Influence of the Concentration of Tetraethylammonium Hydroxide as Template on Structure and Thermal Decomposition of as-Synthesized Beta Zeolite

Effects of the concentration of tetraethylammonium hydroxide(TEA-OH)in gel on the structure and the thermal decomposition of as-synthesized zeolite Beta have been explored.Under synthetic conditions of this study,the optimum concentration of TEA-OH(TEA+/Al)is from 2.10 to 1.68,the relative crystallinity of synthetic β-zeolite is over 84%.The relationship between aluminium content(Al/Al+Si)or framework aluminum content(TdAl/TdAl+OhAl) in β-zeolite and TEA+/Al ratio in gel,has an optimum point.At the optimum point of TEA+/Al in gel with 1.9,Beta zeolite with a lower non-framework aluminium(OhAl) content and a higher framework Si/Al ratio can be obtained.The thermal decomposition of as-synthesized Beta zeolite is Hofmann degradation,and the weight-loss by TGA,the total endotherm by DSC are closely related to the TEA content in as-synthesized Beta zeolite.