Faculty of Sciences, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane Qld 4001, Australia.
J Colloid Interface Sci. 2010 May 1;345(1):34-40. doi: 10.1016/j.jcis.2010.01.043. Epub 2010 Jan 25.
The aggregate structure which occurs in aqueous smectitic suspensions is responsible for poor water clarification, difficulties in sludge dewatering and the unusual rheological behaviour of smectite rich soils. These macroscopic properties are dictated by the 3D structural arrangement of smectite finest fraction within flocculated aggregates. Here, we report results from a relatively new technique, transmission X-ray microscopy (TXM), which makes it possible to investigate the internal structure and 3D tomographic reconstruction of the smectite clay aggregates modified by Al(13) Keggin macro-molecule Al(13)(O)(4)(OH)(24)(H(2)O)(12). Three different treatment methods were shown resulted in three different micro-structural environments of the resulting flocculation. In case of smectite sample prepared in Methods 1 and 3 particles fall into the primary minimum where Van der Waals forces act between FF oriented smectite flakes and aggregates become approach irreversible flocculation. In case of sample prepared using Method 2, particles contacting by edges (EE) and edge to face (EF) orientation fell into secondary minimum and weak flocculation resulted in severe gelation and formation of the micelle-like texture in fringe superstructure, which was first time observed in smectite based gel.
水基蒙脱石悬浮液中出现的聚集结构导致水澄清不良、污泥脱水困难以及富含蒙脱石土壤的异常流变行为。这些宏观性质是由絮凝聚集体中蒙脱石最细部分的 3D 结构排列决定的。在这里，我们报告了一种相对较新的技术——透射 X 射线显微镜 (TXM) 的结果，该技术可用于研究经 Al(13)Keggin 大分子Al(13)(O)(4)(OH)(24)(H(2)O)(12)修饰的蒙脱石粘土聚集体的内部结构和 3D 断层扫描重建。三种不同的处理方法导致了絮凝聚集体的三种不同的微结构环境。在方法 1 和 3 制备的蒙脱石样品中，颗粒落入初级最小位，范德华力作用于定向的蒙脱石薄片之间，并且聚集体变得不可逆絮凝。在使用方法 2 制备的样品中，通过边缘 (EE) 和边缘到面 (EF) 接触的颗粒落入次级最小位，弱絮凝导致严重的凝胶化，并在边缘超结构中形成胶束样纹理，这是首次在基于蒙脱石的凝胶中观察到的。
