Bioinspired Graphene Oxide Membranes with Dual Transport Mechanisms for Precise Molecular Separation

The implementation of membrane technology to replace or combine with energy‐intensive cryogenic distillation for precise separation of ethylene/ethane mixture proves an extremely important yet highly challenging task. Inspired by the hierarchical structure and facilitated gas transport of biological membranes, a highly selective ethylene/ethane separation membrane is explored through the fixation of a silver ion carrier and the impregnation of ionic liquid within 2D nanochannels of graphene oxide laminate, where plenty of ethylene‐permeating in‐plane nano‐wrinkles and ethylene‐facilitated plane‐to‐plane nanochannels are constructed. By virtue of synergistic effects of molecular sieving and carrier‐facilitated transport, an unprecedented combination of high ethylene permeance (72.5 GPU) and superhigh ethylene/ethane selectivity (215) is achieved, out‐performing currently reported advanced membranes. Moreover, molecular dynamics simulations verify a favorable membrane nanostructure for fast and selective transport of ethylene molecules. This bioinspired approach with dual transport mechanisms may open novel avenues to the design of high‐performance membranes for precise molecular separation.     

Sorption‐Enhanced Mixed Matrix Membranes with Facilitated Hydrogen Transport for Hydrogen Purification and CO2 Capture

Mixed matrix membranes (MMMs) comprising size‐sieving fillers dispersed in polymers exhibit diffusivity selectivity and may surpass the upper bound for gas separation, but their performance is limited by defects at the polymer/filler interface. Herein, a fundamentally different approach employing a highly sorptive filler that is inherently less sensitive to interfacial defects is reported. Palladium nanoparticles with extremely high H₂ sorption are dispersed in polybenzimidazole at loadings near the percolation threshold, which increases both H₂ permeability and H₂/CO₂ selectivity. Performance of these MMMs surpasses the state‐of‐the‐art upper bound for H₂/CO₂ separation with polymer‐based membranes. The success of these sorption‐enhanced MMMs for H₂/CO₂ separation may launch a new research paradigm that taps the enormous knowledge of affinities between gases and nanomaterials to design MMMs for a wide variety of gas separations.     

Synergistic Multilevel Sieving Membranes: Integrating Cellular Graphene Skeleton with Continuous MOFs Nanolayer for Superior Multiphase Water Separation

The emergence of MOF–based separation membranes has transformed liquid contaminant filtration with impressive sieving properties. However, their use in multiphase water filtration is hindered by a limited sieving range and susceptibility to collapse in solution. To address this challenge, an innovative solution is presented: the Multilevel Cellular Graphene Skeleton (MCGK) induced by femtosecond laser, onto which a continuous MOF nanolayer (CMN), specifically ZIF–8, is grown. This forms a groundbreaking multistage micron/nanocomposite pore membrane. The MCGK/CMN membrane significantly expands the range of filterable contaminants and enhances stability. It utilizes a multilevel, multi–pore size sieving strategy for effective multiphase water filtration, achieving an impressive 90% efficiency in self–driven solar steam generation sieving. Additionally, it excels in removing organic pollutants and over 80% of volatile organic compounds (VOCs), while reducing metal ion concentrations. In liquid pressure–driven filtration, it achieves complete oil adsorption and reduces VOCs and metal ion concentrations. This innovative multistage micron/nanocomposite pore membrane holds great potential for diverse practical applications and provides insights for next–generation nanofiltration membranes, promising more efficient and resilient water purification technologies in the future.     

Heterogeneous MXene/PS-b-P2VP Nanofluidic Membranes with Controllable Ion Transport for Osmotic Energy Conversion

Membrane-based osmotic power harvesting is a strategy for sustainable power generation. 2D nanofluids with high ion conductivity and selectivity are emerging candidates for osmotic energy conversion. However, the ion diffusion under nanoconfinement is hindered by homogeneous 2D membranes with monotonic charge regulation and severe concentration polarization, which results in an undesirable power conversion performance. Here, an asymmetric nanochannel membrane with a two-layered structure is reported, in which the angstrom-scale channels of 2D transition metal carbides/nitrides (MXenes) act as a screening layer for controlling ion transport, and the nanoscale pores of the block copolymer (BCP) are the pH-responsive arrays with an ordered nanovoid structure. The heterogeneous nanofluidic device exhibits an asymmetric charge distribution and enlarged 1D BCP porosity under acidic and alkaline conditions, respectively; this improves the gradient-driven ion diffusion, allowing a high-performance osmotic energy conversion with a power density of up to 6.74 W m⁻² by mixing artificial river water and seawater. Experiments and theoretical simulations indicate that the tunable asymmetric heterostructure contributes to impairing the concentration polarization and enhancing the ion flux. This efficient osmotic energy generator can advance the fundamental understanding of the MXene-based heterogeneous nanofluidic devices as a paradigm for membrane-based energy conversion technologies.