Molecular level nucleation mechanisms of hierarchical MFI and MOR zeolite structures <i>via</i> non-stochastic pathways

Şahin, Volkan; Karabakan, Abdülkerim

doi:10.1039/d0nr03334k

Cited by 5 publications

(7 citation statements)

References 43 publications

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“…The growth rate of crystals approximately approached 0, and the crystallinity did not almost change finally. 38 As could be seen from Figure 5(C), the crystallization rate gradually tended to 0 as the crystallization time exceeded 8 h so that the crystallinity of products maintained the constant, indicating that different crystallization temperatures and times had certain effects on the nucleation/growth process of NaP zeolite.…”

Section: The Fitting Results Of the Arrhenius Equationmentioning

confidence: 87%

“…When the concentration of the crystal nucleus reached the supersaturation state, the NaP zeolite tiny particles were generated gradually and exhibited a massive production with the prolongation of crystallization time; (iii) the third stage that a large number of tiny particles slowly aggregated to the NaP zeolite crystal grains was the stable growth period. The growth rate of crystals approximately approached 0, and the crystallinity did not almost change finally 38 . As could be seen from Figure 5(C), the crystallization rate gradually tended to 0 as the crystallization time exceeded 8 h so that the crystallinity of products maintained the constant, indicating that different crystallization temperatures and times had certain effects on the nucleation/growth process of NaP zeolite.…”

Section: Resultsmentioning

confidence: 90%

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Evolution of nucleation/growth kinetics for NaP zeolite crystals and the adsorption removal of phenol compound

Zhang,

Deng,

Zhai

et al. 2023

J Am Ceram Soc.

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The NaP zeolite with excellent crystallinity and adsorption performance was obtained by adopting the Na2SiO3 and NaAlO2 from coal fly ash as the raw materials. As the synthesis condition of aging for 0.5 h at 30°C and crystalizing for 8 h at 120°C with n(H2O)/n(SiO2) = 116, n(Na2O)/n(SiO2) = 1.4, and n(SiO2)/n(Al2O3) = 2.8, NaP zeolite owned higher crystallinity (98.98%) and spherical morphology (∼2.78 μm). During the crystallization, the nucleation/growth kinetics was calculated to survey the crystallization mechanism via the theoretical calculation and characterization methods. The diffusion of reactants in the solid–liquid‐phase interface was dominant, wherein the heterogeneous nucleation and solid‐phase transformation were also proposed based on the fitting results of Avarami–Erofeev and simple kinetic equations. The activation energy results of nucleation (En, 27.67 kJ/mol) and growth (Eg, 13.31 kJ/mol) demonstrated that the induced nucleation period was the critical step during the crystallization. Hence, the method of rapid nucleation was introduced and the induced nucleation time was shortened 50% (from ∼2.0 to ∼1.0 h) as the crystal seed was added. Moreover, the grain size of NaP‐Seed zeolite reduced to ∼2.02 μm. Meanwhile, the synthesized NaP zeolite adsorbent was employed for the removal of phenol compound from the aqueous solution. Under the synergistic effect of electrostatic interaction and pore filling effect, NaP zeolite exhibited better adsorption with the removal rate of 82.63% (pH = 5.0 and 40 min) and stability in the five consecutive cycles.

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Section: The Fitting Results Of the Arrhenius Equationmentioning

confidence: 87%

Section: Resultsmentioning

confidence: 90%

Evolution of nucleation/growth kinetics for NaP zeolite crystals and the adsorption removal of phenol compound

Zhang,

Deng,

Zhai

et al. 2023

J Am Ceram Soc.

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“…It was reported that each framework developed according to a distinct pathway, which was used as putative evidence for the common CBU not being an essential aspect of growth mechanisms. 251 Schuẗh and Corma 252 have noted that even in situations where CBUs are observed in more concentrated growth solutions than those employed for ESI-MS analysis, such evidence cannot definitively demonstrate that these species function as growth units since CBUs might "assemble directly, exchange structural fragments, or depolymerize" throughout crystallization. It is also possible that incomplete or fragmented CBUs can function as growth units since they are known to be more reactive for condensation compared to their pristine counterparts.…”

Section: Soluble Speciesmentioning

confidence: 99%

“…A similar conclusion was reached by Sahin and Karabakan. 251 The collective findings from spectroscopic studies indicate that the active soluble species in growth solutions are silicate oligomers with structures that are influenced by the nature of the cation but are likely not pristine CBUs since missing/ distorted bonds or other imperfections putatively increase their reactivity toward oligomerization.…”

Section: Soluble Speciesmentioning

confidence: 99%

The Current Understanding of Mechanistic Pathways in Zeolite Crystallization

Mallette,

Shilpa,

Rimer

2024

Chem. Rev.

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Zeolite catalysts and adsorbents have been an integral part of many commercial processes and are projected to play a significant role in emerging technologies to address the changing energy and environmental landscapes. The ability to rationally design zeolites with tailored properties relies on a fundamental understanding of crystallization pathways to strategically manipulate processes of nucleation and growth. The complexity of zeolite growth media engenders a diversity of crystallization mechanisms that can manifest at different synthesis stages. In this review, we discuss the current understanding of classical and nonclassical pathways associated with the formation of (alumino)silicate zeolites. We begin with a brief overview of zeolite history and seminal advancements, followed by a comprehensive discussion of different classes of zeolite precursors with respect to their methods of assembly and physicochemical properties. The following two sections provide detailed discussions of nucleation and growth pathways wherein we emphasize general trends and highlight specific observations for select zeolite framework types. We then close with conclusions and future outlook to summarize key hypotheses, current knowledge gaps, and potential opportunities to guide zeolite synthesis toward a more exact science.

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“…Electrospray ionization mass spectrometry (ESI-MS) and laser desorption ionization-time of flight mass spectrometry (LDI-TOF MS) [25] have ever been used as a powerful tool to detect the pre-nucleating [26] and nucleating [27] solutions of the zeolite synthetic system, but less application can be found for the analysis of the SAPO system. In order to analyze BM34P-L7 by FT-ICR MS, the liquid was first filtered by ultrafiltration membrane.…”

Section: Identification Of the Transparent Liquid Precursormentioning

confidence: 99%

Recognizing the Minimum Structural Units Driving the Crystallization of SAPO‐34 in a Top‐Down Process

Zhang

Yang

Wang³

et al. 2023

Chemistry A European J

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Recognizing the structure and nature of the nuclei for zeolites crystallization on an atomic level is of great importance, which can provide guidance on the control of crystallization kinetics and the rational synthesis of zeolites. However, it remains a long‐standing challenge due to the difficulty in characterization of amorphous precursor with limited crystal nuclei. Herein, a top‐down synthesis system was designed for SAPO‐34 molecular sieve and well investigated. A clear precursor solution with abundant SAPO‐34 crystal nuclei was obtained under a depolymerization‐dominant condition. The species in the liquid precursor were identified by FT‐ICR MS, solid‐state MAS NMR and atomic pair distribution function analyses. In combination with various designed experiments, it is revealed that both the formation of small species containing Si−O−Al bonds and reaching a certain concentration, is crucial for driving the crystallization of SAPO‐34, rather than structural units with specific spatial conformation. This work provides an important understanding on the (pre)nucleation of SAPO‐34 and sheds light on the synthesis control of SAPO molecular sieves.

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Molecular level nucleation mechanisms of hierarchical MFI and MOR zeolite structures via non-stochastic pathways

Abstract:
Understanding the chemical mechanism of crystal nucleation at molecular level is crucial for the design of architectural structures of valuable materials in the future. In this study, it has been...

Cited by 5 publications

References 43 publications

Evolution of nucleation/growth kinetics for NaP zeolite crystals and the adsorption removal of phenol compound

Evolution of nucleation/growth kinetics for NaP zeolite crystals and the adsorption removal of phenol compound

The Current Understanding of Mechanistic Pathways in Zeolite Crystallization

Recognizing the Minimum Structural Units Driving the Crystallization of SAPO‐34 in a Top‐Down Process

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Molecular level nucleation mechanisms of hierarchical MFI and MOR zeolite structures via non-stochastic pathways

Abstract: Understanding the chemical mechanism of crystal nucleation at molecular level is crucial for the design of architectural structures of valuable materials in the future. In this study, it has been...

Cited by 5 publications

References 43 publications

Evolution of nucleation/growth kinetics for NaP zeolite crystals and the adsorption removal of phenol compound

Evolution of nucleation/growth kinetics for NaP zeolite crystals and the adsorption removal of phenol compound

The Current Understanding of Mechanistic Pathways in Zeolite Crystallization

Recognizing the Minimum Structural Units Driving the Crystallization of SAPO‐34 in a Top‐Down Process

Contact Info

Product

Resources

About

Abstract:
Understanding the chemical mechanism of crystal nucleation at molecular level is crucial for the design of architectural structures of valuable materials in the future. In this study, it has been...