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-synthesize polite 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 dosely related to the TEA content in as-synthesized Beta zeolite.