scholarly journals Application of Pd-Sn Modified Ru-Ir Electrode For Treating High Chlorine Ammonia-Nitrogen Wastewater

2021 ◽  
Author(s):  
Zhen-xing Yang ◽  
Wen-yu Xie ◽  
Fang-fang Ye ◽  
De-hao Li
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Ammonia Nitrogen ◽  
Reaction Conditions ◽  
Chlorine Evolution ◽  
Zero Order Kinetics ◽  
Start Up ◽  
Catalytic Treatment ◽  
Easy Operation ◽  
Minimal Generation

Abstract Electro-catalytic technology has attracted increasing attention as a promising approach for wastewater treatment, owing to its easy operation, minimal generation of secondary pollution, small foot-print and rapid start-up. In this work, the chlorine evolution potential of the Pd-Sn modified ruthenium(Ru)-iridium(Ir) electrode was investigated for electro-catalytic treatment of high chlorine ammonia-nitrogen wastewater. The effect of reaction conditions on the removal of ammonia-nitrogen, kinetics and apparent activation energy of the electro-catalytic treatment of ammonia-nitrogen were studied. The possible denitrification process of high chlorine ammonia-nitrogen wastewater treated by electrocatalysis was discussed. The results indicated that the chlorine evolution potential of the Pd-Sn modified Ru-Ir electrode was 1.0956 V(vs. SCE). The rule of electro-catalytic treatment of high chlorine ammonia-nitrogen conformed to zero-order kinetics, and the removal process was endothermic reaction with the apparent activation energy of 14.089 kJ/mol. With the current is 0.5 A, the removal efficiency of ammonia-nitrogen could achieve 100% at the reaction time of 40 min. Indirect oxidation played an essential role in the electro-catalytic ammonia-nitrogen removal using the Pd-Sn modified Ru-Ir electrode. This paper demonstrated that the electro-catalytic technology was a promising approach for efficiently treating the high chlorine ammonia-nitrogen wastewater.

The Kinetics and Activation Energy of Photocatalytic Degradation of Phenol by TiO2 and TiO2/ PANI Photocatalyst under UV Irradiation

2012 ◽  
Vol 430-432 ◽  
pp. 57-60
Author(s):  
Xue Yan Li ◽  
Qing Zhi Luo ◽  
Jing An ◽  
De Song Wang
Keyword(s):  
Activation Energy ◽  
Photocatalytic Degradation ◽  
Apparent Activation Energy ◽  
Tio2 Nanoparticles ◽  
Uv Irradiation ◽  
Zero Order ◽  
Zero Order Kinetics ◽  
Catalytically Active ◽  
Kinetics And Activation Energy

The kinetics and activation energy of photocatalytic degradation of phenol has been studied using the catalytically active TiO2 and PANI modified TiO2 nanoparticles. The reaction follows a pseudo-zero-order kinetics. Apparent activation energy of phenol photocatalytic degradation in water was 13.76kJ/mol by TiO2 and was 12.31kJ/mol by TiO2/PANI.

Nickel-Catalyzed Multicomponent Coupling Reaction of Alkyl Halides, Isocyanides and H2O: An Expedient Way to Access Alkyl Amides

Synthesis ◽  
2020 ◽  
Vol 52 (22) ◽  
pp. 3466-3472
Author(s):  
Yunkui Liu ◽  
Bingwei Zhou ◽  
Qiao Li ◽  
Hongwei Jin
Keyword(s):  
Functional Group ◽  
Coupling Reaction ◽  
Alkyl Halides ◽  
Previous Literature ◽  
Catalytic Cycle ◽  
Reaction Conditions ◽  
Multicomponent Coupling ◽  
Easy Operation

We herein describe a Ni-catalyzed multicomponent coupling reaction of alkyl halides, isocyanides, and H2O to access alkyl amides. Bench-stable NiCl2(dppp) is competent to initiate this transformation under mild reaction conditions, thus allowing easy operation and adding practical value. Substrate scope studies revealed a broad functional group tolerance and generality of primary and secondary alkyl halides in this protocol. A plausible catalytic cycle via a SET process is proposed based on preliminary experiments and previous literature.

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

Catalysts ◽  
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.

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

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.

scholarly journals Effect of CaO on catalytic combustion of semi-coke

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.

Effect of orienting coatings on the apparent activation energy of boundary film destruction

2007 ◽  
Vol 28 (1) ◽  
pp. 12-18 ◽  
Author(s):  
I. A. Buyanovskii ◽  
Yu. N. Drozdov ◽  
Z. V. Ignatieva ◽  
T. M. Savinova ◽  
V. A. Levchenko ◽  
...  
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Boundary Film

Kinetic Model of the 1,2-Propanediol Oxidation Reaction in the Presence of 3wt%Pd/α-Al2O3 Catalyst

2021 ◽  
Vol 903 ◽  
pp. 143-148
Author(s):  
Svetlana Cornaja ◽  
Svetlana Zhizhkuna ◽  
Jevgenija Vladiko
Keyword(s):  
Activation Energy ◽  
Lactic Acid ◽  
Kinetic Model ◽  
Catalytic Oxidation ◽  
Molecular Oxygen ◽  
Oxidation Reaction ◽  
Main Product ◽  
Oxidation Process ◽  
Water Solution ◽  
Reaction Conditions

Supported 3wt%Pd/α-Al₂O₃ catalyst was tested in selective oxidation of 1,2-propanediol by molecular oxygen. It was found that the catalyst is active in an alkaline water solution. Lactic acid was obtained as the main product of the reaction. Influence of different reaction conditions on 1,2-PDO conversion and oxidation process selectivity was studied. Partial kinetic orders of the reaction with respect to 1,2-propanediol, c0(NaOH), p(O2), n(1,2-PDO)/n(Pd)) were determined and an experimental kinetic model of the catalytic oxidation reaction was obtained. Activation energy of the process was calculated and was found to be about 53 ± 5 kJ/mol.

scholarly journals Nickel-catalyzed annulations of ortho-haloarylimines

2021 ◽  
Author(s):  
Srinivas Kolluru ◽  
Manvendra Singh ◽  
Bryce Gaskins ◽  
Zarko Boskovic
Keyword(s):  
Activation Energy ◽  
Secondary Amine ◽  
Oxidative Addition ◽  
Reaction Conditions ◽  
Quantitative Manner

Abstract We report the discovery, development, and mechanism of a nickel-catalyzed annulation reaction between o-haloarylimines and electron-poor olefins. The reaction produces two adjacent anti stereocenters and a free secondary amine. Spirocycles are formed from cyclic imines. We characterized the key oxidative addition intermediate and identified a major path leading to competing homo-coupling products. The activation energy of oxidative addition, and the rate of oxidative addition complex isomerization were determined. Sensitivity of the reaction to reaction conditions was established in a quantitative manner and both the scope and limitations of the method are presented.

scholarly journals Influence of dimensionality on phase transition in VO2 nanocrystals

2013 ◽  
Vol 45 (3) ◽  
pp. 305-311 ◽  
Author(s):  
V.A. Blagojevic ◽  
N. Obradovic ◽  
N. Cvjeticanin ◽  
D.M. Minic
Keyword(s):  
Phase Transition ◽  
Activation Energy ◽  
Transition Temperature ◽  
Apparent Activation Energy ◽  
Phase Transition Temperature ◽  
Bulk Material ◽  
Two Dimensional ◽  
Lower Phase ◽  
One Dimensional ◽  
Simultaneous Movement

Hydrothermally synthesized one-dimensional and two-dimensional nanocrystals of VO2 undergo phase transition around 65?C, where temperature and mechanism of phase transition are dependent on dimensionality of nanocrystals. Both nanocrystalline samples exhibit depression of phase transition temperature compared to the bulk material, the magnitude of which depends on the dimensionality of the nanocrystal. One-dimensional nanoribbons exhibit lower phase transition temperature and higher values of apparent activation energy than two-dimensional nanosheets. The phase transition exhibits as a complex process with somewhat lower value of enthalpy than the phase transition in the bulk, probably due to higher proportion of surface atoms in the nanocrystals. High values of apparent activation energy indicate that individual steps of the phase transition involve simultaneous movement of large groups of atoms, as expected for single-domain nanocrystalline materials.

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