Effect of Sodium Concentration on the Synthesis of Faujasite by Two-step Synthesis Procedure

International audience; The relationship between concentration of sodium cations and the properties of faujasite (FAU) zeolite using a two-step synthesis procedure including (1) formation of amorphous aluminosilicate precursors and separation of amorphous nanoparticles, and (2) transformation of these amorphous particles into zeolite crystals by treatment with alkali solutions (NaOH) were studied. Three representative samples including two nano-sized zeolites and one micron-sized zeolite were prepared using different concentration of sodium hydroxide. The crystallization process of these zeolites was studied in details by FTIR, NMR, XRD, SEM, TEM, N 2 adsorption. The results indicated that minor changes in the concertation of inorganic cations can significantly shorten the induction period and crystallization time and thus affect the morphology, size and chemical composition of the zeolite crystals.