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Kinetic Analysis of Crystal Growth of Zeolite A

Sanja Bosnar ; Ruđer Bošković Intitute, Laboratory for the Synthesis of New Materials, Division of Material Chemistry, P.O. Box 180, Zagreb, Croatia
Boris Subotić orcid id orcid.org/0000-0002-3589-7845 ; Ruđer Bošković Intitute, Laboratory for the Synthesis of New Materials, Division of Material Chemistry, P.O. Box 180, Zagreb, Croatia


Puni tekst: engleski pdf 134 Kb

str. 663-681

preuzimanja: 432

citiraj


Sažetak

Changes of the concentrations of aluminium, cAl, and of Silicon, cSi, in the liquid phase as well as of the dimension, Lm, of the largest crystals were measured during crystallization of zeolite A from the amorphous aluminosilicate precursor (1.03 Na2O ⋅ Al2O3 ⋅ 2.38 SiO2 ⋅ 1.66 H2O) dispersed in alkaline Solutions (1.2 or 1.4 M NaOH solution) containing or not containing dissolved Al2O3 and/or SiO2 of appropriate concentrations. Analysis of the relationship between the concentration factors f(c) = f(cAl,cSi) relevant to different growth models and the growth rate of zeolite A crystals have shown that the growth is governed by the reaction of monomeric and/or low-molecular aluminate, silicate and aluminosilicate anions from the liquid phase on the surfaces of growing zeolite crystals, and hence that the kinetics of the growth rate of zeolite A crystals may be expressed as: dL/dtc = kg[cAl - cAl(eq)][cSi - cSi(eq)] = kgf(c) , where tc is the time of crystallization, cAl(eq) and cSi(eq) are the aluminium and Silicon concentrations in the liquid phase, corresponding to the solubility of zeolite A under given crystallization conditions, and kg is the rate constant of the linear growth of zeolite A crystals.

Ključne riječi

zeolite A, crystallization, crystal growth, mechanism, kinetics

Hrčak ID:

127548

URI

https://hrcak.srce.hr/127548

Posjeta: 777 *