镍铝基柱撑蒙脱石的热行为研究

Study on the Thermal Action of Ni/Al-pillared Montmorillionite

以钠基蒙脱石为原料,采取共聚法制备镍铝基柱化剂,并用湿法工艺合成镍铝基柱撑蒙脱石,采用X射线衍射、傅里叶红外光谱分析以及N2吸附-脱附等分析方法对柱撑蒙脱石的热处理（300～700℃）产物进行研究.研究结果表明：随着焙烧温度的升高,镍铝柱撑蒙脱石层间的聚合羟基阳离子发生脱水脱羟基反应,羟基阳离子释放的质子进入Si-O八面体层,与Si-O-Al键反应形成Si-OH和Al-OH键.柱撑蒙脱石随焙烧温度的升高,结晶性变差,当温度达到600℃时,（001）面衍射峰已不明显,层结构受到严重破坏,比表面积大幅减小.d（001）由1.9023 nm减小至1.3591 nm,比表面积由156.39 m2/g减小到71.02 m2/g,而平均孔径由5.126 nm增加至9.362 nm.

Na-montmorillonite was used as raw material to get Ni-Al-pillared montmorillonite.Ni-Al-pillared agent was synthesized by ion-exchange method and Ni-Al-montmorillonite was prepared with wet technology.Thermal action of the Ni-Al-montmorillonite was investigated by X-ray diffraction,infrared spectroscopy and nitrogen absorption-desorption.The results showed that,with the increasing of heat treat temperature,the dehydroxylation and dehydration reaction of pillared montmorillonite started,the protons releases from the polymerized hydroxyl cation which may either enter the octahedral sheet combining with structural hydroxyl groups to react with tetrahedral Si-O-Al bonds （the weaker bonds） to give Si-OH and Al-OH.With the increasing of heat treat temperature,the crystallinity of pillared montmorillionite decreased.When the temperature reaches 600 ℃,the diffraction of （001） was not clear and the interlayered structure of montmorillonite was destroyed,the （001） interlayer distance decreased from 1.9023 nm to 1.3591 nm,the specific surface area reduced from 156.39 m2/g to 71.02 m2/g and the average mesoporous pore size increase from 5.126 nm to 9.362 nm.