32852 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 20

Author(s):

Ryosuke Sinmyo ◽

Elena Bykova ◽

Sergey V. Ovsyannikov ◽

Catherine McCammon ◽

Ilya Kupenko ◽

...

Keyword(s):

Applied Sciences ◽

Crystal Structure ◽

Iron Oxide ◽

Iron Oxides ◽

Industrial Applications ◽

Ambient Conditions ◽

X Ray Diffraction ◽

X Ray ◽

High Pressure High Temperature ◽

Insight Into

Abstract Iron oxides are fundamentally important compounds for basic and applied sciences as well as in numerous industrial applications. In this work we report the synthesis and investigation of a new binary iron oxide with the hitherto unknown stoichiometry of Fe7O9. This new oxide was synthesized at high-pressure high-temperature (HP-HT) conditions, and its black single crystals were successfully recovered at ambient conditions. By means of single crystal X-ray diffraction we determined that Fe7O9 adopts a monoclinic C2/m lattice with the most distorted crystal structure among the binary iron oxides known to date. The synthesis of Fe7O9 opens a new portal to exotic iron-rich (M,Fe)7O9 oxides with unusual stoichiometry and distorted crystal structures. Moreover, the crystal structure and phase relations of such new iron oxide groups may provide new insight into the cycling of volatiles in the Earth’s interior.

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