Alkaline Hydrothermal Synthesis
Mostrando 1-10 de 10 artigos, teses e dissertações.
-
1. Easy and Fast Preparation of TiO2 - based Nanostructures Using Microwave Assisted Hydrothermal Synthesis
TiO2 derivatives with distinct morphologies have been successfully obtained by microwave assisted hydrothermal synthesis in acidic and alkaline medium using mild conditions. Titanium tetraisopropoxide (TTIP) was used as precursor in different environmental conditions under low temperatures, inferior to 150 °C, and short synthesis times, from 2 to 60 min. X
Mat. Res.. Publicado em: 10/04/2017
-
2. Crystallization of Zeolite A Coatings from Natural Zeolite
An investigation was carried out to determine the possibility of preparing coatings of synthetic zeolites on stainless steel from mixtures containing natural zeolite. Hydrothermal synthesis was applied and the coatings obtained were characterized by various techniques. It was observed that crystalline zeolite A coatings could be prepared from natural clinopt
Mat. Res.. Publicado em: 10/11/2016
-
3. Synthesis and Characterization of Boehmites Obtained from Gibbsite in Presence of Different Environments
In this study, results related to boehmite synthesis by hydrothermal processes starting from a Bayer commercial gibbsite are reported. The processes have been conducted from aqueous suspensions with initial acidic or alkaline pH, without or with acetate ion, at 160oC for 72h to 168h. The final materials were characterized by X-ray diffraction (XRD), thermal
Mat. Res.. Publicado em: 15/04/2016
-
4. Synthesis and characterization of zeolite NaP using kaolin waste as a source of silicon and aluminum
The synthesis of zeolite NaP using kaolin waste, from the Amazon region, as a predominant source of silicon and aluminum has been studied. The zeolitisation process occurred in hydrothermal conditions using static autoclaving and the effects of time, temperature, and the Si/Al ratio were investigated. The starting material and the phases formed as reaction p
Mat. Res.. Publicado em: 25/03/2014
-
5. Synthesis of high value-added zeolitic materials using glass powder residue as a silica source
In this work, zeolite A was obtained using alkaline fusion followed by a hydrothermal treatment of glass powder residue derived from the manufacturing of glass. The following parameters were evaluated: leaching of the stock material (silica source), mineralizing agent, alumina source, and the alkaline fusion and crystallization temperatures. The synthesized
Mat. Res.. Publicado em: 26/11/2013
-
6. Processamento e estudo de ortoniobatos de terras raras e ortotungstatos de metais alcalinos terrosos
Two classes of orthoceramic compounds of general formula ABO4 were investigated in this work. The first group includes the lanthanide orthoniobates (RENbO4, RE = La-Lu, except Pm), which were synthesized by conventional solid-state route at 1150C in different conditions of time aiming the production of crystalline, single phase materials. Alkaline- earth-met
Publicado em: 2010
-
7. Formação de mesoporos na síntese de zeólitas ZSM-5 via nanomoldagem avaliação no craqueamento de n-decano / Formação de mesoporos na síntese de zeólitas ZSM-5 via nanomoldagem avaliação no craqueamento de n-decano
The use of zeolites in the cracking of hydrocarbons is limited because the molecules higher than 0.74 nm do not diffuse in their micropores. In the other hand, molecular sieves as MCM-41, MCM-48 ou SBA-15, whose diameters are up 10 nm for the two formers and up to 30 nm for the last, have low hydrothermal stability and catalytic activity. To overcome those l
Publicado em: 2008
-
8. Utilização de zeólitas sintetizadas a partir de xisto retortado na remoção de arsênio em águas contaminadas
The solid by-product of the oil shale processing (PETROBRAS - Brazil) was used as raw material to synthesize zeolites A and faujasite. Alkaline fusion followed by hydrothermal treatment was the synthesis procedure used, and five different starting material compositions were obtained. The more crystalline zeolite-type materials synthesized, the pretreated oil
Química Nova. Publicado em: 2007-10
-
9. Estudo de titanatos nanoestruturados obtidos por tratamento hidrotérmico de óxido de titânio em meio alcalino / Studies on nanostructured titanates obtained by alkali hydrothermal treatment of titanium oxide
Titanatos nanoestruturados, particularmente TiTanatos NanoTubulares (TTNT), foram sintetizados por tratamento hidrotérmico alcalino de TiO2-anatásio seguido de repetidas lavagens com diversos graus de troca protônica. Amostras de TTNT com diferentes teores de sódio foram caracterizadas na forma de pó seco e após calcinação (200-800C) por difração d
Publicado em: 2007
-
10. Aluminofosfatos e magnesoaluminofosfatos mesoporosos obtidos sobre arranjos supramoleculares
Mesoporous aluminophosphates and magnesium-aluminophosphates have been synthesized with the use of cetyltrimethylammonium bromide (CTAB) as the structure-directing agent in the presence of tetramethylammonium hydroxide (TMAOH). The influence of the concentration of the structure-directing agent, duration of synthesis, temperature of the hydrothermal treatmen
Publicado em: 2000