多光谱表征酸碱电位滴定对天然伊利石表面结构与性质的影响

Spectroscopic investigation of altertions of illite surface properties by acid-base titration

应用多光谱技术研究酸碱电位滴定对不同地域天然伊利石表面性质的影响 .特征衍射线的强度变化与XRD标准模式的匹配结果表明 ,酸碱滴定过程的产物为表面硅铝络合物 ,在显微喇曼光谱中 ,酸量滴定导致Si—O键和Al—O键的谱峰强度显著削弱 ,而在碱量反滴定之后又有所恢复 .在2 7Al核磁共振光谱中 ,四配位铝与六配位铝共振信号的强度比率在酸量滴定前后发生明显变化 ,而样品比表面积的变化却不大 ,这些现象说明伊利石层状晶体结构中相对稳定的基础层面同活性较高的边缘侧面一样对表面反应活性产生影响 .固体基质酸解释放的硅酸。

Spectroscopic approaches were applied to study the changes in surface properties of different natural illites, caused by acid base potentiometric titration. Based on matching results with the standard XRD patterns, the changes in intensities of the diagnostic reflections indicated that the formation of surface Al—Si complexes. Similar features were also shown in the microscopic Raman spectra, where the vibrational peaks of Si—O and Al—O bonds diminished following acid attack, then rose again after hydroxide back titration. The varied ratio of signal intensity between IV Al and VI Al species in the 27 Al NMR spectra, together with the nearly stable BET surface areas after acidic titration, inferred that the basal planes in the layer texture of natural illite contributed to the release of structural components as well as the edge faces. The combined spectroscopic evidence suggested the interactions of illite surface sites with silicic acid and hydrolyzed aluminum, generating from dissolution of illite substrate.