Amygdaloidal, cavity- and fracture-filling zeolites in Eocene volcanic rocks from the Kuh-e-Aradeh of southern Kahrizak, in the northernmost part of Central Iran have been studied in some detail by optical, chemical analysis, SEM, and XRD techniques. The zeolites identified, in order of their relative time of formation from early to late, are tetranatrolite, analcime, natrolite, mesolite, stilb...

Lewis acidity was introduced into zeolite Y (Si/Al = 30) by a facile ion-exchange of aluminum cations followed calcination. X-ray diffraction and nitrogen physisorption suggest that the zeolitic framework is retained after these treatments. With an increase in total extra-framework modified zeolites, there pronounced number acid sites, as illustrated FTIR spectroscopy adsorbed pyridine carbon m...

There have been no reports of the simultaneous application natural fillers, such as magnetite and zeolites, to increase strength composites containing silica (SiO2) fillers reinforcing in rubber. This study has investigated effect magnetically modified zeolite on nanosilica-reinforced rubber that include a mechanical characteristic like human tissue. We use technical specifications (TSR) SIR 20...

The relevance of the subject this scientific research is determined by importance problem using zeolites as catalysts process heavy hydrocarbons’ cracking and studying prospects for modifying heteropolyacids synthesis long-chain α-olefins. purpose to study implementation hydrocarbon on Shankanai zeolite modified with olefins. basis methodological approach in work a combination methods system an...

In addition to their well-known uses as catalysts, zeolites are utilized to adsorb and remove various cations from aqueous system. The adsorption of the cations is ascribed to the negative charge of zeolites derived from isomorphous substitution of Si by Al. The amount of Na+ adsorption on 4A, X, Y, Na-P1 and mordenite type zeolites were determined in aqueous media, in a two-cation (Na+ and H+)...

The Special Issue “Zeolite Catalysis” published in the online journal Catalysts was recently successfully completed. A good number of peer-reviewed publications were published reflecting the broadness of the zeolite syntheses, characterizations and various application fields. This issue brought together recent research of well-known research teams from all over the world. The term “zeolite” is ...

The acid-base properties of zeolites with group 5 transition metal framework sites are investigated, and a first step into the understanding of their acid/base and redox properties is undertaken using DFT reactivity descriptors. It is evidenced, using sodalite as model system, that zeolites with vanadium framework sites are more nucleophilic than zeolites with niobium and tantalum framework sit...

ZSM-5 zeolites were prepared at neutral pH by fluoride-mediated synthesis. The degree of crystallinity, the specific surface area and the crystal size are higher than those of the zeolites prepared under alkaline conditions. Moreover, by varying the F/Si ratio from 0.3 to 1.6, the H–[F]–ZSM-5 zeolites with crystal size ranging from 10 to 75 lm and the specific surface areas from 60 up to 350 m/...

Zeolites have potential application as ion-exchangers, catalysts and molecular sieves. Zeolites are once again drawing attention in Japan as stable adsorbents and solidification materials of fission products, such as (137)Cs(+) from damaged nuclear-power plants. Although there is a long history of scientific studies on the crystal structures and ion-exchange properties of zeolites for practical...

Incorporation of germanium in zeolites is well known to confer static flexibility to their framework, by stabilizing the formation of small rings. In this work, we show that the flexibility associated to Ge atoms in zeolites goes beyond this static effect, manifesting also a clear dynamic nature, in the sense that it leads to enhanced molecular diffusion. Our study combines experimental and the...