Gas separation efficiencies of three zeolite membranes (Faujasite, MFI, and Chabazite) have been examined using the method of molecular dynamics. Our investigation has allowed us to study the effects of pore size and structure, state conditions, and compositions on the permeation of two binary gas mixtures, O(2)N(2) and CO(2)N(2). We have found that for the mixture components with similar sizes...

This review aims to present a global view of the efforts conducted to convert zeolites into efficient supports for the removal of heavy metal oxyanions. Despite lacking affinity for these species, due to inherent charge repulsion between zeolite framework and anionic species, zeolites have still received considerable attention from the scientific community, since their versatility allowed tailo...

Zeolites are promising materials in the field of gas sensors. In this technology-oriented paper, a planar setup for potentiometric hydrocarbon and hydrogen gas sensors using zeolites as ionic sodium conductors is presented, in which the Pt-loaded Na-ZSM-5 zeolite is applied using a thick-film technique between two interdigitated gold electrodes and one of them is selectively covered for the fir...

The present paper describes the previous obtained results concerning purification of gases, water and sewages from toxic components such as mercury, radionuclides and petroleum substances. The tested materials constitute synthetic zeolites obtained in hydrothermal reaction, i.e., Na-X, Na-P1, and natural zeolite clinoptilolite. The zeolites (Na-X, Na-P1 and clinoptilolite) needed for mercury ca...

By treating idealized zeolite frameworks as periodic mechanical trusses, we show that the number of flexible folding mechanisms in zeolite frameworks is strongly peaked at the minimum density end of their flexibility window. 25 of the 197 known zeolite frameworks exhibit an extensive flexibility, where the number of unique mechanisms increases linearly with the volume when long wavelength mecha...

Zeolites, microporous aluminosilicates, are amongst the most widely used catalysts in the petrochemical industry. Zeolite catalytic functionality is influenced by the location of tetrahedral alumina and associated counter-cations in the aluminosilicate framework, yet little is definitively known about the factors that govern the framework aluminium arrangement. It is generally accepted that all...

The adsorption of alkanes and alkenes on zeolites is investigated by comparing the adsorption characteristics for three types of zeolite: ferrierite, ZSM-5, and mordenite. The activation energy for the diffusion of propane and n-butane on ferrierite and the heat of adsorption of C(2)-C(4) alkanes and alkenes on zeolites and silica are estimated based on Fourier transform infrared spectroscopy, ...

Two dyes (4-nitrostilbene, NST and 4-N,N-dimethylamino-4'-nitrostilbene, DANS) included in zeolites with nanometric channels and different Si : Al ratios have been photoexcited and their triplet state studied by time resolved EPR (TR-EPR). This is the first time that a TR-EPR spectrum of photoexcited triplet states of dyes in zeolites has been observed. The zeolites used were ZSM-5 and mordenit...

The synthetic zeolites of Heulandite group were prepared using Microwave-Hydrothermal (M-H) method at 120 ° C/30 min. The powders were characterized using X-ray Diffraction (XRD).The Zeolites were annealed at 60, 80 and 100 o C/1 hr. The d.c resistivity of Heulandite group zeolite was found to be constant upto 378K and increased as the temperature increases. Dielectric spectras (ε ’ and tanδ) o...

Recently the concept of hierarchical zeolites invoked more explicit attention to enhanced accessibility of zeolites. By realizing additional meso-/macroporosity with the intrinsic microporosity of zeolites, a hierarchical pore system arises which facilitates mass transport while maintaining the zeolite shape selectivity. A great number of synthesis strategies have been developed for tailoring t...