主催: The Society of Chemical Engineers, Japan
A model, on the basis of incorporation of probabilities of particle adhesion in combined with pore-blocking and cake-filtration models, was developed in the present work to describe protein fouling during cross-flow microfiltration. It was verified first by scanning electron micrographs (SEM) that the deposition of protein aggregates is responsible for the resistance growth during cross-flow microfiltration of the solution of bovine serum albumin (BSA). Previous researches indicate that BSA aggregates can block membrane pores via the mechanisms of pore blockage and cake filtration during dead-end microfiltration, and a combined model of these two blocking mechanisms was developed accordingly. Such a combined model was modified in the present work in two folds. First, a combined model of intermediate blocking and cake filtration was developed which can describe the growth of filtration resistance more satisfactorily than the original model when microfiltration membranes with interconnected pores are used. Second, probabilities of particle adhesion were incorporated in the combined models to quantitatively describe the resistance growth during cross-flow microfiltration. The probability of particle adhesion on membranes, which can be calculated from estimations of the forces on particles along the flow and permeation directions, was introduced to take into account the effect of particle sweep due to cross flow. The developed models have been proven to be in good agreement with the experimental data obtained. It was found that the adhesion probability and the pore blockage parameter used in the model govern the behavior of resistance growth. With such models, the effects of cross-flow rate, protein concentration, solution pH, and membrane hydrophilicity on particle adhesion and pore blocking during cross-flow microfiltration can be quantitatively investigated.