scholarly journals Synthesis of α-Alumina Nano-Onions by Thermal Decomposition of Aluminum Formate

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Nadia Vargas-Martínez ◽  
Álvaro de Jesús Ruíz-Baltazar ◽  
Nahúm A. Medellín-Castillo ◽  
Simón Yobanny Reyes-López
Keyword(s):  
Thermal Decomposition ◽  
Nmr Spectroscopy ◽  
Specific Surface ◽  
Surface Area ◽  
Nmr Spectra ◽  
Mas Nmr ◽  
Hrtem Image ◽  
Sem Images ◽  
Coordination Numbers ◽  
Aluminum Ions

A simplified route to prepare α-Al2O3 nano-onions and alumina powders with an excellent surface area through the thermal decomposition of aluminum formate (Al(O2CH)3) precursor is proposed. The calcined powders were characterized by infrared and 13C MAS NMR spectroscopy. Coordination numbers and chemical interactions were determined by 27Al MAS NMR spectroscopy. The 27Al MAS NMR spectra showed the presence of η-Al2O3 at 1000°C, and the transformation to α-Al2O3 at 1100°C. The spectral data also showed that while the precursor contained 6-coordinated aluminum ions, four-, five-, and six-coordinated aluminum species were present after calcination at 400°C. SEM images and BET measurements of α-Al2O3 revealed aggregated particles with a specific surface area of 118 m2/g. A nano-onion structure of α-Al2O3 was evident from the HRTEM image.

The Reactivity of Different Active Forms of Sodium Carbonate with Respect to Sulfur Dioxide

1992 ◽  
Vol 57 (11) ◽  
pp. 2302-2308
Author(s):  
Karel Mocek ◽  
Erich Lippert ◽  
Emerich Erdös
Keyword(s):  
Thermal Decomposition ◽  
Liquid Phase ◽  
Sulfur Dioxide ◽  
Specific Surface ◽  
Surface Area ◽  
Sodium Carbonate ◽  
Room Temperature ◽  
Active Form ◽  
The Other ◽  
Kinetics Of

The kinetics of the reaction of solid sodium carbonate with sulfur dioxide depends on the microstructure of the solid, which in turn is affected by the way and conditions of its preparation. The active form, analogous to that obtained by thermal decomposition of NaHCO3, emerges from the dehydration of Na2CO3 . 10 H2O in a vacuum or its weathering in air at room temperature. The two active forms are porous and have approximately the same specific surface area. Partial hydration of the active Na2CO3 in air at room temperature followed by thermal dehydration does not bring about a significant decrease in reactivity. On the other hand, if the preparation of anhydrous Na2CO3 involves, partly or completely, the liquid phase, the reactivity of the product is substantially lower.

scholarly journals Features of obtaining the catalyst for the synthesis of carbon nanotubes

2019 ◽  
Vol 81 (2) ◽  
pp. 261-267 ◽  
Author(s):  
E. A. Burakova ◽  
G. S. Besperstova ◽  
M. A. Neverova ◽  
A. G. Tkachev ◽  
N. V. Orlova ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Thermal Decomposition ◽  
Metal Oxide ◽  
Specific Surface ◽  
Surface Area ◽  
Nanostructured Materials ◽  
Specific Surface Area ◽  
Oxide System ◽  
Decomposition Stage ◽  
Al2o3 Catalyst

In this paper, the features of obtaining a Co-Mo/Al2O3 catalyst to synthesize carbon nanotubes (CNTs) by thermal decomposition were studied. It was revealed that the duration of the pre-catalyst thermal decomposition stage in the process of developing a metal oxide system has a significant impact on its activity in the synthesis of carbon nanostructured materials by chemical vapor deposition (CVD). It was proved that an effective catalyst for CNTs synthesis can be obtained by through thermal decomposition of the pre – catalyst, without calcination of the metal oxide system. The use of the Co-Mo/Al2O3 catalyst, synthesized in such a way, in the CVD process makes it possible to reduce the cost of synthesized CNTs. Using scanning electron microscopy, it was shown that the size of the grains, and specific surface area of the formed Co-Mo/Al2O3 catalyst depend on the thermal treatment conditions of the pre-catalyst. Under the conditions for the implementation of the pre-catalyst thermal decomposition stage (temperature, volume, duration, etc.), it is possible to contro not only the characteristics of the resulting catalyst (specific surface area, efficiency), but also the characteristics of the CNTs (diameter, degree of defectiveness). In the course of experiments, the optimal modes of implementation of the method for obtaining the Co-Mo/Al2O3 catalyst allowed forming a system with a specific surface area of ~ 108 m2/g. The use of the resulting catalyst in the synthesis of nanostructured materials provides a high specific yield of multi-walled CNTs with a diameter of 8-20 nm and a degree of defectiveness of 0.97.

Ultrafast high-resolution magic-angle-spinning NMR spectroscopy

The Analyst ◽  
2015 ◽  
Vol 140 (12) ◽  
pp. 3942-3946 ◽  
Author(s):  
Marion André ◽  
Martial Piotto ◽  
Stefano Caldarelli ◽  
Jean-Nicolas Dumez
Keyword(s):  
Nmr Spectroscopy ◽  
High Resolution ◽  
Nmr Spectra ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Magic Angle ◽  
Solid Samples ◽  
Semi Solid ◽  
Angle Spinning

The acquisition of ultrafast high-resolution magic-angle spinning (HR-MAS) NMR spectra of semi-solid samples is demonstrated.

scholarly journals Microwave solvothermal synthesis and characterization of manganese-doped ZnO nanoparticles

2016 ◽  
Vol 7 ◽  
pp. 721-732 ◽  
Author(s):  
Jacek Wojnarowicz ◽  
Roman Mukhovskyi ◽  
Elzbieta Pietrzykowska ◽  
Sylwia Kusnieruk ◽  
Jan Mizeracki ◽  
...  
Keyword(s):  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Solvothermal Synthesis ◽  
Web Application ◽  
Zinc Acetate Dihydrate ◽  
Average Particle Size ◽  
Average Particle ◽  
Sem Images

Mn-doped zinc oxide nanoparticles were prepared by using the microwave solvothermal synthesis (MSS) technique. The nanoparticles were produced from a solution of zinc acetate dihydrate and manganese(II) acetate tetrahydrate using ethylene glycol as solvent. The content of Mn2+ in Zn1− x Mn x O ranged from 1 to 25 mol %. The following properties of the nanostructures were investigated: skeleton density, specific surface area (SSA), phase purity (XRD), lattice parameters, dopant content, average particle size, crystallite size distribution, morphology. The average particle size of Zn1− x Mn x O was determined using Scherrer’s formula, the Nanopowder XRD Processor Demo web application and by converting the specific surface area results. X-ray diffraction of synthesized samples shows a single-phase wurtzite crystal structure of ZnO without any indication of additional phases. Spherical Zn1− x Mn x O particles were obtained with monocrystalline structure and average particle sizes from 17 to 30 nm depending on the content of dopant. SEM images showed an impact of the dopant concentration on the morphology of the nanoparticles.

scholarly journals Physicochemical and Biological Characterization of Ti6Al4V Particles Obtained by Implantoplasty: An In Vitro Study. Part I

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6507
Author(s):  
Jorge Toledano-Serrabona ◽  
Francisco Javier Gil ◽  
Octavi Camps-Font ◽  
Eduard Valmaseda-Castellón ◽  
Cosme Gay-Escoda ◽  
...  
Keyword(s):  
Cell Viability ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
In Vitro Study ◽  
Vitro Study ◽  
Equivalent Diameter ◽  
Metal Debris ◽  
Aluminum Ions

Implantoplasty is a mechanical decontamination technique that consists of polishing the supra-osseous component of the dental implant with peri-implantitis. This technique releases metal particles in the form of metal swarf and dust into the peri-implant environment. In the present in vitro study, the following physicochemical characterization tests were carried out: specific surface area, granulometry, contact angle, crystalline structure, morphology, and ion release. Besides, cytotoxicity was in turn evaluated by determining the fibroblastic and osteoblastic cell viability. As a result, the metal debris obtained by implantoplasty presented an equivalent diameter value of 159 µm (range 6–1850 µm) and a specific surface area of 0.3 m2/g on average. The particle had a plate-like shape of different sizes. The release of vanadium ions in Hank’s solution at 37 °C showed no signs of stabilization and was greater than that of titanium and aluminum ions, which means that the alloy suffers from a degradation. The particles exhibited cytotoxic effects upon human osteoblastic and fibroblastic cells in the whole extract. In conclusion, metal debris released by implantoplasty showed different sizes, surface structures and shapes. Vanadium ion levels were higher than that those of the other metal ions, and cell viability assays showed that these particles produce a significant loss of cytocompatibility on osteoblasts and fibroblasts, which means that the main cells of the peri-implant tissues might be injured.

scholarly journals Synthesis and sintering of nano-sized BaSnO3 powders containing BaGeO3

2018 ◽  
Author(s):  
Roberto Köferstein
Keyword(s):  
Thermal Decomposition ◽  
Specific Surface ◽  
Relative Density ◽  
Surface Area ◽  
Specific Surface Area ◽  
Solid Solutions ◽  
Sintering Temperature ◽  
Soaking Time ◽  
Fine Microstructure ◽  
Sintering Behaviour

The formation of solid solutions of the type[Ba(HOC2H4OH)4][Sn1−xGex(OC2H4O)3] as BaSn1-x/GexO3 precursor and the phase evolutionduring its thermal decomposition are described in this paper. The 1,2-ethanediolato complexescan be decomposed to nano-sized BaSn1−x/GexO3 preceramic powders. Samples with x = 0.05consist of only a Ba(Sn,Ge)O3 phase, whereas powders with x = 0.15 and 0.25 showdiffraction patterns of both the Ba(Sn,Ge)O3 and BaGeO3 phase. The sintering behaviour wasinvestigated on powders with a BaGeO3 content of 5 and 15 mol%. These powders show a specific surface area of 15.4−15.9 m2/g and were obtained from calcination above 800 °C.The addition of BaGeO3 reduced the sintering temperature of the ceramics drastically.BaSn0.95Ge0.05O3 ceramics with a relative density of at least 90 % can be obtained by sinteringat 1150 °C for 1 h. The ceramic bodies reveal a fine microstructure with cubical-shaped grainsbetween 0.25−0.6 μm. For dense ceramics the sintering temperature could be reduced down to1090 °C, when the soaking time was extended up to 10 h.

Pore structure of pyrolyzed scrap tires

2008 ◽  
Vol 62 (1) ◽  
Author(s):  
Zuzana Koreňová ◽  
Juma Haydary ◽  
Július Annus ◽  
Jozef Markoš ◽  
L’udovít Jelemenský
Keyword(s):  
Thermal Decomposition ◽  
Carbon Black ◽  
Specific Surface ◽  
Pore Structure ◽  
Surface Area ◽  
Specific Surface Area ◽  
Nitrogen Flow ◽  
Solid Matter ◽  
Scrap Tires ◽  
Different Temperatures

AbstractInternal structure of carbon black produced by pyrolysis (CBp) of rubber samples from the top and bottom parts of sidewall and tread of a passenger car tire was investigated in nitrogen flow at different temperatures. The pore structure (specific surface area, pore size distribution, and porosity) of CBp and commercial CB, was compared. The development of pore structure and the increase of the specific surface area were most intensive during the thermal decomposition at temperatures ranging from 300°C to 500°C. This is caused by the intensive release of volatiles during the pyrolysis. After the pyrolysis was finished, at temperatures above 500°C, further decomposition of solid matter was associated with a slight increase of the specific surface area.

scholarly journals Spelt pasta with inulin as a functional food

2015 ◽  
pp. 37-44
Author(s):  
Jelena Filipovic ◽  
Lato Pezo ◽  
Vladimir Filipovic ◽  
Gordana Ludajic
Keyword(s):  
Nmr Spectroscopy ◽  
Functional Food ◽  
Nmr Spectra ◽  
Mas Nmr ◽  
Raw Material ◽  
Simultaneous Increase ◽  
Nutritional Properties ◽  
Deconvolution Analysis ◽  
Technological Characteristics ◽  
Functional Product

Spelt wheat growing without use of pesticides is a suitable raw material for whole meal products. The aim of this study was to enhance the fiber content in spelt pasta by adding inulin HPX. Inulin HPX replaced the spelt farina in the quantity of 0%, 5%, 10% and 20%, thus contributing to a decrease in the toughness, and improving color of the pasta. The presence of inulin can be clearly distinguished from other polysaccharides components by 13C MAS NMR spectroscopy. A simultaneous increase in the area of the peaks at 81, 74, 64 and 58 ppm, obtained during the deconvolution analysis of the NMR spectra, is directly associated with the increase in the inulin content. Inulin contributes positively to the nutritive and technological characteristics of the pasta. Spelt pasta with 20 % of inulin is a new functional product with modified nutritional properties and with decreased digestible carbohydrates in the amuount of 43.2% and reduced energy of 27.2%.

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