scholarly journals Methanol to Formaldehyde: An Overview of Surface Studies and Performance of an Iron Molybdate Catalyst

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 893
Author(s):  
Muhammad Irfan Malik ◽  
Nicolas Abatzoglou ◽  
Inès Esma Achouri

Formaldehyde is a primary chemical in the manufacturing of various consumer products. It is synthesized via partial oxidation of methanol using a mixed oxide iron molybdate catalyst (Fe2(MoO4)3–MoO3). This is one of the standard energy-efficient processes. The mixed oxide iron molybdate catalyst is an attractive commercial catalyst for converting methanol to formaldehyde. However, a detailed phase analysis of each oxide phase and a complete understanding of the catalyst formulation and deactivation studies is required. It is crucial to correctly formulate each oxide phase and influence the synthesis methods precisely. A better tradeoff between support and catalyst and oxygen revival on the catalyst surface is vital to enhance the catalyst’s selectivity, stability, and lifetime. This review presents recent advances on iron molybdate’s catalytic behaviour for formaldehyde production—a deep recognition of the catalyst and its critical role in the processes are highlighted. Finally, the conclusion and prospects are presented at the end.

2005 ◽  
Vol 105 (1-2) ◽  
pp. 23-27 ◽  
Author(s):  
B. Ramachandra ◽  
Jung Sik Choi ◽  
Ko-Yeon Choo ◽  
Jae-Suk Sung ◽  
Sun-Dal Song ◽  
...  

Author(s):  
Xiaohua Li ◽  
Feitian Ran ◽  
Fan Yang ◽  
Jun Long ◽  
Lu Shao

AbstractA growing family of two-dimensional (2D) transition metal carbides or nitrides, known as MXenes, have received increasing attention because of their unique properties, such as metallic conductivity and good hydrophilicity. The studies on MXenes have been widely pursued, given the composition diversity of the parent MAX phases. This review focuses on MXene films, an important form of MXene-based materials for practical applications. We summarized the synthesis methods of MXenes, focusing on emerging synthesis strategies and reaction mechanisms. The advanced assembly technologies of MXene films, including vacuum-assisted filtration, spin-coating methods, and several other approaches, were then highlighted. Finally, recent progress in the applications of MXene films in electrochemical energy storage, membrane separation, electromagnetic shielding fields, and burgeoning areas, as well as the correlation between compositions, architecture, and performance, was discussed.


2021 ◽  
Vol 13 (6) ◽  
pp. 3436
Author(s):  
Hani A. Abu-Qdais ◽  
Muna A. Abu-Dalo ◽  
Yazan Y. Hajeer

Due to their properties, silver nanoparticles (AgNPs) are widely used in consumer products. The widespread use of these products leads to the release of such nanoparticles into the environment, during manufacturing, use, and disposal stages. Currently there is a high margin of uncertainty about the impacts of nano products on the environment and human health. Therefore, different approaches including life cycle assessment (LCA) are being used to evaluate the environmental and health impacts of these products. In this paper, a comparison between four different AgNP synthesis methods was conducted. In addition, four textile products that contain AgNPs were subjected to comparison using LCA analysis to assess their environmental and public health impacts using SimaPro modeling platform. Study results indicate that using alternative methods (green) to AgNPs synthesis will not necessarily reduce the environmental impacts of the synthesizing process. To the best of our knowledge, this is the first study that has compared and assessed the environmental burdens associated with different nanosilver-based textile products at different disposal scenarios. The synthesis of 1 kg of AgNPs using modified Tollens’ method resulted in 580 kg CO2 eq, while 531 kg CO2 eq resulted from the chemical approach. Furthermore, the manufacturing stage had the highest overall impacts as compared to other processes during the life cycle of the product, while the product utilization and disposal stages had the highest impacts on ecotoxicity. Sensitivity analysis revealed that under the two disposal scenarios of incineration and landfilling, the impacts were sensitive to the amount of AgNPs.


2021 ◽  
Vol 13 (14) ◽  
pp. 7600
Author(s):  
Wenting Ma ◽  
Rui Mu ◽  
Martin de Jong

Co-production is a solution by which the government provides public services. Co-production theory is built upon Western experience and currently focuses on the types of co-production in different policy stages, the barriers and governance strategies for co-production. However, little attention is paid to how political background will influence the co-production process. To fill the gap, we analyzed a case of co-production that occurred in China, and we characterized the political background as consisting of three main political features: political mobility, central–local relations, and performance measurement. Based on an in-depth case study of a government project in a medium-sized Chinese city, the impact and the changes of political features affecting governmental projects in different co-production stages are analyzed and assessed. We find that political features play a critical role in the co-production of China’s large government projects and may separately and jointly affect co-production. Government performance measurement affects the co-design and co-implementation of projects. Political mobility and changes in local government and performance measurement also affect the co-implementation continuity of the project. Political focus affects the co-design of projects. Central-local relations influence the support from higher government and the actual practices of lower government in the co-implementation stage.


2021 ◽  
Author(s):  
Clare Guss-West

The Western approach to dance is largely focused on control and mastery of technique, both of which are certainly necessary skills for improving performance. But mindful attention, despite its critical role in high performance, has gotten short shrift—until now. Attention and Focus in Dance, a how-to book rooted in the 20 years of attentional focus findings of researcher Gabriele Wulf, will help dancers unlock their power and stamina reserves, enabling efficient movement, heightening their sensory perception and releasing their dance potential. Author Clare Guss-West—a professional dancer, choreographer, teacher and holistic practitioner—presents a systematic, science-based approach to the mental work of dance. Her approach helps dancers hone the skills of attention, focus and self-cueing to replenish energy and enhance their physical and artistic performance. A Unique, Research-Based Approach Here is what Attention and Focus in Dance offers readers: • A unique approach, connecting the foundations of Eastern movement with Western movement forms • Research-based teaching practices in diverse contexts, including professional dance companies, private studios, and programmes for dancers with special needs or movement challenges • Testimonies and tips from international professional dancers and dance educators who use the book's approach in their training and teaching • A dance-centric focus that can be easily integrated into existing training and teaching practice, in rehearsal, or in rehabilitation contexts to provide immediate and long-term benefits Guss-West explores attentional focus techniques for dancers, teachers and dance health care practitioners, making practical connections between research, movement theory and day-to-day dance practice. “Many dancers are using excessive energy deployment and significant counterproductive effort, and that can lead to a global movement dysfunction, lack of stamina and an increased risk of injury,” says Guss-West. “Attentional focus training is the most relevant study that sport science and Eastern-movement practice can bring to dance.” Book Organisation The text is organised into two parts. Part I guides dancers in looking at the attentional challenges and information overload that many professional dancers suffer from. It outlines the need for a systematic attention and focus strategy, and it explains how scientific research on attentional focus relates to dance practice. This part also examines the ways in which Eastern-movement principles intersect with and complement scientific findings, and it examines how the Eastern and scientific concepts can breathe new life into basic dance elements such as posture, turnout and port de bras. Attention and focus techniques are included for replenishing energy and protecting against energy depletion and exhaustion. Part II presents attention and focus strategies for teaching, self-coaching and cueing. It addresses attentional focus cues for beginners and for more advanced dancers and professionals, and it places attentional focus in the broader context of holistic teaching strategies. Maximising Dance Potential “Whether cueing others or yourself, cueing for high performance is an art,” Guss-West says. “Readers will discover how to format cues and feedback to facilitate effective neuromuscular response and enhance dancer recall of information and accessibility while dancing.” Attention and Focus in Dance offers an abundance of research-backed concepts and inspirational ideas that can help dancers in their learning and performance. This book aids readers in filtering information and directing their focus for optimal physical effect. Ultimately, it guides dancers and teachers in being the best version of themselves and maximising their potential in dance.


2015 ◽  
Vol 168-169 ◽  
pp. 14-24 ◽  
Author(s):  
Silvia R. González Carrazán ◽  
Robert Wojcieszak ◽  
Raquel. M. Blanco ◽  
Cecilia Mateos-Pedrero ◽  
Patricio Ruiz

2009 ◽  
Vol 6 (1) ◽  
pp. 1 ◽  
Author(s):  
Khalid Khazzal Hummadi ◽  
Karim H. Hassan ◽  
Phillip C.H. Mitchell

The selectivity and activity of iron molybdate catalysts prepared by different methods are compared with those of a commercial catalyst in the oxidation of methanol to formaldehyde in a continuous tubular bed reactor at 200-350 oC (473-623 oK), 10 atm (1013 kPa), with a methanol-oxygen mixture fixed at 5.5% by volume methanol: air ratio. The iron(III) molybdate catalyst prepared by co-precipitation and filtration had a selectivity towards formaldehyde in methanol oxidation comparable with a commercial catalyst; maximum selectivity (82.3%) was obtained at 573oK when the conversion was 59.7%. Catalysts prepared by reacting iron (III) and molybdate by kneading or precipitation followed by evaporation, omitting a filtration stage, were less active and less selective. The selectivity-activity relationships of these catalysts as a function of temperature were discussed in relation to the method of preparation, surface areas and composition. By combing this catalytic data with data from the patent literature we demonstrate a synergy between iron and molybdenum in regard to methanol oxidation to formaldehyde; the optimum composition corresponded to an iron mole fraction 0.2-0.3. The selectivity to formaldehyde was practically constant up to an iron mole fraction 0.3 and then decreased at higher iron concentrations. The iron component can be regarded as the activity promoter. The iron molybdate catalysts can thus be related to other two-component MoO3-based selective oxidation catalysts, e.g. bismuth and cobalt molybdates. The iron oxide functions as a relatively basic oxide abstracting, in the rate-controlling step, a proton from the methyl of a bound methoxy group of chemisorbed methanol. It was proposed that a crucial feature of the sought after iron(III) molybdate catalyst is the presence of -O-Mo-O-Fe-O-Mo-O- groups as found in the compound Fe2(MoO4)3 and for Fe3+ well dispersed in MoO3 generally. At the higher iron(III) concentrations the loss of selectivity is due to the presence of iron oxide patches or particles which catalyze the total oxidation of methanol, and the loss of activity to blocking of molybdenum sites. 


2011 ◽  
Vol 84 (4) ◽  
pp. 493-506
Author(s):  
Irene S. Yurovska ◽  
Michael D. Morris ◽  
Theo Al

Abstract Racing tires and motorcycle tires present individual segments of the tire market. For instance, while the average life of car and truck tires is 50 000 miles, the average life of race tires is 100 miles. Because tires play a critical role in a race, technical demands to assure safety and performance are growing. Similarly, tires have a large influence on safety, handling/grip, and performance of the rapidly growing world fleet of motorcycles, due to the fact of only two wheels being in contact with the ground. Thus, the common feature of both market segments is that the typical tire compromise of wear, rolling resistance, and traction is strongly weighted toward traction. Most of the recent efforts of rubber scientists have been directed toward lowering rolling resistance of the tread compounds, which left a certain void in the science of compounding for racing and motorcycle treads. Particularly, the industrial assortment of polymers and fillers used for motorcycle treads is commonly different from that used for car or truck treads, but it is not known how the filler properties affect the hysteresis–stiffness compromise. The objective of this study is to evaluate the effects of the carbon black characteristics on the important properties of a typical racing and motorcycle tire tread compound. More than 50 individual carbon blacks were mixed in a SBR formulation. The acquired data were statistically analyzed, and a linear multiple regression model was developed to relate rubber properties (responses), such as static modulus, complex dynamic modulus, hysteresis, and viscosity to the key carbon black characteristics (variables) of surface area, structure, aggregate size distribution, and surface activity. Prediction profiles created from the model demonstrate rubber performance limits for the range of carbon blacks tested, and indicate the niches to provide required combinations of the rubber properties.


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