- 期刊
Synthesis and Characterization of Nano-Sized Zeolites
奈米級沸石之合成與鑑定
摘要
ZSM-5與高矽沸石(silicalite-1)主要是利用四丙基胺鹽TPA(tetrapropylammonium)當作模板與四乙基矽酸鹽(TEOS)用水熱法在80℃、120℃、170℃ 合成。ZSM-5與silicalite-1的區別在於ZSM-5含有少量的鋁，而silicalite-1則只有矽。本研究探討許多製備的條件，包括合成溫度、模板的種類、合成時間與矽/鋁比對樣品性質的影響。在鑑定樣品的物理性質上，以X光繞射分析鑑定結晶度：由氮吸附、脫附分析測定表面積、孔洞直徑與孔洞分布：藉掃描式電子顯微鏡(SEM)與穿通式電子顯微鏡(TEM)觀察顆粒直徑及其分布。隨著合成溫度的提高，ZSM-5的結晶度增加且粒徑變小，以在170-200℃之間的合成溫度可得到最小粒徑及高結晶度，而利用TPA(tetrapropylammonium hydroxide)當作模板的效果遠比利用TMA(tetramethylammonium hydroxide)當作模板的效果為佳。在合成時間的探討上，24小時即可得到高結晶度，表面積大的silicalite-1。隨著鋁含量的增加，顆粒直徑會隨之變大且結晶度會變差。本研究已成功合成ZSM-5及silicalite-1的奈米沸石，其直徑大約是150 nm，這些沸石具高結晶度。
關鍵字
無資料並列摘要
Synthesis of zeolite ZSM-5 and silicalite-1 by hydrothermal crystallization of clear supersaturated homogeneous synthesis mixture has been achieved. The influence of the templates, synthesis temperature, synthesis time and SiO2/Al2O3 ration on the properties of the nano-sized zeolite has been investigated. The properties of the samples were characterized by X-ray powder diffraction, N2 adsorption/desorption, scanning electron microscopy, and transmission electron microscopy. The results show that the temperature at 170℃ was favorable to synthesize the nano-size zeolites. The use of tetrapropylammonium hydroxide as the template in the hydrothermal synthesis conditions employed was favorable to form nanozeolite than tetramethylammonium hydroxide. The synthesis time also plan an important role. 1 day was required to obtain a fully crystallized product. The longer crystallization time would produce bigger particles. A decrease in Al2O3 content would decrease the crystallite size. The nanosize ZSM-5 and silicalite with crystallite size of 150 nm have been successfully synthesized.