FreeSpace – Reducing Membrane Fouling by Exploiting Hydrodynamic Effects

In this DFG-funded research project, we investigate synergistic influences of membrane surface patterns and feed spacers on hydrodynamics and particle deposition mechanisms in the membrane feed channel. This research will promote our understanding of fundamental design criteria that determine the overall module performance. Using this knowledge, we strive to optimize the geometric arrangement of feed spacers and membrane surface patterns to ultimately reduce membrane fouling and assure higher process efficiency.

Biofouling, the accumulation of microorganisms and subsequent biofilm growth on the membrane, is of particular concern in Reverse Osmosis systems. Therefore, in order to understand the spatial and temporal evolution of biofouling on surface-patterned membranes, we perform accelerated biofouling experiments with semi-synthetic feed water. A pre-defined protocol allows conducting biofouling experiments in a reproducible manner.

In parallel to this experimental approach, we investigate the hydrodynamics in assemblies of feed spacers and membrane surface patterns by CFD Modeling with COMSOL Multiphysics 6.2. We hypothesize that these assemblies have synergistic effects on the hydrodynamics in a feed channel and hence lead to substantially enhanced anti-fouling propensity compared to one of the geometric features alone. In our CFD models, we investigate e.g. wall shear stresses (cf. figure) to understand the respective hydrodynamics.

Recently, we published a critical review of the state-of-the-art of surface-patterned membranes. In this article, we placed a particular focus on assessing experimental and numerical methods employed to test membrane performance and identified key areas for future research.