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Activation energy of the crystal growth of zeolite A nanocrystals

Pure nanosized crystals of zeolite NaA (zeolite 4a) were hydrothermaly synthesized from clear alumosilicate solutions having oxide composition: 10 Na2O 0.3 Al2O3 SiO2 120 H20. Hydrothermal synthesis of were preformed at 40, 50 and 60oC under static conditions using HDPE reactors heated in air convection oven. Solid phase separated from the reaction mixture at different stages of crystallization were characterized by powder X – ray diffraction (phase analysis), scanning electron microscopy, optical microscopy and dynamic light scattering (morphology, size and size distribution). Concentrations of silicon and aluminum in the liquid phase were measured by atomic absorption spectroscopy. Activation energy of the crystal growth was calculated using Arrhenius equation applying the constants of crystal growth at elevated temperatures measured and calculated by Samulevic – Zhdanov method.

Zeolite A; Nanocrystals; Crystal growth; Activation energy

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