Surface-Patterned Water Separation Membranes: A Critical Analysis of Current Knowledge and Future Research Needs

Abstract

Surface-patterned membranes with engineered nano-and microstructures are emerging as a promising approach to mitigate fouling and enhance membrane performance in water treatment and desalination. This review critically evaluates the current state of research, drawing on findings from over 100 studies to highlight key findings and identify knowledge gaps. A significant research gap persists in understanding the performance of surface-patterned membranes in spacer-filled channels, given their relevance for practical applications. This Perspective provides a summary of critical aspects of key fabrication techniques and relevant characterization methods. In addition, reported performance results are assessed, including effects of fabrication methods on membrane permeability and limitations in scaling and biofouling analyses. By consolidating experimental and numerical outputs, we explored prevailing hydrodynamic theories for surface-patterned membranes in spacer-free channels and their implications for fouling control and hydrodynamic cleaning efficiency. These primary mechanistic effects are often found to be case-specific and occasionally contradictory. Notably, limitations in computational fluid dynamics modeling, often reliant on idealized membrane surfaces, are being discussed with recommendations to achieve improved model accuracy. This review concludes by identifying critical research areas and the needs to advance surface-patterned membranes for sustainable water separation applications.