Sio2
Mostrando 13-24 de 841 artigos, teses e dissertações.
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13. Adsorption of Calcium(II), Cadmium(II) and Copper(II) Ions from Water by Prepared Silicon-Aluminum-Zirconium Oxide Using Sol-Gel Process
Ternary oxide silica-alumina-zirconia (SiO2/Al2O3/ZrO2) obtained by the sol-gel process was applied as novel adsorbent of ions in aqueous solution. Batch isotherms were performed using standard CuII, CdII and CaII solutions at variable pH and different concentrations. Adsorption capacity was best at weakly acidic pH. The maximum adsorption capacities were 2.
J. Braz. Chem. Soc.. Publicado em: 2021-07
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14. Acid matrix production from treated natural vermiculite-hydrobiotite
Abstract Given the potential of acid-activated clays in adsorptive and catalytic processes, several studies focusing on acid matrices have grown over the years, making it possible to study vermiculite, a mineral composed of a type 2:1 unit cell with tetrahedral and octahedral sheets. Therefore, this work aimed to study vermiculite treated with acids for the
Cerâmica. Publicado em: 2021-06
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15. Evaluation of the use of silica-alumina refractory waste as a supplementary cementitious material
Abstract The use of supplementary cementitious materials (SMCs) is one of the three essential factors for the sustainability of the cement industry. To reduce CO2 emissions, several studies have introduced new methods for the utilization of industrial wastes such as the addition into cementitious materials. The objectives of this study were to chemically and
Cerâmica. Publicado em: 2021-06
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16. Evaluation of the properties of a foamed geopolymer developed with different types of metakaolin
Abstract The physical and mechanical properties of foamed geopolymers were determined. The geopolymers were made with two different metakaolins (from Metacaulim do Brasil - MB, and Pantano Grande/RS - MPG) as precursors, with NaOH and Na2SiO3 as activators, and with the addition of foam, which was produced with the foaming agent diethanolamide of coconut fat
Cerâmica. Publicado em: 2021-06
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17. Study of Crystallization and Composition on Silicon Oxycarbide (SiOC) and Silicon Boron Oxycarbide (SiBOC) Ceramics Obtained from Alkoxysilanes Precursors
This work deals on the preparation of silicon oxycarbide (SiOC) and silicon boron oxycarbide (SiBOC) ceramics from pyrolysis involving alkoxysilanes with different organic groups. Boron content, organic substituent and annealing time were evaluated on crystallization and composition of resulting ceramics. B-free precursors composed of methyltriethoxysilane (
J. Braz. Chem. Soc.. Publicado em: 2021-06
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18. QUANTIFICAÇÃO DE MULLITA PROVENIENTE DE RESÍDUOS DE CAULIM DA REGIÃO AMAZÔNICA: USO DO MÉTODO DE RIETVELD
Mullite is used to obtain a refractory material, there are several factors that influence the synthesis process of mullite: the preparation of the mixture, the precipitation and the reaction of SiO2 and Al2O3. For the synthesis of mullite, samples of kaolin processing residues were used as precursor material, because it presents SiO2 and Al2O3 in its composi
Quím. Nova. Publicado em: 2021-04
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19. Use of rice husk ash to produce alternative sodium silicate for geopolymerization reactions
Abstract This study investigated the feasibility of synthesizing sodium silicate from rice husk ash (RHA) and its application to produce geopolymers. Samples were prepared at different SiO2/Al2O3 molar ratios (3.0, 3.5, and 4.0) for both sodium silicates (commercial and from RHA). They were underwater cured at 60 ºC for 1 h and then at room temperature (25
Cerâmica. Publicado em: 2021-03
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20. Thermal decomposition and reaction sintering for synthesis of mullite-zirconia composite using kaolin, γ-alumina and zirconia
Abstract The refractory materials used in the wall of the furnaces for glass melting can be prepared from mullite-zirconia composite material. The composite of mullite/zirconia was synthesized from Iraqi kaolin, γ-alumina, and zirconia using thermal decomposition with reaction sintering at 1600 °C. Several batches were prepared with various ratios of kaoli
Cerâmica. Publicado em: 2021-03
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21. Influence of Mn2+ ions on depression of quartz and spessartine in gondite ore
Abstract Low-grade manganese ores that are composed of manganese oxides, wad, quartz, iron oxides, gibbsite, and especially of spessartine (Mn3Al2(SiO4)3) are known as gondite. Spessartine is a mineral with a high content of silica (SiO2) and alumina (Al2O3) that causes a decrease of the enrichment in manganese oxide concentrates by flotation, giving this o
REM, Int. Eng. J.. Publicado em: 2021-01
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22. Síntese e caracterização de zeólita tipo sodalita obtida a partir de resíduo de caulim
Resumo Produtos zeolíticos foram sintetizados a partir de um resíduo industrial do processo de beneficiamento de caulim. O material de partida foi submetido a tratamento térmico a 700 °C durante 2 h. As sínteses foram realizadas com a reação do resíduo com NaOH e uma fonte adicional de sílica, em condições hidrotermais, para relações molares de
Cerâmica. Publicado em: 2020-12
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23. An Electrochemiluminescence Biosensor for the Determination of Mercury Ion via Dual-Amplification Strategy
A novel dual-signal amplificatory electrochemiluminescence (ECL) deoxyribonucleic acid (DNA) biosensor was designed for the determination of Hg2+. One amplification unit was gold nanoparticles (AuNPs) modified on a glassy carbon electrode, and the other was single-stranded DNA (ssDNA) (with amino at the 3’ terminal and thiol at the 5’ terminal) labeled w
J. Braz. Chem. Soc.. Publicado em: 2020-12
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24. Síntese e caracterização de biovitrocerâmica com adição de SrO a partir de sílica de casca de arroz
Resumo A casca de arroz é um resíduo abundante no Rio Grande do Sul, Brasil, e pode ser utilizada para produção de sílica pura. As biovitrocerâmicas têm a sílica como principal componente. A biocompatibilidade desses materiais pode ser incrementada adicionando componentes, como SrO. Este trabalho objetivou o uso da sílica proveniente da casca de arr
Cerâmica. Publicado em: 2020-12