Ultrafiltration intensification by dynamic operation: Insights from hybrid modeling

Concentration polarization and fouling are the most important issues to be addressed when designing ultrafiltration (UF) and microfiltration (MF) units for a specific application. Dynamic operation in UF and MF, such as backshock, is a method that allows mitigating adverse effects of polarization and fouling thus enhancing the separation performance. However, there is a trade-off between operational conditions (i.e. backshock duration time BS, the time between backshock TBBS, and flux) to achieve the desired effects. Herein, two hybrid mathematical models are developed and tuned to predict the behavior of the polarization layer in dynamic UF (R_adj² of 0.9185 and 0.9626, respectively). Both hybrid models can estimate the concentration on the membrane surface (e.g. 27 g/L when BS is 1.25 s and TBBS is 5 s). The results illustrate the intensifying effect of dynamic operation by decreasing the Molecular Weight Cut-off up to 74 times without decreasing the membrane flux. The performed experiments and developed models provide system insights for membrane systems design where the rejection could be enhanced and tunned according to operating conditions rather than the membrane pore size.