SYNTHESIS OF MAGNETITE NANOPARTICLES BY THERMAL DECOMPOSITION: TIME, TEMPERATURE, SURFACTANT AND SOLVENT EFFECTS

2008 ◽  
Vol 01 (03) ◽  
pp. 189-193 ◽  
Author(s):  
DIPAK MAITY ◽  
JUN DING ◽  
JUN-MIN XUE
Keyword(s):  
Thermal Decomposition ◽  
Particle Size ◽  
Magnetic Properties ◽  
Reaction Time ◽  
Saturation Magnetization ◽  
Size Distribution ◽  
Reaction Temperature ◽  
Particle Surface ◽  
Full Potential ◽  
Magnetite Particles

Monodispersed magnetite ( Fe 3 O 4) nanoparticles can be synthesized by thermal decomposition of iron(III) acetylacetonate, Fe ( acac )3. High saturation magnetization M S of the magnetite particles is extremely important to realize the full potential of magnetite materials in biomedical application. In this work, we have studied the different effects (time, temperature and surfactant) on structure and magnetic properties of Fe 3 O 4 nanoparticles. The M S of the particles are enhanced after the synthesis at a higher reaction temperature and/or a longer reaction time. However, the increase in reaction temperature and/or reaction time resulted in particle size increase and the broadening of the particle size distribution. In this work, high M S value of the magnetite particles has been achieved through adopting surfactant or modification of solvent to overcome the temperature and time effects, while the smaller size particles with an acceptable size distribution has been maintained. Size and morphology of the particles were studied by TEM while magnetic properties of the particles were measured using VSM. The saturation magnetization M S of the particles can be increased at higher reaction temperature and/or longer reaction time, while narrow size distribution of the particles can be maintained either by the selective adsorption of oleic acid to the particle surface or by synthesizing them using solvent free thermal decomposition reaction.

scholarly journals LOW-TEMPERATURE SYNTHESIS OF SUPERPARAMAGNETIC Zn0.8Ni0.2Fe2O4 FERRITE NANOPARTICLES

2018 ◽  
Vol 56 (1) ◽  
pp. 31
Author(s):  
Luong Thi Quynh Anh ◽  
Nguyen Van Dan ◽  
Do Minh Nghiep
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Oleic Acid ◽  
Low Temperature ◽  
Coercive Force ◽  
Saturation Magnetization ◽  
Ferrite Nanoparticles ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
Co Precipitation

The crystalline nanoparticles of Ni0.2Zn0.8Fe2O4 ferrite were synthesized by chemical co-precipitation with precursor concentration of 0.1M, then modified by 0.25M solution of oleic acid in pentanol, finally heated at temperatures 120, 140, 160 and 180oC for 6h in autoclave. The XRD, EDS and TEM confirmed that all of samples are crystalline and their particle size are 6, 6.5, 7 and 8 nm. The magnetic properties showed that the coercive force, the remanence of samples are about zero, the saturation magnetization Ms has values from 14.20 to 27.12 emu/g.

The effect of reaction temperature on the particle size, structure and magnetic properties of coprecipitated CoFe2O4 nanoparticles

2006 ◽  
Vol 60 (29-30) ◽  
pp. 3548-3552 ◽  
Author(s):  
Yuqiu Qu ◽  
Haibin Yang ◽  
Nan Yang ◽  
Yuzun Fan ◽  
Hongyang Zhu ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Reaction Temperature ◽  
Size Structure ◽  
Cofe2o4 Nanoparticles

Taguchi Approach and ANOVA in Optimization of the Dissolution of Colemanite in CO2 and SO2- Water Systems

2020 ◽  
Vol 10 (2) ◽  
pp. 88-97
Author(s):  
Zafer Ekinci ◽  
Esref Kurdal ◽  
Meltem Kizilca Coruh
Keyword(s):  
Particle Size ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Gas Flow ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Process Conditions ◽  
Liquid Ratio ◽  
Positive Effects ◽  
Controllable Factors

Background: Turkey is approximately 72% of the world’s boron sources. Colemanite, tincal, ulexite and pandermite are among the most significant in Turkey. Boron compounds and minerals are widely used in many industrial fields. Objective: The main purpose of this study was to investigate the control of impurities in the boric acid production process using colemanite by carrying out the reaction with a mixture of CO2 and SO2 - water, and determining the appropriate process conditions to develop a new process as an alternative to the use of sulfuric acid. Due to worrying environmental problems, intensive studies are being carried out globally to reduce the amount of CO2 and SO2 gases released to the atmosphere. Methods: The Taguchi method is an experimental design method that minimizes the product and process variability by selecting the most appropriate combination of the levels of controllable factors compared to uncontrollable factors. Results: It was evaluated the effects of parameters such as reaction temperature, solid-to liquid ratio, SO2/CO2 gas flow rate, particle size, stirring speed and reaction time. The optimum conditions determined to be reaction temperature of 45°C; a solid–liquid ratio of 0.083 g.mL−1; an SO2/CO2 ratio of 2/2 mL.s−1; a particle size of -0.354+0 .210 mm; a mixing speed of 750 rpm and a reaction time of 20 min. Conclusion: Under optimum operating conditions, 96.8% of colemanite was dissolved. It is thought that the industrial application of this study will have positive effects on the greenhouse effect by contributing to the reduction of CO2 and SO2 emissions that cause global warming.

Enhanced Photocatalytic Performance and Mechanism of Ag3PO4 Particles Synthesized via a Sonochemical Process

2018 ◽  
Vol 10 (3) ◽  
pp. 337-345 ◽  
Author(s):  
Chengxiang Zheng ◽  
Hua Yang ◽  
Yang Yang ◽  
Haimin Zhang
Keyword(s):  
Particle Size ◽  
Photocatalytic Activity ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Ph Value ◽  
Dye Degradation ◽  
Sonochemical Method ◽  
Simulated Sunlight ◽  
Spherical Nanoparticles ◽  
Direct Oxidation

A facile sonochemical method was used to synthesize Ag3PO4 particles and the effect of pH value, reaction temperature and reaction time on the products was investigated. It is found that the samples prepared at neutral (pH = 7) and alkaline (pH = 11) environments exhibit a similar particle morphology and size. The particles are shaped like spheres with a size distribution majorly focusing on a range of 200–450 nm, and the average particle size is about 300 nm. The sample prepared at acidic environment (pH = 3) is composed of polyhedral microparticles with size of 5–8 μm. At relatively low temperatures of 20–50 °C, the spherical nanoparticles do not undergo obvious morphology/size changes; however, when the temperature is increased up to 80 °C, the nanoparticles are aggregated to form large-sized polyhedral microparticles in the size range of 4–7 μm. Compared to the pH value and reaction temperature, the reaction time has a minor effect on the morphology of Ag3PO4 particles. RhB was chosen as the target pollutant to evaluate the photocatalytic activity of the as-prepared Ag3PO4 samples under simulated-sunlight irradiation. It is shown that the samples consisting of spherical nanoparticles exhibit an extremely high photocatalytic activity, and the degradation percentage of RhB after reaction for 50 min reaches over 90%. The samples of polyhedral microparticles have a relatively low photocatalytic activity, which is possibly due to their large particle size. Hydroxyl (.OH) radical was detected by spectrofluorimetry using terephthalic acid as a .OH scavenger and was not found to be produced over the simulated-sunlight-irradiated Ag3PO4 catalyst. The effect of ethanol, benzoquinone and ammonium oxalate on dye degradation was also investigated. Based on experimental results, the direct oxidation by h+ is suggested to the dominant mechanism toward the dye degradation.

Preparation of Magnetite Nanoparticles by Thermal Decomposition of Hematite Powder in the Presence of Organic Solvent

2007 ◽  
Vol 998 ◽  
Author(s):  
Chun-Rong Lin ◽  
Ray-Kuang Chiang ◽  
Chih-Jung Chen ◽  
Hsin-Yi Lai ◽  
Igor S. Lyubutin ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Reaction Time ◽  
Magnetite Nanoparticles ◽  
Magnetic Measurements ◽  
Spinel Phase ◽  
Reaction Times ◽  
Transformation Process ◽  
Verwey Transition ◽  
Magnetite Particles ◽  
Xrd Patterns

ABSTRACTMagnetite nanoparticles have been synthesized by thermal decomposition of hematite (Fe2O3) powder in the presence of high boiling point solvent. The mixture of hematite and 1- octadecene solvent was heated and stirred in nitrogen gas at the temperature of 320 °C for the desired time (∼2 to 28 hrs). The influence of the reaction time on transformation process was analyzed with X-ray diffraction (XRD), Mössbauer spectroscopy (MS), and magnetic measurements. XRD patterns show that the phase of intermediate was composed of spinel phase and corundum phase (α-Fe2O3). The 57Fe Mössbauer spectra show that the spinel phase originated from the magnetite particles. The structure transformation proportion of hematite to magnetite strongly depends on reaction times. After reflux for 28 hrs the hematite-magnetite transformation was complete. The mean crystallite size of pure phase of magnetite particles is about 40 nm. The saturation magnetization increases with the reaction time, which corresponds to an increase of concentration of magnetite in the samples. A pronounced feature of the Hc and σr/σs observed in samples is the steplike change which appears at 125 K and is characteristic of the Verwey transition. The hyperfine parameters of Mössbauer spectrum measured at low temperature also indicate that the Verwey phase transition occurs. In other words, the Verwey transition is an indication that the magnetite particles exactly grew up in the synthesized compounds. This thermal decomposition process provided a method to prepare pure magnetite as well as magnetite/hematite nanocomposites useful for various magnetic applications.

Scalable Production of Carbon Encapsulated Ni Nanoparticles by Water Arc Discharge: Structural and Magnetic Properties

2005 ◽  
Vol 23 ◽  
pp. 87-90 ◽  
Author(s):  
K.H. Ang ◽  
I. Alexandrou ◽  
N.D. Mathur ◽  
R. Lacerda ◽  
I.Y.Y. Bu ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Arc Discharge ◽  
Narrow Particle Size Distribution ◽  
Ni Nanoparticles ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Water Container

An electric arc discharge in de-ionised water between a solid graphite cathode and an anode made by compressing Ni and C containing powders in a mass ratio of Ni:C = 7:3 was used here to prepare carbon encapsulated Ni nanoparticles in the form of powder suspended in water. The morphology of the produced material was analysed using high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The magnetic properties of the samples were determined using a Princeton vibrating sample magnetometer (VSM). Collection of the powder produced from different depths in the water container has proved to be an effective method for obtaining samples with narrow particle size distribution. Further material purification by dry NH4 plasma etching was used to remove the amorphous carbon content of the samples. XRD and HRTEM analysis showed that the material synthesized is fcc Ni particles with mean particle size ranging from 14 to 30 nm encapsulated in 2 to 5 graphitic cages. The data suggests that the process reported has the ability to mass-produce carbon encapsulated ferromagnetic nanoparticles with desired particle size distribution, and hence with controlled size-dependent magnetic properties.

Анализ параметров медицинского технологического оборудования, учитывающие факторы, влияющие на качество изготовления лекарств

2020 ◽  
pp. 90-95
Author(s):  
T.V. Karlova ◽  
◽  
D.O. Sv ◽  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Particle Shape ◽  
Particle Surface ◽  
Technological Equipment ◽  
Factors Affecting ◽  
Particle Strength ◽  
The Web

The article is devoted to the analysis of parameters of medical technological equipment that take into account factors affecting the quality of manufacture of drugs. Factors such as particle size, particle size distribution, particle shape, particle surface properties, particle strength, which, based on the «Web» method, are used to analyze the «vibrosieve» technological equipment, are considered.

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