Kinetic analysis of experimental intensity curves obtained during zeolite a synthesis using in situ ²⁷Al NMR spectroscopy

Abstract

Intensity curves obtained by in situ 27Al NMR spectroscopy during zeolite A synthesis have been used as a method for comparative kinetic investigation of zeolite crystallization. Based on inflection point analysis of intensity curves, the times of t sed for process of sedimentation, t start for initiation, and t finish for completion of process in liquid phase connected to crystallization were evaluated. Obtained values for t start and t finish indicated that the rate of processes in liquid phase, connected with gel dissolution and growth of zeolite crystal, decreases with the increase of SiO2/Al2O 3 molar ratio for the same Na2O concentration. On the other hand, increase of Na2O concentration for any of specified SiO2/Al2O3 molar ratio increases the rate of the same processes. © 2009 Pleiades Publishing, Ltd.