Low Temperature Hydrothermal Synthesis of Nanophase BaTiO3 and BaFe12O19 Powders

1996 ◽  
Vol 457 ◽  
Author(s):  
Fatih Dogan ◽  
Shawn O'rourke ◽  
Mao-Xu Qian ◽  
Mehmet Sarikaya
Keyword(s):  
Particle Size ◽  
Hydrothermal Reaction ◽  
Average Particle Size ◽  
Reaction Times ◽  
Nanocrystalline Powders ◽  
Molar Ratio ◽  
Average Particle ◽  
Hydrothermal Conditions ◽  
Processing Variables ◽  
Xrd And Tem

ABSTRACTNanocrystalline powders with an average particle size of 50 nm has been synthesized in two materials systems under hydrothermal conditions below 100°C. Processing variables, such as temperature, concentration and molar ratio of reactants and reaction time were optimized to obtain particles of reduced size and stoichiometric compositions. Hydrothermal reaction takes place between Ba(OH)2 solution and titanium/iron precursors in sealed polyethylene bottles in the BaTiO3 and BaFe12O19 systems, respectively. While crystalline BaTiO3 forms relatively fast within a few hours, formation of fully crystalline and stoichiometric BaFei20i9 require considerably longer reaction times up to several weeks and strongly dependent on the Ba:Fe ratio of the precursors. The structural and compositional evaluation of the nanophase powders were studied by XRD and TEM techniques.

Fe3O4 Magnetic Preparation by Bauxite Ore Washing Fine Mud

2014 ◽  
Vol 1010-1012 ◽  
pp. 961-965
Author(s):  
Jian Qiang Xiao ◽  
Guo Wei He ◽  
Yan Jin Hu
Keyword(s):  
Particle Size ◽  
Aging Time ◽  
Average Particle Size ◽  
Xrd Analysis ◽  
Test Methods ◽  
Raw Material ◽  
Molar Ratio ◽  
Average Particle ◽  
Experimental Conditions ◽  
Particle Size Analyzer

Bauxite waste sludge as a raw material, the use of reverse chemical coprecipitation synthesize Fe3O4. Researching temperature, precipitation concentration, aging time and Fe2+/Fe3+ molar ratio effect on the particle size, morphology. Optimal experimental conditions: temperature 70 °C, the precipitant NaOH mass ratio of 10%, aging time 3h, Fe2+/Fe3+ molar ratio of 2:3. Test methods using a laser particle size analyzer, XRD analysis of the products were characterized, the product is Fe3O4, the average particle size of 0.11mm.

Effect of Synthetic Technology on the Properties of Co2O3 Powder

2018 ◽  
Vol 281 ◽  
pp. 46-51
Author(s):  
Ge Xiong ◽  
Hui Min Sun ◽  
Xue Yang ◽  
Jin Shi Li ◽  
Mei Hua Chen ◽  
...  
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Reaction Time ◽  
Hydrothermal Synthesis ◽  
Salt Solution ◽  
Average Particle Size ◽  
Particle Aggregation ◽  
Molar Ratio ◽  
Average Particle

Ultrafine Co2O3powder was prepared via hydrothermal synthesis. The effect of technology on the performance of the superfine Co2O3powders was investigated, and the hydrothermal parameters in preparing Co2O3were gradually improved. In addition, the morphology and grain size of the Co2O3powder were analyzed by FESEM. Results show that reducing the salt–alkali molar ratio resulted in more uniform Co2O3powder and smaller particles, with average particle size of approximately 40 nm. Reaction time displayed little effect on the Co2O3powder, but the particle size decreased with the reaction time. The concentration of salt solution remarkably affected the morphology of the Co2O3powder. Lower concentration resulted in smaller particle aggregation and particle size.

Effect of Ascorbic Acid and Particle Size on Iron Absorption from Ferric Pyrophosphate in Adult Women

2004 ◽  
Vol 74 (4) ◽  
pp. 294-300 ◽  
Author(s):  
Fidler ◽  
Davidsson ◽  
Zeder ◽  
Walczyk ◽  
Marti ◽  
...  
Keyword(s):  
Particle Size ◽  
Ascorbic Acid ◽  
Iron Absorption ◽  
Average Particle Size ◽  
Relative Bioavailability ◽  
Molar Ratio ◽  
Average Particle ◽  
Adult Women ◽  
Mean Particle Size ◽  
Ferric Pyrophosphate

The effects of added ascorbic acid and particle size on iron absorption from ferric pyrophosphate were evaluated in adult women (9–10 women/study) based on erythrocyte incorporation of iron stable isotopes (57Fe or 58Fe) 14 days after administration. Three separate studies were made with test meals of iron-fortified infant cereal (5 mg iron/meal) and the results are presented as geometric means and relative bioavailability values (RBV, FeSO4 = 100%). The results of study 1 showed that iron absorption was significantly lower from ferric pyrophosphate (mean particle size 8.5 mum) than from FeSO4 in meals without ascorbic acid (0.9 vs. 2.6%, p < 0.0001, RBV 36%) and in the same meals with ascorbic acid added at a 4:1 molar ratio relative to fortification iron (2.3 vs. 9.7%, p < 0.0001, RBV 23%). Ascorbic acid increased iron absorption from ferric pyrophosphate slightly less (2.6-fold) than from FeSO4 (3.7-fold) (p < 0.05). In studies 2 and 3, RBV of ferric pyrophosphate with an average particle size of 6.7 mum and 12.5 mum was not significantly different at 52 and 42% (p > 0.05), respectively. In conclusion, the addition of ascorbic acid increased fractional iron absorption from ferric pyrophosphate significantly, but to a lesser extent than from FeSO4. Decreasing the mean particle size to 6.7 mum did not significantly increase iron absorption from ferric pyrophosphate.

scholarly journals Improved biodiesel production from waste cooking oil with mixed methanol–ethanol using enhanced eggshell-derived CaO nano-catalyst

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yeshimebet Simeon Erchamo ◽  
Tadios Tesfaye Mamo ◽  
Getachew Adam Workneh ◽  
Yedilfana Setarge Mekonnen
Keyword(s):  
Particle Size ◽  
Low Cost ◽  
Average Particle Size ◽  
Waste Cooking Oil ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Average Particle ◽  
Cooking Oil ◽  
Nano Catalyst

AbstractIn this report, the utilization of mixed methanol–ethanol system for the production of biodiesel from waste cooking oil (WCO) using enhanced eggshell-derived calcium oxide (CaO) nano-catalyst was investigated. CaO nano-catalyst was produced by calcination of eggshell powder at 900 °C and followed by hydration-dehydration treatment to improve its catalytic activity. The particle size, morphology, and elemental composition of a catalyst were characterized by using XRD, SEM, and EDX techniques, respectively. After hydration-dehydration the shape of a catalyst was changed from a rod-like to honeycomb-like porous microstructure. Likewise, average particle size was reduced from 21.30 to 13.53 nm, as a result, its surface area increases. The main factors affecting the biodiesel yield were investigated, accordingly, an optimal biodiesel yield of 94% was obtained at 1:12 oil to methanol molar ratio, 2.5 wt% catalyst loading, 60 °C, and 120-min reaction time. A biodiesel yield of 88% was obtained using 6:6 equimolar ratio of methanol to ethanol, the yield even increased to 91% by increasing the catalyst loading to 3.5 wt%. Moreover, by slightly increasing the share of methanol in the mixture, at 8:4 ratio, the maximum biodiesel yield could reach 92%. Therefore, we suggest the utilization of methanol–ethanol mixture as a reactant and eggshell-derived CaO as a catalyst for enhanced conversion of WCO into biodiesel. It is a very promising approach for the development of low-cost and environmentally friendly technology. Properties of the biodiesel were also found in good agreement with the American (ASTM D6571) fuel standards.

Preparation and Characterization of Silicone Oil/UF Resin Microcapsules as Erosion Inhibitor

2016 ◽  
Vol 723 ◽  
pp. 481-485 ◽  
Author(s):  
Hong Guang Li ◽  
Shao Sen Lin ◽  
Shi Guo Du ◽  
De Jiang Lin
Keyword(s):  
Particle Size ◽  
High Efficiency ◽  
In Situ Polymerization ◽  
Silicone Oil ◽  
Average Particle Size ◽  
Weight Ratio ◽  
Polymerization Process ◽  
Core Material ◽  
Molar Ratio ◽  
Average Particle

Microcapsules with silicone oil as core and poly (urea-formaldehyde) as shell were prepared by direct in-situ polymerization process. The influences of formaldehyde-urea molar ratios on microcapsules morphologies were investigated by scanning electron microscope (SEM). The microcapsules were characterized by fourier transform infrared spectrometer (FT-IR), particle size analyzer, simultaneous thermal analyzer. The results showed that well dispersive microcapsules were obtained with average particle size of 2.5 μm when formaldehyde-urea molar ratio was 1.8:1.0 and that the weight ratio of silicon dioxide to microcapsule was 15.4%, which produced from pyrolysis of core material silicone oil. The prepared microcapsules were expected to a kind of high-efficiency erosion inhibitor when used in propellant.

Effect of Polyvinylpyrrolidone Ratio on Synthesis of High Concentration Nano-Silver Colloid

2012 ◽  
Vol 466-467 ◽  
pp. 381-385
Author(s):  
Wei Wei Li ◽  
Lu Hai Li ◽  
Li Xin Mo ◽  
Ji Lan Fu
Keyword(s):  
Particle Size ◽  
Silver Nitrate ◽  
Average Particle Size ◽  
Thermo Gravimetric Analysis ◽  
Molar Ratio ◽  
Average Particle ◽  
Gravimetric Analysis ◽  
Silver Colloid ◽  
High Concentration ◽  
Nano Silver

Conductive ink, especially the nano-silver ink is becoming more and more popular in printable electronic field. In order to synthesize high concentration, stable nano-silver colloid, liquid chemical reduction is used and different ratios of PVP to silver nitrate are studied. After precise adjustments of the parameters, colloid with silver content of wt7.8% is obtained. Particle size distribution, UV-Vis spectra, thermo gravimetric analysis and SEM images are conducted to characterize the silver particles. The results show that when molar ratio of PVP to silver nitrate is 0.6, the average particle size is 170nm and some deposit can be seen, while the ratio increases to 1.5, the size decreases to 68nm, and the residue quality of the silver colloid showed in the TG analysis is 7.88%. After aging for 1 month, the colloid is still stable and the color keeps to the original dark green. When the ratio continues increasing to 2.5, particle size becomes 112nm and some larger particles beyond 3μm can be observed.

Preparation of Nanocrystalline Bismuth-Containing Powders through Solution-Phase Reductions

1999 ◽  
Vol 581 ◽  
Author(s):  
Edward E. Foos ◽  
Alan D. Berry ◽  
Arthur W. Snow ◽  
J. Paul Armistead
Keyword(s):  
Particle Size ◽  
Solution Phase ◽  
Nanocrystalline Powders ◽  
Average Particle ◽  
Particle Sizes ◽  
Size Distributions ◽  
Final Particle ◽  
Simultaneous Reduction ◽  
Large Size ◽  
Xrd And Tem

ABSTRACTIn an attempt to both prepare nanocrystalline bismuth and understand the fundamental chemistry behind the formation of this potentially interesting material, we have examined the reduction of BiCl3 in the presence of strongly coordinating solvents and ligands. These studies have resulted in the formation of bismuth powders with approximate average particle sizes of between 20 and 40 nm which exhibit large size distributions. The simultaneous reduction of both gold and bismuth precursors, done in an attempt to better control the final particle size, instead produces Au2Bi of comparable dimensions. There is no evidence that the ligands utilized in either of these systems remain bound to the final product. These nanocrystalline powders have been characterized through XRD and TEM, and full details of the synthesis are presented.

Physical Properties of Nanocrystalline MoS2 and WS2 Particles Produced by CO2 Laser Pyrolysis

1993 ◽  
Vol 327 ◽  
Author(s):  
Xiang-Xin Bi ◽  
Ying Wang ◽  
W. T. Lee ◽  
Kai-An Wang ◽  
S. Bandow ◽  
...  
Keyword(s):  
Particle Size ◽  
Structural Phase ◽  
Average Particle Size ◽  
Nanocrystalline Powders ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Laser Pyrolysis ◽  
Transmission Electron ◽  
Size Crystallite

AbstractNanocrystalline powders of 2H-MoS2 and 2H-WS2 with average particle size 5 and 9 nm, respectively, have been produced using C02laser pyrolysis. Typical production rate for these nanoparticles is 2g/hr. Particle size, crystallite size, and the structural phase were determined using X-ray diffraction(XRD), transmission electron microscopy(TEM), and Raman scattering. Particle size effects may have been observed in the Raman-active modes (WS2 and MoS2) and in the band-edge excitons (MoS2).

Evaluation of Polypyrrole Coating on Fe3O4 and Its Effect on Nanocomposite Properties

2004 ◽  
Vol 847 ◽  
Author(s):  
S. Liong ◽  
A. W. Harter ◽  
R. L. Moore ◽  
W. S. Rees
Keyword(s):  
Particle Size ◽  
Polymer Matrix ◽  
Magnetic Permeability ◽  
Oxidative Polymerization ◽  
Average Particle Size ◽  
Average Particle ◽  
Chemical Coprecipitation ◽  
Xrd And Tem ◽  
Lower Frequencies

ABSTRACTMagnetite (Fe3O4) nanoparticles were synthesized by chemical coprecipitation and were characterized using TEM, XRD, and VSM. XRD and TEM measurements indicate that the average particle size was approximately 10 nm. The nanoparticles were coated with polypyrrole using oxidative polymerization. TGA results show that the polypyrrole coating is 28.5wt%. TEM images indicate that the nanoparticles are bound in clusters by polypyrrole. Measurements show that nanoparticles may hinder curing of the polymer matrix, but they can be effective in producing composites with higher modulus and magnetic permeability at lower frequencies.

Particle Size Control, Structure and Magnetic Characterization of Cobalt Nanoparticles

2007 ◽  
Vol 998 ◽  
Author(s):  
Abhishek Singh ◽  
Nirav Parekh ◽  
Gregory Young ◽  
Kiumars Parvin ◽  
Maninder Kaur ◽  
...  
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Size Control ◽  
Reduction Reaction ◽  
Cobalt Nanoparticles ◽  
Molar Ratio ◽  
Ferromagnetic Behavior ◽  
Average Particle ◽  
Transmission Electron ◽  
Precursor Material

ABSTRACTCobalt nanoparticles were synthesized by means of a hot metal reduction reaction with cobalt chloride as precursor material. The size of cobalt nanoparticles was controlled by the choice of surfactant and the molar ratio of surfactant-to-reagent. Surfactants with larger alkane side chains yielded a smaller average nanoparticle size (diameter) and tighter size distribution, as these chains provided steric hindrance to the growth of the nanoparticles after initial nucleation. For each alkane side chain, a high molar ratio of surfactant-to-reagent (HSR) rendered nanoparticles with smaller particle size, while a low molar ratio of surfactant-to-reagent (LSR) produced larger nanoparticles. Measurements on transmission electron microscope images of cobalt particles synthesized with tri-octylphosphine revealed an average particle size of 6.9 nm (HSR) and 9.1 nm (LSR), while particles synthesized with tri-butylphosphine had a mean diameter of 12.5 nm (HSR) and 14.9 nm (LSR). X-ray diffraction profiles indicated that particles had metastable ε-cobalt structure. Room temperature magnetization measurements showed ferromagnetic behavior with highly square M-H loops indicative of single domain particles with coercive fields in the range of 400–500 Oe.

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