Critical Factors in the Seed-Assisted Synthesis of Zeolite Beta and "Green Beta" from OSDA-Free Na+-Aluminosilicate Gels
Critical Factors in the Seed-Assisted Synthesis of Zeolite Beta and "Green Beta" from OSDA-Free Na+-Aluminosilicate Gels
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DOI：
10.1002/asia.201000234
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发表时间：
2010-01-01
影响因子：
4.1
通讯作者：
Okubo, Tatsuya
中科院分区：
文献类型：
--
作者：
Kamimura, Yoshihiro;Chaikittisilp, Watcharop;Okubo, Tatsuya
无有机结构导向剂（OSDA）的β沸石合成是科学和工业界关注的主题。在此，我们报告了在没有 OSDA 的情况下各种参数对 β 型沸石种子辅助结晶影响的全面研究。 “无 OSDA β”的结晶行为很大程度上受起始 Na+-硅铝酸盐凝胶的化学组成以及使用氢氧化四乙铵 (TEAOH) 制备的煅烧 β 晶种的 Si/Al 比的影响。此外，不含OSDA的β晶种可用于形成β沸石，称为“绿色β”。 XRD、扫描电子显微镜、电感耦合等离子体原子发射光谱和Al-27魔角旋转核磁共振分析表明，不含OSDA的β和绿β具有高纯度和结晶度。与用 OSDA 合成的 β 种子相比，经过煅烧后，不含 OSDA 的 β 和绿色 β 的氮吸附-解吸显示出更高的表面积和更大的微孔区域体积。这些结果为在完全不含 OSDA 的 Na+-铝硅酸盐系统中环保地生产高质量β沸石提供了稳健可靠的工艺。
Organic structure-directing agent (OSDA)-free synthesis of zeolite beta is a subject of both scientific and industrial interest. Herein, we report a comprehensive investigation into the effects of various parameters on the seed-assisted crystallization of zeolite beta in the absence of OSDA. The crystallization behavior of "OSDA-free beta" is strongly governed by the chemical composition of the starting Na+-aluminosilicate gel as well as by the Si/Al ratios of the calcined beta seed crystals, which are prepared using tetraethylammonium hydroxide (TEAOH). Furthermore, OSDA-free beta seed crystals can be used to form zeolite beta, termed "green beta". XRD, scanning electron microscopy, inductively coupled plasma atomic emission spectroscopy, and Al-27 magic angle spinning NMR analyses showed that the OSDA-free beta and green beta were of high purity and crystallinity. The nitrogen adsorption-desorption of OSDA-free beta and green beta revealed higher surface areas and larger volumes in the micropore region than those of the beta seeds synthesized with OSDA after calcination. These results provide a robust and reliable process for the environmentally friendly production of high-quality zeolite beta in a completely OSDA-free Na+-aluminosilicate system.