Analysis of filtration with virus removal filters using the characteristic form of blocking model

Abstract

For virus filtration behavior not adequately described by the equations and analysis methods of the conventional four blocking models, i.e., complete blocking, standard blocking, intermediate blocking and cake filtration models, a modified approach is proposed using a generalized equation derived from the characteristic form of the blocking model with consideration of the multilayer membrane structure with pore size distribution (Manabe model). The two parameters of the characteristic form, blocking index, n, and characteristic form coefficient, k, for the filtration behavior, are easily determined by applying the modified characteristic form to experimental data. The generalized filtration equation with these two parameters shows good fit for both constant pressure filtration and constant flux filtration. For high filterability virus filter behavior, n is a negative value, and the physical meaning of a negative value can reasonably be explained in consideration of the multilayer membrane structure with pore size distribution. The assumptions of the conventional blocking model, i.e., the membrane structure consisting of single active layer with single pore size is not applicable for virus filters. Instead, the Manabe model is essential for explaining the stable filtration of the virus filter.