ANALYSIS OF DEAD-END ULTRAFILTRATION BASED ON ULTRACENTRIFUGATION METHOD

In order to clarify the internal structures of the filter cake formed in protein ultrafiltration, ultracentrifugation experiments were conducted. The local specific flow resistance at the various solution concentrations was determined by the sedimentation velocity technique. The porosity was related to the solute compressive pressure by the high-speed sedimentation equilibrium technique. A method has been developed for evaluating the internal structures in the cake on the basis of a compressible cake resistance model using ultracentrifugation data. The decline in the filtration rate in dead-end ultrafiltration was accounted for by considering the internal structures of the compressible cake. The properties of the cake were determined from ultrafiltration experiments in which a filter was subjected to a sudden reduction in its filtration area. The results accorded well with the calculations. This study revealed that the filtration behavior of ultrafiltration can be accurately described by a compressible cake resistance model.