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Zeolite A Synthesis under Dynamic Conditions, after Hydrogel Ageing

Palčić, Ana; Sekovanić, Lavoslav; Subotić, Boris; Bronić, Josip (2012) Zeolite A Synthesis under Dynamic Conditions, after Hydrogel Ageing. Croatica Chemica Acta, 85 (3). pp. 297-301. ISSN 0011-1643

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Abstract

Zeolites are crystalline, microporous, alumo-silicate materials (around 400 types) which are used in many applications. Each field of usage (catalysis, ion exchange, sorption, molecular sieving, etc.) has demands regarding crystals' structural and particulate properties. Detailed understanding of the mechanisms of crystals' formation and growth enables the control of these properties. Hydrogels of the starting composition 3.2 Na2O x 2 SiO2 x 1.05 Al2O3 x 250 H2O were heated in stainless steel reactor at 80 degrees C under dynamic conditions, after ageing for t(A) = 0-209 h at 25 degrees C. Solid phase samples were characterized using microscopy (OM, SEM), PXRD and laser light scattering (LLS). Specific number of zeolite A crystals was calculated from particle size distributions. It was shown that the some particulate properties: specific number of crystals and crystal size distribution, are changing towards higher number of crystals and wider size distribution while the morphology of the crystals remains the same. Also, the crystal growth rate is higher in the systems which are treated under dynamic conditions. Obtained results were compared with data of systems crystallized under static conditions and commented on the grounds of the autocatalytic nucleation theory.

Item Type: Article
Uncontrolled Keywords: zeolite A; autocatalytic nucleation; crystal size distribution; hydrogel ageing; silicalite-1; NNA
Subjects: NATURAL SCIENCES > Chemistry
Divisions: Division of Materials Chemistry
Projects:
Project titleProject leaderProject codeProject type
Studij utjecaja svojstava alumosilikatnih prekursora na njihove transformacije[117985] Josip Bronić098-0982904-2953MZOS
Depositing User: Josip Bronić
Date Deposited: 11 Oct 2013 12:16
Last Modified: 07 Feb 2014 10:05
URI: http://fulir.irb.hr/id/eprint/776
DOI: 10.5562/cca2055

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