Owing to the recent progress in the area of hardware and software of the pulsed field gradient NMR technique, molecular transport in real-life zeolite systems, such as zeolite beds and particles of formulated fluid catalytic cracking (FCC) catalysts, can be investigated in detail. These studies have revealed a number of important features of molecular transport in zeolites, which are reviewed i...

1. Introduction 1. Introduction Information on mass transport in polycrystalline zeolite membranes is necessary for a theoretical estimation of the membrane performances. Zeolite membranes are usually prepared as thin layer of an assembly of small zeolite crystals including many intercrystalline regions. Thus, the intercrystal region would influence their individual diffusion properties, which ...

The present study attempts to provide insights for both the chemical composition (Si/Al) and the crystal morphology of ZSM-5 zeolites while using biomass template compounds in the synthesis. The solution containing biomass-derivative compounds was obtained after treating biomass in a sodium hydroxide aqueous solution under reflux. The latter alkaline solution was used as a solvent for zeolite n...

Self-pillared pentasil (SPP) zeolite is a hierarchically-structured zeolite comprised of single-unit cell thick MFI nanosheets arranged in a ‘‘house of cards’’ structure. The nucleation and growth of SPP proceeds through three phases involving the evolution of precursor amorphous nanoparticles to MFI nanosheets and then rotational intergrowth of sheets to produce the SPP morphology. This paper ...

We have applied our previously reported model of silica based on low coordination and strong association [J. Chem. Phys. 121, 8415 (2004)], to the calculation of phase stability of zeolite frameworks SOD, LTA, MFI, and FAU as silica polymorphs. We applied the method of Frenkel and Ladd for calculating free energies of these solids. Our model predicts that the MFI framework structure has a regim...

We report the synthesis and characterization of a series of new mesoporous zeolite and zeotype materials made available by combining new and improved procedures for directly introducing carbon into reaction mixtures with the fluoride route for conventional zeolite synthesis. The mesoporous materials were all prepared by hydrothermal crystallization of gels adsorbed on carbon matrices which were...

The separation of saturated branched and linear alkanes may be investigated by selective adsorption on microporous organophilic MFI type zeolite. From the literature, adsorption equilibria of mixtures show a favourable selectivity for less branched alkanes [1]. However the separation process is significantly influenced by the transport properties. The knowledge of the transport coefficients of ...

A series of catalysts based on hybrid intergrowth structure zeolites MFI-MEL, MFI-MTW, and MFI-MCM-41 are studied in the reaction olefins synthesis from dimethyl ether at atmospheric pressure a temperature 340 °C. The total acidity zeolite-based is shown to correlate with their activity. However, use zeolite MFI-MCM-41, which characterized by high content medium acid sites, additionally catalyz...

Stable suspensions of zeolite nanosheets (3 nm thick MFI layers) were prepared in ethanol following acid treatment, which partially removed the associated organic structure-directing agent. Nanosheets from these suspensions could then be dispersed at the air-water interface and transferred to silicon wafers using Langmuir-Schaefer deposition. Using layer-by-layer deposition, control on coating ...

mfi zeolite membranes were prepared on porous α-alumina substrates, using secondary growth of nano-seeded layers. the resulting membranes were characterized by means of scanning electron microscopy (sem), x-ray diffractometry (xrd), and pervaporation performance tests for separation of benzene, toluene and xylene (btx) mixture from contaminated water. the morphology, thickness, homogeneity, cry...