ABSTRACT
Emulsions are used in a wide range of applications and industries. Their size distribution is an important parameter because it influences most of the emulsion properties of emulsions. Several techniques of characterization are used to determine the granulometric distribution of emulsions, but they are generally limited to dilute samples and are based on complex algorithms. We describe a method that allows characterization of the droplet size distribution of emulsions using thermal analysis (thermogranulometry). This method permits the use of very concentrated samples without any dilution or perturbation of the system. We first define our method by a thermodynamic and kinetic approach. We studied a real system, i.e., crude oil emulsions, which form very concentrated, viscous, and opaque emulsions with water. We present a correlation between the size of droplets and their freezing temperature, corresponding to our system. Then we compare the size distributions obtained by our method with those derived by direct microscopy observations. The results obtained show that thermogranulometry may be an interesting method of characterization of emulsions, even for concentrated systems.
ABSTRACT
Adsorption of nonionic surfactant on kaolins of different origins was studied. The shape of the isotherm differs only slightly according to the origin of the kaolin, but the amount adsorbed is quite different. The relation between the morphology of the kaolin particles and the shape of the isotherm is not clear. Fluorescence studies show two different solubilization sites for adsorbed pyrene molecules. However, these two environments could not be correlated to the basal and lateral surfaces of the mineral particles.
