部份层无序锆交联蒙脱土结构的研究

Structural Studies on Partially Disordered Layer Lattice of Zirconium Pillared Montmorillonite

通过锆交联蒙脱土的X射线衍射、阳离子交换量及孔径分布等实验测定,利用部分无序层状结构的衍射公式,建立了相应的三维统计结构模型.交联剂中Zr(Ⅳ)主要以四聚及三聚的方式存在,在与Na-Mt交联过程中,四聚及三聚Zr(Ⅳ)离子先吸附一定量的水,与水共同支撑开蒙脱土层,使层间距分别达到2.55nm和2.10nm,如此层间距的层在整体结构中分别占35％和27％.水分子进入了其余层间域,层间距为1.26nm.

The structure of pillared montmorillonite is the partially disordered layer lattice. Its basal spacings can be expanded to many possible values with different probabilities depending on the type and structure of the pillars. If a formula describing the X-ray diffraction intensity of partially disordered layer lattice as a function of basal spacings and the corresponding probabilities is computationally simulated with the experimental XRD pattern, the basal spacings and probabilities can thus be obtained. In this paper, zirconium pillared montmorillonite samples were prepared. The simulated results show that the basal spacings are expanded to 2. 55 nm, 2. 10 nm and 1. 26 nm with probabilities of 35% , 2.7% and 38% corresponding to [Zr4(OH)8(H2O)16]8+ , [Zr3(OH)4(H2O)5]8+ ions together with some adsorbed water molecules and H2O as the main pillaring species in the interlamellar regions, respectively. The experimental results obtained from CBC, ICP etc. are applied to calculating the distribution of the pillars in the interlayer zone. The fashion of the connection between pillars and unite layers is also given. Subsequently, a three-dimensional statistical structural model is built up. The agreement of the pore-volume between the theoretical calculation and experimental result verifies the rationality of the structural model. Therefore, the basal spacing characterized by d001 which is calculated from Bragg e-quation is not exact actually.