摘要
利用Keggin结构可以发生同晶取代的性质,合成了含过渡金属离子铬、镍的羟基铝交联蒙托土,并运用XRD、^(27)Al-NMR、UV-DRS、XPS、TPR等方法研究了Keggin结构的作用。结果表明,铬、镍都可以和铝生成具有Keggin骨架结构的羟基共聚体,并以此作柱子支撑着蒙托土的层间。铬的取代反应比镍容易发生。共聚法合成出的羟基镍铝交联蒙托土中镍存在两种状态;过量的金属离子对Keggin结构有较大地破坏;Keggin结构的存在增加了交联蒙托土的热稳定性。
The Cross-linked Montmorillonites containing chromiun and nickel ions, were prepared by substituting chromium and nickel for aluminum in Al_(?)^(7+) oligocation which has Keggin structure. The function of Keggin structure pillars was studed by XRD,^(27)A1-NMR, UV-DRS, XPS and TPR. The results suggest that chromium and nickel ions can raplace aluminum in Keggin structure producing mixed matal complexes which can intercalate between the layers of montmorillonites. Substituting of chromium ion for Al^(3+) occured more easily than that of nickel ion. There are two states of nickel in hydroxy-alumino-nickel montmorillonites. Excessive amounts of transition metal ions can destroy the Keggin structure. The existence of Keggin structure can improve the thermal stabilities of the pillared clays.
出处
《燃料化学学报》
EI
CAS
CSCD
北大核心
1992年第3期278-286,共9页
Journal of Fuel Chemistry and Technology
关键词
交联
蒙托石
铬
镍
分子筛
cross-linked montmorillonite
pillared clay
chromium
nickel
