Article
Energy & Fuels
Mario Benes, Guillermo Pozo, Maria Abian, Angela Millera, Rafael Bilbao, Maria U. Alzueta
Summary: The possibility of using ammonia as a fuel and energy carrier with low emissions can contribute to the transition to a low-carbon economy. Experimental studies on the pyrolysis of ammonia show that H2 and N2 are the main products, and the conversion rate of ammonia increases with longer gas residence times. Working in different reactors or using different gases does not significantly impact the conversion values of ammonia under pyrolysis conditions.
Article
Materials Science, Multidisciplinary
Trishelle M. Copeland-Johnson, Charles K. A. Nyamekye, Lynne Ecker, Nicola Bowler, Emily A. Smith, Raul B. Rebak, Simerjeet K. Gill
Summary: Understanding the oxidation process of Inconel 600 (A600) in different environments is important for the development of accident tolerant nuclear fuel rod claddings. This study combines synchrotron-based diffraction, Raman spectroscopy, and nano-scale electron microscopy techniques to investigate the oxidation of A600 in steam and air environments. It was found that a Cr2O3-enriched surface layer forms in steam, while a mixed phase oxide layer containing NiFe2O4, Cr2O3, Fe3O4, and Fe((3-x))CrxO(4) forms in air.
Article
Chemistry, Multidisciplinary
Pierre Funk, Ruben B. Richrath, Fabian Bohle, Stefan Grimme, Andreas Gansauer
Summary: A titanocene-catalyzed reaction for synthesizing acetals and hemiaminals from benzylic ethers and benzylic amines, respectively, using pendant epoxides is described. The reaction mechanism involves catalysis in single-electron steps, including oxidative addition, H-atom transfer to generate a benzylic radical, and organometallic oxygen rebound as reductive elimination. Stereoselectivity is controlled by hyperconjugative interactions and steric interactions between the titanocene catalyst and the aryl groups of the substrate, with an interesting aspect being the oxidation of the benzylic center under reducing conditions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Nataliia Vereshchuk, Jan Holub, Marcos Gil-Sepulcre, Jordi Benet-Buchholz, Antoni Llobet
Summary: The study reveals the oxidative degradation of a water oxidation catalyst under catalytic conditions, leading to the generation of a new complex with detailed analysis of its oxidative transformations. Under turnover conditions, the complex undergoes a series of transformations including the generation of catalytically active and inactive molecular water oxidation catalyst intermediates.
Article
Materials Science, Multidisciplinary
Xian Wu, Jianyun Shen, Feng Jiang, Hairong Wu, Liang Li
Summary: This paper investigates the oxidation of WC-Co cemented carbide under both isothermally and laser irradiation conditions, and reveals that the microstructures of oxide layer in laser-induced oxidation are very different to isothermal oxidation. The oxide layer in laser-induced oxidation shows more porous structures and a mountain shape due to the Gaussian profile of pulsed laser beam. The oxygen content curve in laser-induced oxidation increases rapidly at the beginning and then stabilizes with increasing laser power.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2021)
Article
Engineering, Environmental
Kevin J. Nihill, Qing Ye, Francesca Majluf, Jordan E. Krechmer, Manjula R. Canagaratna, Jesse H. Kroll
Summary: Organic oxidation reactions in the atmosphere can be complex due to branching pathways within each molecule's reaction mechanism. This study found that NOx concentration has indirect effects on product distribution and concentration, impacting the formation of secondary organic aerosol. This highlights the importance of considering NOx concentration beyond simple RO2 branching in atmospheric oxidation experiments.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2021)
Article
Chemistry, Physical
Pinjing Xu, Hui Li, Yanxin Chen
Summary: The synergistic effect of carbon powder and CO reducing atmosphere can effectively reduce the decomposition temperature of phosphogypsum. The factors affecting the decomposition rate of phosphogypsum are temperature, time, atmosphere and carbon powder content in turn, and the factors affecting the desulfurization rate are time, temperature, atmosphere and carbon powder content in turn. The highest decomposition rate and desulfurization rate of phosphogypsum under laboratory conditions are 97.73% and 97.2% respectively, with specific reaction conditions.
Article
Materials Science, Ceramics
Gabriella Cunha Costa Miranda, Laure Ramond, Florent Lebreton, Patrice Signoret, Philippe Martin, Abibatou Ndiaye, Thierry Gervais, Guillaume Bernard-Granger
Summary: Sintering and thermogravimetric experiments, along with microstructure and phase structure analyses, were conducted on a homogeneous U0.89Pu0.11O2+x MOX fuel under an atmosphere of Ar + 4 vpm O2. It was observed that the fuel showed significant weight gain at low temperatures without any swelling, followed by weight loss and pellet swelling at higher temperatures. Raman spectroscopy analysis confirmed the presence of the M3O7 phase. The temperature range of 590-1200 degrees C was mainly associated with densification and grain growth.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2023)
Article
Materials Science, Multidisciplinary
Christopher J. South, Lindsay E. Roy
Summary: The thermal decomposition of plutonium oxalate to oxide and the intermediates involved have been studied using solid state density functional theory calculations. The results suggest that anhydrous analogues of the hydrated Pu(IV) and Pu(III) oxalates are preferred crystal structures formed through an overall exothermic reaction process, with a possibility of more complex structures with higher energy formation as well.
JOURNAL OF NUCLEAR MATERIALS
(2021)
Article
Engineering, Chemical
Zi-Zheng Xie, Meng Zhang, Xing-Bao Wang, Liang Guo, Zhen-Yi Du, Wen-Ying Li
Summary: The study analyzed the hydrodeoxygenation process of dibenzofuran on Ni surface, revealing a stepwise hydrogenation to produce intermediate compounds such as 2-cyclohexylphenol. This mechanism provides insights for further optimization of nickel-based catalyst design.
CHINESE JOURNAL OF CHEMICAL ENGINEERING
(2021)
Article
Forestry
Axel Martinsson, Merima Hasani, Hans Theliander
Summary: Oxidation of kraft pulp using hydrogen peroxide can create new functionality of the fibres, but the concentration of hydrogen peroxide must be higher than consumed by the oxidation reactions. This study investigates the consequences of recirculating the oxidation liquid, which leads to an accumulation of transition metal ions. These metal ions can cause the degradation of carbohydrates and rapid consumption of hydrogen peroxide, making it important to carefully control their concentration in the industrial context.
Article
Mechanics
Cong Sun, Lianzhou Wang
Summary: This study analyzed the evolution mechanisms of propeller wakes from near to far field under different inflow conditions. It was found that turbulent inflow contributes to the destabilization process of the tip vortex system by accelerating the interference between adjacent tip-vortex structures and intensifying the instability motion of the tip vortex. The Sparsity-Promoting Dynamic Mode Decomposition (SPDMD) successfully selected the influential dynamic modes for the approximation of the snapshot sequence.
Article
Meteorology & Atmospheric Sciences
Cheng Liu, Jianping Huang, Xinyu Tao, Lichen Deng, Xiaozhen Fang, Yonghui Liu, Li Luo, Zhongyi Zhang, Hong-Wei Xiao, Hua-Yun Xiao
Summary: This study investigated the impact of aerosol radiative effect on entrainment processes under heavy aerosol pollution conditions using unmanned aerial vehicles and LiDAR. Results showed that aerosol radiative effect reduced surface heat fluxes, influenced entrainment substantially, and modified parameters describing entrainment processes. The study provides valuable evidence for high-resolution modeling studies of entrainment under heavily-polluted aerosol conditions.
ATMOSPHERIC RESEARCH
(2021)
Article
Environmental Sciences
Yujue Wang, Zeyu Feng, Qi Yuan, Dongjie Shang, Yuan Fang, Song Guo, Zhijun Wu, Chao Zhang, Yang Gao, Xiaohong Yao, Huiwang Gao, Min Hu
Summary: This study conducted a comparative investigation to illustrate the sources and key environmental factors of WSOC formation under different atmospheric conditions. The results obtained from five field campaigns at different inland sites and a coastal site during different seasons were summarized. The formation of WSOC was influenced by atmospheric oxidants, aerosol liquid water, and ambient relative humidity, with their roles varying in different atmospheres.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Engineering, Environmental
Yaochun Yu, Shun Che, Changxu Ren, Bosen Jin, Zhenyu Tian, Jinyong Liu, Yujie Men
Summary: The recently discovered microbial reductive defluorination provides valuable insights into the environmental fate of PFASs and potential bioremediation strategies. This study systematically investigates the role of C=C double bonds in the biodegradability of unsaturated PFASs. The results show that alpha,beta-unsaturation is crucial for FCA biotransformation, and specific unsaturated FCA structures with trifluoromethyl branches exhibit enhanced degradability and defluorination capability.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2022)
Article
Chemistry, Inorganic & Nuclear
Thamsanqa Ncube, Hans Oskierski, Gamini Senanayake, Bogdan Z. Dlugogorski
Summary: This study investigates an alternative process route for lithium extraction from alpha-spodumene using potassium sulfate, which also produces leucite as a slow release fertilizer. The reaction sequence between alpha-spodumene and potassium sulfate is documented using synchrotron X-ray diffraction and differential scanning calorimetry, providing insights into the mechanism of the transformation process.
INORGANIC CHEMISTRY
(2021)
Article
Environmental Sciences
Mohammednoor Altarawneh, Mansour H. Almatarneh, Bogdan Z. Dlugogorski
Summary: The study focuses on the thermal transformation of perfluoropentanoic acid in gas-phase reactions, constructing a gas-phase submodel with 56 reactions and 45 species. Theoretical estimates for the operation of PFAS thermal destruction systems were provided based on the formation of small fluorocarbon compounds in a specific temperature window and residence time.
Article
Environmental Sciences
Mohammednoor Altarawneh, Bogdan Z. Dlugogorski
Summary: This study aims to elucidate the primary chemical phenomena of low-temperature combustion of brominated compounds, constructing a detailed kinetic model and providing insights into temperature-dependent profiles of reaction products and intermediates. Experimental observations demonstrate that the model satisfactorily explains the yields of compounds like dibromophenols from oxidative reactions of 2-bromophenol molecules.
Article
Chemistry, Physical
I. Nur Azreena, H. L. N. Lau, N. Asikin-Mijan, Saiman Mohd Izham, M. A. Hassan, Eric Kennedy, Michael Stokenhuber, Y. H. Taufiq-Yap
Summary: This study compared the efficiency of mesoporous catalysts HZSM-5 and zeolite beta in the hydrodeoxygenation (HDO) of oleic acid (OA) for renewable diesel production, finding zeolite beta to exhibit superior activity with diesel selectivity around 77%.
REACTION KINETICS MECHANISMS AND CATALYSIS
(2021)
Article
Chemistry, Multidisciplinary
Penghui Yan, Xinxin Tian, Eric M. Kennedy, Olga Petrovna Tkachenko, Michael Stockenhuber
Summary: The study found that adding small amounts of Mo or Fe can significantly improve the HDO activity of the Ni/BEA catalyst, while the addition of W decreases the HDO rate. The Ni-Fe/BEA catalyst promotes the rate of direct hydrogenolysis of guaiacol to aromatics, while the Ni-Mo/BEA catalyst shows higher hydrogenation and HDO rates compared to Ni/BEA.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2021)
Article
Engineering, Chemical
Nathan H. Weber, Cameron S. Delva, Sebastian P. Stockenhuber, Charles C. Grimison, John A. Lucas, John C. Mackie, Michael Stockenhuber, Eric M. Kennedy
Summary: Pyrolysis of PFOS was studied, and a new low-temperature product C2F4 was discovered. The pyrolysis mechanism and adsorption behavior were investigated.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2022)
Article
Engineering, Chemical
Nathan H. Weber, Cameron S. Delva, Sebastian P. Stockenhuber, Charles C. Grimison, John A. Lucas, Michael Stockenhuber, John C. Mackie, Eric M. Kennedy
Summary: The thermal decomposition of PFOS was investigated using an alpha-alumina reactor and helium as a carrier gas. The presence of water vapor was found to significantly decrease the concentration of fluorocarbons.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2022)
Article
Energy & Fuels
Sidra Jabeen, Xiangpeng Gao, Jun-ichiro Hayashi, Mohammednoor Altarawneh, Bogdan Z. Dlugogorski
Summary: This study highlights the significant impacts of product recovery methods on the yields and properties of hydrochars produced from algal biomass through hydrothermal carbonization. Direct filtration results in higher hydrochar yield with residue biocrude, leading to considerable differences in properties compared to DCM-aided filtration. DCM-aided filtration produces hydrochars with lower volatile matter contents but higher fixed carbon and ash contents, showing greater specific reactivity due to higher concentrations of catalytic alkali and alkaline earth metals.
Article
Engineering, Chemical
Nathan H. Weber, Cameron S. Delva, Sebastian P. Stockenhuber, Charles C. Grimison, John A. Lucas, John C. Mackie, Michael Stockenhuber, Eric M. Kennedy
Summary: The thermal decomposition of perfluorooctanesulfonic acid (PFOS) was studied in an alpha-alumina reactor using air as the bath gas. It was found that COF2 and trace amounts of C2F4 were detected in the absence of water vapor, while the addition of water vapor enabled the mineralization of PFOS into HF, CO2, and SO2. The destruction removal efficiency of PFOS reached over 99.99999% at temperatures above 700 degrees C. A chemical kinetic model was developed to understand the role of O2 and water vapor in the decomposition process, with OH radicals playing a significant role in the reaction.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2023)
Article
Green & Sustainable Science & Technology
Hamed M. Hussain, Khalil Rahi, Mohammednoor Al Tarawneh, Christopher Preece
Summary: This study investigates the utilization of solar panels in houses in Abu Dhabi city and identifies the reasons and optimal scenario for their installation. By conducting a survey and analyzing the results, it is found that financial support during the installation process is the most preferred scenario. The research highlights the high interest in solar power among homeowners in Abu Dhabi.
Article
Chemistry, Multidisciplinary
Penghui Yan, Shibo Xi, Hong Peng, David R. G. Mitchell, Luke Harvey, Matthew Drewery, Eric M. Kennedy, Zhonghua Zhu, Gopinathan Sankar, Michael Stockenhuber
Summary: A novel and simplified method (vacuum-heating) is presented to decompose metal precursors for the preparation of catalysts with uniform metal nanocluster distribution. This eco-friendly and cost-effective method does not require the use of organic compounds and can be scaled-up for different metal species and precursors.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Engineering, Chemical
Nathan H. Weber, Lewis J. Dixon, Sebastian P. Stockenhuber, Charles C. Grimison, John C. Mackie, Michael Stockenhuber, Eric M. Kennedy
Summary: The thermal decomposition of PFOA was studied in an a-alumina flow reactor, revealing that it starts at 400 degrees C. Below 600 degrees C, the main products formed are C7F14, CO2, and HF, with minor amounts of C7F14O and CO. This contradicts quantum chemical calculations which predicted different major products. It was also found that PFOA can be physisorbed onto an alumina nanocluster, releasing C7F14 and CO2.
CHEMICAL ENGINEERING SCIENCE
(2023)
