A force balance model for estimating the surface porosity of cake in cake filtrations of submicron particles is proposed. The major factors affecting particle packing, such as filtration rate, particle size, zeta potential of particles, and electrolyte concentration, are discussed. A most compact cake is constructed when the drag force is equal to the net interparticle force. For a given size of particles with a given surface potential, the value of surface porosity decreases in a small filtration rate region but increases with filtration rate in a large filtration rate region. For particles with a low zeta potential, the surface porosity increases with the increase of particle size and the decrease of electrolyte concentration. However, this tendency will be reversed if the particles have a zeta potential higher than the critical value. The results estimated by this study are very close to those obtained by the Brownian dynamic simulation, but minimal calculation times was required.
Journal of the Chinese institute of chemical engineers=中國化學工程學會會誌 28(2), pp.121-129