Combustion Synthesis of α-Al2O3 Powders

2006 ◽  
Vol 530-531 ◽  
pp. 631-636 ◽  
Author(s):  
Normanda Lino de Freitas ◽  
Elias Fagury-Neto ◽  
Hélio Lucena Lira ◽  
Lucianna Gama ◽  
Ruth Herta Goldsmith Aliaga Kiminami ◽  
...  
Keyword(s):  
Nitrogen Adsorption ◽  
Ceramic Materials ◽  
Laser Diffraction ◽  
X Ray Diffraction ◽  
Solution Composition ◽  
X Ray ◽  
Urea Content ◽  
Chemical Concepts ◽  
Α Al2o3 ◽  
New Applications

Among ceramic materials, the alumina has high importance because of its characteristics of resistance and refractory. The possibility to improve the final characteristics of this material, open possibilities for new applications. The aim of this work is to synthesize (α-Al2O3) alumina powders by combustion reaction and to evaluate the effect of the urea content in the final characteristics of the α-Al2O3 powders. Three compositions were studied : a) stoichiometric, b) with 10% of urea reduction and c) with 20% of urea reduction. The initial solution composition was based on the total valence of the reagents by using chemical concepts of the propellant. This powders were characterized by X-ray diffraction (XRD), granulometric determination by laser diffraction, nitrogen adsorption by BET, scanning electron microscopy (SEM), infrared spectroscopy (IR) and helium picnometer. The results showed that the urea reduction change the temperature of the reaction from 525 to 463oC , the characteristics of the powders, and principally the reduction of the particles size.

Study of ceramic materials in the SrSnO3–NaNbO3 system by X-ray diffraction, dielectric and Raman spectroscopy

2009 ◽  
Vol 484 (1-2) ◽  
pp. 356-359 ◽  
Author(s):  
Abdelhedi Aydi ◽  
Hamadi Khemakhem ◽  
Annie Simon ◽  
Dominique Michau ◽  
Régnault von der Mühll
Keyword(s):  
Raman Spectroscopy ◽  
Ceramic Materials ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Preparation and Characterization of Porous Ceramic Membranes for Micro-Filtration from Clay/CuZn Using Extrusion Methods

2018 ◽  
Vol 156 ◽  
pp. 08015 ◽  
Author(s):  
Muh Amin ◽  
Muhammad Subri
Keyword(s):  
Porous Ceramic ◽  
Ceramic Materials ◽  
Ceramic Membranes ◽  
Extrusion Process ◽  
X Ray Diffraction ◽  
Percentage Composition ◽  
X Ray ◽  
Ceramic Support ◽  
Fabrication And Characterization

In this study, fabrication and characterization of ceramic membranes preparation was carried out. Porous ceramic membranes were fabricated by extrusion process from different percentage composition of CuZn on (80 wt% Clay, 10 wt% TiO2, 5 wt% Carbon and 5 wt% PVA). The fabricated membranes were sintered at 900°C for 1 hour in an electrical box furnace with heating rate 1oC/min and holding time for 1 hour. Apparent density and porosity were determined by standar methods for ceramic materials. Phase composition of the ceramic support was established by X-Ray Diffraction analysis. SEM studies of the membranes added at different CuZn were carried out.

Influence of Organophilization Process Variables in Bentonite Clays from Cubati-PB

2012 ◽  
Vol 727-728 ◽  
pp. 1467-1472
Author(s):  
Carla Dantas da Silva ◽  
Rosa do Carmo de Oliveira Lima ◽  
Julliana Marques Rocha Costa ◽  
Gelmires Araújo Neves ◽  
Heber Carlos Ferreira
Keyword(s):  
Thermogravimetric Analysis ◽  
Bentonite Clay ◽  
Laser Diffraction ◽  
Ionic Surfactants ◽  
Organic Media ◽  
Process Variables ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bentonite Clays ◽  
Sodium Form

This work aims at the development of organoclay from two varieties of bentonite for use in organic media using ionic surfactants, studying the influence of process variables in the organophilization process. We used the following materials: natural bentonite clay from Cubati-PB District, and the ionic quaternary ammonium salt: Praepagen WB® with 45% active matter. The clays were benefited and then turned into sodium form and subsequently into organoclays. The bentonites were characterized by laser diffraction (GA) X-ray fluorescence chemical composition (EDX), thermogravimetric analysis (TGA), thermogravimetry (DTA) and X-ray diffraction (XRD). The organoclays were characterized by (XRD) thermogravimetric analysis (TGA) and thermogravimetry (DTA). The results showed that the clay has potential for application in the organophilization process and that there is influence of process variables.

Application of raw and modified Uruguayan clays to phosphate adsorption for water remediation

MRS Advances ◽  
2018 ◽  
Vol 3 (61) ◽  
pp. 3543-3549
Author(s):  
Pablo González ◽  
Andrea C. De Los Santos ◽  
Jorge R. Castiglioni ◽  
María A. De León
Keyword(s):  
Nitrogen Adsorption ◽  
Pillared Clay ◽  
Water Remediation ◽  
Phosphate Adsorption ◽  
X Ray Diffraction ◽  
Order Model ◽  
Freundlich Model ◽  
X Ray ◽  
First Order ◽  
Adsorption Desorption

ABSTRACTA raw clay from Uruguay was modified with aluminium to obtain an aluminium pillared clay (Al-PILC). The solids were characterized by scanning electron microscopy, X-ray diffraction and nitrogen adsorption-desorption isotherms. The Al-PILC retained the typical laminar structure of montmorillonite. The specific surface area and the microporous volume of the Al-PILC, 235 m2 g-1 and 0.096 cm3 g-1, respectively, were much higher than those of the clay. The phosphate adsorption capacity of the Al-PILC was higher than those of the clay. The phosphate adsorption kinetic followed the pseudo-first-order model for both, the clay and the Al-PILC, and the phosphate adsorption isotherm for the Al-PILC fit the Freundlich model.

The Adsorption and Chemistry of Tripropyl phosphate (TPP) into Microporous and Mesoporous NaX Zeolites

2011 ◽  
Vol 1304 ◽  
Author(s):  
Qingguo Meng ◽  
David C. Doetschman ◽  
Apostolos K. Rizos ◽  
Min-Hong Lee ◽  
Jürgen T. Schulte ◽  
...  
Keyword(s):  
Solid State ◽  
Structural Properties ◽  
Nmr Spectra ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nax Zeolite ◽  
Stoichiometric Amount ◽  
Polydiallyldimethylammonium Chloride ◽  
Adsorption Analysis

ABSTRACTAdsorption and chemistry of tripropylphosphate (TPP) in mesoporous NaX zeolite, which was templated by cationic templated polymer (polydiallyldimethylammonium chloride, PDADMAC) with two different length chains, was investigated. The structural properties of the zeolites were characterized by X-ray diffraction (XRD) and nitrogen adsorption analysis. The chemical activities of different zeolites toward the decomposition of TPP were determined with solid state 31P NMR spectra. After exposure of zeolites to TPP was sufficient and equilibrium was reached, a stoichiometric amount of water was also adsorbed and hydrolysis was observed. The TPP decomposition yields in different NaX zeolites were compared.

scholarly journals VISUALISASI STRUKTUR KRISTAL KERAMIK PEROVSKITE MENGGUNAKAN VESTA

2018 ◽  
Vol 15 (1) ◽  
pp. 46
Author(s):  
Sundami Restiana ◽  
Ari Sulistyo Rini
Keyword(s):  
Crystal Structure ◽  
Diffraction Pattern ◽  
Critical Concentration ◽  
Ceramic Materials ◽  
Lattice Parameter ◽  
Peak Position ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Information ◽  
Software Program

Visualization of crystal structures and simulation of X-ray diffraction patterns of perovskite ceramic was successfully performed by VESTA software programs. The purpose of this research is to obtain the relation of lattice parameter, and composition to the diffraction pattern. The software program produces crystal structure information and a representative X-ray diffraction pattern for the ceramic materials. The program needs several input parameters such as the coordinates of each constituent atom, lattice parameters, and space symmetry. The obtained output of the software program are in the form of diffraction pattern graph and crystal structure data which gives the description of the profile and type (phase) of ceramic material. The results showed that the peak position and intensity of the diffraction pattern are influenced by the arrangement of  the atoms within the unit cell. The addition of impurity atoms such as Sr on the Ba side in BaTiO3 causes the BaTiO3 structure changes from Orthorombic (a≠b≠c) to Tetragonal (a=b≠c) structure. Based on the simulation, it can be predicted that the critical concentration of the change of structure occur at Sr concentration about 0.4.

scholarly journals COMPOSITION, STRUCTURE AND TEXTURAL CHARACTERISTICS OF DOMESTIC ACID ACTIVATED BENTONITE

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Zоrаn Pеtrоvić ◽  
Pеrо Dugić ◽  
Vојislаv Аlеksić ◽  
Sаbinа Bеgić ◽  
Vlаdаn Мićić ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Low Temperature ◽  
Layered Structure ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
Textural Characteristics ◽  
X Ray ◽  
Before And After ◽  
Activated Bentonite ◽  
Composition Structure

Bentonites are aluminosilicate minerals which, due to their porosity, layered structure and composition have a wide application. Structural and textural characteristics of bentonite may be improved by different modification procedures. The aim of this study was to investigate compositional, structural and textural characteristics of domestic bentonite in place Gerzovo, before and after the activation with sulfuric acid. These characteristics were investigated by analytical methods, X-ray diffraction (XRD) and the method of low-temperature nitrogen adsorption (BET). Characteristics of acid-activated bentonite were compared with the characteristics of commercial active clay. The obtained results showed that the activation of bentonite with sulfuric acid leads to a significant improvement in structural and textural characteristics. Using these results it can be assumed that this bentonite will have good adsorption characteristics and can serve as an alternative in comparison with imported commercial aluminosilicate-based adsorbents.

Structural and surface aspects of thermally treated copper aluminium mixed hydroxides

1991 ◽  
Vol 69 (10) ◽  
pp. 1511-1515 ◽  
Author(s):  
Awad I. Ahmed ◽  
S. E. Samra ◽  
S. A. El-Hakam
Keyword(s):  
Pore Structure ◽  
Copper Content ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Phase Changes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Structure Surface ◽  
Adsorption Desorption

CuO–Al2O3 catalysts containing various amounts of copper oxide have been prepared by precipitation. The phase changes were studied by X-ray diffraction. The results obtained revealed that the thermal treatment of solid CuO–Al2O3 at 700 °C produced only crystalline CuO. Heating to 900 °C led to the formation of copper alumina spinel together with unreacted CuO and γ-Al2O3. The spinel content was found to increase with increasing copper content. Nitrogen adsorption–desorption isotherms on the calcined samples have been measured. Surface areas have been calculated and the pore structure analysed. The textural properties of the system were found to depend on both the copper content and the calcination temperature. Key words: CuO, Al2O3 catalysts, structure, surface area, pore structure.

scholarly journals Bulk Versus Surface Modification of Alumina with Mn and Ce Based Oxides for CH4 Catalytic Combustion

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1771 ◽  
Author(s):  
Stefan Neatu ◽  
Mihaela M. Trandafir ◽  
Adelina Stănoiu ◽  
Ovidiu G. Florea ◽  
Cristian E. Simion ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Combustion ◽  
Mixed Oxides ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Catalytic Combustion Of Methane ◽  
Adsorption Desorption

This study presents the synthesis and characterization of lanthanum-modified alumina supported cerium–manganese mixed oxides, which were prepared by three different methods (coprecipitation, impregnation and citrate-based sol-gel method) followed by calcination at 500 °C. The physicochemical properties of the synthesized materials were investigated by various characterization techniques, namely: nitrogen adsorption-desorption isotherms, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and H2–temperature programmed reduction (TPR). This experimental study demonstrated that the role of the catalytic surface is much more important than the bulk one. Indeed, the incipient impregnation of CeO2–MnOx catalyst, supported on an optimized amount of 4 wt.% La2O3–Al2O3, provided the best results of the catalytic combustion of methane on our catalytic micro-convertors. This is mainly due to: (i) the highest pore size dimensions according to the Brunauer-Emmett-Teller (BET) investigations, (ii) the highest amount of Mn4+ or/and Ce4+ on the surface as revealed by XPS, (iii) the presence of a mixed phase (Ce2MnO6) as shown by X-ray diffraction; and (iv) a higher reducibility of Mn4+ or/and Ce4+ species as displayed by H2–TPR and therefore more reactive oxygen species.

scholarly journals Sustainable Ceramic Materials Manufactured from Ceramic Formulations Containing Quartzite and Scheelite Tailings

2020 ◽  
Vol 12 (22) ◽  
pp. 9417
Author(s):  
Jucielle Veras Fernandes ◽  
Danyelle Garcia Guedes ◽  
Fabiana Pereira da Costa ◽  
Alisson Mendes Rodrigues ◽  
Gelmires de Araújo Neves ◽  
...  
Keyword(s):  
Rio Grande ◽  
Ceramic Materials ◽  
Linear Shrinkage ◽  
X Ray Diffraction ◽  
Ceramic Tiles ◽  
X Ray ◽  
Mining Companies ◽  
Ceramic Samples ◽  
Sustainable Materials ◽  
Mineralogical Phases

In this study, we develop ceramic formulations based on quartzite and scheelite tailings collected from mining companies in the northeast of Brazil (Rio Grande do Norte State). New ceramic samples (27 wt% of kaolin, 29 wt% of plastic clay, 11 wt% of quartzite tailing, and 0–8 wt% scheelite tailing) were uniaxially pressed in two steps (20 MPa and 50 Mpa for 20 s); dried at 110 °C for 24 h; and sintered at 1150 °C, 1200 °C, and 1250 °C. The main mineralogical phases (mullite, quartz, calcite, and anorthite) of the sintered samples were identified using X-ray diffraction (XRD). After evaluation of the physical-mechanical properties (water absorption, linear shrinkage, apparent porosity, and flexural strength), it was observed that the incorporation of scheelite tailing by up to 8 wt% did not significantly alter the properties of samples sintered at all temperatures. Our results indicate that the new ceramics formulations developed have strong potentials in manufacturing sustainable materials such as ceramic tiles and porcelain stoneware.

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