Chemically controlled particulate properties of zeolites: Towards the face-less particles of zeolite A. 2. Influence of aluminosilicate batch concentration and alkalinity of the reaction mixture (hydrogel) on the size and shape of zeolite A crystals

Bosnar, Sanja; Bronić, Josip; Brlek, Đurđica; Subotić, Boris

doi:10.1016/j.micromeso.2010.12.027

Cited by 39 publications

(25 citation statements)

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“…7 and 6), it is clear that increasing alkalinity (from 6% to 12%), the crystallinity increases and the crystals size decreases. Similar results were obtained by S. Bosnar and W. Chandra 4,29) . However, the increase of alkalinity will result on the reduction of the production yield due to faster zeolite dissolution rate in a higher alkaline condition.…”

Section: The Effect Of Sodium Hydroxide Concentrationsupporting

confidence: 89%

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Synthesis of Pure Na–X and Na–P Zeolite from Acid-Extracting Residues of CFB Fly Ash by a Single-Step Hydrothermal Method

et al. 2016

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Acid-extracting residue of circulating uidized bed (CFB) y ash is still underutilized leaving disposal problems. In fact, high silica content inside this material opens a possibility to become a potential zeolites precursor. In this study, ne particles of acid residues have been reused to prepare zeolite Na-X and Na-P with high purity and intensity. Acid residue was used to synthesize zeolite Na-X and Na-P using a single-step hydrothermal process. The effects of crystallization time, temperature and sodium hydroxide concentration on the end products were investigated. The results revealed that crystallization time and temperature determined whether or not zeolite Na-X or Na-P was formed. The zeolites were characterized in terms of their mineralogical composition, morphology, and fourier-transform infrared spectroscopy.

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Section: The Effect Of Sodium Hydroxide Concentrationsupporting

confidence: 89%

“…The effect of sodium hydroxide concentration on the zeolite crystallization by a two-step hydrothermal method has been previously studied 28,29) . For instance, increasing sodium hydroxide concentration in the reaction mixture enhances the kinetic of the zeolite nucleation and crystal growth.…”

Section: The Effect Of Sodium Hydroxide Concentrationmentioning

confidence: 99%

Synthesis of Pure Na–X and Na–P Zeolite from Acid-Extracting Residues of CFB Fly Ash by a Single-Step Hydrothermal Method

et al. 2016

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“…6-8 , [12][13][14] In syntheses performed in the absence of organic compounds, its appearance has been related to a decrease in the Si/Al ratio, 12 although it has been shown recently that a more complex relationship to the overall gel/solution composition dictates its formation. 13,14 In synthesis where organic molecules are present additional organic-surface interactions may influence the formation of a particular face, but in the case of TEA, it has been found that the molecule is not included in the pore space of the final zeolite A products, indicating a lack of strong interaction between organic and framework. In the case of DEA there is no data available in the literature regarding its inclusion in the zeolite A pore space 4 , for that reason we performed C-NMR on some of the synthesised crystals.…”

Section: Discussionmentioning

confidence: 99%

Atomic Force Microscopy and High Resolution Scanning Electron Microscopy Investigation of Zeolite A Crystal Growth. Part 2: In Presence of Organic Additives

et al. 2014

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractThe nanoscopic details of the crystal growth of zeolite A in the presence of the organic modifiers diethanolmaine (DEA) and triethanolamine (TEA) has been determined using a combination of atomic force microscopy (AFM) and high-resolution scanning electron microscopy (HRSEM) coupled with Monte Carlo simulations. Crystallization of zeolite A in the presence of TEA was faster than when the growing solution contained DEA. In addition the morphology of the final zeolite A crystals depended on the type of organic molecule, with TEA producing crystals bound only by {100} facets and DEA leading to the formation of relatively large {110} faces. These features can be explained in terms of the relative Si/Al in the growing medium and its control due to the different affinity of the organic molecules toAl. In addition, synthesis performed at 90 °C showed the appearance of {211} facets. Careful review of the HRSEM and AFM images, in addition to comparison with the MC simulations reveal that these are in fact pseudo-facets, product of the slow dissolution of the metastable zeolite A crystals. This proves that the final habit of the LTA crystals can be governed by very small changes of saturation of the growing medium and a control of this paremeter can prove advantageous when designing crystals for industrial applications.

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“…Experimental analyses confirm that the degree of relative crystallinity of the LTA zeolites depends mainly on the concentration of components in reaction mixture, operating parameters, and synthesis method [13,[24][25][26]. Initial silicon dioxide (SiO 2 ), aluminum oxide (Al 2 O 3 ), sodium oxide (Na 2 O) and water content in the reaction mixture, crystallization time, aging time, stirring speed, temperature, and heating method are the parameters which have a substantial influence on the degree of relative crystallinity of the LTA zeolites [13,[24][25][26].…”

Section: Introductionmentioning

confidence: 84%

“…Chemically controlled particulate properties of zeolites [13], kinetics of zeolite crystallization [14], effect of thermal and hydrothermal treatment [15], influence of anions on the kinetics of zeolite crystallization [16], growth mechanism [17], and heating methods [18,19] are the most popular aspects of zeolites which have extensively been investigated by different researchers. In spite of a large amount of experimental studies on zeolites, they have not been effectively investigated from * E-mail: behzad.vaferi@gmail.com the theoretical point of view, and mathematical simulations of their behavior have not been fully developed.…”

Section: Introductionmentioning

confidence: 99%

Prediction of degree of crystallinity for the LTA zeolite using artificial neural networks

Ghanbari

Vaferi

2017

Materials Science-Poland

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Zeolites are microporous aluminosilicate/silicate crystalline materials with three-dimensional tetrahedral configuration. In this study, the degree of crystallinity of the synthesized Linde Type A (LTA) zeolite, which is the main indicator of its quality/purity is tried to be modeled. Effect of crystallization time, temperature, molar ratio of the synthesis gel on the relative crystallinity of the LTA zeolites is investigated using artificial neural networks. Our experimental observations and some data collected from literature have been used for adjusting the parameters of the proposed model and evaluating its performance. It has been observed that two-layer perceptron network with eight hidden neurons is the most accurate approach for the considered task. The designed model predicts the experimental datasets with a mean square error of 3.99 × 10 −6 , absolute average relative deviation of 8.69 %, and regression coefficient of 0.9596. The proposed model can decrease the required time and number of experiments to evaluate the extent of crystallinity of the LTA zeolites.

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Chemically controlled particulate properties of zeolites: Towards the face-less particles of zeolite A. 2. Influence of aluminosilicate batch concentration and alkalinity of the reaction mixture (hydrogel) on the size and shape of zeolite A crystals

Cited by 39 publications

References 38 publications

Synthesis of Pure Na–X and Na–P Zeolite from Acid-Extracting Residues of CFB Fly Ash by a Single-Step Hydrothermal Method

Synthesis of Pure Na–X and Na–P Zeolite from Acid-Extracting Residues of CFB Fly Ash by a Single-Step Hydrothermal Method

Atomic Force Microscopy and High Resolution Scanning Electron Microscopy Investigation of Zeolite A Crystal Growth. Part 2: In Presence of Organic Additives

Prediction of degree of crystallinity for the LTA zeolite using artificial neural networks

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