盐酸酸溶对蒙脱石结构的影响

INFLUENCE OF HYDROCHLORIC ACID-DISSOLUTION ON THE STRUCTURE OF MONTMORILLONITE

通过X射线衍射分析、Brunauer-Eammett-Teller法、透射电镜分析研究了盐酸酸溶对蒙脱石结构的影响。结果表明:随着蒙脱石酸溶程度增加,层间可交换阳离子与八面体中Al3+逐渐溶出,蒙脱石晶体逐渐被破坏,四面体片残留逐渐转变为无定型SiO2。酸溶产物比表面积先增加到144m2/g,然后减小,酸溶过程中没有大孔产生。H+置换晶层间阳离子和八面体中部分Al3+,使微孔表面积增大,酸溶程度过高则使晶体骨架崩塌,微孔大幅度减少。中孔是蒙脱石颗粒堆垛形成,蒙脱石酸溶在某种程度上强化了蒙脱石晶片的剥片作用,增加了中孔表面积。

The influences of hydrochloric acid-dissolution on the structure of montmorillonite were investigated with X-ray diffraction, Brunauer-Emmett-Teller method and transmission electron microscopy. The results indicate that as the reaction time increases, the interbedded cations and octahedral cations first are dissolved, montmorillonite crystals are destroyed, tetrahedron remains and the products becomes amorphous fiber-like silica. The specific surface area of the acid-dissolved products increases to 144 m^2/g and then decreases. Few macropores are formed in the whole process. The substitution of the interbedded cations and octahedral cations with H^＋ causes an increase in the micropore surface area; however, intensive acid dissolution can destroy the crystals, resulting in the decrease of the micropore surface area. Mesopores are formed by the piling of montmorillonite slices. Acid dissolution intensifies the rupture of montmorillonite slices and leads to an increase in the mesopore surface area.