Huang Jian-hua, Liu Yuan-fa, Jin Qing-zhe, Wang Xing-guo
Key Laboratory of Food Science and Safety, School of Food Science and Technology, Southern Yangtze University, Wuxi 214036, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2007 Feb;27(2):408-10.
There are four different types of molecules of hydroxyl groups of the natural attapulgite. The band at 3614 cm(-1) was attributed to the stretching modes of hydroxyls coordinated with the magnesium. The band at 3415 cm(-1) is associated with the hydroxyl stretching vibrations of absorbed water. The bands at 3581 and 3552 cm(-1) were attributed to the symmetric and antisymmetric stretching modes of molecular water coordinated with the magnesium at the edges of the channels. The band at 1653 cm(-1) is associated with the hydroxyl stretching vibrations of zeolitic water. The structures of the natural palygorskite and its products dried at different temperatures for 30 min were analysed by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The absorbed, zeolitic and co-ordinated water decreased during the drying process at the same time. The absorbed water was completely-dehydrated firstly, then the zeolitic water, and lastly the co-ordinated water. And the hydroxyl groups remained until about 600 degrees C. When the co-ordinated water was dehydrated completely at 450 degrees C, the crystalloid was destroyed. The mechanism of the palygorskite structure change was also discussed in detail.
天然凹凸棒石的羟基有四种不同类型的分子。3614 cm(-1)处的谱带归因于与镁配位的羟基的伸缩振动模式。3415 cm(-1)处的谱带与吸附水的羟基伸缩振动有关。3581和3552 cm(-1)处的谱带归因于在通道边缘与镁配位的分子水的对称和反对称伸缩振动模式。1653 cm(-1)处的谱带与沸石水的羟基伸缩振动有关。通过傅里叶变换红外光谱(FTIR)和X射线衍射(XRD)分析了天然坡缕缟石及其在不同温度下干燥30分钟后的产物结构。在干燥过程中，吸附水、沸石水和配位水同时减少。吸附水首先完全脱水，然后是沸石水，最后是配位水。并且羟基一直保留到约600℃。当配位水在450℃完全脱水时，晶体结构被破坏。还详细讨论了坡缕缟石结构变化的机理。
