Hydrothermal conversion of zeolite omega from magadiite with assistance of seed crystals

Abstract

In this work, we report a rapid and sustainable synthetic strategy of zeolite omega with the addition of omega seeds via the transformation of magadiite with an initial chemical recipe of 0.76 NaOH: SiO2: 0.01 Al2O3: 7–14H2O, and the crystallization time was shortened to 5 h at 80 °C. The effect of experiment parameters has been discussed in details. In addition, the conversion behavior and the changes of secondary building units were characterized and studied by X-ray diffraction (XRD), scanning electron microscopy, Fourier Transform infrared (FT-IR), and Raman spectroscopy and 27Al magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy. During the conversion process, omega seeds would be partially destroyed and residual seeds supplied substrate for the growth of zeolite omega, most parts of five-membered rings and six-membered rings in magadiite were remained as building units to promote the formation of zeolite omega, and Al species preferred to enter T2 position which was located in six-membered rings. The toluene adsorption property of final product was also measured.