Assembly of Sponge-Like Metal–Organic Framework Architecture on an Ultrathin Polymer Membrane for Various H2/Hydrocarbon Separations

Emissions from the petrochemical industry often contain by-product hydrogen alongside various hydrocarbons, leading to both resource wastage and increased air pollution. The separation of H 2 from these hydrocarbons is thus of considerable economic and environmental importance. Conventional polymer membranes face inherent trade-offs between gas permeability and selectivity. To overcome this limitation, this study introduces a strategy to assemble metal–organic framework (MOF) nanoparticles into a sponge-like architecture on the surface of an ultrathin rubbery polysiloxane membrane, achieved by synergistically harnessing spin-coating-induced centrifugal forces and polymer–MOF chemical pinning forces. The resulting intricate sponge-like structure greatly promotes repeated adsorption–desorption cycles for the more condensable hydrocarbons, thereby markedly slowing their permeation through the membrane. The composite membrane achieves H 2 /CH 4 , H 2 /C 2 H 6 , and H 2 /C 3 H 8 separation factors of 136, 1370, and 1610, respectively, while maintaining H 2 permeances of 439 to 473 GPU. The membrane's effectiveness is further demonstrated for hydrogen separation from a simulated hydrocarbon-rich industrial tail gas: H 2 is enriched from 10% to 83% in the permeate. In doing so, the membrane not only efficiently recovers hydrogen but also reduce the combined emissions of six representative C 1 –C 4 hydrocarbons by 78%. This sponge-like MOF-polymer composite introduces a new paradigm for advanced H 2 /hydrocarbon separation membranes.