Magnetically Aligned and Enriched Pathways of Zeolitic Imidazolate Framework 8 in Matrimid Mixed Matrix Membranes for Enhanced CO2 Permeability

Abstract

Metal-organic frameworks (MOFs) as additives in mixed matrix membranes (MMMs) for gas separation have gained significant attention over the past decades. Many design parameters have been investigated for MOF based MMMs, but the spatial distribution of the MOF throughout MMMs lacks investigation. Therefore, magnetically aligned and enriched pathways of zeolitic imidazolate framework 8 (ZIF−8) in Matrimid MMMs were synthesized and investigated by means of their N2 and CO2 permeability. Magnetic ZIF−8 (m–ZIF−8) was synthesized by incorporating Fe3O4 in the ZIF−8 structure. The presence of Fe3O4 in m–ZIF−8 showed a decrease in surface area and N2 and CO2 uptake, with respect to pure ZIF−8. Alignment of m–ZIF−8 in Matrimid showed the presence of enriched pathways of m–ZIF−8 through the MMMs. At 10 wt.% m–ZIF−8 incorporation, no effect of alignment was observed for the N2 and CO2 permeability, which was ascribed anon-ideal tortuous alignment. However, alignment of 20 wt.% m–ZIF−8 in Matrimid showed to increase the CO2 diffusivity and permeability (19%) at 7 bar, while no loss in ideal selectivity was observed, with respect to homogeneously dispersed m–ZIF−8 membranes. Thus, the alignment of MOF particles throughout the matrix was shown to enhance the CO2 permeability at a certain weight content of MOF.

Hierarchical ZIF-8 composite membranes: Enhancing gas separation performance by exploiting molecular dynamics in hierarchical hybrid materials

“…magnetically aligned 111-ZIF-8 to enhance enriched pathways of 111-ZIF-8 through Matrimid® that showed an increase in CO2 diffusivity with no loss in ideal selectivity [28].…”

Metal–Organic Frameworks (MOFs)‐Based Mixed Matrix Membranes (MMMs) for Gas Separation: A Review on Advanced Materials in Harsh Environmental Applications

“…Numerous studies on high-pressure applications have been conducted using ZIF-based MMMs. [102,127,128] To improve CO 2 / CH 4 selectivity, the ZIF-8/Matrimid cross-linked MMMs were thermally treated up to 350 °C that allowed the adhesion between ZIF-8 and Matrimid. [129] Through thermal treatment, the MMMs developed with 40 wt% ZIF-8 possessed a high plasticization resistance property with the CO 2 /CH 4 selectivity of 134 at 40 bar.…”

“…Meanwhile, Van Essen et al added Fe 3 O 4 to ZIF-8 to form magnetized-ZIF-8. [128] The hybrid fillers could magnetically align, which enriched additional permeation pathways in Matrimid MMMs. The MMMs embedded of 20 wt% m-ZIF-8 in Matrimid had a CO 2 permeability of 12 Barrer and CO 2 /N 2 selectivity of 34 at 27 bar, which attributed to the increment in CO 2 diffusivity.…”

Correlating MOF-808 parameters with mixed-matrix membrane (MMM) CO2 permeation for a more rational MMM development

“…MMMs are believed to profit from the best of both worlds, having improved separation capacity due to nanoparticle addition while maintaining the good film-forming properties of the polymer. Much research has been dedicated in the past 10 years to find better combinations of polymers and MOFs with enhanced performance compared to the state-of-the-art 2,[7][8][9][10][11][12][13] . A lot of these literature reports focus on the use and modification of conventional MOFs, frequently employing a trial-and-error approach for developing novel MMMs.…”