Zhou Qin, Frost Ray L, He Hongping, Xi Yunfei, Liu Hongwei
Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
J Colloid Interface Sci. 2007 Mar 15;307(2):357-63. doi: 10.1016/j.jcis.2006.11.047. Epub 2006 Dec 2.
para-Nitrophenol adsorbed on hexadecyltrimethylammonium bromide modified montmorillonite has been studied using a combination of X-ray diffraction TEM and infrared spectroscopy. Upon formation of the organoclay, the properties change from hydrophilic to hydrophobic. It is proposed that para-nitrophenol is adsorbed onto the water in the cation hydration sphere of the organoclay. As the cation is replaced by the surfactant molecules the para-nitrophenol replaces the surfactant molecules in the clay interlayer. Significant changes in the water vibrations occur in this process. Bands attributed to CH stretching and bending vibrations in general decrease as the concentration of the surfactant (CEC) increases up to 1.0 CEC. After this concentration the bands increase approaching a value the same as that of the surfactant. Strong changes occur in the HCH deformation modes of the methyl groups of the surfactant. These changes are attributed to the methyl groups locking into the siloxane surface of the montmorillonite. Such a concept is supported by changes in the SiO stretching bands of the montmorillonite siloxane surface. This study demonstrates that para-nitrophenol will penetrate into the untreated clay interlayer and replace the intercalated surfactant in surfactant modified clay, resulting in the change of the arrangement of the intercalated surfactant.
采用X射线衍射、透射电子显微镜和红外光谱相结合的方法，对吸附在十六烷基三甲基溴化铵改性蒙脱石上的对硝基苯酚进行了研究。形成有机粘土后，其性质从亲水性变为疏水性。研究表明，对硝基苯酚吸附在有机粘土阳离子水合球中的水上。随着阳离子被表面活性剂分子取代，对硝基苯酚取代了粘土夹层中的表面活性剂分子。在此过程中，水的振动发生了显著变化。一般来说，随着表面活性剂（阳离子交换容量，CEC）浓度增加到1.0 CEC，归因于CH伸缩振动和弯曲振动的谱带会降低。超过该浓度后，谱带增加，接近表面活性剂的谱带值。表面活性剂甲基的HCH变形模式发生了强烈变化。这些变化归因于甲基锁定在蒙脱石的硅氧烷表面。蒙脱石硅氧烷表面的SiO伸缩谱带变化支持了这一概念。本研究表明，对硝基苯酚会渗透到未处理的粘土夹层中，并取代表面活性剂改性粘土中插层的表面活性剂，从而导致插层表面活性剂排列的变化。
