Enhanced gas separation performance of 6FDA-DAM based mixed matrix membranes by incorporating MOF UiO-66 and its derivatives

Mohd Zamidi Ahmad, Marta Navarro, Miloslav Lhotka, Beatriz Zornoza, Carlos Téllez, Wiebe M. de Vos, Nieck E. Benes, Nora M. Konnertz, Tymen Visser, Rocio Semino, Guillaume Maurin, Vlastimil Fila, Joaquín Coronas* (Corresponding Author)

*Corresponding author for this work

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Functionalization and post-synthetic modification (PSM) of metal-organic frameworks (MOFs) are two important routes to obtain MOFs with full potential in mixed matrix membrane (MMM) fabrication. We synthesized UiO-66 and two derivatives UiO-66-NH2 and UiO-66-NH-COCH3 with less than 50 nm particle size. The CO2 uptakes at 10 bar in the two functionalized UiO-66s were improved by 44% and 58%, respectively, with respect to the pristine solid. The MOF nanoparticles were incorporated into the highly permeable polymer 6FDA-DAM, making MMMs with 5–24 wt% particle loadings. All fillers and membranes were characterized accordingly, and their gas separation performances were evaluated by feeding CO2/CH4 equimolar mixtures at 2 bar pressure difference at 35 °C. CO2 permeability (PCO2) of pristine 6FDA-DAM (PCO2 = 997 ± 48 Barrer, αCO2/CH4 = 29 ± 3) increased by 92% with 20 wt% UiO-66 loading, while maintaining the CO2/CH4 selectivity. Improvements of 23% and 27% were observed for PCO2 with the same 20 wt% loading of UiO-66-NH2 and UiO-66-NH-COCH3, respectively. The αCO2/CH4 was improved up to 16% using both functionalized UiO-66 type MOFs. The best separation performance in this work was obtained with 14 wt% UiO-66 MMM (PCO2 = 1912 ± 115 Barrer, αCO2/CH4 = 31 ± 1), 16 wt% UiO-66-NH2 MMM (PCO2 = 1223 ± 23 Barrer, αCO2/CH4 = 30 ± 1) and 16 wt% UiO-66-NH-COCH3 MMM (PCO2 = 1263 ± 42 Barrer, αCO2/CH4 = 33 ± 1) at 2 bar feed pressure difference. The measurement was also conducted with various binary compositions (CO2 = 10 – 90%), both at low and high pressures up to 40 bar at 35 °C, showing no pressure-related CO2-induced plasticization. The atomistic modelling for the MOF/polymer interface was consistent with a moderate MOF surface coverage by 6FDA-DAM which did not play a detrimental role in the membrane performance.

Original languageEnglish
Pages (from-to)64-77
Number of pages14
JournalJournal of membrane science
Early online date26 Apr 2018
Publication statusPublished - 15 Jul 2018


  • Gas separation
  • Metal organic framework
  • Mixed matrix membrane
  • Zr-based MOF
  • 6FDA-DAM

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