铝柱撑蒙脱石的热稳定性和微结构变化规律研究

Thermal stability and microstructure variation laws of Al-pillared montmorillonite

采用XRD,FTIR,比表面积及孔径分析等方法,对不同投料比和煅烧温度下制备的铝柱撑蒙脱石的热稳定性和微结构变化规律进行了系统研究.结果表明,随着投料比的增加,铝柱撑蒙脱石层间距呈先增后减的趋势,当投料比为10mmol/g,煅烧温度为500℃时,其层间距d(001)值达到1.802nm;煅烧温度<700℃时,铝柱撑蒙脱石能够保持稳定的层柱结构;随着煅烧温度由300℃升高至800℃,其层间距d(001)值、BET比表面积、BJH脱附总孔容积和总孔比表面积、微孔容积和微孔比表面积均有不同程度的降低;铝柱撑蒙脱石的BJH脱附孔体积分布呈最可几分布,最可几孔半径为2nm左右,属中孔范畴.

The thermal stability and microstructural variations of the Al-pillared montmorillonite prepared under different ratios of pillared agent（[Al13O4（OH）24（H2O）12]7＋） to montmorillonite and different calcination temperatures were studied using XRD,FTIR,specific surface area measurement and pore size analysis.The results show that the interlayer spacing of Al-pillared montmorillonite increased at first and then decreased with the increasing of the ratio of pillared agent to montmorillonite,and reached to its peak value of 1.802 nm at the ratio of 10 mmol/g.Under the calcination temperature of 700 ℃,the Al-pillared montmorillonite shows a stable pillared structure.The microstructural parameters such as the interlayer spacing d（001）,the BET specific surface area,BJH total pore specific surface area and pore volume,micropore volume and micropore specific surface area of the Al-pillared montmorillonite decreased with the increasing of calcination temperature from 300 ℃ to 800 ℃.The BJH pore size distribution of the Al-pillared montmorillonite exhibits the characteristics of the most probable distribution,and the most probable pore size is about 2 nm,which belongs to the mesopore scale.