Direct hydrothermal synthesis and stabilization of high-silica mordenite (Si∶Al = 25) using tetraethylammonium and fluoride ions

2003 ◽  
Vol 13 (5) ◽  
pp. 1173-1179 ◽  
Author(s):  
Hitoshi Sasaki ◽  
Yasunori Oumi ◽  
Keiji Itabashi ◽  
Baowang Lu ◽  
Toshiharu Teranishi ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Fluoride Ions ◽  
High Silica

SDA-Free Hydrothermal Synthesis of High-Silica Ultra-nanosized Zeolite Y

2017 ◽  
Vol 17 (3) ◽  
pp. 1173-1179 ◽  
Author(s):  
Maeva Borel ◽  
Mathias Dodin ◽  
T. Jean Daou ◽  
Nicolas Bats ◽  
Bogdan Harbuzaru ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Zeolite Y ◽  
High Silica ◽  
Nanosized Zeolite

Effect of NaF Addition on Hydrothermal Synthesis of High-Silica Mordenite

2004 ◽  
Vol 112 (1306) ◽  
pp. 332-337
Author(s):  
Tomohiro TSUDA ◽  
Baowang LU ◽  
Yasuyuki YAO ◽  
Yasunori OUMI ◽  
Keiji ITABASHI ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
High Silica

Floating Adsorbent for Organic Removal Fabricated Through Crystallization of Silicalite-1 on Hollow Glass Microspheres

2020 ◽  
Vol 12 (2) ◽  
pp. 173-179 ◽  
Author(s):  
Supinya Nijpanich ◽  
Takeshi Hagio ◽  
Yuki Kamimoto ◽  
Ryoichi Ichino
Keyword(s):  
Hydrothermal Synthesis ◽  
Crystallization Rate ◽  
Glass Microspheres ◽  
Hollow Glass Microspheres ◽  
Structure Directing Agent ◽  
Hollow Glass ◽  
Key Factor ◽  
Type Zeolite ◽  
High Silica ◽  
Filter Clogging

MFI-type zeolite is a crystalline microporous aluminosilicate with an intersecting two-dimensional pore structure and well-defined windows of approximately 0.55 nm. It generally crystallizes in high silica to alumina ratios, leading to a rather hydrophobic character. This makes it an attractive adsorbent for removing organic pollutants from wastewater. However, separating the conventional powdery-zeolites from the media after treatment is difficult because they require considerable time to settle. They also trigger filter clogging. In this work, high silica MFI-type zeolite, namely, silicalite-1, was synthesized on the surfaces of hollow glass microspheres to develop a floating adsorbent with high hydrophobicity. Tetraethylorthosilicate and tetrapropylammonium hydroxide were used as the additional silica source and structure directing agent, respectively. The crystallization of silicalite-1 on hollow glass microspheres was performed using hydrothermal synthesis at 180 °C or 150 °C for 40 h using a precursor sol with a molar composition of 3SiO2:1TPA:14EtOH:286H2O. The surface coverage and crystallinity of the as-prepared samples were optimized, and the floatability and adsorption performance of the optimized sample were investigated. Well-covered microspheres were obtained when hydrothermal synthesis was conducted at 180 °C using 0.5 g of hollow glass microspheres and 15 g of a precursor sol adjusted to pH 12.5. The balance between the dissolution rate of the hollow glass microspheres and the crystallization rate of silicalite-1 appeared to be the key factor in the successful synthesis.

Hydrothermal synthesis of high silica zeolite Y using tetraethylammonium hydroxide as a structure-directing agent

2016 ◽  
Vol 52 (86) ◽  
pp. 12765-12768 ◽  
Author(s):  
Dawei He ◽  
Danhua Yuan ◽  
Zhijia Song ◽  
Yansi Tong ◽  
Yaqi Wu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Hydrothermal Synthesis ◽  
Zeolite Y ◽  
Hydrothermal Stability ◽  
Structure Directing Agent ◽  
Tetraethylammonium Hydroxide ◽  
High Silica

Zeolite Y with a SiO2/Al2O3 ratio of 7.76 and outstanding thermal stability and hydrothermal stability is synthesized using TEAOH as an SDA.

Direct Hydrothermal Synthesis of High-silica SSZ-39 Zeolite with Small Particle Size

2016 ◽  
Vol 45 (8) ◽  
pp. 919-921 ◽  
Author(s):  
Naoto Nakazawa ◽  
Satoshi Inagaki ◽  
Yoshihiro Kubota
Keyword(s):  
Particle Size ◽  
Hydrothermal Synthesis ◽  
Small Particle ◽  
Small Particle Size ◽  
High Silica

Effect of Aluminum Source on Hydrothermal Synthesis of High-Silica Mordenite in Fluoride Medium, and It's Thermal Stability

2004 ◽  
Vol 16 (2) ◽  
pp. 286-291 ◽  
Author(s):  
Baowang Lu ◽  
Tomohiro Tsuda ◽  
Hitoshi Sasaki ◽  
Yasunori Oumi ◽  
Keiji Itabashi ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Hydrothermal Synthesis ◽  
High Silica ◽  
Fluoride Medium

Influence des ions fluorure et de la silice amorphe sur la solubilité des gels de zircone et caractérisation des fluoro-complexes de zirconium en milieu moyennement acide

1999 ◽  
Vol 77 (12) ◽  
pp. 2099-2104 ◽  
Author(s):  
Rémi Valéro ◽  
Bernard Durand ◽  
Jean-Louis Guth ◽  
Thierry Chopin
Keyword(s):  
Hydrothermal Synthesis ◽  
Key Words ◽  
Amorphous Silica ◽  
Simultaneous Presence ◽  
Fluoride Ions ◽  
Molar Ratios ◽  
Ph Values

The solubility of zirconia gels versus pH is studied in order to state first the influence of F- ions alone, then the influence of the simultaneous presence of F- and amorphous silica. Two concentrations of F- ions are chosen, 0.094 and 0.314 mol L-1, corresponding to initial molar ratios F/Zr = 0.6 and 2.0. Metal fluorocomplexes formed at pH 0.5 and 2.5 are characterized by 19F NMR. The influence of F- on the solubility of zircon is also studied. It is shown that the formation of silicon complexes rich in fluorine shifts the equilibriums between the zirconium fluorocomplexes toward the complexes poor in fluorine and that, in the presence of F-, the crystallization of zircon by hydrothermal synthesis can be forecasted, for pH values in the range 0-10.Key words: zirconia gels, silica, zircon, fluoride ions, solubility, 19F NMR.

Effect of ammonium salts on hydrothermal synthesis of high-silica mordenite

2005 ◽  
Vol 81 (1-3) ◽  
pp. 365-374 ◽  
Author(s):  
Baowang Lu ◽  
Yasunori Oumi ◽  
Keiji Itabashi ◽  
Tsuneji Sano
Keyword(s):  
Hydrothermal Synthesis ◽  
Ammonium Salts ◽  
High Silica

Effect of Aluminum Source on Hydrothermal Synthesis of High-Silica Mordenite in Fluoride Medium, and Its Thermal Stability.

ChemInform ◽  
2004 ◽  
Vol 35 (15) ◽  
Author(s):  
Baowang Lu ◽  
Tomohiro Tsuda ◽  
Hitoshi Sasaki ◽  
Yasunori Oumi ◽  
Keiji Itabashi ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Hydrothermal Synthesis ◽  
High Silica ◽  
Fluoride Medium
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