Preparation of copper compounds of different compositions and particle morphologies

1991 ◽  
Vol 6 (4) ◽  
pp. 766-777 ◽  
Author(s):  
Stanka Kratohvil ◽  
Egon Matijević
Keyword(s):  
Essential Role ◽  
Solid Phase ◽  
Particle Morphology ◽  
Chemical Compositions ◽  
Rapid Phase ◽  
Copper Compounds ◽  
Sulfate Solutions ◽  
Amorphous Particles ◽  
Particle Shapes ◽  
Nitrate Solutions

Copper compounds of different chemical compositions and particle shapes were prepared by homogeneous precipitation from copper salt solutions in the presence of urea. It was demonstrated that the nature of the anions played an essential role in the properties of the generated solid phase. Thus, Cu(II)-nitrate solutions yielded spherical amorphous particles which had the composition of malachite [Cu2(OH)2CO3], the Cu(II)-chloride solutions gave bipyramidal particles of atacamite [CuCl2 · 3Cu(OH)2], and in Cu(II)-sulfate solutions needle-shaped brochantite [3Cu(OH)2 · CuSO4] or platelets of posnjakite [3Cu(OH)2 · CuSO4 · H2O] were formed. The addition of NaOH to prepared dispersions resulted in a rapid phase transformation of all above solids into needle-like Cu(OH)2. Calcination of various copper basic compounds at 700–800 °C temperature produced CuO, while the particle morphology was retained.

scholarly journals Dependence of the Staphylococcal Volatilome Composition on Microbial Nutrition

Metabolites ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 347
Author(s):  
Carrie L. Jenkins ◽  
Heather D. Bean
Keyword(s):  
Solid Phase ◽  
Brain Heart Infusion ◽  
Nutritional Composition ◽  
In Vitro Cultivation ◽  
Chemical Compositions ◽  
Flight Mass Spectrometry ◽  
Rich Media ◽  
Free Glucose ◽  
Relative Abundances

In vitro cultivation of staphylococci is fundamental to both clinical and research microbiology, but few studies, to-date, have investigated how the differences in rich media can influence the volatilome of cultivated bacteria. The objective of this study was to determine the influence of rich media composition on the chemical characteristics of the volatilomes of Staphylococcus aureus and Staphylococcus epidermidis. S. aureus (ATCC 12600) and S. epidermidis (ATCC 12228) were cultured in triplicate in four rich complex media (brain heart infusion (BHI), lysogeny broth (LB), Mueller Hinton broth (MHB), and tryptic soy broth (TSB)), and the volatile metabolites produced by each culture were analyzed using headspace solid-phase microextraction combined with comprehensive two-dimensional gas chromatography—time-of-flight mass spectrometry (HS-SPME-GC×GC-TOFMS). When comparing the chemical compositions of the staph volatilomes by the presence versus absence of volatiles produced in each medium, we observed few differences. However, when the relative abundances of volatiles were included in the analyses, we observed that culturing staph in media containing free glucose (BHI and TSB) resulted in volatilomes dominated by acids and esters (67%). The low-glucose media (LB and MHB) produced ketones in greatest relative abundances, but the volatilome compositions in these two media were highly dissimilar. We conclude that the staphylococcal volatilome is strongly influenced by the nutritional composition of the growth medium, especially the availability of free glucose, which is much more evident when the relative abundances of the volatiles are analyzed, compared to the presence versus absence.

scholarly journals Interaction of methoxy- and methylenedioxyamphetamines with carbon and polymeric adsorbents in polar liquids

2010 ◽  
Vol 8 (4) ◽  
pp. 750-757
Author(s):  
Waldemar Tomaszewski ◽  
Vladimir Gun’ko ◽  
Roman Leboda ◽  
Jadwiga Skubiszewska-Zięba
Keyword(s):  
Free Energy ◽  
Surface Area ◽  
Surface Composition ◽  
Solid Phase ◽  
Chemical Compositions ◽  
Phase Extraction ◽  
Polar Liquids ◽  
Polymeric Adsorbents ◽  
Chemically Modified ◽  
Amphetamine Derivatives

AbstractSolid phase extraction (SPE) of methoxy- and methylenedioxyamphetamines from diluted aqueous solutions was investigated on carbon and polymeric adsorbents of different textures and chemical compositions. Those adsorbents were applied cartridges packed with three chemically modified carbons prepared from plum stones (initial A2PS, oxidized A2PS-O, and reduced A2PS-H) and commercially available adsorbents (polymeric LiChrolut EN, graphitized Hypercarb and Carboprep). Several factors influence the recovery rates of amphetamine derivatives such as the polarity of adsorbates (free energy of salvation), the specific surface area and surface composition of adsorbents, and the solvent characteristics. Different combinations of these factors affect the recovery rate (R1) for high- and low-surface area adsorbents. The minimal R1 values are observed for an amphetamine derivative at a maximal solvation effect and for a set of amphetamines adsorbed on graphitized carbons.

scholarly journals Study of the Origin of the Unexpected Pearlite during the Cooling Stage of Two Cast High-Speed Steels

2011 ◽  
Vol 172-174 ◽  
pp. 803-808 ◽  
Author(s):  
Jérôme Tchoufang Tchuindjang ◽  
Jacqueline Lecomte-Beckers
Keyword(s):  
Retained Austenite ◽  
High Speed ◽  
Solid Phase ◽  
Casting Process ◽  
Eutectic Phase ◽  
Chemical Compositions ◽  
Spin Casting ◽  
Eutectic Carbides ◽  
Similar Chemical ◽  
The Matrix

Two HSS grades (A and B) belonging to the complex system Fe-Cr-C-Si-X, where X is a strong carbide-forming element such as V, Mb or W, were studied. Samples in the as-received conditions came from an industrial spin casting process, with a varying cooling rate during processing. Chemical compositions of both alloys were closed to each other and were chosen to enhance their hardenability and to avoid less resistant phases such as pearlite and ferrite. Differential Thermal Analysis was performed on both alloys, in order to increase their crystallization behaviour. Light microscopy and SEM associated with EDS analyses were done to characterize the microstructure of both alloys in the as-received conditions and after DTA trials. The matrix of both HSS grades was composed of eutectic carbides, martensite and retained austenite, these phases exhibiting similar chemical compositions in both alloys. Unexpected pearlite was found in the as-cast HSS alloy B without W, this grade containing more Mo, more V and less Cr than the HSS grade A. It appeared from DTA tests that pearlite found in the alloy B arose more from the destabilisation of the Cr-rich retained austenite associated with the plate-like M2C carbide, than from the matrix itself. In fact, pearlite zones located in the vicinity of M2C are due to related isothermal solid phase transformations form the previous austenitic eutectic phase that is enriched with Cr and Mo.

scholarly journals Thermo-optical reaction changes of a PCM filled glass system

2021 ◽  
Vol 2069 (1) ◽  
pp. 012195
Author(s):  
T Cabanová ◽  
M Kuruc ◽  
J Čurpek ◽  
D Urbán ◽  
M Čekon
Keyword(s):  
Phase Transition ◽  
Optical Properties ◽  
Phase Change ◽  
Solid Phase ◽  
Spectral Feature ◽  
Heat Of Fusion ◽  
Base Line ◽  
Test Procedures ◽  
Rapid Phase ◽  
Physical Changes

Abstract This paper analyzes thermo-optical reactions of the PCM-based glass element which has the capability to store thermal energy together with a variable transparency level through the energy storage process corresponding to phase change. Optical properties are determined by the level of phase transition at given boundary conditions over time. Special uncommon thermo-optical changes occur during its internal phase transition processes, from liquid to solid phase and vice versa (latent heat of fusion) within a given narrow range of temperature interval. PCM acts as random and diffusive media with relevant scattering effects in solid phase, however in liquid state are highly transparent with direct transmission and no relevant scattering effect. These internal physical changes were detailly identified by experimental test procedures based on optical properties measurements performed using a spectrophotometry, and parallelly with the stabilization of each temperature set provided by environmental chamber. As result of that, relevant differences in the PCM spectral feature can be identified for its different states (solid/liquid) in which transmittance spectra are unstable during rapid phase change process. This provides a substantial base line for the optimization of a PCM glazing system in terms of various degree of freedom for different building types and climate zones.

An Innovative Low Density Synthetic Carbonate with a Composite Structure

2014 ◽  
Vol 617 ◽  
pp. 3-9
Author(s):  
Marion Lorgouilloux ◽  
Robert Gaertner ◽  
Thierry Chopin
Keyword(s):  
Solid Phase ◽  
Control Process ◽  
Particle Morphology ◽  
Raw Material ◽  
Spherical Particles ◽  
Low Density ◽  
Insulation Material ◽  
Precipitated Calcium Carbonate ◽  
Bet Specific Surface Area ◽  
Specific Particle

A new low density mineral material has been synthesized via a simple, flexible, cheap and easy to control process. This material is a synthetic carbonate produced by carbonation of a solid phase composed of a calcic part and a magnesian part. Typically, its production process includes the calcination of a raw dolomite (general formula CaCO3.MgCO3) into the oxide form, followed by an at least partial hydration of this oxide and a subsequent carbonation step. This process is thus close to the well-known process used for the production of Precipitated Calcium Carbonate (PCC), a common filler and pigment in plastic, paper and rubber, except that the raw material is a dolomite instead of a limestone. It has to be pointed out that flue gases from different industries can be used as a source of CO2 for the carbonation. Many parameters have been studied, such as the hydration conditions or the carbonation conditions, allowing the production of a whole range of products. The products obtained via this process are composed of a calcic part, mainly as calcite and aragonite (CaCO3), and a magnesium containing part, mainly as hydromagnesite (4MgCO3.Mg (OH)2.4H2O). Compared to standard PCC, this material has a particularly low density (100-250 kg/m3 instead of 300-600 kg/m3 for standard PCC), a rather high BET specific surface area (15-35 m2/g instead of 4-15 m2/g for standard PCC) and a specific particle morphology and structure. The particles are indeed commonly spherical particles composed of a core of calcite/aragonite covered by a layer of hydromagnesite. This structure can be described as a core-shell structure. Due to these special features, this product could be used in multiple applications, such as raw material for the manufacture of insulation material, flame retardant, filler in plastics, paints, paper, rubber, and many more.

scholarly journals Anticorrosive efficiency of alkyd resin-based coatings containing Mg–Zn–Fe mixed oxide-based pigments

2017 ◽  
Vol 61 (2) ◽  
pp. 39-53
Author(s):  
A. Kalendová ◽  
E. Halecká ◽  
K. Nechvílová ◽  
M. Kohl
Keyword(s):  
Mixed Oxide ◽  
Alkyd Resin ◽  
Solid Phase ◽  
Surface Hardness ◽  
Particle Morphology ◽  
Mechanical Tests ◽  
Pigment Volume Concentration ◽  
Accelerated Corrosion ◽  
Accelerated Corrosion Tests ◽  
Paint Films

Abstract Mixed oxide-based pigments Mg–Zn–Fe with different particle morphologies were prepared by high-temperature solid phase reactions. The core shell pigments containing ferric oxide and non-isometric particles of layered silicates were also prepared. The pigments were tested in paints, the pigment volume concentrations in the modified alkyd resin based binder being 5%, 10%, and 15%. The paint properties were examined by accelerated corrosion tests and by physico-mechanical tests. The effect of the pigment particle morphology on the surface hardness of the paint films was also studied. The influence of pigment volume concentration on the coating properties, and the optimum concentrations providing the most efficient anticorrosive protection were processed. A higher anticorrosion efficiency was observed for the paints with pigments possessing the lamellar particle shape.

scholarly journals A Solution-Based Approach for Mo-99 Production: Considerations for Nitrate versus Sulfate Media

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Amanda J. Youker ◽  
Sergey D. Chemerisov ◽  
Michael Kalensky ◽  
Peter Tkac ◽  
Delbert L. Bowers ◽  
...  
Keyword(s):  
Uranyl Nitrate ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Fission Products ◽  
Sulfate Solution ◽  
Medical Community ◽  
High Radiation ◽  
Uranyl Sulfate ◽  
Sulfate Solutions ◽  
Nitrate Solutions

Molybdenum-99 is the parent of Technetium-99m, which is used in nearly 80% of all nuclear medicine procedures. The medical community has been plagued by Mo-99 shortages due to aging reactors, such as the NRU (National Research Universal) reactor in Canada. There are currently no US producers of Mo-99, and NRU is scheduled for shutdown in 2016, which means that another Mo-99 shortage is imminent unless a potential domestic Mo-99 producer fills the void. Argonne National Laboratory is assisting two potential domestic suppliers of Mo-99 by examining the effects of a uranyl nitrate versus a uranyl sulfate target solution configuration on Mo-99 production. Uranyl nitrate solutions are easier to prepare and do not generate detectable amounts of peroxide upon irradiation, but a high radiation field can lead to a large increase in pH, which can lead to the precipitation of fission products and uranyl hydroxides. Uranyl sulfate solutions are more difficult to prepare, and enough peroxide is generated during irradiation to cause precipitation of uranyl peroxide, but this can be prevented by adding a catalyst to the solution. A titania sorbent can be used to recover Mo-99 from a highly concentrated uranyl nitrate or uranyl sulfate solution; however, different approaches must be taken to prevent precipitation during Mo-99 production.

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