Airfoil-shaped filament feed spacer for improved filtration performance in water treatment

Abstract

Optimal spacer design enhances the filtration performance in spiral-wound modules by controlling the local hydrodynamics inside the filtration channel. A novel airfoil feed spacer design fabricated using 3D-printing technology is proposed in this study. The design is a ladder-shaped configuration with primary airfoil-shaped filaments facing the incoming feed flow. The airfoil filaments are reinforced by cylindrical pillars supporting the membrane surface. Laterally, all the airfoil filaments are connected by thin cylindrical filaments. The performances of the novel airfoil spacers are evaluated at Angle of Attack (AOA) of 10° (A-10 spacer) and 30° (A-30 spacer) and compared with commercial (COM) spacer. At fixed operating conditions, simulations indicate steady-state hydrodynamics inside the channel for A-10 spacer, while an unsteady state is found for A-30 spacer. Numerical wall shear stress for airfoil spacers is uniformly distributed and has a higher magnitude than the COM spacer. A-30 spacer design is the most efficient in ultrafiltration process with enhanced permeate flux (228%) and reduced specific energy consumption (23%) and biofouling development (74%) as characterized by Optical Coherence Tomography. Results systematically demonstrate the influential role of airfoil-shaped filaments for feed spacer design. Modifying AOA allows localized hydrodynamics to be effectively controlled according to the filtration type and operating conditions.

Optimizing Reverse Osmosis Feed Spacer Design for Enhanced Dimethylphenol Removal from Wastewater: A Study of Hydrodynamics and Performance Indicators

“…Undoubtedly, the concentration polarization happens when solutes build up on the membrane surface, which results in less effectual mass transfer operation. Accordingly, the design and configuration of the feed spacer should be optimized while considering the aspects of hydrodynamics [16,17]. The concentration polarization can be mitigated through an optimal feed spacer design that endorses uniform flow, moderates stagnant areas, and increases mass transfer across the membrane [18,19].…”