title: Modulated UiO-66-Based Mixed-Matrix Membranes for CO2 Separation.
abstract: Mixed-matrix membranes (MMMs) composed of polyimide (PI) and metal-organic frameworks (MOFs) were synthesized using Matrimid as the polymer and zirconium terephthalate UiO-66 as the filler. The modulation approach, combined with the use of amine-functionalized linkers, was used for synthesis of the MOF fillers in order to enhance the intrinsic separation performance of the MOF and improve the particle-PI compatibility. The presence of amine groups on the MOF outer surface introduced either through the linker, through the modulator, or through both led to covalent linking between the fillers and Matrimid, which resulted in very stable membranes. In addition, the presence of amine groups inside the pores of the MOFs and the presence of linker vacancies inside the MOFs positively influenced CO2 transport. MMMs with 30 wt % loading showed excellent separation performance for CO2/CH4 mixtures. A significant increase in the mixed-gas selectivity (47.7) and permeability (19.4 barrer) compared to the unfilled Matrimid membrane (i.e., 50% more selective and 540% more permeable) was thus achieved for the MMM containing the MOF prepared from 2-aminoterephthalic acid and 4-aminobenzoic acid, respectively used as the linker and as the modulator.
authors.affiliation: Centre for Surface Chemistry and Catalysis, Faculty of Bioscience Engineering, KU Leuven , Kasteelpark Arenberg 23, Box 2461, 3001 Leuven, Belgium.
authors.forename: M Waqas
authors.initials: MW
authors.lastname: Anjum
authors.affiliation: Centre for Surface Chemistry and Catalysis, Faculty of Bioscience Engineering, KU Leuven , Kasteelpark Arenberg 23, Box 2461, 3001 Leuven, Belgium.
authors.forename: Frederik
authors.initials: F
authors.lastname: Vermoortele
authors.affiliation: Department of Chemical Engineering, COMSATS Institute of Information Technology , Lahore, Pakistan.
authors.forename: Asim Laeeq
authors.initials: AL
authors.lastname: Khan
authors.affiliation: Centre for Surface Chemistry and Catalysis, Faculty of Bioscience Engineering, KU Leuven , Kasteelpark Arenberg 23, Box 2461, 3001 Leuven, Belgium.
authors.forename: Bart
authors.initials: B
authors.lastname: Bueken
authors.affiliation: Centre for Surface Chemistry and Catalysis, Faculty of Bioscience Engineering, KU Leuven , Kasteelpark Arenberg 23, Box 2461, 3001 Leuven, Belgium.
authors.forename: Dirk E
authors.initials: DE
authors.lastname: De Vos
authors.affiliation: Centre for Surface Chemistry and Catalysis, Faculty of Bioscience Engineering, KU Leuven , Kasteelpark Arenberg 23, Box 2461, 3001 Leuven, Belgium.
authors.forename: Ivo F J
authors.initials: IF
authors.lastname: Vankelecom
keywords: CO2/CH4 separation; UiO-66; gas separation; mixed-matrix membranes; modulated MOFs