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对用不同酸度处理的仇山钙基膨润土进行了化学分析、X射线衍射(XRD)、27Al和29Si魔角旋转核磁共振(MASNMR)、吡啶吸附样品的红外光谱(IR)、比表面积、阳离子交换容量(CEC)和脱色率等测定。结果表明,随着处理酸度的增加和蒙脱石中阳离子的溶出,它的d(00l)的衍射强度降低,同时其Si和Al原子局域结构环境发生了显著的改变,Al原子由AlⅥ变成AlⅣ,Si原子由Q3Si(0Al)结构向Q4Si(0Al)和Q3Si(1OH)结构转变。八面体片阳离子的溶出和Si、Al原子局域结构环境的改变,显著地增加了比表面积和孔结构;AlⅥ向AlⅣ的转变形成了Lewis酸中心,而Si原子局域结构环境的改变形成了Brnsted酸中心。膨润土脱色率随处理酸度增加的本质原因是在Si和Al原子局域环境的变化过程中,在其表面分别形成了Brnsted酸中心和Lewis酸中心。
The chemical analysis of Qiu Shan Ca-based bentonites treated with different acidity were carried out. X-ray diffraction (XRD), 27Al and 29Si magic angle rotation nuclear magnetic resonance (MASNMR), IR spectra of pyridine adsorption samples, specific surface area, cation exchange Volume (CEC) and decolorization rate determination. The results show that the diffraction intensity of d (00l) decreases with the increase of acidity and the dissolution of cations in montmorillonite. At the same time, the local structure of Si and Al atoms changes significantly. The Al atom changes from Al Ⅵ Into Al Ⅳ, Si atoms from Q3Si (0Al) structure to Q4Si (0Al) and Q3Si (1OH) structure transition. The dissolution of the octahedral sheet cation and the change of the local structure of Si and Al atoms significantly increased the specific surface area and pore structure. The transformation from AlVI to AlⅣ formed the Lewis acid center, and the change of the local structure of Si atom formed Brnsted Acid Center. The essential reason for decoloration rate of bentonite with increasing acidity is that Brnsted acid sites and Lewis acid sites are formed on the surface of Si and Al atoms in the local environment.