scholarly journals EFFECT OF HYDROTHERMAL TEMPERATURE ON SYNTHESIS OF HYDROXYAPATITE FROM LIMESTONE VIA HYDROTHERMAL METHOD

2018 ◽  
Vol 10 (1) ◽  
pp. 136 ◽  
Author(s):  
Novesar Jamarun ◽  
Asregi Asril ◽  
Zulhadjri Zilfa ◽  
Upita Septiani
Keyword(s):  
Hydrothermal Method ◽  
Crystal Size ◽  
Spherical Shape ◽  
X Ray Diffraction ◽  
Hydrogen Phosphate ◽  
Hydrothermal Temperature ◽  
X Ray ◽  
Nano Powder ◽  
Diammonium Hydrogen ◽  
Scanning Electron

Objective: In this study, the effect of hydrothermal temperature on the synthesis of hydroxyapatite (HAp) from limestone was investigated.Methods: Precursors of limestone (CaCO3) and diammonium hydrogen phosphate ((NH4)2HPO4) with Ca/P ratio of 1.67 was mixed at pH 10 in order to synthesize hydroxyapatite by hydrothermal method. The solution was hydrothermally treated in an autoclave at various temperatures of 120, 160 and 200 °C for 24 h. Nano powder formed was then characterized.Results: The hydroxyapatite obtained by hydrothermal method at various temperatures was characterized. The analysis of Fourier Transform Infrared (FTIR) revealed that HAp had phosphate (PO43-) and hydroxyl (O-H) groups although carbonate (CO32-) group remained. X-Ray Diffraction (XRD) revealed that the size of nanosize crystals was formed and then provided a large surface area. Scanning Electron Microscopy (SEM) results showed that HAp had a spherical shape. There was more agglomeration at 200 °C than at 160 °C. The ratio of the results of Energy Dispersive X-ray (EDX) analysis in 160 °C was 1.95 and at 200 °C was 1.71Conclusion: The hydroxyapatite prepared at a temperature of 200 °C had smaller crystal size than the hydroxyapatite prepared at the temperatures of 120 and 160 °C. SEM pictures showed that the nanoparticle hydroxyapatite had a spherical shape.

scholarly journals Effect of Surfactant Addition on Bi2Te3 Nanostructures Synthesized by Hydrothermal Method

2017 ◽  
Vol 62 (2) ◽  
pp. 1005-1010 ◽  
Author(s):  
Peyala Dharmaiah ◽  
C.H. Lee ◽  
B. Madavali ◽  
Soon-Jik Hong
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Method ◽  
Figure Of Merit ◽  
Bulk Sample ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coarse Grains ◽  
Scanning Electron ◽  
Nanostructured Sample

AbstractIn the present work, we have prepared Bi2Te3nanostructures with different morphologies such as nano-spherical, nanoplates and nanoflakes obtained using various surfactant additions (EG, PVP, and EDTA) by a hydrothermal method. The shape of the nanoparticles can be controlled by addition of surfactants. The samples were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). It is found that the minority BiOCl phase disappears after maintained pH at 10 with EG as surfactant. SEM bulk microstructure reveals that the sample consists of fine and coarse grains. Temperature dependence of thermoelectric properties of the nanostructured bulk sample was investigated in the range of 300-450K. The presence of nanograins in the bulk sample exhibits a reduction of thermal conductivity and less effect on electrical conductivity. As a result, a figure of merit of the sintered bulk sample reached 0.2 at 400 K. A maximum micro Vickers hardness of 102 Hv was obtained for the nanostructured sample, which was higher than the other reported results.

scholarly journals Structural and thermoelectric properties of the Pr2Zr2O7 compound

2019 ◽  
pp. 4-9
Author(s):  
Adolfo Quiroz-Rodríguez ◽  
Cesia Guarneros-Aguilar ◽  
Ricardo Agustin-Serrano
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Crystal Size ◽  
Ambient Pressure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Increasing Temperature ◽  
Thermal Stability Of ◽  
Scanning Electron

In this research, it is presented a detailed study of the structural and thermoelectric properties of the pyrochlore zirconium Pr2Zr2O7 compound prepared by solid-state reaction (SSR) in air at ambient pressure. The synthesized sample was characterized using powder X-ray diffraction. The thermal stability of the thermoelectric compound (TE) Pr2Zr2O7 was tested by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). Scanning electron microscopy shows that the crystal size varies between 0.69 and 2.81μm. Electrical conductivity (\sigma) of the sample calcined at 1400 °C presented values increase irregularly with the increasing temperature from 0.001 to 0.018 S cm-1 as expected in a semiconductor material. The thermal conductivity is lower than 0.44 - 775 W m-1 K-1 which is quite anomalous in comparison with the thermal conductivity of other oxides.

Influence of Nanosized α-Ni(OH)2 Addition on the Electrochemical Performance of β-Ni(OH)2 Electrode

2007 ◽  
Vol 121-123 ◽  
pp. 1265-1268 ◽  
Author(s):  
T.A. Han ◽  
J.P. Tu ◽  
Jian Bo Wu ◽  
Y.F. Yuan ◽  
Y. Li
Keyword(s):  
Electrochemical Performance ◽  
Active Material ◽  
Spherical Shape ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
Galvanostatic Charge ◽  
X Ray ◽  
Co Precipitation ◽  
Charge Discharge ◽  
Scanning Electron

Al-substituted α-Ni(OH)2 was synthesized by a chemical co-precipitation. The as-prepared α-Ni(OH)2 particles were characterized by the means of X-ray diffraction (XRD) and scanning electron microscope (SEM). The obtained α-Ni(OH)2 particles were well crystallized, spherical shape with the particle sizes of 20-35 nm. The electrochemical performance of β-Ni(OH)2 electrode with addition of nanosized α-Ni(OH)2 was investigated by galvanostatic charge-discharge tests. The nanosized α-Ni(OH)2 as additive in the commercial microsized spherical β-Ni(OH)2 electrode improved the discharge capability. As compared to commercial β-Ni(OH)2 electrode, the electrode with nanosized α-Ni(OH)2 exhibited excellent better charge-discharge cycling stability. It may be a promising positive active material for alkaline secondary batteries.

Preparation and Properties of CaF2 Nano-Powder

2016 ◽  
Vol 680 ◽  
pp. 257-260
Author(s):  
Meng Yun Dong ◽  
Cheng Zhang ◽  
Jin Feng Xia ◽  
Hong Qiang Nian ◽  
Dan Yu Jiang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Sintering Temperature ◽  
Raw Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nano Powder ◽  
Direct Precipitation ◽  
Scanning Electron

CaF2 nano-power was prepared by direct precipitation methods with Ca(NO3)2 and KF as raw materials. The influences of presintering temperature and sintering temperature on the particle size and distribution of CaF2 nano-power were studied by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM). This study provided an experimental method for preparation of CaF2 nano-power. The results show that the best presintering temperature of CaF2 nano-power is 500°C and the best sintering temperature of CaF2 ceramic is 900°C.

Characterization of Lead Zirconate Titanate Powders Prepared by a Hydrothermal Method

2005 ◽  
Vol 902 ◽  
Author(s):  
Lingjuan Che ◽  
Yongping Ding ◽  
Jinrong Cheng ◽  
Chao Chen ◽  
Zhongyan Meng
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Method ◽  
Lead Zirconate Titanate ◽  
Fourier Transformation ◽  
Lead Zirconate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zirconate Titanate ◽  
Scanning Electron

AbstractLead Zirconate Titanate (PZT) powders have been synthesized by a hydrothermal method at the processing temperatures of 120-220 °C for 1.5-50 hours, based on the reaction of Pb(CH3COOH)2·3H2O, ZrOCl2·8H2O, Ti(C4H9O)4 and KOH. Hydrothermally treated PZT powders were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transformation infrared (FTIR) techniques respectively. The influences of hydrothermal synthesize conditions on the crystalline structure and the morphology of PZT particles were investigated. Crystallized PZT powders could be synthesized at the KOH concentration of >2.5 mol/l.

scholarly journals Synthesis and Catalase Mimic Activity of MnO2 Nano Powder Prepared by Hydrothermal Process

2019 ◽  
Vol 27 (2) ◽  
pp. 228-237 ◽  
Author(s):  
Rashed T. Rasheed ◽  
Sariya D. Al-Algawi ◽  
Rosul M. N.
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Annealing Temperature ◽  
Hydrothermal Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nano Powder ◽  
Atomic Force ◽  
Different Temperatures ◽  
Scanning Electron

Manganese dioxide (MnO2) nanopowder has been synthesized by hydrothermal method. MnO2 was annealed at different temperatures (250, 400, 550, 700˚C). The crystal structure and surface morphology of these nanostructures were characterized by X-ray diffraction (XRD), Atomic Force Microscope (AFM) and Scanning Electron Microscopy (SEM). The catalase mimic activity (catalytic activity) of MnO2 against hydrogen peroxide (H2O2) was studied by using the new method and found that 400˚C is the best annealing temperature.

scholarly journals Obtaining hydroxyapatite with different precursors for application as a biomaterial

Cerâmica ◽  
2019 ◽  
Vol 65 (373) ◽  
pp. 99-106
Author(s):  
K. A. S. Farias ◽  
W. J. B. Sousa ◽  
M. J. B. Cardoso ◽  
R. J. S. Lima ◽  
M. A. Rodriguez ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Thermal Decomposition ◽  
Fourier Transform ◽  
Calcium Oxide ◽  
Crystal Size ◽  
X Ray Diffraction ◽  
Thermal Decomposition Process ◽  
X Ray ◽  
Scanning Electron

Abstract The hydroxyapatite (HAp) is a ceramic biomaterial with wide application in the bone regeneration. It can be obtained by different routes and different precursors. In this study, the synthesis of HAp was carried out by precipitation and subsequent thermal treatment using different calcium precursors: calcium hydroxide from synthetic origin and calcium oxide obtained from the eggshell. The obtained materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy. By SEM, variations of the crystal size and the concentration of agglomerates were observed. FTIR and XRD analyses proved the formation of HAp and how the (mineral and biological) precursors affected the microstructure. The thermal decomposition process of the calcium oxide obtained from the eggshell showed to be more effective for the synthesis of the hydroxyapatite, resulting in more stable morphology and microstructure.

Preparation and Characterizations of a-Fe2O3 Nanorods and their Properties

2016 ◽  
Vol 852 ◽  
pp. 346-348
Author(s):  
Hong Cai ◽  
Qing Bo Du ◽  
Ji Gui Xu ◽  
Hong Wei Shi ◽  
Jun Zhu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrothermal Method ◽  
Magnetic Measurement ◽  
Remnant Magnetization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Fundamental Research ◽  
Scanning Electron

a-Fe2O3 nanorods over large areas were successfully synthesized by hydrothermal method, using FeCl3 as iron source and PVP as surfactant. The as-synthesized a-Fe2O3 nanorods were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and magnetic measurement system (SQUID-VSM) . The results show that the nanorods prepared by hydrothermal method with the diameter of about 70 nm and the length of about 300 nm. The magnetic properties of the synthesized nanorods were studied, and the remnant magnetization and coercivity of the α-Fe2O3 nanorods at 300K are found to be 0.07emu/g and 2300Oe, respectively. The a-Fe2O3 nanorods reported here may have opportunities for both fundamental research and technological applications.

Phase Composition and Morphology of Pottery Stone Microcrystalline Powders Synthesized by Hydrothermal Method

2013 ◽  
Vol 664 ◽  
pp. 620-624
Author(s):  
Amnouy Larpkasemsuk ◽  
Saowaroj Chuayjuljit ◽  
Dujreutai Pongkao Kashima
Keyword(s):  
Phase Composition ◽  
Hydrothermal Method ◽  
X Ray Diffraction ◽  
Major Phase ◽  
X Ray ◽  
Polyhedral Particles ◽  
Naoh Solution ◽  
Xrd Patterns ◽  
Aluminium Silicates ◽  
Scanning Electron

Pottery stone (PTS) microcrystalline powders were synthesized by a hydrothermal method using two concentrations of NaOH solution (2 M and 4 M) at 60, 80 and 120°C for 8 h in a Teflon- lined stainless steel autoclave. The phase composition and morphology of the samples were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The major phase compositions of the as-prepared PTS powders appeared in the XRD patterns are all silicate compounds such as tridymite, crystobalite, quartz, feldspar, albite, sodium silicate, analcime, hydroxyl-cancrinite and sodium aluminium silicates, depending on the NaOH concentration and the reaction temperature. Moreover, SEM micrographs showed the spherical polyhedral particles ranging from 8 to 14 µm in diameters and needle-like particles with a mean aspect ratio of 5.7 that obtained by the hydrothermal treatment operated at 120°C using 2 M and 4 M of NaOH, respectively.

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