| Water-in-oil emulsions of Athabasca bitumen diluted in toluene have been studied using the latest advances in Acoustic and Electroacoustic Spectroscopy. From the sound attenuation spectra of emulsions, the water droplet size distribution is derived. The electrical surface charge density of the droplets is obtained from the colloid vibration current. In case of freshly prepared water-in-oil emulsions, the water droplet size increases while the surface charge density decreases with time. The time span of this transient behavior ranges from several hours to three days. Such long transients are probably due to the slow adsorption/desorption kinetics of bituminous components at the water-oil interface. This study illuminates the contribution of the electrostatic interactions to the stability of water-in-oil emulsions. |
