Entwicklung und Einsatz eines optischen Messgeraets zur Erfassung der Asphaltenflokkulation bei der Entasphaltierung mit CO_2

SIGLETIB Hannover: DR 9924 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Desorption Of Ethyl Acetate From Adsorbent Surfaces (organoclays) By Supercritical Carbon Dioxide

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 CO2 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 CO2 in its supercritical region.Supercritical fluid extraction was used to regenerate organically modified montimorillonite-clay (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 CO2 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 CO2 in its supercritical region.401364368Brady, B.O., Kao, C.-P.C., Dooley, K.M., Knopf, F.C., Gambrell, R.P., Supercritical Extraction of Toxic Organics from Soils (1987) Ind. Eng. Chem. Res., 26, p. 261Alexandrou, N., Lawrence, M.J., Pawliszyn, J., Cleanup of Complex Organic Mixtures Using Supercritical Fluids and Selective Adsorbents (1992) Anal. Chem., 64, p. 30

Adsorption of ethyl acetate onto modified clays and its regeneration with supercritical CO2

Modified clays were used to remove ethyl acetate from aqueous solutions. These clays were regenerated using supercritical CO2. 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 CO2 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

Regeneration strategies for spent solid matrices used in adsorption of organic pollutants from surface water: a critical review

Adsorption is a very important physicochemical process used for several purposes including separation and purification of proteins and in water treatment. This article reviews the various strategies that have been employed in the regeneration of spent adsorbents used in the adsorption of organic pollutants from aqueous solutions. The principles, advantages, disadvantages, and factors influencing each of these techniques are discussed. Future perspectives on the use of these techniques in regeneration process are provided for further studies with the view to make the regeneration process of spent solids more efficient and sustainable