Mesoporous Molecular Sieves
Mostrando 1-12 de 19 artigos, teses e dissertações.
-
1. Influence of Crystallization and Ageing Time on the Reproducibility of Mesoporous Molecular Sieve SBA-15
ABSTRACT The study aimed to assess how the crystallization and ageing times in SBA-15 synthesis influence the reproducibility and particle size of mesoporous molecular sieves. X-ray diffraction showed that higher crystallization times provide greater reproducibility of mesoporous silica, due to the fact that there is no significant variation in the width and
Matéria (Rio J.). Publicado em: 10/06/2019
-
2. Comparison of Kinetic Study of CTMA+ Removal of Molecular Sieve Ti-MCM-41 Synthesized with Natural and Commercial Silica
This work aimed to determine and compare the apparent activation energy, involved in thermal decomposition of CTMA+ from the pores of Ti-MCM-41 synthesized by two different source of silica in order to evaluate their influence in the template removal. The molecular sieves Ti-MCM-41 were synthesized using rice husk ash (RHA), as alternative low cost source of
Mat. Res.. Publicado em: 2015-06
-
3. Adsorção de CO2 em peneiras moleculares micro e mesoporosas
Microporous molecular sieves of type Y, Beta, ZSM-5, ZSM-12 and ZSM-35, and mesoporous molecular sieves of type MCM-41 and MCM-48, and these sieves modified with triethanolamine and ethylenediamine were obtained and characterized by XRD, FTIR, TGA and nitrogen adsorption. The adsorption tests were performed by the gravimetric method under a stream of CO2 at
Quím. Nova. Publicado em: 2014
-
4. DESENVOLVIMENTO DE PENEIRAS MOLECULARES MESOPOROSAS DO TIPO MCM-41 E MCM-48 IMPREGNADAS COM AMINAS PARA UTILIZAÇÃO NA ADSORÇÃO DE CO2. / DEVELOPMENT OF TYPE MESOPOROUS MOLECULAR SIEVES MCM-41 AND MCM-48 IMPREGNATED WITH AMINES FOR USE IN ADSORPTION CO2.
O aumento significativo das emissões de dióxido de carbono na atmosfera vem acentuando o efeito do aquecimento global. A busca por fontes energéticas que minimizem as emissões é de grande importância, como também o uso de ações complementares como processos para captura deste gás das principais fontes emissoras. Dentre alguns processos já bem conh
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 25/07/2012
-
5. Iodeto de potássio suportado em peneiras moleculares mesoporosas (SBA-15 e MCM-41) como catalisador básico para síntese de biodiesel
Iodide potassium incorporated on mesoporous molecular sieves (SBA-15 and MCM-41) was used as heterogeneous catalysts in the transesterification of sunflower oil under different conditions of reaction time and ratio catalyst/oil (w/w). The results have showed that the system supported in SBA-15 has been more active than the supported in MCM-41, promoting a co
Química Nova. Publicado em: 2012
-
6. Mesoporous molecular sieve MCM-41 synthesis from fluoride media
A study of the synthesis of MCM-41 mesoporous molecular sieves in fluoride media, having no alkaline metal ions, was performed by changing the gel composition and crystallization temperature and time. X-ray diffraction and nitrogen adsorption analyses showed that highly ordered MCM-41 samples were obtained from gels with a NH4OH/SiO2 molar ratio in the 3.25-
Brazilian Journal of Chemical Engineering. Publicado em: 2011-12
-
7. Synthesis, characterization and catalytic activity of mesoporous materials Al-MCM-41 in transesterification reaction of cottonseed oil / Síntese, caracterização e avaliação catalítica do aluminossilicato mesoestruturado AI-MCM-41 na transesterificação de óleos vegetais
Molecular sieves have been applied to the processing of triacylglycerols, to produce biofuels. In this context, the mesoporous catalyst Al-MCM-41 was proposed in this work as an alternative to acid heterogeneous transesterification of cottonseed oil with ethanol. This material was prepared using various Si/Al molar ratios (25, 50, 75 and 100) with reaction t
Publicado em: 2010
-
8. Síntese e caracterização de peneiras moleculares mesoporosas do tipo MCM-41 e AlMCM-41 a partir de fontes alternativas de sílica e de alumínio
The mesoporous molecular sieves of MCM-41 and AlMCM-41 type are considered as promising support for metal in the refining processes of petroleum-based materials as catalysts and adsorbents for environmental protection. In this work the molecular sieves MCM-41 and AlMCM-41 were synthesized by replacing the source of silica conventionally used, for quartz, an
Publicado em: 2009
-
9. Aplicação de peneiras moleculares contendo cátions orgânicos em catálise básica
This thesis was aimed at studying novel basic catalysts based on molecular sieves containing alkylammonium cations. The studied molecular sieves were faujasite zeolites (FAU) and mesoporous silicate (like MCM-41). The following parameters were evaluated: (1) different alkylammonium cations, (2) different amount of alkylammonium cations and (3) application of
Publicado em: 2008
-
10. 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
-
11. Síntese e caracterização de materiais nanoporosos para pirólise catalítica de óleos pesados
The present work reports the study of nanoporous structures, aiming at their use in research directed to the current demand of the petroleum industry to value heavy oil. Initially, two ways were chosen for the synthesis of porous structures from the molecular sieves of type Si-MCM-41. In the first way, the structure MCM-41 is precursory for heteroatom substi
Publicado em: 2008
-
12. Application of molecular sieves in the fractionation of lemongrass oil from high-pressure carbon dioxide extraction
The aim of this work was to study the feasibility of simultaneous process of high-pressure extraction and fractionation of lemongrass essential oil using molecular sieves. For this purpose, a high-pressure laboratory-scale extraction unit coupled with a column with four different stationary phases for fractionation: ZSM5 zeolite, MCM-41 mesoporous material,
Brazilian Journal of Chemical Engineering. Publicado em: 2006-06