The Adsorption of Sulphonate on Fluorite Single Crystals as Examined by in-situ FT-IR Internal Reflectance Spectroscopy

Abstract

The adsorption densities of dioctyl sodium sulphosuccinate (AOT) at the surface of a fluorite single crystal were calculated from in situ FT-IR internal reflection spectroscopic data. The results were analyzed according to the modified Frumkin isotherm in order to evaluate the lateral interaction coefficient, a, and the adsorption free energy change, ΔG θ 0 . The adsorption kinetics of AOT at a fluorite internal reflection element (IRE) were studied. In addition, by monitoring the –CH 2 adsorption band using polarized light, it was possible to investigate the orientation of the adsorbed species on the fluorite IRE surface.