Zeolite A Synthesis under Dynamic Conditions, after Hydrogel AgeingReport as inadecuate

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Croatica Chemica Acta, Vol.85 No.3 October 2012. -

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 × 2 SiO2 × 1.05 Al2O3 × 250 H2O were heated in stainless steel reactor at 80 °C under dynamic conditions, after ageing for tA = 0–209 h at 25 °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. doi: 10.5562-cca2055

zeolite A; autocatalytic nucleation; crystal size distribution; hydrogel ageing

Author: Ana Palčić - ; Ruđer Bošković Institute, Bijenička 54, 10 000 Zagreb, Croatia Lavoslav Sekovanić - ; Geotechnical Faculty,

Source: http://hrcak.srce.hr/


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