Study of the crystallization of zeolite NaA by quasi-elastic light-scattering spectroscopy and electron microscopy

Góra, Leszek; Streletzky, Kiril A.; Thompson, Robert W.; Phillies, George D. J.

doi:10.1016/s0144-2449(96)00144-3

Cited by 101 publications

(65 citation statements)

References 17 publications

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“…Thus, it appears that the nucleation and subsequent crystallization occur with aggregates of constant size. A close association of the initially formed nuclei with the gel particles has already been described by Gora et al [17] However, it is difficult, to discuss the transport of the nutrient during this stage.…”

Section: Discussionmentioning

confidence: 56%

“…( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) tion through gel transformation, even for situations considered before as homogeneous. [20,22] The presence of aluminosilicate nanoparticles in the early stages of nucleation of zeolite A has been confirmed by quasi-elastic light scattering and SAXS, [11] dynamic light scattering (DLS), [17,18] TEM, [8] and AFM. [7,14] SAXS observations [19Ϫ21] have suggested that some physical rearrangements occur within the amorphous aluminosilicate particles during the nucleation process.…”

Section: Introductionmentioning

confidence: 86%

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Investigation of the Crystallization Stages of LTA‐Type Zeolite by Complementary Characterization Techniques

2003

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This paper reports on the physicochemical reorganizations, at 40°C, of a template-free aluminosilicate system yielding an LTA-type zeolite. The events that take place in the system during the transformations of the amorphous material into a crystalline material were monitored by various characterization techniques which provide information from the molecular to the micrometer scale. High-resolution solid-state 29 Si and 27 Al MAS NMR spectroscopy, small-angle X-ray scattering (SAXS), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were used in order to achieve a better understanding of the structural properties of the precursor gel and its transformation into a crystalline zeolite-type material. The experimental results show that the first crystallization stage

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Section: Discussionmentioning

confidence: 56%

Section: Introductionmentioning

confidence: 86%

Investigation of the Crystallization Stages of LTA‐Type Zeolite by Complementary Characterization Techniques

2003

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“…The acquisition of experimental data is very difficult during the nucleation process due to the extremely small nature of nuclei and only few a researchers have been successful in providing direct experimental evidence of nucleation phenomena [29,[35][36][37]. The crystal growth period can be correlated to the steady increase of the US-attenuation occurring between 180 and 220 min in Fig.…”

Section: Discussionmentioning

confidence: 99%

“…8 that show a reduction of the amorphous material as the size and number of zeolite A crystals increases. The growth rate of zeolite A crystals was reported to be around 37 nm/min at near optimum compositions at around 80 • C [36]. The chemistry of development of order during the fundamental steps of crystal formation and growth has been discussed in depth by Cundy and Cox [29] as well as by Chang and Bell [35].…”

Section: Discussionmentioning

confidence: 99%

In situ ultrasonic monitoring of zeolite A crystallization from coal fly ash

Musyoka

Petrik

Hums³

et al. 2012

Catalysis Today

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In this study, high phase purity of zeolite A was prepared from coal fly ash precursors. The molar regime of both the clear solution extract and unseparated fly ash slurry was adjusted to achieve the right com-position for zeolite A crystallization. The formation process for zeolite A from coal fly ash precursors was monitored in detail using an in situ ultrasonic system and was complemented by use of ex situ techniques such as XRD, FTIR, SEM and FTIR. The findings from both the in situ ultrasonic monitoring process and ex situ techniques clearly contributed significantly in unmasking the formation process of zeolite A from coal fly ash compared to previous studies reported in the literature. The study also enriches the existing body of literature by deeply investigating the gel-solutioncrystal interactions starting from this complex feedstock. Comparable ultrasonic signals were generated when both clear and unseparated fly ash based precursor solutions were used during the zeolite synthesis process.

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“…Many studies have been performed to investigate how zeolite crystals grow. Based on the results reported from these studies it is generally found that the growth linearly proceeds during the crystallization of most zeolites and this is applicable for both gel and clear solution syntheses (Subotic et al 2003;Zhdanov et al 1980;Bosnar et al 1999;Iwasaki et al 1995;Bosnar et al 2004;Cora et al 1997;Kalipcilar et al 2000;Schoeman et al 1997;Caputo et al 2000). Parameters such as gel composition, aging, stirring and temperature can affect on growth in zeolites (Subotic et al 2003;Cundy et al 2005).…”

Section: Monitoring Processes With Afmmentioning

confidence: 97%