(381u) Polymer Composite Membranes Containing UiO-66 MOFs with Co-Continuously Segregated Structures for CO2-Related Gas Separations

Gas separation membranes have been considered as one of the most promising techniques in replace of the conventional gas separations processes. Recently, UiO-66 metal-organic framework (MOF) containing polymer composite membranes have been demonstrated to achieve better gas separation performance, especially for CO₂-related separations. Until now, few studies used morphological control strategies for enhancing gas transport properties of composite membranes. In this work, we prepared polymer composites with co-continuously segregated structures, comprising UiO-66 porous nanoparticles and immiscible 6FDA-based polyimide blends. The gas permeability and gas sorption properties of pure gases (e.g., H₂, CO₂, N₂, O₂, CH₄) in the dense membranes and composite membranes were measured using the constant-volume variable-pressure method and the dual-volume pressure decay method. Based on the solution-diffusion model, the contributions of gas sorption and gas transport to the overall gas permeation properties were evaluated and studied. We found a considerable increase in CO₂ permeability by 635% (104.7 Barrer) along with the almost unchanged selectivities of CO₂/N₂ (16.5) and CO₂/CH₄ (32.8) for the composite membrane at 35 wt.% of the UiO-66 content. The overall gas separation results suggested that both the addition of UiO-66 porous nanoparticles and the morphology of co-continuously segregated structure would contribute to the dramatical enhancement in gas separation performance of the composite membranes.