Analysis of resistance growth during protein microfiltration
Date Issued
2004
Date
2004
Author(s)
Shiau, Jia-Shyan
DOI
zh-TW
Abstract
The growth of filtration resistance during protein microfiltration is strongly related to the associated phenomena of pore blocking, particle deposition and cake compression, caused by the protein aggregates deposited on membrane surface. Models combining pore blocking and cake filtration were developed to describe the growth of filtration resistance during protein microfiltration under different operation conditions. In addition, a model of cake compression was introduced to take into account the effect of the compressibility of protein aggregates.
Theoretical models, combining pore blocking and cake filtration, were derived for constant-pressure and constant-rate dead-end microfiltrations to provide a smooth transition from the pore blockage to cake formation regimes based on the concepts that the total flow rate is the sum of the flow rates through the open and blocked pores. Moreover, the probability of particle adhesion, which can be obtained from estimations of the forces on particles along the flow and permeation directions, was introduced into the combined models of pore blocking and cake filtration to take into account the effect of particle sweep due to cross flow for constant-pressure and constant-rate cross-flow microfiltrations. When the effect of the compressibility of protein aggregates is not negligible, a cake compression model was incorporated to make the combined models complete.
In order to verify the applicability of the developed models, experiments of BSA microfiltration were performed. The obtained data were in good agreement with the combined models for all the studied cases. It was also found that the combined model of complete pore blockage and cake filtration, was suitable for describing the resistance growth for membranes with straight-through pore. On the other hand, for membranes with interconnected structure, the combined model of intermediate pore blockage and cake filtration is more adequate.
The physical meanings of the model parameters were examined and the results indicate that the membrane structure and hydrophilicity have strong effect on the initial blocking mechanism and the following filtration behavior. For initial resistance growth, the comparison of pore blocking parameters was listed as follow that the interconnected membranes (β=1500∼2400 m2/kg) were larger than straight-through membrane (β=600 m2/kg) while the hydrophobic membrane (β=2400 m2/kg) was higher than hydrophilic membrane (β=1700 m2/kg).
Subjects
濾餅過濾
膜孔堵塞
阻力成長
微過濾
蛋白質
Pore Blocking
Cake Filtration
Resistance Growth
Protein
Microfiltration
Type
thesis