This study reports on the EPR of C r 5 + and C u 2 + ions, introduced by solidand liquid-state reactions with the synthetic zeolites 3A, 4A and 5A, and the natural zeolite clinoptilolite. C r 3 + was oxidized to Cr 5 + in the samples, the coordination around Cr 5 + being square pyramidal. Superhyperfine (shf) interaction of Cr with A1 nucleus was observed in both solidand liquid-stateintroduced...

Conversion of 1and 2-tetralone was investigated over acid HY zeolite under various reaction conditions in the vapor phase. Reactions were conducted in a fixed-bed reactor at 300, 400 and 500 C in hydrogen atmospheric pressure. It was found that 1and 2-tetralone are thermally unstable and thermal reaction has a contribution, particularly at high temperatures. The reactivity of 2-tetralone was si...

Zeolite Beta/MCM-41 composites have been prepared with various crystallinities of zeolite Beta through a twostep crystallization process involving the combination of low crystallinity zeolite Beta synthesis gel with cetyltrimethylammonium bromide surfactant solution. The composites are characterized by XRD, SEM, Si and Al MAS NMR, N2 adsorption, NH3-TPD and catalytic cracking. The experimental ...

Zeolitic products formed by hydrothermal treatment of coal fly ash (FA) with KOH aqueous solution under various reaction conditions were examined. Only linde F-type zeolite (K2Al2Si2O8·3H2O) was newly formed at atmospheric pressure, except formation of a small amount of kalsilite (KAlSiO4) at longer reaction time. The yield of the linde F zeolite was highest when reaction time, temperature, KOH...

effect of natural zeolites and nano-zeolite on gut flora, tibia bone characteristics, blood parameters and performance of broilers investigated with 336 male ross 308 broilers chicks allocated to   seven treatments with four replicates and 12 chicks per each. experimental treatments were control (no zeolite supplemented), natural zeolite (0.5, 1 and 1.5 percent) and nano-zeolite (0.5, 1 and 1.5...

Growth of silicalite with graphene oxide (GO) nanosheets occurred via attachment of GO onto the silicalite surface, and entrapment of GO nanosheets inside single crystals. Electrically conductive composites were produced by calcination in nitrogen whereas silicalite crystals with slit-like mesopores of sizes 20-25 Å were obtained after GO burn-off.

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...

Zeolite materials are microporous aluminosilicates with various uses, including acting as important catalysts in many processes. One such process is the methanol to gasoline reaction, used widely in industry. This reaction is known to be associated with Brønsted acid sites in the zeolite, formed when Si is substituted by Al in the framework, with an associated Hq being bound nearby to maintain ...

We explore the flexibility windows of the 194 presently-known zeolite frameworks. The flexibility window represents a range of densities within which an ideal zeolite framework is stress-free. Here, we consider the ideal zeolite to be an assembly of rigid corner-sharing perfect tetrahedra. The corner linkages between tetrahedra are hard-sphere oxygen atoms, which are presumed to act as freely-r...

The present paper aims to miniaturize a graphite-epoxy and synthetic zeolite-modified graphite-epoxy composite macroelectrode as a quasi-microelectrode aiming in vitro and also, envisaging in vivo simultaneous electrochemical detection of dopamine (DA) and ascorbic acid (AA) neurotransmitters, or DA detection in the presence of AA. The electrochemical behavior and the response of the designed m...