Membrane-based nanotechnology possesses high separation efficiency, low economic and energy consumption, continuous operation modes and environmental benefits, and has been utilized in various separation fields. Two-dimensional nanomaterials (2DNMs) with unique atomic thickness have rapidly emerged as ideal building blocks to develop high-performance separation membranes. By rationally tailoring and precisely controlling the nanochannels and/or nanoporous apertures of 2DNMs, 2DNM-based membranes are capable of exhibiting unprecedentedly high permeation and selectivity properties. In this review, the latest breakthroughs in using 2DNM-based membranes as nanosheets and laminar membranes are summarized, including their fabrication, structure design, transport behavior, separation mechanisms, and applications in liquid separations. Examples of advanced 2D material (graphene family, 2D TMDs, MXenes, metal–organic frameworks, and covalent organic framework nanosheets) membrane designs with remarkably perm-selective properties are highlighted. Additionally, the development of strategies used to functionalize membranes with 2DNMs are discussed. Finally, current technical challenges and emerging research directions of advancing 2DNM membranes for liquid separation are shared.

Metal-organic framework (MOF) glasses represent an emerging frontier in porous materials that uniquely combine the structural tunability of crystalline MOFs with the superior processability commonly found in traditional polymers. Unlike their crystalline counterparts, MOF glass-based membranes inherently eliminate grain boundary defects and display excellent thermal stability. The melt-quenching process also enables the formation of unsaturated metal sites and coordination defects, which can be tailored to optimise adsorption affinity, pore size distribution, and diffusion pathways. This review provides a comprehensive overview of the formation mechanisms, structural features, classifications, and advanced characterisation of MOF glass-based membranes, with a focus on their roles in high-selectivity and scalable gas separation. It further discusses the design principles of meltable MOFs, the structural evolution during the crystal-to-glass transition, and critical structure–property relationships. Key challenges fabrication and industrial integration are evaluated, and future research directions are proposed to guide the development of MOF glass membranes as a transformative platform in separation science.