傅里叶红外光谱在微波水热合成镁皂石中的应用研究

微波水热法在不同压力(1×105, 5×105, 1.5×106, 2.5×106, 3.5×106 Pa)条件下合成得到的皂石矿物进行了傅里叶红外光谱研究。结果显示，低频振动(归属于Si—O—Mg)强度和峰形对于合成条件变化非常敏感。特别是归属于Si—O—Mg弯曲振动模式的吸收强度随着合成压力的增加有了明显的增强。随微波水热合成压力的提高，Si(Al)—O伸缩振动频率红移清晰地反映了层状材料片层结构大小，揭示了硅氧四面体层铝取代量的多少，可以作为分析合成皂石样品结晶度的一个简单而有效的指示性参数。此外，对微波水热法合成皂石还进行了SEM和XRD表征。

Application of FTIR Technique in Microwave-Hydrothermal Synthesis of Saponite

FTIR was employed in the structure analysis of the saponites with an ideal chermical formula Si6.5Al1.5]IV Mg6]VI O20(OH)4 the starting gel synthesized by microwave-hydrothermally under different pressures (1 x 10(5), 5 x 10(5), 1.5 x 10(6), 2.5 x 10(6) and .5 x 10(6) Pa). It was found that low frequency absorption region in infrared spectrum was sensitive to the crystallization of the product and the amorphous materials produced in synthesis of saponite under the radiation of microwave. The absorptions belong to amorphous materials were decreased with increasing pressure. Saponite synthesized at 3.5 x 10(6) Pa showed no amorphous absorptions (1240, 90-602 cm(-1)), indicating the purity and quality of the synthetic mineral. It was worthy to note that Si(AI)-O stretching vibration infrared absorption could be regarded as an index in assessing the quality of synthetic 2:1 trioctahedral smectite sample with the same chemical compositions. With the increasing pressure, this strong vibration shifted to low frequency (1022, 1020, 1016, 1016, 1005 cm(-1)) in the medium frequency of the whole infrared spectrum. Since the sensitivity, easiness and simplicity, this infrared index d be meaningful in practical saponite-related minerals analysis. In addition, powder X-ray diffraction and scanning electronic croscopy were employed in charactering the saponite synthesized by microwave-hydrothermal method in this work.