Synergistic CO2 capture using PANI-polymerized UiO-66 embedded in PEBAX mixed matrix membranes

Abstract

In this study, mixed-matrix membranes (MMMs) were fabricated using a composite of UiO-66 and polyaniline (PANI) integrated into a polyether-block-amide (PEBAX) matrix. The successful synthesis of the UiO-66 and PANI@UiO-66 composites and their incorporation into the PEBAX matrix were validated through X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) Spectroscopy, Brunauer–Emmett–Teller (BET) analysis, and Thermogravimetric Analysis (TGA). Quantitative permeation tests revealed that the CO₂ permeability in UiO-66 based MMMs increased by 90 % at 30 % filler loading (from 82 to 156 Barrer), and by 45 % (from 82 to 119 Barrer) in PANI@UiO-66 based MMMs, alongside substantial improvements in selectivity. For UiO-66 membranes we observed a selectivity drop for both gas pairs (CO₂/CH₄ and CO₂/N₂) that led to our motivation to modify the MOF. The CO₂/CH₄ selectivity of the PANI@UiO-66 based MMMs enhanced from 22 to 29 (34%) and the CO₂/N₂ selectivity from 48 to 57 (18%). Mixed-gas permeation tests further confirmed the efficacy of the membranes in real-world separation scenarios. The diffusivity and solubility results provide insights into the gas transport mechanisms, revealing the synergistic effects of filler incorporation on membrane performance. The integration of UiO-66 and PANI with PEBAX offers a promising pathway for developing efficient and effective gas separation technologies, aligning with the industrial requirements for environmental sustainability and energy efficiency.