Alkali effect and kinetic studies on the crystallization of a small pored titanium silicate molecular sieve, ETS-4 using different sources of silica and titanium under stirring

Kim, Shin Dong; Noh, Si Hyun; Kim, Wha Jung

doi:10.1016/j.micromeso.2003.08.002

Cited by 12 publications

(1 citation statement)

References 17 publications

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“…In that sense, it is known that induction time may be affected by different factors; − therefore, to compensate the physical limit used to characterize the nucleation rate, the concept of transition period was introduced to clearly define and separate nucleation from crystallization stages. In our study, we used the approach adopted by Kim et al to estimate the activation energy for the transition period. ,, …”

Section: Methodsmentioning

confidence: 99%

Kinetic Study of Seed-Assisted Crystallization of ZSM-5 Zeolite in an OSDA-Free System Using a Natural Aluminosilicate as Starting Source

Corregidor

Acosta

Destéfanis

2018

Ind. Eng. Chem. Res.

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We studied the crystallization of ZSM-5 zeolite by hydrothermal treatment in the absence of organic structure directing agents (OSDA) at 170, 180, and 190 °C, using Perlite as a natural source of SiO2 and Al2O3. Experimental data were fitted by nonlinear regression following the Kolmogorov–Johnson–Mehl–Avrami’s nucleation/crystallization model in order to calculate kinetic constants (k), induction periods (t 0), and Avrami’s exponents (n). A constant value of n = 3.4 implicates the same mechanism in the studied range of temperature with a contribution from three dimensions to crystal growth and a nucleation that may include both sporadic and instantaneous mechanisms. Different stages of crystallization were clearly differentiated, and specific kinetics parameters were calculated. Compared with previously reported preparations, we found that the synthesis from Expanded Perlite is a promising alternative as it not only avoids the use of OSDA but also consumes less energy. Finally, a five steps crystallization mechanism has been proposed.

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