Role of the water content of clear synthesis solutions on the thickness of silicalite layers grown on porous alpha-alumina supports

Date

2002-03-01

Author

Kalıpçılar, Halil

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

46
views

0
downloads

In situ hydrothermal synthesis of silicalite layers on rnacroporous alpha-Al2O3 disks were performed from a batch composition of 6.5Na(2)O:25SiO(2):xH(2)O:6.9TPABr by varying the water content of a clear crystallization solution from 500 to 2000 moles at 200 degreesC. As the water content of the clear solution was increased, continuous and thinner silicalite layers formed from smaller crystals were obtained and the layer quality was improved. The silicalite layer which was synthesized from the most concentrated batch was formed from crystals with an average size of 100 mum and had a thickness of 36 mum. The layer thickness and average crystal size decreased to about 8 and 7 mum, respectively, when the batch containing 1400 moles of water was used for synthesis. The results showed that the layer thickness on porous alumina supports could be adjusted by varying the water content of the synthesis solution. As-synthesized membranes were impermeable to N-2 after a single crystallization step. The membranes were tested for possible pinholes and microcracks by measuring single gas permeations of N-2 and SF6 after calcination at 500 degreesC by a slow and step-wise calcination procedure. The calcined membranes showed an N-2 permeance of 16.3 mmoV(bar m(2) s) and an ideal selectivity of 1630 for N-2/SF6 at room temperature. The high selectivity showed, that the silicalite layer is free of large interzeolitic pores and the applied calcination procedure is, suitable for TPA removal without forming microcracks.

Subject Keywords

N-2/SF6 selectivity, N-2 permeance, Calcination procedure, Layer thickness, Silicalite membrane

URI

https://hdl.handle.net/11511/41065

Journal

MICROPOROUS AND MESOPOROUS MATERIALS

DOI

https://doi.org/10.1016/s1387-1811(01)00479-6

Collections

Department of Chemical Engineering, Article

Suggestions

OpenMETU
Core

Effect of Midsynthesis Addition of Silica to the Synthesis Medium on the Properties of MFI-Type Zeolite Membranes Soydas, Belma; Kalıpçılar, Halil; Culfaz, Ali (American Chemical Society (ACS), 2010-06-02) Thin zeolite membranes of MFI type were prepared on alpha-Al2O3 supports by midsynthesis addition of silica in a recirculating flow system at 95 degrees C The synthesis was started with the batch composition of 80SiO(2): 30TPAOH:1500H(2)O which was changed to 80SiO(2)center dot 9TPAOH:1500H(2)O by addition of silica Mkt 24, 48, or 72 h Compared to synthesis at constant composition. it is possible to affect the rates of nucleation and crystal growth to obtain membranes with better quality by changing the ove...
Influence of TiO2 Content on the Photocatalytic Activity of TiO2 B2O3 Glasses Prepared by the Sol gel Process Akkuş, Sıtkı Can; Kalem, Volkan; Park, Jongee; Öztürk, Abdullah (2016-12-01) A series of binary (1-x)TiO2 xB2O3 glasses with TiO2 content up to 80 mol% were prepared by the sol-gel technique using titanium tetraisopropoxide (C12H28O4Ti) and boric acid (H3BO3) precursors. Effects of initial precursor amount, and calcination temperature and time on the formation and photocatalytic properties of the glasses were investigated. The optimum amount of TiO2 was researched to get a glass possessing self-cleaning ability. The photocatalytic performance of the glasses was evaluated by the deco...
EFFECT OF ION ASSOCIATION ON THE PROPERTIES OF IONOMERS OBTAINED FROM METHYL-METHACRYLATE METHACRYLIC-ACID COPOLYMER KOCAK, HI; ARAS, L (Elsevier BV, 1990-07-01) The solution behaviour of Na, Ba, Zn and Al ionomers of methyl methacrylate-methacrylic acid copolymer (P(MMA-MAA)) with different ion contents has been studied by viscosity and dipole moment measurements. Two solvents with different character are chosen for viscosity measurements: dioxane (ε = 2.22) and acetone (ε = 20.7). The expected polyelectrolyte behaviour of the ionomers in acetone is reflected by the viscometric measurements. Mean squared dipole moment 〈μ2〉 values are calculated over a temperature r...
Effect of Synthesis Conditions on the Structure and Catalytic Performance of V- and Ce-Incorporated SBA-15-like Materials in Propane Selective Oxidation Aktas, Ozge; YAŞYERLİ, SENA; DOĞU, GÜLŞEN; Doğu, Timur (2010-08-04) Vanadia- and/or ceria-incorporated SBA-15-like materials were prepared by impregnation and one-pot hydrothermal synthesis procedures at different solution pH values. The pH of the synthesis solution was found to have a very strong effect on the pore structure, chemical composition, and morphology of the synthesized materials. Materials synthesized by impregnation of V and/or Ce and by the one-pot hydrothermal route at pH << 1.0 showed the characteristic ordered pore structure of SBA-15. However, the materia...
Influence of the sol-gel preparation method on the photocatalytic NO oxidation performance of TiO2/Al2O3 binary oxides Polat, Meryem; Soylu, Asli M.; Altunöz Erdoğan, Deniz; Erguven, Huseyin; Vovk, Evgeny I.; Ozensoy, Emrah (2015-03-01) In the current work, TiO2/Al2O3 binary oxide photocatalysts were synthesized via two different sol-gel protocols (P1 and P2), where various TiO2 to Al2O3 mole ratios (0.5 and 1.0) and calcination temperatures (150-1000 degrees C) were utilized in the synthesis. Structural characterization of the synthesized binary oxide photocatalysts was also performed via BET surface area analysis, X-ray diffraction (XRD) and Raman spectroscopy. The photocatalytic NO(g) oxidation performances of these binary oxides were m...

Citation Formats

H. Kalıpçılar, “Role of the water content of clear synthesis solutions on the thickness of silicalite layers grown on porous alpha-alumina supports,” MICROPOROUS AND MESOPOROUS MATERIALS, pp. 39–54, 2002, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/41065.