Mechanism of zeolite formation: Seed-gel interaction

Dutta, Prabir K.; Bronić, Josip

doi:10.1016/0144-2449(94)90092-2

Cited by 50 publications

(25 citation statements)

References 18 publications

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“…Magic angle spinning nuclear magnetic resonance ( 29 Si MAS NMR) and 27 Al MAS NMR experiments were performed at room temperature on a Bruker Advance 400 spectrometer at a resonance frequency of 130.34 MHz using a 5 mm-probe. In the experiments, 29 Si MAS NMR with high power proton decoupling was recorded using a p/4 single pulse length of 2 ls, a recycle delay of 80 s, and a spinning rate of ca.14 kHz.…”

Section: Characterizationmentioning

confidence: 99%

“…In the experiments, 29 Si MAS NMR with high power proton decoupling was recorded using a p/4 single pulse length of 2 ls, a recycle delay of 80 s, and a spinning rate of ca.14 kHz. 27 Al MAS NMR was recorded with a pulse length of 0.5 ls (6p/12), a recycle delay of 1 s, and a spinning rate of 8 kHz. The chemical shifts of 29 Si MAS NMR were externally referenced to TMS, whereas that of 27 Al MAS NMR was referenced to Al 2 (SO 4 ) 3 Á12H 2 O.…”

Section: Characterizationmentioning

confidence: 99%

“…Techniques of adding seeds for the enhancement of the SiO 2 / Al 2 O 3 ratios of zeolites were recently established [26][27][28][29][30]. Highly crystalline MOR zeolites with a bulk SiO 2 /Al 2 O 3 ratio of approximately 60 were successfully prepared by adding MOR nanocystalline seeds with or without NaF [28].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Synthesis of high-silica EU-1 zeolite in the presence of hexamethonium ions: A seeded approach for inhibiting ZSM-48

Gong

et al. 2011

Journal of Colloid and Interface Science

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Section: Characterizationmentioning

confidence: 99%

Section: Characterizationmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis of high-silica EU-1 zeolite in the presence of hexamethonium ions: A seeded approach for inhibiting ZSM-48

Gong

et al. 2011

Journal of Colloid and Interface Science

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“…During the second-step synthesis, the growth of Mordenite zeolite prefers the external surface of Beta zeolite to the mother liquor of synthesis system due to the higher surface area of Beta zeolite crystals [17]. The external surface of Beta crystals is therefore the key place responsible for the formation of the polycrystalline agglomerates.…”

Section: Synthesis and Characterization Of Thementioning

confidence: 99%

Synthesis and Catalytic Property of a Zeolite Composite for Preparation of Dimethyl Ether from Methanol Dehydration

Zheng

Wang

et al. 2009

Catal Lett

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A zeolite composite with Beta and Mordenite zeolite structures (denoted as BMZ) was synthesized with a two-step hydrothermal crystallization process, and characterized by X-ray diffraction, scanning electron microscopy, N 2 adsorption, NH 3 -TPD and in situ IR spectra of pyridine. The results show that the composite has microprous and mesoporous structures and distinguished acid properties, the acid amount and concentration ratio of Lewis to Brönsted-acid sites in the composites can be controlled by changing the alkalinity in the second-step synthesis. Over the composite catalyst H-BMZ, the conversion of methanol in the mild condition reached 90% and the selectivity of dimethyl ether almost kept 100%.

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“…22 -24 The role of seeds in promoting the zeolite crystallization rate is due to the formation of new nuclei on the seed crystal surface, and subsequently the growth of these new crystallites of the same phase. 11 In the sol-gel system, according to Prabir's work, 25 the seed provides the nuclei for crystal growth while the gel's role then is to provide a source of nutrients for nuclei growth. For this present work, we thus fixed the composition at SiO 2 : Al 2 O 3 : 3Na 2 O:410H 2 O, aging at half a day, varying seed at 1-3 wt%, and microwave heating at 80…”

Section: Effect Of Seed Wt%mentioning

confidence: 99%

Preparation of uniform and nano‐sized NaA zeolite using silatrane and alumatrane precursors

Kuanchertchoo¹,

Kulprathipanja²,

Aungkavattana³

et al. 2006

Applied Organom Chemis

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Nano-sized Na A zeolite was successfully synthesized via the sol-gel process and microwave techniques. The synthesis parameters, such as hydroxide ion concentration, seed amount, as well as heating time and temperature, were studied to obtain the most uniform and very small sized NaA zeolite using the composition of SiO 2 :Al 2 O 3 : xNa 2 O:410H 2 O; 3 ≤ x ≤ 6. It was found that hydroxide ion concentration affects the crystal size and heating time, whereas a higher amount of seed provides smaller sized NaA zeolite. The zeolite product can be synthesized using a higher temperature for a shorter time or lower temperature for a longer time. The best conditions for synthesizing the smallest size, 0.1-0.2 µm, and the most homogeneous NaA zeolite is to use the composition of SiO 2 :Al 2 O 3 :3Na 2 O:410H 2 O and 3 wt% crystal seed at 80 • C microwave heating for 6 h. The synthesized NaA zeolite was characterized using XRD and SEM.

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Mechanism of zeolite formation: Seed-gel interaction

Cited by 50 publications

References 18 publications

Synthesis of high-silica EU-1 zeolite in the presence of hexamethonium ions: A seeded approach for inhibiting ZSM-48

Synthesis of high-silica EU-1 zeolite in the presence of hexamethonium ions: A seeded approach for inhibiting ZSM-48

Synthesis and Catalytic Property of a Zeolite Composite for Preparation of Dimethyl Ether from Methanol Dehydration

Preparation of uniform and nano‐sized NaA zeolite using silatrane and alumatrane precursors

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