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...

In this paper, the performances of potential zeolite membranes were estimated by the Maxwell-Stefan model and then they were placed in Robeson plot of propylene/propane separation. Additionally, the effects of feed pressure and the mole fraction of propylene in the feed on both the propylene permeabilities and membrane permselectivities were investigated. The results showed that zeolite membran...

The oxide fuel reduction process, based on an electrochemical method as well as the long-lived radioactive nuclides partitioning process based on pyroprocessing, which are being developed at the Korea Atomic Energy Research Institute (KAERI), are to generate molten salt wastes such as a LiCl salt and a LiCl-KCl eutectic salt, respectively. The treatment process of waste LiCl salt, consisting of...

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 ...

background: catalytic ozonation has recently been applied as a new method of contaminant removal from water and wastewater. in this study, copper coated pumice and zeolite were used to catalyze the ozonation of phenol as a target pollutant from aqueous solutions. methods: the pumice and zeolite stone were modified by cuso 4 (1n). modified pumice and zeolite were characterized by adsorption/deso...

The immobilization and electrochemical behaviors of cytochrome c on a NaY zeolite modified electrode were studied. The interaction between cytochrome c and NaY zeolite particles was examined by using UV-Vis spectroscopy and electrochemical methods. The direct electron transfer of the immobilized cytochrome c exhibited a pair of redox peaks with the E1/2 of −(44±3)mV (versus SCE) in 0.1 M pH 7.0...

In this paper, the utilisation of zeolites synthesised from fly ash (FA) and related co-disposal filtrates as low-cost adsorbent material were investigated. When raw FA and co-disposal filtrates were subjected to alkaline hydrothermal zeolite synthesis, the zeolites faujasite, sodalite and zeolite A were formed. The synthesised zeolites were explored to establish its ability to remove lead and ...

MFI type zeolite membranes were synthesized on two types of supporting materials, alumina (α-alumina) and yttria-stabilized zirconia (YSZ) coated alumina. Membranes were prepared by template-free secondary growth method with multiple growth steps in order to minimize intercrystalline gaps. Gas permeation characteristics, thermal and hydrothermal stability for MFI type zeolite membranes were exa...

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...