Preparation and characterization of alumina membranes and alumina–titania composite membranes

1999 ◽  
Vol 14 (9) ◽  
pp. 3599-3603 ◽  
Author(s):  
Li Shi ◽  
Ning-Bew Wong
Keyword(s):  
Thermal Analysis ◽  
Particle Size ◽  
Differential Thermal Analysis ◽  
Sol Gel ◽  
Composite Membranes ◽  
Particle Sizes ◽  
Pore Sizes ◽  
Surface Areas ◽  
Alumina Membranes

Supported and unsupported γ-alumina membranes and alumina–titania composite membranes were prepared using the sol-gel method. In the course of preparation, effects of acid concentration, type of acid, alkoxide, and binder on the particle size of the sols and pore size of the membranes were investigated by thermogravimetry and differential thermal analysis, N2 physisorption, and light scattering. It was observed that the particle sizes of all the sols had only a small affect on the pore sizes of the membranes. Qualities of the membranes were improved by addition of polyvinyl alcohol as binder to the boehmite precursor. This resulted in less critical but more controllable drying and calcining procedures. Composite membranes with different pore sizes from 3.2 to 4.8 nm and surface areas retained above 100 m2/g could be regulated by different alumina-to-titania ratios.

Synthesis and Characterization of Ti, Fe-Doped Mullite-I

2011 ◽  
Vol 217-218 ◽  
pp. 163-168 ◽  
Author(s):  
Lin Xin Tong ◽  
Jin Hong Li ◽  
Jian Cao
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Phase Separation ◽  
Powder Diffraction ◽  
Sol Gel ◽  
Synthesis And Characterization ◽  
Formation Temperature ◽  
Gel Method ◽  
X Ray

A series of gels with 3Al2O3•2SiO2 were prepared by Sol-gel method and heated at several temperatures for 2 h to synthesize Ti, Fe-doped mullite. The powers were characterized by differential thermal analysis (DSC-TG) and X-ray powder diffraction (XRD). Phase separation was promoted by doping both TiO2 and Fe2O3; with increasing the amount of dopant ions the formation temperature of Si-Al spinel decreased and the formation temperature of mullite increased by TiO2 doping but decreased by Fe2O3 doping. The formation temperature of pure mullite was about 1250-1350 °C.

Preparation And Characterization Of Ultra-Small Sized Metal And Semiconductor Particles In Sol-Gel Materials

1994 ◽  
Vol 346 ◽  
Author(s):  
Kyung Moon Choi ◽  
Kenneth J. Shea
Keyword(s):  
Pore Size ◽  
Surface Area ◽  
Sol Gel ◽  
High Vacuum ◽  
Particle Sizes ◽  
Transition Metal Clusters ◽  
Surface Areas ◽  
Sol Gel Process ◽  
Bridged Silsesquioxanes

ABSTRACTPoly(l,4-phenylene)-bridged and poly(1,6-hexylene)-bridged silsesquioxanes (PPS and HPS) were prepared by the sol-gel process. The surface areas and pore diameters of these porous xerogels were obtained by BET and BJH methods, respectively. These porous materials were used as a confinement matrix for the growth of small-sized semiconductor and transition metal clusters. Quantum-sized CdS particles in PPS (approximately 58+12 Â) and HPS (91+16 Â) matrices were prepared by first soaking the xerogel in a CdCl2 solution. Following a washing with water, a Na2S solution was then added. EDAX and electron diffraction techniques were used to identify the CdS particles. The particle sizes of CdS in PPS and HPS were determined by both UV measurements and from TEM images. Small-sized Cr clusters were prepared in dried xerogels by an internal doping method. Mixed Cr/CdS phases were also prepared by internal loading of a chromium metal precursor. Following deposition of CdS the xerogel was heated at 120 °C under high vacuum, resulting in formation of intimately mixed phases of Cr metal and CdS. Changes in morphology, in particular the surface area and pore size distribution were noted. A decrease in surface area and an increase in pore size were observed as a result of Cr metal deposition.

Crystalline phases of sol-gel ZrO2 in the ZrO2-SiO2 system: Differential thermal analysis and electron microscopy studies

1995 ◽  
Vol 10 (6) ◽  
pp. 1397-1402 ◽  
Author(s):  
D.R. Acosta ◽  
O. Novaro ◽  
T. López ◽  
R. Gómez
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Zirconium Oxide ◽  
Sol Gel ◽  
Thermal Treatments ◽  
Crystalline Phases ◽  
Preparation Conditions ◽  
Zirconium Acetate

Zirconium oxide dispersed in silica was synthesized by the cogelation of tetraethoxysilane and zirconium acetate. For the gelation, acid and basic media were used. The final zirconia concentration was around 6.7 wt. %. Differential thermal analysis, thermogravimetric analysis, as well as electron microscope techniques were used for the characterization of the samples. It was found that the stabilization of the crystalline phases depends on the preparation conditions and thermal treatments. Tetragonal and monoclinic ZrO2 phases were identified in basic preparations. However, in acidic samples only low-temperature tetragonal phase was identified.

Fabrication and Microstructure of ZnO-TiO2 Composite Membranes by a Reverse Micelle and Sol-Gel Processing

2006 ◽  
Vol 510-511 ◽  
pp. 786-789 ◽  
Author(s):  
Dong Sik Bae ◽  
Byung Ik Kim ◽  
Kyong Sop Han
Keyword(s):  
Particle Size ◽  
Reverse Micelle ◽  
Porous Alumina ◽  
Sol Gel ◽  
Average Particle Size ◽  
Composite Membranes ◽  
Dip Coating ◽  
Narrow Particle Size Distribution ◽  
Average Particle ◽  
Alumina Support

ZnO-TiO2 nanoparticles were synthesized by a reverse micelle and sol-gel process. The average particle size of the colloid was below 30 nm and well dispersed in the solution. ZnOTiO2 composite membranes were fabricated by using the dip-coating method on a porous alumina support. ZnO-TiO2 composite membranes showed a crack-free microstructure and narrow particle size distribution even after the heat treatment up to 600°C. The average particle size of the membrane was 30-40nm, and the pore size of ZnO-TiO2 composite membrane was below 10 nm.

scholarly journals Thermal and structural characterization of the vitreous samples in the SiO2 - PbO - Na2O system

2006 ◽  
pp. 89-95 ◽  
Author(s):  
Catalina Mocioiu ◽  
Georgeta Jitianu ◽  
Maria Zaharescu
Keyword(s):  
Thermal Stability ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Infrared Spectroscopy ◽  
Silicate Glasses ◽  
Lead Silicate ◽  
High Chemical ◽  
Nuclear Techniques ◽  
Infrared Data

Lead-containing glasses have been used from the ancient time. Recently, due to the possible application in optics, electronics, nuclear techniques, wastes inactivation. the interest in these types of glasses has been renewed. For lead waste inactivation, glasses with high amount of PbO in the composition are required, those exhibiting at the same time a high chemical and thermal stability. Thermal behavior of lead-silicate glasses was examined by differential thermal analysis (DTA). Infrared spectroscopy was used to investigate the structure of the glasses. The spectra were interpreted in terms of the structures of silicate group by comparison with the spectra of other silicate crystals. The DTA and infrared data were correlated with the chemical stability tests.

Purification of Bentonite Clays from Cubati, PB, Brazil, for Diversified Applications

2014 ◽  
Vol 805 ◽  
pp. 486-491
Author(s):  
J.M.R. Figueirêdo ◽  
Juliana Melo Cartaxo ◽  
I.A. Silva ◽  
C.D. Silva ◽  
Gelmires Araújo Neves ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Chemical Analysis ◽  
Laser Diffraction ◽  
The State ◽  
X Ray Diffraction ◽  
X Ray ◽  
Granulometric Analysis ◽  
Bentonite Clays

The State of Paraíba, Brazil, retains about 88.5% of all Brazilian bentonite, and much of this production comes from deposits in the District of Boa Vista, PB. Nevertheless, the deposits are almost depleted. Recently, new deposits were found, which will increases the reserves of the State, in the regions of Cubati and Pedra Lavrada, PB. The objective of this work is to characterize and develop purified clays, through sieving and hydrocycloning techniques, from those recently discovered bentonites for several applications. The characterization of the sample was done through granulometric analysis by laser diffraction, X-ray diffraction, chemical analysis by X-ray fluorescence, and thermogravimetric and differential thermal analysis. The results show that the samples are typical of bentonite clays, and that the purification solely by hydrocyclone presents the best results.

Preparation and Characterization of Cu-Inorganic Antibacterial Material Containing Rare Earths

2009 ◽  
Vol 79-82 ◽  
pp. 989-992 ◽  
Author(s):  
Bin Zhang ◽  
Xiao Ning Tang ◽  
Gang Xie ◽  
Su Qiong He ◽  
Yang Dong
Keyword(s):  
Particle Size ◽  
Rare Earths ◽  
Inductively Coupled Plasma ◽  
Sol Gel ◽  
Measurement Instrument ◽  
Particle Size Measurement ◽  
Inductively Coupled ◽  
New Material ◽  
Antibacterial Material

In this study, we synthesized a new inorganic antibacterial material, of which Cu2+ was selected to be the antibacterial ion, cerous nitrate served as the additives, and the white carbon black was chosen as the carrier, which was prepared by a sol-gel method. The as-synthesized antibacterial material was characterized by inductively coupled plasma, particle size measurement instrument, scanning electron microscope and enumeration tests. The result showed that the amount of antibacterial ions and bacteriostasis rate of this new material are higher than those for the common Cu-inorganic antibacterial material without rare earths. In addition, the particle size of this material can be extended down to 20 μm with a narrow size distribution. Other advantages of this material are its loose and dispersive structure.

Preparation and Characterization of Blended Composite Membranes

2012 ◽  
Vol 488-489 ◽  
pp. 506-510 ◽  
Author(s):  
Sikander Rafiq ◽  
Zakaria Man ◽  
Abdulhalim Maulud ◽  
Nawshad Muhammad ◽  
Saikat Maitra
Keyword(s):  
Spectroscopic Analysis ◽  
Sol Gel ◽  
Composite Membranes ◽  
Hybrid Membranes ◽  
Ftir Analysis ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Thermal Stability Of ◽  
Scanning Electron

Composite membranes were prepared by incorporating inorganic silica nanoparticles into blends of polysulfone/polyimide (PSF/PI) membranes via sol-gel route. Morphological structures of the developed membranes were carried out by scanning electron microscopy (SEM). Spectroscopic analysis of the hybrid membranes were done by fourier transform infrared spectroscopy (FTIR) analysis. Differential scanning calorimetry (DSC) analysis shows that the glass transition temperature (Tg) increased from 209oC to 238oC in the hybrid membranes followed by thermogravimetric analysis (TGA) that showed significant improvement in thermal stability of the developed membranes.

scholarly journals Size Effects on Magnetic Properties ofNi0.5Zn0.5Fe2O4Prepared by Sol-Gel Method

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Min Zhang ◽  
Zhenfa Zi ◽  
Qiangchun Liu ◽  
Peng Zhang ◽  
Xianwu Tang ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Measurements ◽  
Sol Gel ◽  
Domain Wall Motion ◽  
Blocking Temperature ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
Gel Method ◽  
Sol Gel Method ◽  
Cation Redistribution

Ni0.5Zn0.5Fe2O4particles with different particle sizes have been synthesized by sol-gel method. X-ray diffraction results show that all the samples are pure cubic spinel structure with their sizes ranging from 9 to 96 nm. The lattice constant significantly decreases with further increasing annealing temperature. The magnetic measurements show superparamagnetic nature below the particle size of 30 nm, while others show ferrimagnetic nature above the corresponding blocking temperature. The blocking temperature increases with the increase in particle size, which can be explained by Stoner-Wohlfarth theory. The saturation magnetization increases as the particle size increases, which can be explained by the cation redistribution on tetrahedral A and octahedral B sites and the domain wall motion. The variation of coercivity as a function of particle size is based on the domain structure.

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