交联蒙托石的表面酸性和热稳定性

Surface Acidity and Thermal Stability of Cross Linked Montmorillonite

采用不同的方法和条件 ,把聚合羟基铝镍离子引入蒙托石层间 .利用 X射线衍射图、红外光谱图及非水溶液滴定法 ,研究制备方法及条件变化对蒙托石表面酸性及热稳定性的影响 .结果表明 ,不同的方法交联蒙托石 ,其表面酸性及热稳定性均发生较大的变化 .原因主要在于交联剂的形成方法及条件不同 ,导致生成不同结构的羟基铝镍聚合体 .同时 ,Al/ Ni,(Al+Ni) /土和老化温度等条件的变化对表面酸性 ,及热稳定性也有较大影响 .表面酸性主要与层间有效镍离子的含量相关 ,而结构羟基与蒙托石板层结合的牢固程度 ,决定交联蒙托石的热稳定性 .交联蒙托石在4 0 0℃以下 ,热稳定性较好 .

Hydroxy AlNi oligocations belong to inorganic macromolecular oligomers.The authors lead them onto interlaminar spaces of montmorillonite by adopting different methods and conditions;and study the effects of the change of preparing method and condition upon surface acidity and thermal stability of montmorillonite by using X ray diffractogram and infra red spectrogram and nonaqueous titration.The results show that the surface acidity and the thermal stability of montmorillonite change greatly after it is cross linked by different methods.The authors′ view on the main cause is presented as follows:The difference in method and condition for forming cross linking agent leads to the generation of different structural hydroxy Al/Ni oligocations;and moreover,the changes in such conditions as Al/Ni,(Al+Ni)/clay,and ageing temperature exert also fairly great influence upon surface acidity and thermal stability.Acids on the surface are correlated chiefly with the amount of interlamellar effective nickel cations,while thermal stability of cross linked montmorillonite depends upon the firmness of the binding between hydroxyl groups and basal layer of montmorillonite.Generally,the cross linked montorillonite shows a fairly good thermal stability up to 400℃