Anionic surfactant adsorption on to asphalt-covered clays

Abstract Asphalt adsorption from from water-saturated tolene on Na − kaolinite, Ca 2− kaolinite, Na − illite and Ca 2− illite clays was investigated. It was found that the kaolinite surface adsorbed more asphalt than illite for both the Na − -and the Ca 2− exchanged forms. Adsorption from aqueous solutions of sodium dodecylbenzenesulphonate (SDBS) and sodium dodecyl sulphate (SDS) on various asphalt-covered clays was also studied. The shape of the isotherms depended on the asphalt-clay substrate and showed a much lower adsorption of SDBS beyond the CMC. Desorption of asphalt from various clays with SDBS and SDS surfactants was measured spectrophotometrically. The percentage weight of asphalt desorbed with SDBS was twofold higher than that desorbed with SDS surfactant.