scholarly journals Extraction–Pyrolytic Method for TiO2 Polymorphs Production

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 431
Author(s):  
Vera Serga ◽  
Regina Burve ◽  
Aija Krumina ◽  
Marina Romanova ◽  
Eugene A. Kotomin ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Xrd Analysis ◽  
Nanocrystalline Powders ◽  
Precipitation Method ◽  
Synthesis Methods ◽  
Scanning Calorimetry ◽  
Nanocrystalline Tio2 ◽  
Organic Impurities ◽  
Transmission Electron ◽  
The Fourier Transform

The unique properties and numerous applications of nanocrystalline titanium dioxide (TiO2) are stimulating research on improving the existing and developing new titanium dioxide synthesis methods. In this work, we demonstrate for the first time the possibilities of the extraction–pyrolytic method (EPM) for the production of nanocrystalline TiO2 powders. A titanium-containing precursor (extract) was prepared by liquid–liquid extraction using valeric acid C4H9COOH without diluent as an extractant. Simultaneous thermogravimetric analysis and differential scanning calorimetry (TGA–DSC), as well as the Fourier-transform infrared (FTIR) spectroscopy were used to determine the temperature conditions to fabricate TiO2 powders free of organic impurities. The produced materials were also characterized by X-ray diffraction (XRD) analysis and transmission electron microscopy (TEM). The results showed the possibility of the fabrication of storage-stable liquid titanium (IV)-containing precursor, which provided nanocrystalline TiO2 powders. It was established that the EPM permits the production of both monophase (anatase polymorph or rutile polymorph) and biphase (mixed anatase–rutile polymorphs), impurity-free nanocrystalline TiO2 powders. For comparison, TiO2 powders were also produced by the precipitation method. The results presented in this study could serve as a solid basis for further developing the EPM for the cheap and simple production of nanocrystalline TiO2-based materials in the form of doped nanocrystalline powders, thin films, and composite materials.

scholarly journals Nanocrystalline TiO2 Powder Prepared by Sol-Gel Method for Dye-Sensitized Solar Cells

2016 ◽  
Vol 61 (2) ◽  
pp. 833-836 ◽  
Author(s):  
L. A. Dobrzański ◽  
M. M. Szindler ◽  
M. Szindler ◽  
K. Lukaszkowicz ◽  
A. Drygała ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Sol Gel ◽  
Dye Sensitized Solar Cells ◽  
Nanocrystalline Structure ◽  
Titanium Isopropoxide ◽  
Thin Layers ◽  
Nanocrystalline Tio2 ◽  
Transmission Electron ◽  
Dioxide Powder ◽  
Titanium White

Abstract In this study titanium dioxide nanopowder has been manufactured and examined. Nanocrystalline TiO2 powder has been obtained by hydrolysis and peptization of a solution of titanium isopropoxide and isopropanol. Subsequently, produced powder has been subjected to structural analysis by using a transmission electron microscope, X-ray diffractometer, and Raman spectrometer. For comparison purposes, a commercially available titanium dioxide powder (i.e. titanium white) was also used. Thin layers have been made from this powder and further have been examined by using a UV/VIS spectrometer. Completed research shows the nanocrystalline structure of obtained layers and their good properties such as absorbance at the range of wavelength equal 200 - 1000 nm.

scholarly journals Synthesis and characterization of gold nanoparticles on titanium dioxide for the catalytic photodegradation of 2,4-dichlorophenoxyacetic acid

2018 ◽  
Vol 16 (5) ◽  
Author(s):  
E. Romero Torres ◽  
M. Gutiérrez Arzaluz ◽  
V Mugica Alvarez ◽  
L. González Reyes ◽  
M. Torres Rodríguez ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Titanium Dioxide ◽  
Uv Light ◽  
Anatase Phase ◽  
Precipitation Method ◽  
Dichlorophenoxyacetic Acid ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Average Size ◽  
2,4 Dichlorophenoxyacetic Acid

The photocatalytic degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) using a Au/TiO2 catalyst and ultraviolet (UV) light energy source (9 mW/cm2) discussed. Gold nanoparticles were synthesized by controlled urea reduction and deposited on titanium dioxide (TiO2) by the deposition-precipitation method. The average size of the nanoparticles was 6-8 nm. X-ray diffraction (XRD) characterization confirmed that TiO2 was present in the anatase phase, whereas the presence and particle size of gold were determined by transmission electron microscopy (TEM). The results of the degradation showed that the activity of TiO2 was improved when Au nanoparticles were present on the surface. The reactions were performed at atmospheric pressure and room temperature.

Synthesis and Luminescence Properties of Yb3+/Ho3+ Co-Doped Lu2O3 Nanocrystalline Powders

2007 ◽  
Vol 280-283 ◽  
pp. 521-524
Author(s):  
Li Qiong An ◽  
Jian Zhang ◽  
Min Liu ◽  
Sheng Wu Wang
Keyword(s):  
Electron Microscopy ◽  
Upconversion Luminescence ◽  
Nanocrystalline Powders ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Excitation Spectra ◽  
X Ray ◽  
Transmission Electron ◽  
Co Precipitation ◽  
Co Doped

Yb3+ and Ho3+ co-doped Lu2O3 nanocrystalline powders were synthesized by a reversestrike co-precipitation method. The as-prepared powders were examined by the X-ray diffraction and transmission electron microscopy. The phase composition of the powders was cubic and the particle size was in the range of 30~50 nm. Emission and excitation spectra of the powders were measured by a spectrofluorometer and the possible upconversion luminescence mechanism was also discussed.

scholarly journals DEVELOPMENT AND CHARACTERIZATION OF NOVEL HERBAL FORMULATION (POLYMERIC MICROSPHERES) OF SYZYGIUM CUMINI SEED EXTRACT

2018 ◽  
Vol 10 (5) ◽  
pp. 226
Author(s):  
Ranu Biswas ◽  
Kalyan Kumar Sen
Keyword(s):  
Drug Release ◽  
Entrapment Efficiency ◽  
Xrd Analysis ◽  
Syzygium Cumini ◽  
Sustained Drug Release ◽  
Scanning Calorimetry ◽  
Polymeric Microspheres ◽  
Herbal Formulation ◽  
Alkaline Dissolution ◽  
The Fourier Transform

Objective: The purpose of the present investigation was to develop and characterize a novel herbal formulation (polymeric microspheres) of Syzygium cumini seed extract.Methods: The extract-loaded microspheres using biological macromolecule ethyl cellulose (EC) was prepared by o/w emulsion solvent evaporation technique using polyvinyl alcohol (PVA) emulsifier. The effect of various process and formulation variables (stirring speed, evaporation time, drug/polymer ratio and organic/aqueous phase ratio) on the properties of microspheres was evaluated.Results: Micromeritic properties indicated good flow properties, and scanning electron microscopy (SEM) confirmed the spherical nature of the prepared microspheres. The particle size and entrapment efficiency were varied between 34.25 to 176.25 µm and 10.51 to 42% depending upon the variables. All the formulations showed minimal drug release in an acidic environment (pH 1.2) confirming the prevention of drug release in the stomach and enteric nature of the polymer. Sustained drug release has been observed in alkaline dissolution media (pH 7.4) after 12 h of drug release study except for formulation F7 which contains a lower concentration of polymer. The fourier transform infrared spectroscopy (FTIR) analysis indicated the compatibility of the extract with the polymer. The absence of extract-polymer interaction was indicated by the differential scanning calorimetry (DSC) thermogram. x-ray diffraction (XRD) analysis revealed the amorphous nature of the extract in the microspheres which in pure form exhibits a crystalline structure.Conclusion: The findings of this present study suggest that microsphere formulation was a promising carrier for novel delivery of herbal drugs.

Preparation and characterization of 1,2,4,5-benzenetetra carboxylic-chitosan

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Nurhidayatullaili Muhd Julkapli ◽  
Zulkifli Ahmad ◽  
Hazizan Md Akil
Keyword(s):  
Xrd Analysis ◽  
Absorption Capacity ◽  
Cross Linking ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
H Nmr ◽  
Crystalline Nature ◽  
The Fourier Transform

AbstractChemically cross-linked chitosan (MC) containing 1,2,4,5- benzenetetracarboxylic acid (BCA) as the cross-linking agent was prepared to improve the metal ions absorption capacity of native chitosan (NC) and limit its biodegradability. The Fourier transform infra-red (FTIR) and proton neutron magnetic resonance (1H NMR) results showed that BCA was successfully linked onto N-position of NC. The crystalline nature of NC was reduced significantly after cross-linking as examined by X-ray diffraction (XRD) analysis. Therefore, the glass transition temperature (Tg) of MC was higher than NC as reported by differential scanning calorimetry (DSC). Moreover, thermogravimetric (TGA) analysis showed that, MC had better thermal stability than NC. Morphology changes on the surface of NC and MC were characterized by field emission scanning electron microscopy (FESEM) and showed that MC had more porous surface than NC. In pH medium of 3 to 6, MC had excellent Cu (II) ions absorption capacity with a maximum 16 % higher than NC.

scholarly journals Synthesis of Calcium Phosphate Extracted from Eggshell Waste through Precipitation Method

2021 ◽  
Vol 11 (6) ◽  
pp. 15058-15067
Keyword(s):  
Calcium Phosphate ◽  
Xrd Analysis ◽  
Precipitation Method ◽  
Synthesis Methods ◽  
Edge Structure ◽  
High Calcium ◽  
Calcium Source ◽  
Different Temperatures ◽  
Phosphate Source ◽  
Eggshell Waste

Biomaterials for bone engineering applications are eagerly developing as traditional bone grafting methods show several drawbacks after and during operation. Eggshell waste contains high calcium suitable for developing biomaterials in hard tissue engineering as bone made up of calcium and phosphate. The precipitation method is one of the synthesis methods to produce calcium phosphate (CaP). In this work, calcium source was extracted from eggshell waste while phosphate source was from ortho-phosphoric acid. The synthesized CaP powder was calcined at different temperatures. X-ray diffraction (XRD) analysis shows two types of CaP patterns are hydroxyapatite (HA) and β-Tricalcium phosphate (β-TCP). Fourier transform infrared (FTIR) shows phosphate ion band in every sample while scanning electron microscopy (SEM) shows the transformation of structure from needle-like to more fluffy and rounded-edge structure from uncalcined to 1000°C. From the results obtained, CaP extracted from eggshell waste was successfully synthesized from the precipitation method. This method contributes to the materials processing cost reduction and increases the application of natural materials instead of synthetic ones.

SYNTHESIS OF MO-CO ALLOY NANOPOWDER BY CO-PRECIPITATION METHOD FOLLOWED BY H2 REDUCTION

2012 ◽  
Vol 05 ◽  
pp. 142-150
Author(s):  
KAMAL SABERYAN ◽  
SADEGH FIROOZI ◽  
AMIN MORADMAND ◽  
ALI REYHANI
Keyword(s):  
Electron Microscope ◽  
Aqueous Media ◽  
Spherical Shape ◽  
Xrd Analysis ◽  
Hydrogen Gas ◽  
Precipitation Method ◽  
Transmission Electron ◽  
Bed Materials ◽  
Size And Morphology ◽  
Co Precipitation

Cobalt-Molybdenum alloy nanopowder has magnetic properties and is used as catalyst for production of carbon nanotubes. Properties of this nanopowder depend on, for example, its size, morphology and internal residual stress. Synthesis of nanopowder of Molybdenum-Cobalt alloy by co-precipitation in an aqueous media using NH 4 OH as precipitating agent followed by calcination and reduction was investigated. The synthesis was started by dissolving salts of Cobalt and Molybdenum in water. A suspension of alumina or silica powders was used as a bed for precipitation. The effect of bed materials on size and morphology of the precipitate was investigated. The particles observed with scanning electron microscope possess a spherical shape and a needle shape for the samples participated on alumina and silica beds, respectively. XRD analysis of the calcined precipitate showed the formation of mixed oxide of CoMoO 4 as well as single oxides of Co 3 O 4 and MoO 3. Particle size of the precipitate observed with transmission electron microscope was about 100 nm. Finally, the powders were reduced by hydrogen gas in a tubular furnace to prepare metallic nanopowder with composition of Co 3 Mo .

scholarly journals A Comparative Study on Luminescence Properties of Y2O3: Pr3+ Nanocrystals Prepared by Different Synthesis Methods

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1574
Author(s):  
Andrea Diego-Rucabado ◽  
Marina T. Candela ◽  
Fernando Aguado ◽  
Jesús González ◽  
Fernando Rodríguez ◽  
...  
Keyword(s):  
Optical Properties ◽  
Comparative Study ◽  
Figure Of Merit ◽  
Luminescence Decay ◽  
Synthesis Methods ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Reaction Conditions ◽  
Wet Chemistry ◽  
Transmission Electron

Pr3+-doped Y2O3 nanocrystals (NCs) have been obtained via five wet-chemistry synthesis methods which were optimized in order to achieve superior optical properties. To this end, a systematic study on the influence of different reaction parameters was performed for each procedure. Specifically, precursor concentration, reaction temperature, calcination temperature, and time, among others, were analyzed. The synthesized Y2O3: Pr3+ NCs were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), and reflectance and Raman spectroscopy. In addition, the optical properties of such NCs were investigated by excitation, emission, and luminescence decay measurements. Concretely, emission from the 1D2 level was detected in all samples, while emission from 3PJ was absent. Finally, the effect of the synthesis methods and the reaction conditions on the luminescence decay has been discussed, and a comparative study of the different methods using the fluorescence lifetime of so-obtained Y2O3: Pr3+ NCs as a figure of merit has been carried out.

Study of Precipitation Hardening in Two Al-Mg-Si Alloys with and without Copper and Excess Silicon Using Kissinger and Boswell Methods

2019 ◽  
Vol 397 ◽  
pp. 101-110
Author(s):  
Fares Serradj ◽  
Hichem Farh ◽  
Brahim Belfarhi
Keyword(s):  
Isoconversional Methods ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Electron Microscopic ◽  
X Ray ◽  
Excess Silicon ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Dsc Curves

The precipitation of two 6xxx (Al-Mg-Si) alloys with and without copper (Cu) and excess silicon (Si) has been investigated by using the differential scanning calorimetry (DSC), transmission electron microscopic (TEM) and X ray diffraction (XRD) analysis. The analysis of the DSC curves found that the excess Si accelerate the precipitation. The values of activation energies for each peak of DSC curves were determined by using Kissinger–Akahira–Sunose (KAS) and Boswell isoconversional methods. The alloy which has an excess Si and copper require larger activation energy for precipitation despite the acceleration of the precipitation by the excess Si. TEM observation result shows there is smaller size and higher density of precipitate in excess Si alloy than those of excess-free.

Characterization of Al2(WO4)3 Synthesized by Co-Precipitation Method

2014 ◽  
Vol 798-799 ◽  
pp. 85-89 ◽  
Author(s):  
E.S.G. Junior ◽  
P.M . Jardim
Keyword(s):  
Precipitation Method ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Tem Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Co Precipitation ◽  
Alpha Alumina

Al2(WO4)3was synthesized by co-precipitation using Na2WO4and Al (NO3)3as precursors. After drying the precipitate, it was calcined at different temperatures between 500°C and 800°C. The crystallization and degradation temperatures of the samples were evaluated by means of Differential Scanning Calorimetry (DSC), Thermogravimetry (TG) and X-Ray Diffraction (XRD). It was observed that the crystallization starts at around 600°C, however Transmission Electron Microscopy (TEM) analysis showed that at this temperature the sample is partially amorphous. The degradation of the material starts at around 1200°C and at 1400°C the tungsten oxide has almost completely evaporated and the material is transformed mainly in alpha-alumina.

Sign in / Sign up

Export Citation Format

Share Document