Adsorption isotherms of nonionic surfactants in SBA-15 measured by micro-column chromatography

In this work, micro-column liquid chromatography has been employed for the study of the adsorption of ethylene glucol monoether (C8E4) and pentaethylene glucol monoether (C10E5) nonionic surfactants into the nanopores of SBA-15 silica at two temperatures. The adsorption process for both the surfactants has been investigated in the range of concentration from very dilute solution to "just above" critical micelle concentration (CMC). The adsorption data for both the surfactants are characterized as typical LC-shaped isotherms with plateau near the CMC. A simple two-step adsorption model has been applied to represent an experimental data. An attempt to estimate the thickness of the surfactant layer in the pores, from the experimental data, has been made.