3D helical membranes for process intensification of membrane separation via generation of Dean vortices

Abstract

A novel three-dimensional (3D) helical membrane is developed for process intensification via generation of Dean vortices in helical membrane channel. 3D helical porous polyethersulfone membrane is fabricated by casting the membrane forming solution on the surface of 3D-printed porous substrate with a 3D helical channel structure by high-speed rotation method, and then curing by vapor-induced phase separation. The optimal helical radius and internal channel height are both 19 mm for the prepared 3D helical membranes. When the feed flowrate is higher than the minimum critical flowrate, Dean vortices can be easily generated in the 3D helical membrane channel, and thus the membrane fouling can be effectively mitigated. The ratio of average transmembrane flux of 3D helical membrane to that of conventional cylindrical membrane increases from 1.0 to ∼2.0 when the feed flowrate increases from 2.1 to 106.1 mm s−1, and from 1.0 to ∼1.9 when the feed particle concentration increases from 0 to 20 g L−1. No matter how the microstructures of particles in feed solutions vary, Dean vortices generated in 3D helical membrane channels are always efficient to diminish the particle deposition on membrane surface. The proposed strategy is highly promising for developing efficient membranes with different materials for various applications.