The permeability of reverse osmosis membranes is limited by the diffusive transport of water across a non-porous polyamide active layer. Alternatively, fabricating a microporous active layer capable of rejecting salt ions while allowing for water transport would increase the permeability while maintaining high salt rejection. Zeolites provide a model porous network which is capable of performin...

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...

Ultrathin MFI-zeolite nanosheets can be packed on porous supports to create molecular sieve membranes. The nanosheets on porous support reduce morphological damage seen in regular MFIzeolite crystals [1]. MFI-zeolite belongs to pentasil family of zeolites where the periodic building unit (PerBU) is composed of 12 interconnected SiO4 tetrahedral (T12) units of 41m2 (D2d) symmetry [2]. Rotation 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...

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 trea...

Two-dimensional zeolite nanosheets that do not contain any organic structure-directing agents were prepared from a multilamellar MFI (ML-MFI) zeolite. ML-MFI was first exfoliated by melt compounding and then detemplated by treatment with a mixture of H2 SO4 and H2 O2 (piranha solution). The obtained OSDA-free MFI nanosheets disperse well in water and can be used for coating applications. Deposi...

Hierarchical MFI zeolite was synthesized following a synthesis route using organic-inorganic hybrid surfactants; the resultant zeolite with mesoporous/microporous hierarchical structure exhibited remarkably high resistance to deactivation in catalytic activity of various reactions such as isomerization of 1,2,4-trimethylbenzene, cumene cracking, and esterification of benzyl alcohol with hexanoi...

The catalytic behavior of Brønsted acid sites in three acidic zeolite materials (one MWW and two MFI zeolites) containing dual meso-/microporosity was studied using ethanol dehydration and monomolecular conversion of propane and isobutane as probe reactions. The meso-/microporous MWW zeolite, MCM-36 or pillared MWW, consists of a zeolitic layer structure, with independent microporosity and meso...

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 ...

Pre-shaped mesoporous amorphous rice husk ash (RHA) and MCM-41 derived from RHA as a silica source were transformed into MFI-type zeolites using two different structure-directing agents. Tetrapropylammonium hydroxide (TPAOH) was utilized as an alkali source for silica dissolution and structure control during the direct transformation of RHA into zeolite. A monopropylamine (PA)-containing alkali...