Microwave preparation of Li-zeolite directly from alumatrane and silatrane

Li-zeolites were successfully synthesized in a one-step sol–gel process and microwave technique using silatrane and alumatrane as precursors and lithium hydroxide as the hydrolytic agent. Many types of Li-zeolites were obtained by controlling synthesis parameters. Perfect crystalline zeolite, EDI type zeolite, was obtained at 90 °C after heating for 60 min while ABW type zeolite was produced after heating for 300 min at 110 °C. With increasing temperature, a higher packing density product was generated. Changing Si/Al loading ratio highly influenced the morphology of the synthesized product. With increasing Al loading, more irregular morphology products were obtained. Changing Li2O/SiO2 ratio, led to changes in the unit cell structure and crystal morphology. Lowering the Li2O/SiO2 ratio to one produced FAU type zeolite at 110 °C for 240 min. The thermal stability of EDI and ABW were very low while that of FAU was higher which might come from the effect of low ring strain construction of FAU.