Nanofluidic membranes: Discover a new avenue in membrane-based processes - A comprehensive review.

Nanofluidic membranes, featuring angstrom-to-nanometer transport pathways where interfacial effects dominate, have rapidly evolved into a versatile platform for selective ion transport, energy conversion, sensing, and advanced separations. This review consolidates two decades of progress by (i) summarizing the governing electrokinetic mechanisms in confined nanochannels (e.g., electric double-layer regulation, ion selectivity, and ionic current rectification), (ii) providing a multidimensional classification of nanofluidic membranes based on channel dimensionality, constituent materials, structural origin, and channel-wall properties, and (iii) critically comparing key fabrication strategies alongside modeling and simulation approaches used to rationalize transport and guide design. We further highlight persistent barriers to practical implementation, including scalable manufacturing of well-defined nanochannels, stability and fouling resistance under realistic conditions, and the need for standardized performance metrics and predictive structure-property relationships. By linking mechanism, architecture, and fabrication to performance and limitations, this review offers an integrated framework and actionable perspectives to accelerate the translation of nanofluidic membranes from model systems to robust membrane-based technologies.