نتایج جستجو برای: structure zeolite

تعداد نتایج: 1575663  

In this study, beta nanozeolite, ultra-stable Y zeolite (USY) and amorphous silica-alumina (ASA) were synthesized. These compounds were used as the support of hydrocracking catalyst. Ni-Mo/beta zeolite-ASA and Ni-Mo/USY zeolite-ASA catalysts were prepared by the impregnation method. The samples were characterized with X-Ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM)...

2009
Seong Kon Lee

Zeolite A and MCM-41 have extensive applications in basic science, petrochemical science, energy conservation/storage, medicine, chemical sensor, air purification, environmentally benign composite structure and waste remediation. However, the use of zeolite A and MCM-41 in these areas, especially environmental remediation, are restricted due to prohibitive production cost. Efficient recycling o...

2016
Haibo Zhu Edy Abou-Hamad Yin Chen Youssef Saih Akshaya Kumar Samal Weibing Liu Marie Basset

A new kind of organosilane (1,6-bis (diethyl(3-trimethoxysilylpropyl)ammonium) hexane bromide) with a geminitype structure was prepared and used as a mesoporogen for the synthesis of hierarchical porous ZSM-5 zeolite. There are two quaternary ammonium centers along with double hydrolysable -RSi(OMe)3 fragments in the organosilane, which results in a strong interaction between this mesoporogen a...

Journal: :Dalton transactions 2014
Hao Xu Lili Jia Haihong Wu Boting Yang Peng Wu

Nu-6(1) zeolite, the lamellar precursor of NSI topology, was firstly synthesized with 4'4-bipyridine as the structure-directing agent (SDA) and then subjected to HCl-EtOH treatment for the purpose of structural modification. Interlayer deconstruction and reconstruction took place alternately in this acid treatment. An intermediate named ECNU-4 was separated at the initial stage of this continuo...

Journal: :Angewandte Chemie 2010
Anders B Laursen Karen T Højholt Lars F Lundegaard Søren B Simonsen Stig Helveg Ferdi Schüth Michael Paul Jan-Dierk Grunwaldt Søren Kegnaes Claus H Christensen Kresten Egeblad

Over the years, many strategies have been developed to address the problem of sintering of nanoparticle catalysts, including encapsulating metal nanoparticles in protective shells, and trapping nanoparticles in the cavities of certain zeolites in post-synthesis steps. In general, materials that contain metal nanoparticles that are only accessible via zeolite micropores are intriguing, specifica...

Journal: :journal of sciences islamic republic of iran 0

zeolite zsm-5 presents a great source of interest in catalysis because of its shape selective properties. the absence of a relationship between the template size and shape of the structure generated during the synthesis of zeolites is illustrated by the case of zsm-5. in this study, we have investigated the role of ethanol, methyltriphenylphosphonium bromide (mtpbr) and cetyltrimethylammonium b...

Journal: :Molecules 2011
Anabelle C L Batista Emílio R Villanueva Rosa Valéria S Amorim Maria Teresa Tavares Galba M Campos-Takaki

This research evaluated the importance of the adsorption properties of chitosan a chitosan/zeolite conjugate film for the removal of Cr(VI) ions from solutions in the 5-260 mg/L concentration range, when the pH was adjusted to 4.0 and 6.0. The uptake capacities of the films formed by chitosan and by the chitosan/zeolite conjugate were calculated by mass balance. The equilibrium isotherms were f...

2006
K. A. Mahgoub S. Al-Khattaf

_____________________________________________________________ Different catalysts based on Y-zeolite, ZSM-5 and amorphous kaolin were prepared and characterized. The catalytic cracking of 1,3,5-triisopropylbenzene (1,3,5-TIPB), 1,4diisopropylbenzene (1,4-DIPB) and n-dodecane were used to investigate the effect of catalyst nature on the catalytic performance. Cracking the largest molecule (1,3,5...

2009
Hyungjun Kim Wei-Qiao Deng William A. Goddard Seung Soon Jang Georgia Mark E. Davis Yushan Yan

To investigate the effect of hydration on the diffusion of sodium ions through the aluminum-doped zeolite BEA system (Si/Al ) 30), we used the grand canonical Monte Carlo (GCMC) method to predict the water absorption into aluminosilicate zeolite structure under various conditions of vapor pressure and temperature, followed by molecular dynamics (MD) simulations to investigate how the sodium dif...

2007
Aditya Bhan Rajamani Gounder Josef Macht Enrique Iglesia

Compensation between adsorption entropies and enthalpies results in less than a two-fold variation in adsorption equilibrium constants for C3–C6 alkanes at temperatures relevant for monomolecular cracking; the size-independent activation energy for C–C bond activation in C3–C6 alkanes indicates that the marked increase in monomolecular cracking turnover rates observed with alkane chain size ref...

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