Molecular Sieving in a Nanoporous b-Oriented Pure-Silica-Zeolite MFI Monocrystal Film

Abstract

The molecular sieving property of a continuous b-oriented pure-silica-zeolite (PSZ) MFI monocrystal film was demonstrated in a zeolite-modified electrode (ZME) configuration using redox molecules of different sizes. Ru(NH3)63+ (diameter approximately 5.5 A) was able to traverse the film, while Co(phen)32+ (diameter approximately 13.0 A) was completely excluded. This film has excellent adhesion to the electrode and is stable in strong acidic conditions.

Desalination of seawater ion complexes by MFI-type zeolite membranes: Temperature and long term stability

“…They found that zeolite pore structure is ideally suited to reject ions. The size exclusion of hydrated ions is the separation mechanism of the perfect ZK-4 zeolite membrane [15]. The aperture of the ZK-4 zeolite (diameter 0.42 nm) is significantly smaller than the kinetic sizes of hydrated ions (e.g.…”

Rational synthesis of Beta zeolite with improved quality by decreasing crystallization temperature in organotemplate-free route

“…Zeolites with intricate micropores have been extensively studied for a long time as an important class of industrial materials in different fields of the chemical industries such as adsorption, ion exchange, shape selective catalysis [1][2][3][4][5][6][7][8][9][10][11][12]. The early processes for synthesis of zeolites such as LTA and FAU were carried out in aluminosilicate gels containing inorganic cations, while the modern synthesis methodologies are typically involved in the use of organic structure-directing agents (SDAs) that direct the assembly pathway and ultimately fill the pore space [13,14].…”

Effective manipulation of the microstructure of zeolite film by hydrothermal pretreatment

“…Taking Mordenite Framework Inverted (MFI) zeolite [1] (symmetry: orthorhombic; space group: P nma ; unit cell constants: a = 20.1 Ǻ , b = 19.9 Ǻ , and c = 13.4 Ǻ ) as an example, the pore system consists of straight channels (pore size: 0.53 9 0.56 nm) interconnected by zigzag channels (0.51 9 0.55 nm) [2]. In addition to their traditional uses as catalysts, adsorbents and ionic exchangers [3], zeolites can also be fabricated into thin films and used as separation membranes [4][5][6][7][8], selective sensors [9,10], low-k materials [11,12], corrosion-resistant coatings [13], and optical materials [14,15]. In the synthesis of high-quality zeolite films, the accurate manipulation and optimization of their microstructures, such as crystallographic preferred orientation (CPO), thickness, intergrowth and grain boundary structures, is critical.…”