Peng Anna, Lu Xinqing, Ma Rui, Fu Yanghe, Wang Shuhua, Zhu Weidong
Zhejiang Engineering Laboratory for Green Syntheses and Applications of Fluorine-Containing Specialty Chemicals, Institute of Advanced Fluorine-Containing Materials, Zhejiang Normal University 321004 Jinhua People's Republic of China
Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Institute of Physical Chemistry, Zhejiang Normal University 321004 Jinhua People's Republic of China.
RSC Adv. 2020 Jul 23;10(46):27523-27530. doi: 10.1039/d0ra04293e. eCollection 2020 Jul 21.
In the last three decades, the all-silica deca-dodecasil 3R (DD3R) zeolite has been extensively studied as a significant potential class of porous materials in adsorptive separations. However, the use of most existing synthesis methods is unable to produce pure DD3R crystals with a uniform morphology and size. The present research, is therefore intended to provide a facile protocol to synthesize pure DD3R crystals with a controllable morphology and size and with a high reproducibility and productivity. Special attention was focused on investigating the effects of the type of seeds and the mineralizing reagent on the phase-purity, morphology, and crystal size of the resultant DD3R crystals. Various techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), N adsorption-desorption at 77 K, and thermogravimetric analysis (TGA) were then used to characterize the synthesized samples. The results show that by adding a small amount of "amorphous" DD3R or "amorphous" ZSM-58 seeds, the pure DD3R crystals with a uniform morphology and size can be synthesized using 1-adamantanamine (1-ADA) as a structure-directing agent (SDA), KF was used as a mineralizing reagent, and LUDOX AS-30 as a silicon source at 443 K for 1 d. In addition, the pure, large and uniform hexahedron DD3R crystals can be prepared using fumed silica as seeds, although the crystallization time takes a longer period of 3 d. The present work could stimulate fundamental research and industrial applications of the all-silica DD3R zeolite.
在过去三十年中，全硅十二硅铝3R（DD3R）沸石作为吸附分离领域中一类具有重大潜在价值的多孔材料，受到了广泛研究。然而，大多数现有合成方法无法制备出具有均匀形态和尺寸的纯DD3R晶体。因此，本研究旨在提供一种简便的方法，以合成具有可控形态和尺寸、高重现性和高产量的纯DD3R晶体。特别关注了研究晶种类型和矿化剂对所得DD3R晶体的相纯度、形态和晶体尺寸的影响。随后，采用各种技术，如X射线衍射（XRD）、扫描电子显微镜（SEM）、77 K下的N吸附-脱附以及热重分析（TGA）对合成样品进行表征。结果表明，通过添加少量“无定形”DD3R或“无定形”ZSM-58晶种，以1-金刚烷胺（1-ADA）作为结构导向剂（SDA）、KF作为矿化剂、LUDOX AS-30作为硅源，在443 K下反应1天，可以合成具有均匀形态和尺寸的纯DD3R晶体。此外，虽然结晶时间较长，需要3天，但使用气相二氧化硅作为晶种可以制备出纯的、大尺寸且均匀的六面体DD3R晶体。本工作可能会推动全硅DD3R沸石的基础研究和工业应用。
