Ångstrom-level pore size engineering of Zr-based MOF membranes for efficient hexane isomer separation

The separation of hexane isomers from light naphtha is critical to advancing energy-efficient refining and supporting environmental sustainability. However, this application requires membranes capable of precise molecular discrimination. In this work, we focus on hard acid–hard base coordinated Al-/Zr-MOFs due to their exceptional stability and tunable pore environments. Through combined thermodynamic and kinetic evaluations, four Al-MOFs (KMF-1, CAU-23, MIL-160, Al-bttotb) and Zr-MOF(UiO-66) emerged as promising candidates. UiO-66 was ultimately identified as the optimal platform due to its excellent membrane compactness and techno-economic potential. We subsequently employed a mixed-linker strategy to achieve Ångstrom-level pore size engineering in UiO-66, the resulting UiO-66-NH 2 membrane exhibited superior discrimination between linear/mono-branched (n-hexane, 3-methylpentane) and di-branched (2,2-dimethylbutane) isomers, achieving an ideal selectivity of 4.8—a performance that exceeds most current state-of-the-art MOF membranes. Pervaporation experiments with a simulated C 5 –C 6 naphtha mixture further confirmed the ability of the membrane to efficiently enrich ethylene cracking precursors, while the retentate effectively concentrated high-octane gasoline additives. These results underscore the strong industrial potential of Ångstrom-precision engineered MOF membranes for simultaneous production of high-value chemical feedstocks and premium fuel components from light naphtha.