锌皂石的非水热合成与插层组装性能研究

以尿素为羟基缓释剂和pH值控制剂, 在常压和低于100 ℃的温和实验条件下, 用非水热法合成出了八面体片阳离子为Zn^2＋的皂石, 研究了原料的硅铝配比(n_Si/n_Al), 溶液pH值、晶化温度和晶化时间对锌皂石合成的影响, 利用XRD, TEM, IR等手段对样品进行了表征. 结果表明: 合成样品具有三八面体皂石结构; 在比较宽的投料范围内 (n_Si/n_Al＝5.67～19), 合成皂石的晶相和晶形无明显变化; 在初始pH＝6的体系中, 90 ℃晶化12.5 h即可获得结构完整、晶相单一的锌皂石; 非水热条件下, 锌皂石在a向和b向上择优生长, c向生长速度相对较慢; 另外, 利用层间域离子的可交换性和层板带电荷的相反性, 将带正电荷的类水滑石客体层板引入到带负电荷的皂石层间, 形成了c向上单个皂石主体层板与单个类水滑石客体层板交叉堆垛的结构方式.

Study on Non-hydrothermal Synthesis and Intercalation Assembly of Zn-saponite

Saponite with the incorporation of Zn^2＋ in the octahedral sheets were synthesized under non-hydrothermal condition of below 100 ℃ and at normal pressure by using urea for hydroxyl slow-releasing and pH controlling. The effects of n_Si/n_Al ratios, pH, crystallization time and temperature on the synthesis of Zn-saponite were studied. The synthesized samples were characterized by XRD, TEM and IR techniques. The reflection peaks of XRD pattern confirmed the trioctahedral layer structure of the product. The synthesized saponite with different n_Si/n_Al ratios (from 5.67 to 19) exhibited similar product phase and crystallinity. By adjusting initial mixture pH to 6, the unique saponite with high crystallinity could be synthesized at 90 ℃ for 12.5 h. The saponite grew preferentially on a- and b-axis plane direction. Based on the capability of ion exchange and the difference in sheet-charge, NiAl-HTLcs/saponite layer composites was synthesized through the intercalation of the HTLcs sheet to the interlayer of the two adjacent saponite sheets.