Abstract

Here, the ZSM-5 zeolite was prepared under organic template-free conditions at different reaction temperatures and initial gel compositions using a hydrothermal process. A kinetic study of the synthesis of Zeolite was performed based on crystal growth. The crystallinity degree of the prepared samples was calculated from the PXRD and FT-IR results and then the crystallization curves were obtained. From these curves, the kinetic parameters were computed. The obtained results showed that by increasing the Na⁺ content of the initial gel composition, the activation energy for the crystal growth was reduced and as a result, the crystallization rate of ZSM-5 zeolite was enhanced due to the structure-directing role of Na⁺ cation. The activation energy of the induction step, transition step and crystal growth step are 122.8, 46.2, and 48.5 kJ/mol respectively for the molar ratios of 29Na₂O:63SiO₂:Al₂O₃:2400H₂O:16H₂SO₄ and 141.0, 70.4, and 80.8 kJ/mol respectively for the molar ratios of 16Na₂O:31SiO₂:Al₂O₃:2400H₂O:16H₂SO₄.

摘要

在这里，ZSM-5 沸石是在无有机模板条件下、不同反应温度和初始凝胶组成下使用水热法制备的。基于晶体生长对沸石的合成进行了动力学研究。根据 PXRD 和 FT-IR 结果计算所制备样品的结晶度，然后获得结晶曲线。根据这些曲线，计算了动力学参数。所得结果表明，通过增加初始凝胶组合物中的 Na ⁺含量，晶体生长的活化能降低，因此，由于 Na 的结构导向作用，ZSM-5 沸石的结晶速率提高⁺阳离子。_{对于29Na 2} O:63SiO ₂ :Al ₂ O ₃ :2400H ₂ O:16H ₂ SO ₄的摩尔比，诱导步骤、转变步骤和晶体生长步骤的活化能分别为122.8、46.2和48.5 kJ/mol 16Na ₂ O:31SiO ₂ :Al ₂ O ₃ :2400H ₂ O:16H ₂ SO ₄的摩尔比分别为141.0、70.4和80.8 kJ/mol 。