Filtration behaviors of suspension of dual-sized submicron particles through semi-permeable microfiltration membrane

Particulate filtration behaviors such as the flux decline and particle retention by the membrane during the course of filtration were examined for dead-end constant pressure microfiltration of dilute suspension of dual-sized submicron polystyrene latex (PSL) particles through a semi-permeable membrane with a pore size larger than both particle sizes. The variation of rejection of both larger and smaller particles with the progress of filtration was approximated by the logistic equation. Our analysis was based on the cake filtration model accompanied by partial permeation of particles through the membrane. The model enabled us to evaluate the variation of the reciprocal filtration rate with the filtrate volume per unit effective membrane area, the relation between the filtrate volume and the filtration time, and the characteristic filtration curve frequently employed in the analysis of the blocking filtration law, on the basis of the data of temporal variation of particle retention. It was found that the retention of smaller particles was particularly promoted by the increase in the relative concentration of larger to smaller particles. It was also found that lower applied filtration pressure promoted the retention of both larger and smaller particles, resulting in the profound flux decline. (C) 2017 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.