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

Two dealuminated β-zeolites, zeolite Y and MCM-22 as well as silicalite, MCM-41 and AlPO4-5 have been studied as hydrophobic adsorbents in water solutions. Dealuminated β-zeolite, MCM-22 and silicalite all adsorb alcohols from water solutions. Enhanced adsorption is obtained for alcohols with longer alkyl chains. Adsorption in the practically most interesting 10–80% range of zeolite filling may adequately be described by Langmuir isotherms. The Langmuir adsorption constants are similar for β-zeolite, MCM-22 and silicalite. This indicates that the adsorption is independent of the pore structure for the alcohols tested in this study. The surface silanol density is however important, such that a low SiOH density is required to give lipophilic properties. In line with this, dealuminated zeolite Y, as prepared here, and MCM-41 give only a poor preference for alcohols from water. For the β-zeolite, the dealumination procedure is important for retaining the micropore volume and adsorption capacity of the zeolite. AlPO4-5 shows no potential as an adsorbent for alcohols from water solutions.

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Characterization of high-silica mordenites synthesized by various direct hydrothermal synthesis methods

Molecular Sieves: From Basic Research to Industrial Applications, Proceedings of the 3rd International Zeolite Symposium (3rd FEZA) - Studies in Surface Science and Catalysis ◽

10.1016/s0167-2991(05)80406-9 ◽

2005 ◽

pp. 725-732 ◽

Cited By ~ 2

Author(s):

B.-W. Lu ◽

T. Kanai ◽

Y. Oumi ◽

H. Itou ◽

K. Itabashi ◽

...

Keyword(s):

Hydrothermal Synthesis ◽

Synthesis Methods ◽

High Silica

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Influencing factors on rapid crystallization of high silica nano-sized zeolite Y without organic template under atmospheric pressure

Journal of Porous Materials ◽

10.1007/s10934-008-9200-4 ◽

2008 ◽

Vol 16 (3) ◽

pp. 299-306 ◽

Cited By ~ 30

Author(s):

Young Chang Kim ◽

Ji Yeon Jeong ◽

Ji Yeong Hwang ◽

Shin Dong Kim ◽

Wha Jung Kim

Keyword(s):

Influencing Factors ◽

Atmospheric Pressure ◽

Zeolite Y ◽

Organic Template ◽

Rapid Crystallization ◽

High Silica

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

Journal of the Ceramic Society of Japan ◽

10.2109/jcersj.112.332 ◽

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

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Sulfonamide Antibiotics Embedded in High Silica Zeolite Y: A Combined Experimental and Theoretical Study of Host−Guest and Guest−Guest Interactions

Langmuir ◽

10.1021/la9049132 ◽

2010 ◽

Vol 26 (12) ◽

pp. 9524-9532 ◽

Cited By ~ 43

Author(s):

Ilaria Braschi ◽

Giorgio Gatti ◽

Geo Paul ◽

Carlo E. Gessa ◽

Maurizio Cossi ◽

...

Keyword(s):

Theoretical Study ◽

Zeolite Y ◽

Sulfonamide Antibiotics ◽

High Silica

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

Science of Advanced Materials ◽

10.1166/sam.2020.3622 ◽

2020 ◽

Vol 12 (2) ◽

pp. 173-179 ◽

Cited By ~ 1

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.

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