Synthesis of Ultrafine SrCO3 Powders by High Gravity

2012 ◽  
Vol 531-532 ◽  
pp. 226-229
Author(s):  
Xing Wu Zou ◽  
Shu Xuan Wang ◽  
Zhan Shou Yang ◽  
Mi Xiang Qi ◽  
Shu Ya Wang
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Particle Dispersion ◽  
Strontium Carbonate ◽  
Raw Material ◽  
Spherical Particles ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
High Gravity ◽  
Rotating Speed

A new synthetic technology of Strontium carbonate with high gravity is introduced in this paper. We got ultrafine SrCO3 powders with Sr(NO3)2 and NaCO3 or CO2 as raw material by high gravity method. We studied flows, the rotating speed, additives and CO2 as the reactants on the morphology of strontium carbonate. The results show that the presence of additive-free, we got rod-like structure of strontium carbonate. Added EDTA, we got a good dispersion of spherical particles of narrow particle size distribution. The presence of EDTA, the average particle size of spherical particles decreases with the speed increases. CO2 alternative Na2CO3 as the reactants, the presence of additive-free, we got the bundle structure of strontium carbonate. The presence of EDTA, we got spherical particles, but the particle dispersion is not well, gathered together.

scholarly journals Application of surfactants for the synthesis of qualitative hydroxide and metallic cobalt nanopowders

2021 ◽  
pp. 4-11
Author(s):  
Van Minh Nguyen ◽  
Tien Hiep Nguyen ◽  
Stanislav V. Gorobinsky
Keyword(s):  
Particle Size ◽  
Hydrogen Reduction ◽  
Cetylpyridinium Chloride ◽  
Average Particle Size ◽  
Sodium Dodecyl ◽  
Chemical Precipitation ◽  
Spherical Particles ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Application Of Surfactants

In this work, nanopowders (NP) Co(OH)2 were obtained by chemical precipitation from aqueous solutions of cobalt nitrate Co(NO3)2 and alkali NaOH (10 wt. %) using surfactants: sodium dodecyl sulfate (SDS) and cetylpyridinium chloride (CPC) (0.1 wt. %). It was shown that Co(OH)2 NP with 0.1% SDS is the best quality product, since its dispersion increases more than 2 times compared to the samples with 0.1% CPC and without surfactants. In this case, the Co(OH)2 NP has the form of flakes with an irregular shape and a nanometer size (about 100 nm) with an average thickness of 30 nm. It was found that the average particle size of Co NP obtained by hydrogen reduction of Co(OH)2 NP with 0.1% SDS at 280°C has a maximum on the distribution histogram shifted to the interval 41–50 nm, which is characterized by a narrow particle size distribution and represents spherical particles sintered with each other.

Fabrication and Microstructure of ZnO-TiO2 Composite Membranes by a Reverse Micelle and Sol-Gel Processing

2006 ◽  
Vol 510-511 ◽  
pp. 786-789 ◽  
Author(s):  
Dong Sik Bae ◽  
Byung Ik Kim ◽  
Kyong Sop Han
Keyword(s):  
Particle Size ◽  
Reverse Micelle ◽  
Porous Alumina ◽  
Sol Gel ◽  
Average Particle Size ◽  
Composite Membranes ◽  
Dip Coating ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Alumina Support

ZnO-TiO2 nanoparticles were synthesized by a reverse micelle and sol-gel process. The average particle size of the colloid was below 30 nm and well dispersed in the solution. ZnOTiO2 composite membranes were fabricated by using the dip-coating method on a porous alumina support. ZnO-TiO2 composite membranes showed a crack-free microstructure and narrow particle size distribution even after the heat treatment up to 600°C. The average particle size of the membrane was 30-40nm, and the pore size of ZnO-TiO2 composite membrane was below 10 nm.

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.

scholarly journals Preparation, Characterization, and In Vivo Pharmacokinetic Study of the Supercritical Fluid-Processed Liposomal Amphotericin B

Pharmaceutics ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 589 ◽  
Author(s):  
Chang-baek Lim ◽  
Sharif Md Abuzar ◽  
Pankaj Ranjan Karn ◽  
Wonkyung Cho ◽  
Hee Jun Park ◽  
...  
Keyword(s):  
Particle Size ◽  
Amphotericin B ◽  
Supercritical Fluid ◽  
Liposomal Amphotericin ◽  
Average Particle Size ◽  
Spherical Particles ◽  
Liposomal Amphotericin B ◽  
Average Particle ◽  
In Vivo Pharmacokinetics

Here, we aimed to prepare and optimize liposomal amphotericin B (AmB) while using the supercritical fluid of carbon dioxide (SCF-CO2) method and investigate the characteristics and pharmacokinetics of the SCF-CO2-processed liposomal AmB. Liposomes containing phospholipids, ascorbic acid (vit C), and cholesterol were prepared by the SCF-CO2 method at an optimized pressure and temperature; conventional liposomes were also prepared using the thin film hydration method and then compared with the SCF-CO2-processed-liposomes. The optimized formulation was evaluated by in vitro hemolysis tests on rat erythrocytes and in vivo pharmacokinetics after intravenous administration to Sprague-Dawley rats and compared with a marketed AmB micellar formulation, Fungizone®, and a liposomal formulation, AmBisome®. The results of the characterization studies demonstrated that the SCF-CO2-processed-liposomes were spherical particles with an average particle size of 137 nm (after homogenization) and drug encapsulation efficiency (EE) was about 90%. After freeze-drying, mean particle size, EE, and zeta potential were not significantly changed. The stability study of the liposomes showed that liposomal AmB that was prepared by the SCF method was stable over time. In vivo pharmacokinetics revealed that the SCF-CO2-processed-liposomes were bioequivalent to AmBisome®; the hemolytic test depicted less hematotoxicity than Fungizone®. Therefore, this method could serve as a potential alternative for preparing liposomal AmB for industrial applications.

Effect of Surfactant on the Preparation of Nano-powder for Yb Doping Laser Transparent YAG Ceramic

2013 ◽  
Vol 32 (5) ◽  
pp. 511-515 ◽  
Author(s):  
Xiao Guo Cao ◽  
Jia Wang ◽  
Qi Bai Wu ◽  
Hai Yan Zhang
Keyword(s):  
Particle Size ◽  
Polyethylene Glycol ◽  
Average Particle Size ◽  
Ammonium Bicarbonate ◽  
Spherical Particles ◽  
Precipitation Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Nano Powder ◽  
Co Precipitation

AbstractYb:YAG transparent ceramic nano-powder was prepared by chemical co-precipitation method, with ammonium bicarbonate as the precipitant and polyethylene glycol as surfactant. The addition of polyethylene glycol can reduce the agglomeration and particle size of the prepared Yb:YAG powder. The morphology, thermal stability and phase structure of Yb:YAG nano-powder were charactered by scanning electron microscopy (SEM), thermogravimetry and differential thermal analysis (TG-DTA), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy. The results show that well-crystallized nano-powder was obtained by calcining the precursors at 900 °C for 3 h. The average particle size of Yb:YAG powder is about 100–200 nm. When the volume amount of polyethylene glycol is 2.0%, well-dispersed Yb:YAG powder with spherical particles of 100 nm diameter was obtained.

scholarly journals Structural and Optical Properties of Silicon Carbide Powders Synthesized from Organosilane Using High-Temperature High-Pressure Method

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3111
Author(s):  
Evgeny A. Ekimov ◽  
Vladimir S. Krivobok ◽  
Mikhail V. Kondrin ◽  
Dmitry A. Litvinov ◽  
Ludmila N. Grigoreva ◽  
...  
Keyword(s):  
Particle Size ◽  
Optical Properties ◽  
Average Particle Size ◽  
Synthesis Temperature ◽  
Narrow Particle Size Distribution ◽  
High Tech ◽  
Average Particle ◽  
Coupled Modes ◽  
Dominant Type ◽  
High Structure

The development of new strategies for the mass synthesis of SiC nanocrystals with high structure perfection and narrow particle size distribution remains in demand for high-tech applications. In this work, the size-controllable synthesis of the SiC 3C polytype, free of sp2 carbon, with high structure quality nanocrystals, was realized for the first time by the pyrolysis of organosilane C12H36Si6 at 8 GPa and temperatures up to 2000 °C. It is shown that the average particle size can be monotonically changed from ~2 nm to ~500 nm by increasing the synthesis temperature from 800 °C to 1400 °C. At higher temperatures, further enlargement of the crystals is impeded, which is consistent with the recrystallization mechanism driven by a decrease in the surface energy of the particles. The optical properties investigated by IR transmission spectroscopy, Raman scattering, and low-temperature photoluminescence provided information about the concentration and distribution of carriers in nanoparticles, as well as the dominant type of internal point defects. It is shown that changing the growth modes in combination with heat treatment enables control over not only the average crystal size, but also the LO phonon—plasmon coupled modes in the crystals, which is of interest for applications related to IR photonics.

A New Process for Preparing Nanosize Ceramic Powders

1994 ◽  
Vol 351 ◽  
Author(s):  
Yong S. Zhen ◽  
Kenneth E. Hrdina ◽  
Robert J. Remick
Keyword(s):  
Particle Size ◽  
Metal Oxides ◽  
Average Particle Size ◽  
Cost Effective ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Mixed Metal Oxides ◽  
Ceramic Powders ◽  
New Process ◽  
The Cost

ABSTRACTWe have developed a new poly-foam process for the cost effective preparation of ceramic nanoparticles. The process utilizes the chemistry of polyurethane reactions and is proven to be effective for forming nanometer size ceramic powders of a great variety of single metal oxides and mixed metal oxides. In general, ceramic powders can be prepared by this process having a range of average particle size between 3 to 50 nm, with very narrow particle size distribution. They are free of hard agglomerates, are chemically pure and uniform, and are essentially spherical in shape.

Preparation and Characterization of Macromeritic Tungsten Powder Reduced by Ammonium Paratungstate at Medium Temperature

2012 ◽  
Vol 468-471 ◽  
pp. 2584-2587
Author(s):  
Rui Xin Wang ◽  
Zhi Meng Guo ◽  
Jun Jie Hao ◽  
Ji Luo ◽  
Yan Jun Xin
Keyword(s):  
Particle Size ◽  
Hydrogen Reduction ◽  
Tungsten Powder ◽  
Average Particle Size ◽  
Raw Material ◽  
Metal Salts ◽  
Average Particle ◽  
Medium Temperature ◽  
Ammonium Paratungstate ◽  
Ammonium Tungstate

The macromeritic tungsten powder was prepared by wet hydrogen reduction at medium temperature; the coarse powder of Ammonium paratungstate powder (APT) was used as raw material. It is obtained by evaporating and crystallizating adding alkalia metal salts in the solution of ammonium tungstate. The microstructure, phase composition and particle size of the macromeritic tungsten powder were investigated by SEM, XRD and test analysis sieves. The effects of kinds, contents of alkali metal salts and the temperature in the reduction were studied. The results revealed that ideal tungsten powder, with the good fluditity, spherical, integrate and well-distributed, could be obtained. The raw material is the solution of ammonium tungstate adding NaCl, Li2CO3 and KCl , the concentration of them are all 3g/L, and it is under the condition of 1000°C,180min in wet hydrogen atmosphere. The average particle size is 67μm, the maximum is 150μm, the biggest loose density is 13.41g/cm3, and the best powder flowability is 9s/50g.

scholarly journals Effect of dopants [Gd3+, Sm3+, Ca2+, Sr2+ and Ba2+] on the performance characteristics of ceria based electrolytes for application in solid oxide fuel cells

2014 ◽  
Vol 10 (2) ◽  
Author(s):  
M.L. Reni ◽  
A. Samson Nesaraj
Keyword(s):  
Particle Size ◽  
Fuel Cells ◽  
Low Temperature ◽  
Solid Oxide Fuel Cells ◽  
Average Particle Size ◽  
Solid Oxide ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Doped Ceria ◽  
Oxide Fuel

Doped CeO2 based materials are now-a-days proposed as alternate electrolyte materials for solid oxide fuel cells (SOFCs) working at low temperature (~723 – 873 K). In this research work, nanoparticles of CeO2 doped with Gd3+, Sm3+, Ca2+, Sr2+ and Ba2+were prepared by a simple homogeneous chemical precipitation method. The prepared materials (after heat treatment at 1023 K for 2 hours) were systematically characterized by XRD, EDAX analysis, FTIR , particle size analysis and SEM.  Lattice parameters were calculated from the XRD data. The XRD results indicate that all the doped ceria samples studied are single phase with a cubic fluorite structure. The average particle size of the doped ceria powder was about 48 – 115 nm and the particles have shown narrow particle size distribution patterns. AC impedance spectroscopy studies performed on the sintered specimens have shown better oxide ion conductivity values and hence these materials may be suitable for application as electrolyte materials in solid oxide fuel cells working at low temperature (~723 – 873 K). ________________________________________GRAPHICAL ABSTRACT

scholarly journals Design of a Reversible Cholinesterase Inhibitor Mamentine HCL Nanogel: Formulation and In-vitro Evaluation

2021 ◽  
pp. 352-359
Author(s):  
Subhasri Mohapatra ◽  
Sourabh Jain ◽  
Karunakar Shukla
Keyword(s):  
Particle Size ◽  
Cholinesterase Inhibitor ◽  
Average Particle Size ◽  
In Vitro Release ◽  
Storage Period ◽  
Spherical Particles ◽  
Average Particle ◽  
In Situ Gel

Memantine hydrochloride is a is a reversible cholinesterase inhibitor used in the treatment of Alzheimer’s disease, low-moderate affinity, uncompetitive n-methyl-d-aspartate (NMDA) receptor antagonist, with strong voltage dependency and rapid blocking/unblocking kinetics. The present study was explore the potential of thermosensitive nanogel of mamentine loaded nanoparticle. In situ gel choosing due to restrict unwanted exposure in blood and other healthy tissues, thus eliminate hemolytic side effects of the drug and offer easy administration in vivo. Nanoparticle prepared by ionic gelation method and further the dried nanoparticle incorporates with in situ gel.  The in situ gel prepared by cold method using the solutions of Poloxamer-188 and Carbopol-934. The Transmission electron microscopy showed the spherical particles  with  smooth surface which was in conformity  with the SEM and Zetasizer  data for particle size. The pH of the formulations was found to be satisfactory and was in the range of 6.8±0.039 -7.4±0.053 and also mucoadhesive strength was show in table. The mucoadhesive strength of all formulations was varies from 2398±0.0004 to 4945±0.0002 dynes/cm2. In-vitro diffusion study of the in situ gel (N1-N8) was performed using modified Franz diffusion cell with dialysis membrane in phosphate buffer pH 6.5 for a period of 24 hours. The in vitro release study were fitted into various kinetic models viz zero order, first order, higuchi model and korsmeyer peppas equation. Stability studies for optimized formulations were carried out at 4.0 ± 0.5°C and 37 ± 0.5ºC for a period of four weeks. There was no significant variation found in physical appearance, average particle size and % drug content of the in situ nanogel N2. No visible changes in the appearance of the gel formulation were observed at the end of the storage period.

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