FOULING MITIGATION IN MEMBRANE-BASED SEPARATION VIA SURFACE ENGINEERING AND ELECTROCHEMICAL APPROACH

Abstract

This dissertation aims to explore the membrane fouling mechanisms and develop scalable anti-fouling strategies. First, the relationship between roughness and fouling in reverse osmosis was investigated through specially designed experimental and computational protocols. Results indicated that surface roughness influenced the fouling process through size effect, vortex formation and flux distribution. Next, facile approaches to fabricate micrometer- and millimeter-level patterned membranes have been developed for low-scaling desalination. Micrometer-level patterns were resistant to scaling through both spatial and hydrodynamic effects, and millimeter-level patterns were also effective in reducing scaling solely due to hydrodynamic effects. Furthermore, an experimental and modeling study of the concentration polarization on patterned membranes was conducted. Different trends were observed when comparing different pattern orientations, where relative concentration polarization degree was found dependent on solute molecular weight. Lastly, our study on electro-assisted pressure-driven membrane process revealed that superior anti-scaling performance could be achieved with non-conductive membranes and alternating current.