Adsorption of Intan-100 at the bitumen/aqueous solution interface studied by spinning drop tensiometry

We present an experimental study on the adsorption behaviour of Intan-100, a non-ionic surfactant, at the bitumen/water interface when the density dif ference between the two phases is increased by diluting the crude oil with 10% xylene by weight or using heavy water (deuterium oxide) as the aqueous phase. The equilibrium interfacial tension, surface excess and critical mic elle concentration of Intan-100, at 30, 60 and 75 degreesC, are determined using a spinning drop tensiometer, which gives fast and accurate results fo r low and high values of tension. Comparison with previously published data indicate that the use of heavy water is to be preferred over dilution of t he heavy crude oil when the densities of the two phases are closely matched . (C) 2001 Elsevier Science B.V. All rights reserved.