Synthesis kinetics and particle size distribution of zeolite A

AFM and HRSEM Invesitigation of Zeolite A Crystal Growth. Part 1: In the Absence of Organic Additives

“…Through the use of HRSEM, it is possible to follow in detail the evolution of zeolite A growth much earlier than has been possible with conventional SEM. ,− This is exemplified in Figure which shows HRSEM micrographs of crystals removed from solution at 2.5, 4, 8, and 20 h for the 60 °C synthesis. Figure a shows that, initially (2.5 h), zeolite A crystals have a rounded shape.…”

“…Previous studies on the growth of zeolites have shown that crystal growth and nucleation rates always follow similar trends as a function of time. 41,42 Figure 4b shows the evolution of these parameters for the 60 °C synthesis (with the nucleation rate curve obtained using the Zhdanov method 41 ) along with the evolution of supersaturation in the system. Although a precise definition of supersaturation for zeolite synthesis is still lacking, 13,39 it can be safely hypothesized that it increases at the beginning of the synthesis and reaches a maximum over the constant growth rate stage, after which it decreases until it reaches equilibrium.…”

Coating and Intergrowth of NaX Molecular Sieve Films on Porous Ceramic Paper for Membranes

“…However, there are two major technical problems when zeolite powder is used to produce a molecular sieve films on the ceramics. One of the problems results from the adhension strength of coated zeolite; it is very difficult to make coating films on the ceramic supports unless significant amounts of organic and inorganic binders are used [4,5]. The other problem is that the coated zeolite layer must be calcined at temperature (300∼450℃) to maintain the microporous structure of the zeolites.…”