ABSTRACT
The surface properties of asphaltenes and resins at interfaces were studied. Asphaltenes and resins are the polar, polyaromatic, high molecular weight fractions of crude oil and bitumen that can be precipitated by the addition of low molecular weight alkanes. Asphaltenes and resins were isolated from a Brazilian crude oil from Campos basin at Rio de Janeiro or from a Brazilian shale from Irati in Parana by precipitation with an alkane. The adsorption of asphaltenes or resins by the mineral samples was determined by measuring the reduction in concentration of the toluene solution of these compounds after a contact period of 4 hours with the minerals. Asphaltenes, precipitated using n-pentane, and resins, dissolved in an adequate solvent, spread at the air/water interface. Asphaltenes and resins are chemically related fractions being formed by paraffinic and naphthenic chains as well as condensed aromatic hydrocarbons.
