A Novel Shear-Detachment Approach for Modeling Dynamics of Membrane Cleaning

Abstract

We report a novel shear-detachment (SD) approach to simulate the dynamics of flux recovery in the membrane cleaning process. In this model, the rate of foulant detachment away from the membrane is governed by both the shear intensity and the probability of successful foulant detachment, with the latter modeled by Boltzmann distribution. Our SD predictions exhibit good agreement with experimental results, accurately capturing the dynamics of flux recovery. Modeling outcomes reveal that the time required for fully restoring water flux is largely independent of the initial cake mass but significantly dependent on crossflow-flushing velocity and adhesive energy of foulant to membrane. Higher flushing velocity and/or lower adhesive energy can create a shear-limited condition where almost all shear events bring about successful foulant detachment, facilitating rapid flux recovery. Conversely, a smaller flushing velocity or greater adhesive energy can result in increasingly detachment-limited situations, where the cleaning efficiency is primarily dictated by the probability of foulant detachment. Our study offers profound insights into the importance of shear rate and detachment probability in governing foulant detachment kinetics and self-cleaning behavior, which carry significant implications for membrane preparation and process operation.