Preparation of Mesocarbon Microbeads (MCMB) from Suspensions of a Synthetic Naphthalene Isotropic Pitch

2017 ◽  
Vol 753 ◽  
pp. 231-236
Author(s):  
Sheng Juan Ji ◽  
Xiang Lin Cheng ◽  
Jian Hong Zhao ◽  
Qing Ling Bi ◽  
Liu Cheng Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Diameter ◽  
Average Particle ◽  
Average Particle Diameter ◽  
X Ray ◽  
Mesocarbon Microbeads ◽  
Dispersion Degree ◽  
Isotropic Pitch ◽  
Particle Size Analyzer ◽  
Size Dispersion

A synthetic naphthalene isotropic pitch, which was manufactured with HF/BF3 acting as catalyst, was used as material to prepare mesocarbon microbeads (MCMB) through suspension method. The material pitch was dissolved in tetrahydrofuran (THF) and the pitch-THF solution is dispersed in a 2% polyvinyl alcohol aqueous solution. After THF was volatilized, the solution was cooled and then filtered to attain little pitch sphere. The pitch spheres were oxidized in 65% HNO3 solution, and the oxidized pitch spheres were carbonized up to 1000°C to get MCMB. MCMB was analyzed by scanning electron microscope (SEM), laser particle size analyzer and X ray diffractometer. The result showed that the particle size of MCMB was 2-30 μm and the average particle diameter size of D50 was 15.83 μm. The particle size distribution accords to the normal distribution, and the particle size dispersion degree was 0.7574. The effect of 65% HNO3 oxidation of the pitch sphere showed a satisfactory result. After carbonization at 1000°C, the oxidized pitch sphere exhibited a better orientation arrangement, the distance between the aromatic plane (d002) was decreased, and the thickness of the piled plane is increased.

scholarly journals Preparation of ultrafine iron phosphate micro-powder from phosphate slag

2018 ◽  
Vol 238 ◽  
pp. 02002
Author(s):  
Fangjing Sun ◽  
Yi Zhang ◽  
Jiawei Zhang ◽  
Xixi Yan ◽  
Xiaoyu Liu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Electron Microscope ◽  
Average Particle Size ◽  
Iron Phosphate ◽  
Average Particle ◽  
X Ray ◽  
Particle Size Analyzer ◽  
Phosphate Slag ◽  
Scanning Electron

In this experiment, ultrafine iron phosphate micro-powder was prepared by hydrothermal method which used phosphate slag as an iron source. The effects of reaction temperature, surfactants type and amount on its particle size were explored. The samples were characterized by using Malvern Laser Particle Size Analyzer (MS2000), X-Ray Diffractometer (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray Spectroscopy (EDX).The results showed that at 160 °C, 1 wt%CTAB, monoclinic iron phosphate micro-powder was obtained with an average particle size about 0.4 μm which also has a good dispersion in aqueous solution.

Use of Calixarene Host Molecules to Stabilize Quantum-confined Cadmium Sulfide Formation

1992 ◽  
Vol 272 ◽  
Author(s):  
Robin R. Chandler ◽  
Jeffery L. Coffer ◽  
C. David Gutsche ◽  
Iftikhar Alam ◽  
Hong Yang ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Diameter ◽  
Spectroscopic Studies ◽  
Average Particle ◽  
Average Particle Diameter ◽  
Absorption And Emission ◽  
Zinc Blende ◽  
High Resolution Tem ◽  
Quantum Confined ◽  
Macrocyclic Molecules

ABSTRACTWe describe here the use of calixarenes, methylene (-CH2-) linked phenolic macrocyclic molecules, to stabilize the formation of quantum-confined (Q-) CdS clusters. Specifically, we focus on the use of an amino-derivatized calixarene, para-[(dimethylamino)- methyl]calix[6]arene, to stabilize Q-CdS clusters which have been characterized by High Resolution TEM (HREM), as well as absorption and emission spectroscopies. Under typical preparative conditions, an average particle diameter of 36 Å is obtained. HREM, in combination with Selected Area Diffraction (SAD), confirms the structure of the clusters as zinc blende CdS. Spectroscopic studies using absorption and emission methods indicate that both particle size and cluster photophysics are sensitive to the ratio of CdS to calixarene.

Minimum Particle Diameter of the Sulfur-Doped Nano-TiO2 Transparent Hydrosol at Room Temperature

2014 ◽  
Vol 587-589 ◽  
pp. 788-791
Author(s):  
Ling Li ◽  
Hua Yan Zhang ◽  
Xiao Wei Li ◽  
Zi Hao Xu ◽  
Sen Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Room Temperature ◽  
Photocatalytic Performance ◽  
Raw Materials ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Synthesis Process ◽  
Average Particle ◽  
Hydrolysis Method ◽  
Particle Size Analyzer

Sulfur-doped nanoTiO2transparent hydrosol with an average particle size of 3.8 nm was synthesized by a novel complexation-controlled hydrolysis method at room temperature and atmospheric pressure by using TiCl4, thiourea, organic carboxylic acid, NH3H2O, D-sorbitol etc. as raw materials. The composition, phase structure, particle size, absorbance spectrum, and photocatalytic performance of samples were characterized by XRD, nanolaser particle size analyzer, ultraviolet-visible spectrophotometer. In addition, the influence of reaction conditions in the synthesis process was also studied. The results indicate that when nanoparticle doped with 0.5% S, and the reflux time was 15 min, the photocatalytic performance of sulfur-doped TiO2hydrosol was best.

“Colloidal” Zinc Oxide

1937 ◽  
Vol 10 (2) ◽  
pp. 309-311
Author(s):  
H. A. Curran ◽  
T. R. Dawson
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
Manufacturing Industry ◽  
Average Particle Size ◽  
Particle Diameter ◽  
Average Particle ◽  
Average Particle Diameter ◽  
Zinc Oxides ◽  
Two Samples ◽  
Good Grade

Abstract Some ten years ago, when so-called “colloidal” zinc oxides were being introduced to the rubber manufacturing industry, two samples were investigated to determine their behavior in rubber compared with ordinary good quality zinc oxide used in rubber. According to accounts published at the time, “colloidal” zinc oxide possesses an average particle size just within the limit of resolution of high-power microscopes, and an average particle diameter of 0.15 micron. In rubber it has been claimed to impart superior reinforcement, higher tensile strength, greater resistance to abrasion, and enhanced activation of organic accelerators. In the following report, samples A and B represent two samples of the same grade of “colloidal” zinc oxide, and C a good grade of regular zinc oxide.

scholarly journals Sintesis Nanopartikel Perak Menggunakan Ekstrak Daun Salam (Syzygium polyanthum) Sebagai Bioreduktor Dan Uji Aktivitasnya Sebagai Antioksidan

2019 ◽  
Vol 7 (1) ◽  
pp. 51-60
Author(s):  
Paulina Taba ◽  
Nadya Yuli Parmitha ◽  
Syahruddin Kasim
Keyword(s):  
Particle Size ◽  
Silver Nanoparticles ◽  
Leaf Extract ◽  
Average Particle Size ◽  
Average Diameter ◽  
Average Particle ◽  
X Ray ◽  
Synthesis Of Nanoparticles ◽  
Particle Size Analyzer ◽  
Ic50 Value

Silver nanoparticles have been synthesized by the reduction method using salam leaf extract (Syzygium polyanthum) as a reducing agent. The silver nanoparticles produced were then tested for their activity as antioxidants. The formation of silver nanoparticles was carried out by adding the leaf extract into the solution of AgNO3 and homogenized using a magnetic stirrer. A UV-Vis spectrophotometer was used to confirm the formation of silver nanoparticles. Particle Size Analyzer (PSA), Scanning Electron Microscope (SEM), X-Ray Diffractometer (XRD) and Fourir Transform Infra Red (FTIR) spectrometers were used to characterize the nanoparticles produced before being tested for antioxidant activity. The results showed that the absorbance value increased with increasing reaction contact time. The maximum uptake was obtained at wavelengths of 432-446 nm using a UV-Vis spectrophotometer. The particle size was determined using a PSA with an average particle size distribution of 45.7 nm. The average diameter of silver nanoparticles was 10.06 – 13.97 nm and the silver nanoparticles had rod-shapes. Functional groups that play a role in the synthesis of nanoparticles were –OH, –C=O, and –C-O groups. Silver nanoparticles inhibited free radicals as antioxidants with the IC50 value of 582.7 ppm.

scholarly journals Synthesis of monodisperse poly(styrene-co-divinyl benzene) microspheres by precipitation polymerization in acetonitrile and n-butanol mixture

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Jiang Hongyan ◽  
Chen Hou ◽  
Liang Ying ◽  
Xuan Yuhong ◽  
Wang Mingliang
Keyword(s):  
Thermal Stability ◽  
Particle Size ◽  
Particle Diameter ◽  
Reaction Medium ◽  
Precipitation Polymerization ◽  
Average Particle ◽  
Average Particle Diameter ◽  
Initiator Concentration ◽  
Reaction Parameters ◽  
Divinyl Benzene

AbstractNarrow disperse poly(styrene-co-divinylbenzene) microspheres were prepared by precipitation polymerization using acetonitrile/n-butanol mixture as the reaction medium and 2,2’-azobis(2-methylpropionitrile) (AIBN) as initiator. The resulting particles have smooth surfaces due to the absence of any additional stabilizer. Effects of the reaction parameters such as n-butanol fraction in the reaction medium, monomer and initiator concentration, and divinylbenzene content were investigated. It was found that the particle size increased with an increasing concentration of monomer and initiator, while the uniformity was kept constant. The number-average particle diameter ranged from 2.36 to 1.63 μm and decreased with an increasing divinylbenzene concentration. In addition, the uniformity was enhanced as the concentration of divinylbenzene increased. On the basis of the DSC and TGA data, the microspheres prepared by the precipitation polymerization possessed a highly crosslinked structure and the thermal stability improved with the DVB concentration.

The Effect of Nanometer Polysilicon Material on Properties of Wax-Diesel Oil Systems

2013 ◽  
Vol 774-776 ◽  
pp. 1237-1241
Author(s):  
Ren Yuan Sun ◽  
Kun Kun Fan ◽  
Lei Wang ◽  
Xiao Meng Huang ◽  
Chao Sun
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Dispersion Model ◽  
Particle Diameter ◽  
Diesel Oil ◽  
Average Particle ◽  
Scattering Method ◽  
Average Particle Diameter ◽  
Laser Scattering

The effect of nanometer polysilicon material (NMPM) on properties of wax-diesel oil systems was experimentally studied. The particle size distribution of NMPM-diesel oil, wax-diesel oil system and wax-NMPM-diesel oil system were measured by laser scattering method. The viscosity of wax-diesel oil system was compared with that of systems with NMPM addition. A new wax growth and dispersion model was built up to analyze the mechanism for wax solubility increasing and size changing. Experiments show that the solubility of wax increases with the increase of temperature and the NMPM concentration in the wax-diesel oil system. The average particle diameter of NMPM-wax-diesel oil system is larger than that of wax-diesel oil system. The viscosity of wax-diesel oil system decreases with the NMPM addition.

A Critical Evaluation of the Reduced-Iron Method for Reduction of Nitrates

1963 ◽  
Vol 46 (4) ◽  
pp. 599-603
Author(s):  
J A Brabson ◽  
W G Burch ◽  
T C Woodis
Keyword(s):  
Particle Size ◽  
Reaction Time ◽  
Critical Evaluation ◽  
Particle Diameter ◽  
Average Particle ◽  
Average Particle Diameter ◽  
Electrolytic Iron ◽  
Large Excess

Abstract The first action reduced iron method for nitrogen in fertilizers specifies the use of electrolytic iron and indicates that a large excess of iron is required for the reduction of nitrates. Iron reduced by hydrogen, however, is a more efficient reductant than electrolytic iron, but it requires a longer reaction time. The specified amount of iron is excessive. The particle size of the iron is important, and 250-mesh is the largest particle size that should be used; specification of the average particle diameter in microns is recommended. The reduced iron method is, at best, a cumbersome procedure, and other, more efficient, reductants for nitrate should be sought.

scholarly journals Effect of Particle Size Distributions on Minimum Fluidization Velocity with Varying Gas Temperature

2020 ◽  
Vol 11 (11) ◽  
pp. 524-529
Author(s):  
Krittin Korkerd ◽  
◽  
Chaiwat Soanuch ◽  
Pornpote Piumsomboon ◽  
Benjapon Chalermsinsuwan
Keyword(s):  
Particle Size ◽  
Standard Deviation ◽  
Particle Diameter ◽  
Skewed Distribution ◽  
Average Particle ◽  
Average Particle Diameter ◽  
Gas Temperature ◽  
Minimum Fluidization Velocity ◽  
Fluidization Velocity ◽  
Minimum Fluidization

The particle size distribution (PSD) is an important property that can influence the hydrodynamics and chemical conversion in fluidized bed system. The objective of this study is to investigate the effect of PSDs of particle and gas temperature on minimum fluidization velocity (Umf). Here, the silica sand with three average diameters and five PSDs including narrow cut, Gaussian, Gaussian with high standard deviation, negative skewed distribution and positive skewed distribution were used. The considered gas temperature ranged from 30 to 120 °C. The results showed that the Umf values with wide PSDs were lower than the Umf values for narrow cut particle with the same average diameter. The reason can be explained by the addition of smaller particle will improve the fluidization characteristics. The standard deviation and skewness of PSD also influenced on the Umf. The Umf was observed to decrease with increasing gas temperature. In addition, the effect of average particle diameter could also be seen. The Umf increased with the increasing of average particle diameter.

Use of the Processed Waste from Kaolin and Granite Sawing in the Manufacture of Tubular Ceramic Membranes

2014 ◽  
Vol 805 ◽  
pp. 337-342 ◽  
Author(s):  
Alexsandra Cristina Chaves ◽  
Gelmires Araújo Neves ◽  
Hélio Lucena Lira ◽  
Danielle Nascimento Silva Oliveira ◽  
Ana M.G.D. Mendonça
Keyword(s):  
Particle Size ◽  
Mercury Porosimetry ◽  
Particle Diameter ◽  
Ceramic Membranes ◽  
Raw Material ◽  
Average Particle ◽  
Average Pore ◽  
X Ray ◽  
Ceramic Mass ◽  
Indiscriminate Disposal

The incorporation of waste from various industrial activities in ceramic products comes as a technological alternative to reduce the environmental impacts caused by the indiscriminate disposal of wastes in the environment. The kaolin and granite processing industries have been mentioned as sources of contamination and pollution, due to the enormous amounts of wastes they produce. The use of these wastes as raw material and its transformation into products that can be commercialized and/or show economic viability, presents as an alternative to the industries. The aim of this work was to use ceramic masses incorporated with kaolin waste (35%), granite (35%) and bentonite (30%) for the confection of tubular ceramic membranes using extrusion as production process. The ceramic mass was characterized through analysis techniques of thermogravimetric, chemical, particle size and X-ray. The membranes produced, after sintering in temperatures of 850, 900, 950 and 1000oC, were submitted to characterizations of scanning electron microscopy, mercury porosimetry and permeability test by tangential flow. The preliminary result of the particle size analyses identified that the ceramic mass presents an average particle diameter of 37.00μm. The membranes presented porosity of approximately 32%, and average pore diameter within the ultrafiltration range.

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