Simultaneous ultrafiltration and diafiltration

A model with simultaneous ultrafiltration and diafiltration, which inludes the rejection coefficients, is presented in this study. Adding a diafiltration solution at a constant, lower rate than the filtrate rate results in a constant decrease of the solution volume in the tank. This enables the simultaneous attainment of the desired macrosolute concentration and microsolute dilution. The proposed model, based on incomplete macrosolute rejection and incomplete microsolute permeation through a membrane, as well as constant permeate flux, is compared to the classical, constant volume, diafiltration process. The obtained results show that less diafiltration volume is necessary with this process. Simultaneously, the duration of the process, for higher purification requirements, is shorter in this case.