Syntheses of Hydroxyapatite Nanospheres Through a Facile Sol-gel Method

2009 ◽  
Vol 1239 ◽  
Author(s):  
Kai Li ◽  
Sie Chin Tjong

AbstractHydroxyapatite (HA) nanospheres were synthesized via the sol-gel route in the presence of poly(vinyl alcohol) (PVA). The HA nanospheres were formed from the reaction between (NH4)2HPO4 and CaCl2 in ethanol/PVA sol-gel system, in which ammonia solution (NH3•H2O) was added to adjust the pH of solution. The as-synthesized products were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FE-SEM) and energy-dispersive X-ray spectroscopy (EDAX). XRD patterns and FTIR spectra showed that the HA nanospheres exhibit the crystalline structure and vibration bands of HA. The Ca/P molar ratio of HA nanospheres (50˜70nm) approached the stoichiometric value of 1.67, on the basis of EDAX results. Simulated Body Fluid (SBF) immersion test for three weeks demonstrated that the apatite layer can be formed on the HA nanospheres sintered at 550°C.

2015 ◽  
Vol 659 ◽  
pp. 121-126 ◽  
Author(s):  
Pat Sooksaen

Aluminium borate nanowhiskers with varying aspect ratio were synthesized via sol–gel synthesis. The morphology of aluminum borate (Al4B2O9 and Al18B4O33) nanowhiskers could be controlled by varying the aluminum to boron (Al:B) molar ratio in the sol–gel derived precursors. Sintering temperatures (850 and 1100°C) and sintering times (4 and 32 hours) also affected the phase composition and size of the nanowhiskers. Citric acid was also added in the sol–gel derived precursors as a surface stabilizer for obtaining uniform finely dispersed nanostructures. Fine nanowhiskers were obtained by the calcination at 850°C, whereas higher temperature of 1100°C led to thicker and longer nanowhiskers and became rod-like crystals. The morphology and phase composition were investigated by field emission scanning electron microscope and X-ray diffraction. Chemical bond vibrations in the synthesized nanowhiskers were investigated by Fourier-transform infrared spectroscopy.


2011 ◽  
Vol 393-395 ◽  
pp. 1181-1184
Author(s):  
Min Wang ◽  
Qiong Liu ◽  
Qi Xing

Nd-doped Cu11O2 (VO4)6 photocatalyst was synthesized by complexing Sol-gel method and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy Dispersive X-Ray Spectroscopy(EDX). The photocatalytic activity of Nd-doped Cu11O2 (VO4)6 was evaluated by photocatalytic degradation of methyl orange (MO) solution under UV-light. It revealed that the Nd-doped Cu11O2 (VO4)6 prepared with the molar ratio of citric acid to metal inons be 2:1, Nd/Cu molar ratio of 2%, pH=7 and calcinated under 500°C for 4 hours was pure triclinic phase. In this conditions, the sample had highest photocatalytic activity with the photodegradation rate was about 95.73% or so in 60min under 20W ultraviolet lamp.


2019 ◽  
Vol 56 ◽  
pp. 28-38 ◽  
Author(s):  
Uraiwan Werapun ◽  
Jaraslak Pechwang

TiO2 and iron-doped TiO2 were synthesized by sol-gel method. TiO2 and 0.5 %mol Fe:TiO2 were calcined at 500 and 800 °C for 3 h. The synthesized particles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV-VIS diffuse reflectance spectrophotometry (UV/DRS), scanning electron microscopy (SEM) and scanning electron microscope-energy dispersive X-Ray analysis (SEM-EDX). The XRD patterns of all samples that were calcined at 500 °C showed only anatase phase. On increasing temperature from 500 to 800 °C, the anatase phase transformed to rutile phase. For 0.5 %mol Fe:TiO2, pseudobrookite (Fe2TiO5) phase was observed at 800 °C. The particles that contained rutile showed higher antibacterial activities against E.coli, B. subtilis, and S. aureus than anatase phase, under fluorescent irradiation.


2016 ◽  
Vol 16 (4) ◽  
pp. 4233-4238
Author(s):  
Qinglong Wang ◽  
Kexun Chen ◽  
Yali Zhang

The photocatalytic materials were prepared by sol–gel method: the main raw materials were tetrabutyltitanate and the lanthanum nitrate hexahydrate, bentonite was the carrier to support TiO2.The properties of the composites were characterized by specific surface area (BET), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and thermogravimetric analysis (TG). The photocatalytic degradation of cyanide waste water was used to assess the photocatalytic activity of the materials. The experimental results showed that the suitable content of lanthanum and roasted temperature could improve the photocatalytic activity. When the composites were roasted at 400 °C and the molar ratio of La to Ti was 1%, the photocatalyst reached optimal performance.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shady M. EL-Dafrawy ◽  
Mahmoud Tarek ◽  
Salem Samra ◽  
Shawky M. Hassan

AbstractA series of ZnO and ZnO/poly(vinyl alcohol) (PVA) catalysts were prepared using sol–gel method. An X-ray diffraction analysis confirmed the existence of the wurtzite ZnO phase, and scanning electron microscopy (SEM) observation revealed the formation of spherical ZnO and ZnO/PVA nanoparticles. The decomposition of methylene blue (MB) and methyl orange (MO) induced by the synthesized pure ZnO and ZnO/PVA nanoparticles was studied under ultraviolet–visible irradiation. Among the catalysts evaluated, ZnO/5PVA was the most active in the decomposition of MB, whereas ZnO/7PVA was the most active catalyst in the decomposition of MO. Moreover, an investigation of the biological activity of pure ZnO and ZnO/PVA indicated that ZnO/5PVA exhibited the best performance in lowering the glucose level in diabetic rats.


2012 ◽  
Vol 476-478 ◽  
pp. 691-695
Author(s):  
You Jun Wang ◽  
An Zhong Deng ◽  
Jin Ping Shao ◽  
Dong Li

Nanoparticle CdS was prepared by use of microwave irradiation method. CdS/TiO2 composite was prepared by sol-gel method. The characteristics of composite material were investigated by means of X-ray diffraction (XRD), scanning electron microscope (SEM)and Fourier transform infrared (FTIR). Butyl titanate(TBOT) hydrolysis kinetics was discussed. The formation products were mainly anatase TiO2 and hexagonal CdS. Infrared emissivity test results showed: at 650°C, molar ratio of CdS/TiO2 was 2:3, infrared emissivity of composite material was 0.2872.


2011 ◽  
Vol 695 ◽  
pp. 429-432 ◽  
Author(s):  
Jun Zhou ◽  
Xin Zhe Lan ◽  
Ping Ren ◽  
Qiu Li Zhang ◽  
Yong Hui Song ◽  
...  

The flower-sphere molybdenum disulfide has been synthesized by reaction of Na2MoO4 and CS(NH2)2 with NH2OH·HCl or H2C2O4 as reductant. The microstructure and chemical composition of the product were characterized by means of X-ray diffraction and scanning electron microscope. XRD patterns showed that the molar ratio of Mo to S had a great effect on the purity of the product. When the molar ratio of Mo to S was 1:5, the product was nearly pure MoS2. SEM images showed that the particle size increased as the molar ratio of Mo to S reduced. The MoS2 microspheres had rough surfaces and were constructed with sheet-like structures in the two systems. But the product from the system of NH2OH·HCl as reductant has the bigger particle size, clearer petal-sheets, coarser surface and weaker agglomeration than that from the system H2C2O4 as reductant. The possible chemical reactions in hydrothermal systems were preliminarily discussed.


2012 ◽  
Vol 465 ◽  
pp. 198-203 ◽  
Author(s):  
Huai Xiang Li ◽  
Qing Qing Wei ◽  
Yan Yan Liu ◽  
Kang Wu

Cerium (Ce) and antimony (Sb) codoped tin dioxide (SnO2) films (Ce:Sb:Sn=2:3:95 molar ratio) have been prepared on the surface of titanium (Ti) substrate by sol-gel method. A self-assembled layer (SAL) of dodecyl thiol with cholesterol was formed on the surface of Ce-Sb codoped SnO2films/Ti electrode. The SAL was then used with the cholesterol as the template forming the molecular imprinting layer. The extraction of cholesterol has resulted in formation of sites in the layer of dodecyl thiol which could have been used as channels for the ferro-ferric cyanide coupled redox reaction to quantify recombining cholesterol on the sites. This sensor prototype could detect cholesterol concentrations between 40 and 60 μM. X-ray diffraction (XRD) and scanning electron microscopy (SEM) have been used to analyze the structure and morphology of the samples.


Arena Tekstil ◽  
2013 ◽  
Vol 28 (1) ◽  
Author(s):  
Maya Komalasari ◽  
Bambang Sunendar

Partikel nano TiO2 berbasis air dengan pH basa telah berhasil disintesis dengan menggunakan metode sol-gel dan diimobilisasi pada kain kapas dengan menggunakan kitosan sebagai zat pengikat silang. Sintesis dilakukan  dengan prekursor TiCl4 pada konsentrasi 0,3 M, 0,5 M dan 1 M, dan menggunakan templat kanji dengan proses kalsinasi pada suhu 500˚C selama 2 jam. Partikel nano TiO2 diaplikasikan ke kain kapas dengan metoda pad-dry-cure dan menggunakan kitosan sebagai crosslinking agent. Berdasarkan hasil Scanning Electron Microscope (SEM),diketahui bahwa morfologi partikel TiO2 berbentuk spherical dengan ukuran nano (kurang dari 100 nm). Karakterisasi X-Ray Diffraction (XRD) menunjukkan adanya tiga tipe struktur kristal utama, yaitu (100), (101) dan (102) dengan fasa kristal yang terbentuk adalah anatase dan rutile. Pada karakterisasi menggunakan SEM terhadap serbuk dari TiO2 yang telah diaplikasikan ke permukaan kain kapas, terlihat adanya imobilisasi partikel nano TiO2 melalui ikatan hidrogen silang dengan kitosan pada kain kapas. Hasil analisa tersebut kemudian dikonfirmasi dengan FTIR (Fourier Transform Infra Red) yang hasilnya memperlihatkan puncak serapan pada bilangan gelombang 3495 cm-1, 2546 cm-1, dan 511 cm-1,  yang masing-masing diasumsikan sebagai adanya vibrasi gugus fungsi O-H, N-H dan Ti-O-Ti. Hasil SEM menunjukkan pula bahwa kristal nano yang terbentuk diantaranya adalah fasa rutile , yang berdasarkan literatur terbukti dapatberfungsi sebagai anti UV.


2003 ◽  
Vol 67 (6) ◽  
pp. 1243-1251 ◽  
Author(s):  
A. Lu ◽  
D. Zhao ◽  
J. Li ◽  
C. Wang ◽  
S. Qin

AbstractSmall domestic cooking furnaces are widely used in China. These cooking furnaces release SO2 gas and dust into the atmosphere and cause serious air pollution. Experiments were conducted to investigate the effects of vermiculite, limestone or CaCO3, and combustion temperature and time on desulphurization and dust removal during briquette combustion in small domestic cooking furnaces. Additives used in the coal are vermiculite, CaCO3 and bentonite. Vermiculite is used for its expansion property to improve the contact between CaCO3 and SO2 and to convey O2 into the interior of briquette; CaCO3 is used as a chemical reactant to react with SO2 to form CaSO4; and bentonite is used to develop briquette strength. Expansion of vermiculite develops loose interior structures, such as pores or cracks, inside the briquette, and thus brings enough oxygen for combustion and sulphation reaction. Effective combustion of the original carbon reduces amounts of dust in the fly ash. X-ray diffraction, optical microscopy, and scanning electron microscopy with energy dispersive X-ray analysis show that S exists in the ash only as anhydrite CaSO4, a product of SO2 reacting with CaCO3 and O2. The formation of CaSO4 effectively reduces or eliminates SO2 emission from coal combustion. The major factors controlling S retention are vermiculite, CaCO3 and combustion temperature. The S retention ratio increases with increasing vermiculite amount at 950°C. The S retention ratio also increases with increasing Ca/S molar ratio, and the best Ca/S ratio is 2-3 for most combustion. With 12 g of the original coal, 1 to 2 g of vermiculite, a molar Ca/S ratio of 2.55 by adding CaCO3, and some bentonite, a S retention ratio >65% can be readily achieved. The highest S retention ratio of 97.9% is achieved at 950°C with addition of 2 g of vermiculite, a Ca/S ratio of 2.55 and bentonite.


Sign in / Sign up

Export Citation Format

Share Document