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1
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Silica synthesis by the sol-gel method and its use in the preparation of multifunctional biocomposites

100%
Klapiszewski Ł., Królak M., Jesionowski T.
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issue 2
173-184
EN
This study focuses on the optimization process of silica synthesis using the sol-gel method while applying a statistical design of experiments which was based on a multilevel mathematical model. The product obtained in the process of optimized synthesis, characterized by the best dispersive and morphological parameters, was used for the preparation of organic/inorganic composites. The organic precursor was Kraft lignin, a high-molecular natural polymer. Synthesis of silica/lignin biocomposites was carried out by three proposed methods. The physicochemical properties and dispersive-morphological properties of each product were determined using the following available methods: Scanning Electron Microscopy - SEM, Non-Invasive Back-Scattering - NIBS, Fourier Transform Infrared Spectroscopy - FT-IR, Thermogravimetric analysis - TG and others. The electrokinetic and thermal properties of the biocomposites sufficed to be applied for example, as a cheap and biodegradable polymer filler. Further areas of application of these composites were sought, especially in electrochemistry as the advanced electrode materials.
2
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Preparation and characterization of alumina-zirconia composite material with different acid ratios by the sol-gel method

100%
Ergu O., Gürü M., Cabbar C.
Open Chemistry
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2008
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vol. 6
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issue 3
482-487
EN
Alumina-zirconia composite materials were produced with different acid ratios by the sol-gel method using aluminum isopropoxide and zirconium chloride. The composites were produced by changing acid/alkoxside ratio in alumina. The composite materials were calcinated at 600°C, 900°C and 1300°C. The effects of acid concentration and calcination temperature on the surface area and pore radius were determined from the nitrogen adsorption isotherm at 77 K. The density of the composites was also measured. The minimum density of produced material was recorded as 1.35 g cm−3 at an acid/alkoxside ratio of 0.2. The highest specific surface area and pore diameter of the lightest material are 191.86 m2 g−1 and 18.4 Ǻ, respectively. Although pore diameter and specific surface area are not changed at any of the experimental temperatures which were tested by decreasing acid/alkoxside ratio, the density is slightly increased. However, it was observed that the calcination temperature significantly affects the surface area and density of the material. [...]
3
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Removal of azo dye by synthesized TiO2nanoparticles

100%
Amin M. S. A., Uddin M. J., Islam M. A.
Nanomaterials and the Environment
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2013
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vol. 1
18-22
EN
TiO2 nanoparticles were synthesized by one-step Sol-gel method. Prepared nanoparticles were characterized by different characterization (SEM, EDS and XRD) techniques. The aqueous solution of Methylene Blue (MB) has been subjected to evaluate the photocatalytic degradation by UV radiation in the presence of synthesized TiO2 photocatalyst coated reactor. The experiments were conducted with and without aeration, using different dye concentrations, and catalyst loading, revealed that the degradation was strongly influenced by respective experimental parameters. However, maximum MB dye was removed by the photodegradation process operating with aeration and higher catalyst dosing.
4
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Study on Crystal Structure and Magnetic Properties of Ba4Co2Fe36O60 by Sol-Gel Method

100%
Jeong K.-P., Yang S.-W., Kim J.-G.
Archives of Metallurgy and Materials
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2018
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vol. 63
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issue 3
5
Content available remote

Influence of different templates on the morphology of mesoporous aluminas

100%
Berger D., Traistaru G., Matei C.
Open Chemistry
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2012
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vol. 10
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issue 5
1688-1695
EN
Mesoporous alumina has many environmental applications as catalysts support and adsorption or separation material. We studied the synthesis conditions for the mesoporous alumina formation from aluminum isopropoxide in the presence of anionic (lauric and stearic acid), cationic (cetyltrimethylammonium bromide, CTAB) and non-ionic (triblock poly(ethylene oxide)-poly(propylene oxide)-polyethyleneoxide, P123) templates. The X-ray diffraction data show that the alumina mesophases obtained at 550°C in the presence of fatty acids or P123 have amorphous walls, whereas the samples prepared at 500°C by using CTAB, in alkaline medium are crystalline with a γ-alumina structure. The solvothermal treatment caused the alumina mesophase with crystalline walls to be obtained at 550°C. The samples were investigated by nitrogen adsorption-desorption isotherms and scanning electron microscopy. The obtained alumina mesophases have specific surface areas in the range of 300–450 m2 g−1, narrow pore size distribution, and different morphology depending on the template used in the synthesis. [...]
6
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The photocatalytic degradation of 17α-ethynylestradiol by pure and carbon nanotubes modified TiO2 under UVC illumination

88%
Kralchevska R., Milanova M., Bistan M., Pintar A., Todorovsky D.
Open Chemistry
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2012
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vol. 10
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issue 4
1137-1148
EN
Commercial product Degussa TiO2 P25, sol-gel produced TiO2 and TiO2 modified by carbon nanotubes addition (5% of the TiO2 mass) are tested as photocatalysts for the degradation of endocrine disrupting compound 17α-ethynylestradiol (1 µM aqueous solution). The molecular and crystal structure, phase composition, crystallite size, specific surface area, pore average diameter, their area and volume distribution, morphology, IR and UV/Vis spectra of the catalysts are characterized. HPLC is used for estrogen analysis. The sorption ability and photocatalytic activity (measured by degradation rate constant and percentage of the pollutant conversion) of the catalysts under UV (17 W, emission maximum at 254 nm) irradiation is determined. Full destruction of the pollutant is reached after 30 min irradiation in presence of Degussa P25. The performance of some of the catalysts is compared with literature data for their activity under 365 nm-illumination.
7
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Preparation of nanostructured porous SiO2-Al2O3 oxycarbonitride materials obtained by a new chemical precursor method

88%
Ivanova Y., Gerganova T., Fernandes M., Salvado I.
Open Chemistry
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2009
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vol. 7
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issue 1
42-46
EN
Nanostructured hybrid materials containing Al2O3 were synthesized via a sol-gel method through hydrolysis and co-condensation reactions using trimethylsilyl isocyanate (TMSI) as a new silica source in the presence of tetramethoxysilane (TMOS) and three different quantities (10, 20 and 30 wt.%) of aluminum sec-butoxide (Al(OBusec)3 as a modifying agent. The xerogel nanostructured materials are pyrolyzed in nitrogen atmosphere in the temperature range from 400°C to 1100°C. The transformation of the xerogel hybrid networks into Al-Si oxycarbonitride materials has been investigated by XRD, FTIR, SEM, AFM, and 29Si MAS-NMR. To the best of our knowledge, the work reported here is the first synthesis of porous di-urethanesils modified with aluminum and one of the few examples of alumosilica oxycarbonitride materials [...]
8
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AlZn based Co and Ni catalysts for the partial oxidation of bioethanol - influence of different synthesis procedures

88%
Ehrich H., Kraleva E.
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issue 12
1285-1293
EN
The catalytic performance of Co and Ni catalysts on AlZn mixed oxide supports depends on the synthesis procedure used for their preparation. For this study CoAlZn and NiAlZn catalysts were prepared by conventional sol-gel synthesis of the mixed oxide and subsequent impregnation of the support with the transition metal (SG = sol gel method) as well as by a single-step method were a gel is formed based on salts of all components using citric acid as chelating agent (CM = citrate method). The structure and morphology of the catalysts were characterized by nitrogen sorption, XRD and TPR measurements. They showed high activity in the partial oxidation of ethanol at 600–750 °C, but their properties depend on the preparation method. The higher performance of the catalysts prepared by the citrate method, where the transition metal is incorporated into the crystal structure of the support during preparation, is based on a change in morphology and structure, resulting in more active sites exposed on the surface. Compared to the Co catalysts, Ni catalysts showed a higher performance. This might be due to the higher reducibility and the smaller Ni particles size, which allows a better interaction with the support in NiAlZn catalysts.
9
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Optimization of synthesis conditions and the study of magnetic and dielectric properties for MgFe2O4 ferrite

88%
Druc A., Dumitrescu A., Borhan A., Nica V., Iordan A., Palamaru M.
Open Chemistry
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2013
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vol. 11
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issue 8
1330-1342
EN
Nano-sized magnesium ferrites were synthesized by the sol-gel auto-combustion method using a variety of chelating/combustion agents: tartaric acid, citric acid, cellulose, glycine, urea and hexamethylenetetramine. The original purpose of this work was the synthesis of nano-sized magnesium ferrite by using, for the first time, cellulose and hexamethylenetetramine as chelating/combustion agents. Synthesized samples were subjected to different heat treatments at 773 K, 973 K and, respectively 1173 K in air. The disappearance of the organic phase and nitrate phase with the spinel structure formation was monitored by infrared absorption spectroscopy. Spinel structure, crystallite size and cation distribution were evaluated by X-ray diffraction data. The morphology of as-prepared powders was studied using scanning electron microscopy. The magnetic and dielectric properties were studied for the obtained samples. [...]
10
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Content available

Physicochemical Properties of Oxide ZrO2 Layer Deposited by Sol-Gel Method on Ti-6Al-7Nb Alloy

75%
Woźniak A., Ziębowicz B., Ziębowicz A., Walke W.
Archives of Metallurgy and Materials
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2018
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vol. 63
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issue 3
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