Surface and interface engineering in CO2-philic based UiO-66-NH2-PEI mixed matrix membranes via covalently bridging PVP for effective hydrogen purification

• Published in: International journal of hydrogen energy 2021-01, Vol.46 (7), p.5449-5458
• Main Authors: Ashtiani, S., Khoshnamvand, M., Bouša, D., Šturala, J., Sofer, Z., Shaliutina-Kolešová, A., Gardenö, D., Friess, K.
• Format: Article
• Language: English
• Subjects: Facilitated transport membrane; Hydrogen purification; Metal-organic framework; Mixed-matrix membrane; Polymer-filler interaction; UiO-66-NH2
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2020.11.081

We report on the fabrication of the defect-free mixed-matrix membrane (MMM) based on the polyethylenimine (PEI) matrix with uniformly dispersed metal-organic framework (MOF) filler UiO-66-NH2, covalently bonded by polyvinylpyrrolidone (PVP). The key feature of the molecular level-controlled filler deposition in prepared UiO-66-NH2-PVP-PEI membranes was bridging the MOF particles to the PEI polymer matrix via PVP polymer chains. Such an approach improved the polymer-filler interface interactions and boosted the MOF dispersion into the polymer matrix for higher MOF loadings up to 23 wt %. The overall membrane structure and properties were characterized using FTIR, XRD, TG, DSC, SEM and 3D optical profiler techniques. Obtained results revealed the uniform dispersion of UiO-66-NH2, the strong polymer-filler interface interactions and entanglement of PEI with UiO-66-NH2-PVP. Furthermore, the outstanding CO2/H2 separation performance was determined for the UiO-66-NH2-PVP-PEI membrane with 18 wt % of MOF loading; the average CO2 permeability of 394 Barrer and the separation factor of 12 for circa 100 h of the membrane testing overcome the 2008 Robeson reverse upper bound limit. Such improved CO2/H2 separation performance was achieved due to the combination of the diffusion-solution mechanism with the preferential adsorption of the CO2via the reversible bicarbonate reaction with amino groups of the UiO-66-NH2 and PEI which acts as fixed CO2 carrier sites in MMM structure. [Display omitted] •Fabricate new materials for CO2-selective membrane for hydrogen purification.•Strong polymer-filler interface interaction at the interface of UiO-66-NH2 and PEI.•Bridging approach by highly entangled polymer-filler for hydrogen purification.•Enhancement of mixture gas durability and thermal stability of the membrane.