scholarly journals PREPARATION OF ATO NANOPOWDERS WITH Co-PRECIPITATION AND THEIR LASER-REFLECTION PROPERTIES

2021 ◽  
Vol 55 (5) ◽  
Author(s):  
Jing Zhang
Keyword(s):  
Calcination Temperature ◽  
Ph Value ◽  
Raw Materials ◽  
Laser Wavelength ◽  
Molar Ratio ◽  
Precipitation Reaction ◽  
High Concentration ◽  
Calcination Time ◽  
Tin Chloride ◽  
Co Precipitation

Antimony tin oxide (ATO) nanoparticles were prepared using co-precipitation with tin chloride and antimony chloride as the main raw materials. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and ultraviolet-visible spectrophotometry were used to characterize the crystal structure, morphology and laser reflectivity. The effects of the pH value, co-precipitation reaction temperature, calcination temperature and calcination time on the laser reflectivity of ATO nanoparticles were studied. The results show that, compared with the undoped SnO2 powder, the reflectivity of a Sb-doped ATO powder at a laser wavelength of 1.06 µm is significantly reduced, and with an increase in the Sb doping, the reflectivity of the ATO powder at 1.06 µm first decreases and then increases. When the Sb/Sn molar ratio is 2/10, the reflectivity decreases to the lowest point, which is caused by the high concentration of Sb5+. ATO powders (Sb/Sn = 2/10) prepared at a titration-end-point pH of 2, co-precipitation temperature of 70 °C, calcination temperature of 800 °C and calcination time of 6 h have the lowest laser reflectivity at the laser wavelength of 1.06 µm, which is less than 0.02 %.

Catalytic Hydrolysis of Hydrogen Cyanide on Cu-Al Catalyst

2015 ◽  
Vol 1094 ◽  
pp. 15-19
Author(s):  
Lin Xia Yan ◽  
Sen Lin Tian ◽  
Qiu Lin Zhang
Keyword(s):  
Calcination Temperature ◽  
Hydrogen Cyanide ◽  
Influence Factor ◽  
Ph Value ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Cu Content ◽  
Co Precipitation ◽  
The Impact ◽  
Hydrolysis Of

Cu-Al catalysts were synthesized by the co-precipitation method to study hydrolysis of hydrogen cyanide. During the synthesis, the impact of Cu/Al molar ratio, pH value and calcination temperature was investigated and the best synthesis condition was found. The results indicate that the remove of hydrogen cyanide first increases and then decreases with increasing Cu/Al molar ratio, pH value and calcination temperature, which reaches the maxima and remains above 95% at 360 min when Cu/Al molar ratio is 2:1, pH value is approximately 8.0 and calcination temperature is 400°C around. The analysis of X-ray diffraction (XRD) shows that Cu content is the main influence factor at Cu/Al molar ratio below 2:1 whereas crystallinity of catalysts is the key factor at Cu/Al molar ratio above 2:1.

Effect of the Synthesis Method on the Properties of Ultrafine YAG Powder

2018 ◽  
Vol 281 ◽  
pp. 40-45
Author(s):  
Jie Guang Song ◽  
Lin Chen ◽  
Cai Liang Pang ◽  
Jia Zhang ◽  
Xian Zhong Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Calcination Temperature ◽  
Hydrothermal Reaction ◽  
Synthesis Method ◽  
Particle Morphology ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Synthesis Process ◽  
Powder Materials ◽  
Co Precipitation

YAG materials has a number of unique properties, the application is very extensive. In this paper, the superfine YAG powder materials were prepared by co-precipitation method and hydrothermal precipitation method. The influence of synthesis process on the morphology of the powder was investigated. The results showed that the precursor powder prepared via the co-precipitation method is mainly from amorphous to crystalline transition with the increasing calcination temperature, the precursor agglomeration is more serious, In the process of increasing the calcination temperature, the dispersibility of the roasted powder is greatly improved, which is favorable for the growth of the crystal grains, so that the particle size of the powder is gradually increased, the YAG precursor prepared by the co-precipitation method is transformed into YAG crystals, the phase transition occurs mainly between 900 and 1100°C. When the molar ratio of salt to alkali is Y3+: OH-=1: 8 via the hydrothermal reaction, the YAG particles with homogeneous morphology can be obtained. When the molar ratio of salt and alkali is increased continuously, the morphology of YAG particles is not obviously changed. The co-precipitation method is easy to control the particle size, the hydrothermal method is easy to control the particle morphology.

Synthesis Method and its Influence Factors of Hydrotalcite-Like Compounds

2013 ◽  
Vol 690-693 ◽  
pp. 351-354 ◽  
Author(s):  
Hong Dan Xue ◽  
Fu Li Wang ◽  
Guo Li Li ◽  
Pu Liu ◽  
Yong Qing Bai ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Reduction Method ◽  
Ph Value ◽  
Raw Materials ◽  
Sol Gel ◽  
Synthesis Method ◽  
Influence Factors ◽  
Synthetic Methods ◽  
Molar Ratio ◽  
Temperature Reaction

Hydrotalcite-like compounds are a class of anionic lays or layed double hydroxiods (LDHs) which consists of alkalescence, anion-exchanges and memory effect. The synthetic methods of LDHs include coprecipitation, hydrothermal synthesis, mirowave radiation, ion exchange, sol-gel method, roasting reduction method, instant synthesis, etc.The molar ratio of raw materials, pH value,reaction temperature,reaction time and so on have a greater impact on the purity and crystallinity of the LDHs.

Co-Precipitation Synthesis of BiFeO3 Powders

2010 ◽  
Vol 105-106 ◽  
pp. 286-288 ◽  
Author(s):  
Hai Yang Bo ◽  
Guo Qiang Tan ◽  
Hong Yan Miao ◽  
Ao Xia
Keyword(s):  
Calcination Temperature ◽  
Bismuth Ferrite ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Diffraction Field ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Infrared Spectrophotometer ◽  
Lower Temperature ◽  
Co Precipitation

Bismuth ferrite powders were synthesized by a simple citric acid complexing co-precipitation method at much lower temperature of 600°C. The work studies the calcination temperature and molar ratio of Fe and Bi on the structure and morphology. The as-prepared BiFeO3 powder was characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscope and Fourier transform infrared spectrophotometer. The result shows that the phase pure BiFeO3 powders with cubic morphology were prepared as the calcination temperature was 600°C and molar ratio of Fe and Bi was 1:1. The nanoparticles was uniform with the size of about 200nm.

Effect of Calcination Temperature on Phase Transformation and Microstructure of Al2O3/GdAlO3 Compound Powder Prepared by Co-Precipitation Method

2012 ◽  
Vol 512-515 ◽  
pp. 535-538 ◽  
Author(s):  
Shuai Sun ◽  
Qiang Xu
Keyword(s):  
Calcination Temperature ◽  
Raw Materials ◽  
Metastable Phase ◽  
Precipitation Method ◽  
Calcination Process ◽  
Compound Powder ◽  
Average Grain Size ◽  
Different Temperatures ◽  
Diffraction Peaks ◽  
Co Precipitation

A Coprecipitation Method Was Applied to Synthesize Al2O3/GdAlO3 Compound Powder, Using Ammonia as the Precipitator. Gadolinium Oxide and Aluminium Nitrate Were Used as the Raw Materials with the Eutectic Ratio( 77 mol% Al 3+ – 23 mol% Gd 3+ ). the Precursor Was Calcined at Different Temperatures from 1200 to 1600 °C. the Phase Identifications at Different Temperatures Were Characterized by X-ray Diffractometry (XRD). the Growth Morphology of Particles Were Investigated Using Field Emission Electro Microscopy (FE-SEM). the Results Reveal that GdAlO3 Crystallized Earlier than α-Al2O3. the Diffraction Peaks of α-Al2O3 Phase Were Observed after Calcination at 1300°C for 1 H. Metastable Phase Gd3Al5O12 Underwent Complete Decomposition at 1600°C for 1 H. Gadolinium Aluminate and α-Al2O3 Showed Different Growth Mechanism during the Calcination Process. the Average Grain Size of the Calcined Powder Increased from ~40 to ~900 Nm as the Calcination Temperature Increased from 1200 to 1600 °C.

Synthesis and Characterization of Zn-Ca-Mg-Al Hydrotacite-Like Compounds and its Application in the PVC

2011 ◽  
Vol 66-68 ◽  
pp. 65-69
Author(s):  
Long Feng Li ◽  
Yuan Gao ◽  
Mao Lin Zhang
Keyword(s):  
Reaction Time ◽  
Ph Value ◽  
Raw Materials ◽  
Treatment Temperature ◽  
Molar Ratio ◽  
Medium Ph ◽  
X Ray ◽  
Ft Ir ◽  
Thermal Stability Of

Ca-Mg-Al hydrotalcite-like compounds (CaMgAl-HTLcs) were synthesized by a hydrothermal method, and characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and differential thermal analysis (DTA) techniques. The effects of the medium pH value, the molar ratio of the raw materials, the reaction temperature and the reaction time on the structure of CaMgAl-HTLcs were studied. The results showed that increasing treatment temperature and reaction time could improve the crystallinity and monodispersity of hydrotalcite-like compound particles. And well-defined CaMgAl-HTLcs could be prepared at a pH value of 10~11 with n(Zn+Mg+Ca):n(Al) =2. The products synthesized were applied to PVC to improve the thermal stability of PVC.

scholarly journals Superparamagnetic α-Fe2O3/Fe3O4 Heterogeneous Nanoparticles with Enhanced Biocompatibility

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 834
Author(s):  
You Li ◽  
Zhou Wang ◽  
Ruijiang Liu
Keyword(s):  
Calcination Temperature ◽  
Raw Materials ◽  
Combustion Process ◽  
Human Hepatocytes ◽  
Relative Content ◽  
Ferric Nitrate ◽  
Calcination Time ◽  
Solution Combustion ◽  
Key Factor ◽  
Blood Routine

A novel type of magnetic α-Fe2O3/Fe3O4 heterogeneous nanoparticles was prepared via a facile solution combustion process with ferric nitrate and urea as raw materials, and they were characterized by XRD, SEM, TEM, and VSM techniques. The effects of the calcination temperature, the calcination time, the ratio of ferric nitrate and urea, and the heating rate on the relative content of Fe3O4 in the heterogeneous nanoparticles were investigated. The toxicity of α-Fe2O3/Fe3O4 heterogeneous nanoparticles to human hepatocytes L-02, the blood routine, and the histopathological section observation of mice were explored. The results showed that the ratio of ferric nitrate and urea was a key factor to affect the relative content of Fe3O4 in the heterogeneous nanoparticles. The calcination temperature and the calcination time had similar influences, and the corresponding calcination temperature and the calcination time were selected according to their own needs. The CCK8 results initially revealed that α-Fe2O3/Fe3O4 heterogeneous nanoparticles had no effect on cell viability when the concentration of the heterogeneous nanoparticles was less than 100 ng/mL, which suggested their excellent biocompatibility. At the same time, the tail vein administration concentration of 0.9 mg/kg had good biological safety.

scholarly journals Covellite (CuS) Production from a Real Acid Mine Drainage Treated with Biogenic H2S

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 206 ◽  
Author(s):  
Patricia Magalhães Pereira Silva ◽  
Adriano Reis Lucheta ◽  
José Augusto Pires Bitencourt ◽  
Andre Luiz Vilaça do Carmo ◽  
Ivan Patricio Ñancucheo Cuevas ◽  
...  
Keyword(s):  
Acid Mine Drainage ◽  
Mine Drainage ◽  
Raw Materials ◽  
Industrial Applications ◽  
Molar Ratio ◽  
High Concentration ◽  
Dissolved Metals ◽  
X Ray ◽  
Synthesis Conditions ◽  
Acid Mine

Acid Mine Drainage (AMD) is an environmental problem associated with mining activities, which resulted from the exposure of sulfur bearing materials to oxygen and water. AMD is a pollution source due to its extreme acidity, high concentration of sulfate, and soluble metals. Biological AMD treatment is one alternative to couple environmental amelioration for valuable dissolved metals recovery, as a new source of raw materials. Covellite (CuS) particles were synthetized from an AMD sample collected in a Brazilian copper mine, after 48 and 96 h of exposure to hydrogen sulfide (H2S) produced in a bioreactor containing acidophilic sulfate reducing bacteria (SRB). The time of exposure affected the morphology, nucleation, and size of CuS crystals. CuS crystals synthetized after 96 h of H2S exposure showed better ordination as indicated by sharp and intense diffractograms obtained by X-ray diffraction (XRD), and the predominance of placoid sheets with hexagonal habit structure as observed by scanning electrons microscopy (SEM). Energy dispersive X-ray fluorescence (EDXRF) spectrometry indicated a Cu:S molar ratio in agreement with CuS. Granulometric analysis demonstrated that 90% of CuS particles were less than 22 µm size. AMD biological treatment is a potential economical CuS recovery option for metallurgical process chain incorporation, or new industrial applications, since the alteration of synthesis conditions can produce different crystal forms with specific characteristics.

Removal and Recovery of Silica Source from Geothermal Water Recycling System by Calcium Nitrate and Sodium Hydroxide

2012 ◽  
Vol 516-517 ◽  
pp. 380-383
Author(s):  
Shu Qin Bai ◽  
Fan Yang ◽  
Yuan Wang ◽  
Kai Hua Wang
Keyword(s):  
Sodium Hydroxide ◽  
Silicic Acid ◽  
Calcium Silicate Hydrate ◽  
Calcium Nitrate ◽  
Geothermal Water ◽  
Molar Ratio ◽  
Precipitation Reaction ◽  
High Concentration ◽  
Xrd Pattern ◽  
Silica Source

In order to elucidate the possibility of removal of silicic acid from geothermal water, the calcium nitrate and sodium hydroxide as removing agent was investigated under various conditions. The initial concentration of silicic acid in geothermal water was 412 ppm as Si. The concentration of silicic acid decreased rapidly when the removing agent was added. Precipitation reaction for silicic acid reached equilibrium within 30 minutes and was independent of pH. The removing rate of silicic acid increased with increasing the pH of solution. The high concentration of silicic acid in geothermal water was perfectly removed by addition of calcium nitrate with molar ratio of Ca/Si over 2.1 at pH12. XRD pattern showed that the component of precipitation was calcium silicate hydrate Ca2SiO4・nH2O (CSH).

Preparation and Characterization of NiO Nanoparticles

2015 ◽  
Vol 31 ◽  
pp. 93-102 ◽  
Author(s):  
Farrakh Shahzad ◽  
Karl Ettinger ◽  
Ilse Letofsky-Papst ◽  
Julia Weber ◽  
Peter Knoll
Keyword(s):  
Crystallite Size ◽  
Calcination Temperature ◽  
Ph Value ◽  
Sol Gel ◽  
Systematic Change ◽  
X Rays ◽  
Nio Nanoparticles ◽  
Calcination Time ◽  
Transmission Electron

NiO nanoparticles are successfully prepared by sol-gel technique. A systematic change in preparation parameters like calcination temperature, calcination time and pH value has been done in order to study the influence on crystallite size. The prepared samples are characterized by X-ray diffractometer, Transmission electron microscopy, Energy dispersive x-rays analysis and Raman spectroscopy. It is shown that crystallite size mainly depends on the calcination temperature rather than pH value or calcination time.

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