Low Viscosity Precursor No Aluminum Beta Molecular Sieve Synthesis And Application

β zeolite is constructed with a three-dimensional interconnected channel system, and as one of the large pore zeolite, its pore size of12membered rings is0.67nn. Aluminum free β zeolites show potential apllications in the fields of organic/water membrane separation, catalysis and microelectron due to its high physical and chemical stability, and excellent hydrophobic property.However, the synthestic condition of aluminum free (3zeolite is harsh, especially the precursor has high viscosity, which results in large mass transfer resistance during the crystallization process. That is harmful to prepare aluminum free β zeolite membrane due to the low growth rate of inter-zeolite particles. Moreover, the crystallization time is long and about10days as a result of the low crystallization rate in the fluoride media. Therefore, it is important to explore the synthesis of aluminum free β zeolite in low viscosity system with high crystallization rate for understanding the relatioinship between the crystallization process and the synthesis parameters.In this thesis, synthesis of aluminum free β zeolite using low viscosity precursor and in shorter crystallization time is expected. The influences of the synthesis parameters such as the ratio of H2O/SiO2, the crystallization promoter (perchloric acid ion and phosphoric acid), nucleation promoter (GeO2) and the heating way on the crystallization of aluminum free β zeolite were investigated. The results showed that the precursor with low viscosity could be obtained with the molar composition of SiO20.3GeO2:0.68TEAOH:0.57NH4F:0.09HClO4:30H2O by adding seeds, under which aluminum free β zeolite with high crystallinity and particle size of3μm was prepared at150℃for4days. Meanwhile, similar low viscosity precursors were obtained with the molar composition of SiO2:0.3GeO2:2.0TEAOH:0.57NH4F:0.48H3PO4:20-30H2O without seeds, under which high crystallinity aluminum free β zeolite with global morphology and particle size of17μm was synthesized at150℃for4days.The probability of aluminum free β zeolite membrane preparation on the porous α-Al2O3tube was explored. The influence of synthetic parameters such as membrane preparation method, crystallization condition and the precursor composition was investigated. The obtained results are helpful for further preparing defect-free aluminum free β zeolite membrane.