Effect of agitation on the synthesis of zeolite beta and its synthesis mechanism in absence of alkali cations

Zeolite beta was hydrothermally synthesized in the TEAOH–SiO2–Al(0)–H2O system in the absence of alkali cations. The effects of agitation under various TEAOH/SiO2 molar ratios on the crystallization kinetics, particle size, particle size distribution, and framework SiO2/Al2O3 of synthesized zeolite beta were studied. The as-synthesis and calcinated zeolites were characterized by XRD, TEM, N2 adsorption. The effect of the agitation on the induction time, the particle size, and the framework SiO2/Al2O3 ratio of the synthesized zeolites was more pronounced at high TEAOH/SiO2 molar ratio (0.6) than at a low TEAOH/SiO2 molar ratio (0.21 and 0.4). Under agitation, the induction time, the particle size, and the framework SiO2/Al2O3 molar ratio of the zeolite greatly decreased with the increase of the TEAOH/SiO2 ratio. While under the static state, the minimum induction time and the crystal particle size existed at TEAOH/SiO2 ratio = 0.4, and the framework SiO2/Al2O3 molar ratio of the zeolite increased with the increase of TEAOH/SiO2 ratio. The crystallization proceeded via solution phase nucleation mechanism.