Raman spectroscopic study of sorption to CTAB-modified montmorillonite

The sorption of benzene, ethylbenzene, tert-butylbenzene, and quadricyclane onto CTAB-modified montmorillonite was studied. The CTAB was seen to be in a liquid-like form in the clay. It was also seen that quadricyclane was not stable in aqueous solutions and formed tricycloheptan-3-ol. Raman spectroscopy can be used to observe the sorption onto the organo-clay. The free-energy relationship for the sorption of the compounds studied on the organo-clay using an adsorption model was found. A deviation from ideal behavior was observed and a different model was developed that involved the molecular surface area of the surfactant and the molecular volume of the sorbate. If we assumed an absorption model, the agreement between our data and those predicted thermodynamically improved significantly.