Advanced Nanomembranes for Membrane Distillation Desalination: Research Status, Challenges, and Prospects.

The increasingly severe global shortage of freshwater resources underscores the critical importance of seawater desalination. Membrane distillation (MD), as an emerging thermally driven desalination technology, offers several advantages-including mild operating conditions, high salt rejection, and the ability to utilize low-grade heat sources-thus showing great potential for practical application. However, conventional commercial hydrophobic membranes generally suffer from low flux, wetting, and fouling issues, which significantly hinder further development. This review systematically summarizes recent progress in high-performance nanoporous membranes for MD-based seawater desalination. It introduces the fundamental principles of MD, different system configurations, and the critical performance requirements of membrane materials, while analyzing the characteristics and limitations of traditional polymeric and inorganic membranes. Significant emphasis is placed on the fabrication approaches, performance characteristics, and underlying antifouling/antiwetting mechanisms of emerging nanomembranes, including covalent organic framework (COF) membranes, metal-organic framework (MOF) membranes, carbon-based nanomembranes, electrospun nanofiber membranes, and photothermal membranes. Finally, the review outlines future research directions, highlighting the crucial need to overcome challenges related to large-scale membrane fabrication and long-term operational stability to accelerate the industrial implementation of MD technology.