Pressure-drop reduction by oil-infused spacers

• Oil-infused spacers reduce feed channel pressure by up to 46%. • Lower viscosity oils result in a greater reduction in pressure drop. • Slippery oil-infused surfaces improve flow efficiency in membrane modules. • Numerical modeling confirms the impact of slip conditions on pressure drop. This study explores oil-infused polydimethylsiloxane (iPDMS) feed spacers to reduce pressure drop in spiral-wound membrane (SWM) modules. While crucial for structural support and fouling mitigation, conventional feed spacers often increase pressure drop, leading to higher energy demands. By infusing PDMS spacers with silicone oils of varying viscosities (10, 20, and 100 cSt), we achieved significant reductions in pressure drop—up to 46% compared to non-infused spacers. Lower-viscosity oils demonstrated the most pronounced improvements. Numerical simulations corroborate the experimental data, showing that the slippery surface of the oil-infused spacers minimizes flow resistance and reduces energy dissipation. These findings suggest that incorporating oil-infused spacers can enhance SWM module efficiency, offering a promising approach to lowering operational energy costs in membrane-based water treatment systems.