Yuan P, Wu D Q, Lin Z Y, Diao G Y, Peng J L, Wei J F
Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2001 Dec;21(6):783-6.
Using DRIFT spectroscopy, we detected surface hydroxyl structure of diatomite in this study. There were either isolated hydroxyl groups or H-bonded hydroxyl groups on the surface of the diatomite. At room temperature, the diatomite surface was predominantly covered by weakly adsorbed water in cavity and water bonded to surface hydroxyl groups via H-bonds. There appeared a broad band with middle wavenumber at 3,400-3,500 cm-1 as a result in the corresponding DRIFT spectra. With driving off adsorbed water by heating the sample from 200 degrees C to 1000 degrees C, the broad band fade away gradually, and a single band at about 3,745 cm-1, which is attributed to both isolated hydroxyl groups and partial H-bonded hydroxyl groups, became more and more intense with increasing temperature. Under the heat treatment conditions of 1,100 degrees C for one hour, the isolated hydroxyl groups were mostly desorbed from the surface, and the H-bonded hydroxyl groups that existed above the inner wall of micropores with diameter of circa 10 nm, however, had not yet condensed thoroughly. The thermal behavior was supposed to be a speciality of diatomite.
在本研究中，我们使用漫反射红外傅里叶变换光谱（DRIFT）检测了硅藻土的表面羟基结构。硅藻土表面存在孤立羟基或氢键合羟基。在室温下，硅藻土表面主要被孔隙中弱吸附的水以及通过氢键与表面羟基结合的水所覆盖。相应的DRIFT光谱中出现了一个位于3400 - 3500 cm⁻¹的中波数宽带。通过将样品从200℃加热到1000℃以驱走吸附水，该宽带逐渐消失，而一个位于约3745 cm⁻¹的单峰带（归因于孤立羟基和部分氢键合羟基）随着温度升高变得越来越强。在1100℃热处理1小时的条件下，孤立羟基大多从表面解吸，然而，存在于直径约10 nm微孔内壁上方的氢键合羟基尚未完全缩合。这种热行为被认为是硅藻土的一个特性。
