Adsorption and Desorption Behaviour of Organic Molecules on Kaolinite Particles in Non-aqueous Media

Abstract

Organoclays modelling the Athabasca oil sands were prepared in heptane and toluene showing indole loading occurring exclusively on the external surface of the clay, via a multilayer adsorption mechanism. Solvent adsorption was minimal. Vermicular microstructures, similar to natural kaolinite were formed. Isotherms were constructed and fitted to the BET equation, giving monolayer quantities (9.28mg) that matched well to the theoretical amount calculated from surface area measurements (8.87mg). Dispersing the organoclays in isopropanol and in toluene left a monolayer equivalent. Using cellulose as a competitive desorption agent in asphaltene based organoclay dispersions achieved complete disaggregation of the dispersed organoclay stacks.13 C CP - MAS NMR, showed up to a 25% increase in desorption for aliphatic and up to 40% increase in desorption for aromatic functionalities of the loaded organic matter. Investigation of other saccharides and modified celluloses as competitive agents is recommended for future work.