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Supercritical fluid extraction was used to regenerate organically modified montimorilloniteclay (hexadecyltrimethylammonium-clay and tetramethylammonium-clay), after it was used to adsorb ethyl acetate from aqueous solutions. The desorption of ethyl acetate adsorbed over the clays was performed with CO 2 at temperatures ranging from 301 to 333 K and pressures ranging from 69.0 to 413.8 bar. A crossover effect was observed. The experimental data was fitted to a simple model, with the best results corresponding to desorption with CO 2 in its supercritical region.

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-Modified clays were used to remove ethyl acetate from aqueous solutions. These clays were regenerated using supercritical CO 2 . Structural changes in the montmorillonite clay after treatment with quaternary amines were studied. The surface properties of the modified clay changed from highly hydrophilic to highly organophilic. The clay was regenerated by percolation of a stream of CO 2 through the porous montmorillonite matrix. Different pressures and temperatures were employed, resulting in different fluid conditions (gas, liquid, and supercritical). The experimental data was fitted with a simplified model. The best desorption result was found under supercritical conditions. A crossover effect was observed. The capacity of the modified clay as a pollutant attenuator remained almost unchanged after a regeneration cycle.