Design and development of novel feed spacers in spiral wound membrane modules with 3D printing

Feed spacer is a mesh-like structure placed between membrane sheets to create channels for fluid flow in a spiral wound membrane module (SWM). It has an important role in the hydrodynamic conditions of a SWM, which serves to facilitate mass transfer in the feed channel by generating vortex and promoting mixing. However, the challenges of commercial feed spacers include the trade-off between mass transfer and pressure drop along the channel that leads to the rise in energy demand as well as their impact on membrane fouling. With the advent of 3D printing, there is greater design freedom for the development of novel spacers. This paper focuses on the design and optimization of a novel spacer for SWM via 3D printing to maximise mass transfer while minimising pressure drop and membrane fouling. Due to the capability of 3D printing to rapidly prototype complicated and intricate structures, a series of existing, modified and innovative spacer structures against commercial feed spacers were designed, printed and examined to identify the basis form of spacer structure with the greatest potential. Eventually, the sinusoidal flutter designs proved to generate higher flux, lower pressure drop and higher mass transport in contrast to the commercial spacer. Therefore, the sinusoidal design is a potential spacer structure that could surpass the performance of the commercial spacer after further investigation by varying the design parameters to obtain the optimal design.