| As a high-silica zeolite with a three-dimensional structure, beta zeolite has a special catalytic reactivity, and it has a great potential in petrochemical industry. However, a large amount of organic template was used during the synthesis of beta zeolite, and the increased cost limited its industrial applications. In this paper, beta zeolite was synthesized by hydrothermal method, using tetraethylammonium hydroxide as the template. When the amount of seed was0%or10%, we systematically investigated the effect of different TEA+/SiO2molar ratio, and the synthesis of Beta zeolite through seed-transferring was performed. All samples obtained were characterized by XRD, SEM techniques. The results are as follows:1. According to experimental results, synthesizing beta zeolite without seed, more crystallization time was needed as the amount of template reduced. Beta zeolite could be synthesized while the TEA+/SiO2molar ratio was0.2or0.3. In low TEA+/SiO2system, more crystallization time was needed while NaOH was added, and more mordenite was formed. Beta zeolite could be enlarged synthesized while the TEA+/SiO2molar ratio was0.3, and the SiO2/Al2O3molar ratios of the products increased.2. Seed could significantly accelerate the synthesis of beta zeolite, and the amount of template required was also reduced. However, as the amount of TEA OH reduced, more crystallization time was needed, the relative crystallinity of beta zeolite was reduced, because of some mordenite or ZSM-5formed. In seed system, beta zeolite could be enlarged synthesized while the TEA+/SiO2molar ratio was0.2.3. During the process of seed-transferring, whether the calcination of seed or not has little influence on the synthesis of Beta zeolite. But as the seed-transferring, the crystallization time was gradually extended and the particle size was enlarged, whereas the relative crystallinity of beta zeolite was not obviously affected. Seed-transferring could be stable if TEA+/SiO2molar ratio was increased to0.3. |
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