碳氟链与碳氢链表面活性剂在固液界面上的吸附

全氟辛酸及其钠盐和十二烷基硫酸钠在R972上的吸附等温线均为S型或LS型，指示固液界面吸附过程中有表面疏水缔合物生成．碳氟表面活性剂的饱和吸附量显著高于碳氢表面活性剂的饱和吸附量．加电解质于液相使各体系吸附量上升．对于碳氟表面活性剂，甚至引起吸附等温线类型变化．例如，不加电解质时全氟辛酸在R972上的吸附等温线为S型，而加入HCl（c＝0．05mol·dm－3）使吸附等混线变成LS型．全氟辛酸比全氟辛酸钠在R972上的吸附更强．几种表面活性剂在R972上的吸附均随温度升高而减少。应用两阶段吸附模型及通用吸附等温线公式可以很好地解释所得实验结果．

The Adsorptions of FC-Surfactant and HC-Surfactant at Solid/Liquid Interface

The adsorptions of perfluorooctanoic acid, sodium pemuorooctanoate and sodium dodecylsulfate by hydrophobic silica gel have been investigated. The effects of temperature and ionic strength have also been investigated. Adsorption isotherms of Stype or LS-type have been obtained for all of the systems involved. The driting adsorption of the two FC-surfactants are more than that for the HC-surfactant investigated. Among the FC-surfactants the acid shows stronger adsorbability than the sodium salt. The additions of electrolytes not only made the adsorptions larger, but sometfors even changed in type of the adsorption isotherm. Besides, the adsorptions always go down as temperature goes up. All of these erperimental results can be explained well by the application of the two steps adsoption model and the general isotherm equation for adsorption of surfactant at solid-liquld interface.