نتایج جستجو برای: potasic zeolite
تعداد نتایج: 8861 فیلتر نتایج به سال:
Zeolites are crystalline microporous materials with well-defined and uniform pore structure that find extensive industrial uses as adsorbents, catalysts and ion exchangers [1-2]. Zeolite films supported on different materials have been successfully prepared and have potential applications as highly selective membrane separators, membrane reactors, chemical sensor and microdevices [3-10]. Most o...
The influence of framework substituents (Al3+, Ga3+, Fe3+ and B3+) and morphology (bulk vs. nanometer-sized sheets) of MFI zeolites on the acidity and catalytic performance in the methanol-to-hydrocarbons (MTH) reaction was investigated. The Brønsted acid density and strength decreased in the order Al(OH)Si>Ga(OH)Si>Fe(OH)Si≫B(OH)Si. Pyridine 15N NMR spectra confirmed the differences in the Brø...
We describe a simple and highly efficient procedure for the single-step preparation of isatins from the commercially available anilines using H-β zeolite as a truly heterogeneous catalyst. H-β zeolite is readily separated from reaction mixture by simple filtration and reused several times without considerable loss of activity.
A novel synthetic route is designed, employing both high temperature and a nontoxic organic structure-directing agent (SDA), for the synthesis of high silica zeolite Y. The N-methylpyridinium used as an organic SDA is stable during the synthesis, and the high silica zeolite Y shows high hydrothermal stability and good catalytic performance, as well as excellent adsorptive properties.
Hierarchically porous zeolite supported metal nanoparticles are successfully prepared through a base-assisted chemoselective interaction between the silicon species on the zeolite crystal surface and metal salts, in which in situ construction of mesopores and high dispersion of metal species are realized simultaneously.
A composite zeolite adsorbent was prepared by conformally depositing an ultrathin porous TiO2 coating on the external surface of the 5A zeolite by molecular layer deposition (MLD) and subsequent calcination. The composite adsorbent showed significantly improved ideal adsorption selectivity for CO2-CH4, CO2-N2 and propylene-propane.
The synthesis of a mesoporous material with uniform mesopore diameters and crystalline MFI zeolite walls has been achieved, simply by seeding the multiammonium surfactant-directed synthesis with bulk zeolite crystals. The bulk seeds disappeared in the final product. As a result of seeding, the mesoporous zeolites could be generated rapidly even at high Al content.
We report the direct fabrication of mesoporous zeolite with a hollow spherical/ellipsoidal capsule structure by using conventional TPAOH and CTAB as soft micro- and mesopore generating templates; the mesoporous zeolite shows a high surface area of 717 m(2) g(-1) and small mesopore size of around 3 nm.
Microwave heating has been shown to influence various inorganic chemical reactions. Substantial reductions in the synthesis time for materials have been reported (1). Additionally, product characteristics and quality of materials synthesized by microwave heating are different from those synthesized under conventional heating methods. The mechanism which results in microwave enhancement is not c...
Polycrystalline MFI zeolite membranes were prepared on α-alumina tubular support by hydrothermal treatments at 413 K. The synthesized zeolite membranes were characterized by XRD, SEM and single gas permeation. The influence of hydrothermal treatment steps and the calcination time on the zeolite layer formation were investigated. MFI zeolite membrane prepared by four subsequent hydrothermal ...
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