Formation of gel emulsions by filtration-consolidation of O/W emulsions

A method has been developed for preparing the gel emulsions highly concentrated by filtration-consolidation of oil-in-water emulsions. The cake is highly consolidated without the cake cracking or the coalescence of droplets by applying the pressure further after filtration of the whole emulsion was completed. The compressed cake formed by this method has a porosity that is much smaller than that of hexagonal close packing of undistorted spheres. In consideration of the compressibility of the cake, the properties of the filtration period were analyzed on the basis of the Ruth filtration rate equation. It was revealed that the highly compressible filter cake forms on the membrane surface during filtration. Also, the properties of the consolidation period were analyzed using the modified Terzaghi model. The variations over time of the average consolidation ratio and the average porosity in the compressed cake during the consolidation process were well described by the theory. In addition, the properties of the filter cake in filtration were related to those of the compressed cake in consolidation.