Functionalized flexible MOFs as fillers in mixed matrix membranes for highly selective separation of CO2 from CH4 at elevated pressures

Abstract

Mixed matrix membranes (MMMs) composed of a glassy polymer (polysulfone) and the flexible metal organic framework NH(2)-MIL-53(Al) exhibit excellent separation properties. In contrast to most reported membranes, CO(2)/CH(4) separation selectivity increases with pressure, related to the flexibility of the filler.

Visualizing MOF Mixed Matrix Membranes at the Nanoscale: Towards Structure‐Performance Relationships in CO2/CH4 Separation Over NH2‐MIL‐53(Al)@PI

“…This fl ange fi t in a permeation module that was placed inside an oven using the permeation setup described elsewhere. [ 19 ] . An equimolar mixture of CO 2 and CH 4 (100 mL min − 1 total fl ow rate) was employed as feed.…”

“…This temperature is below the glass transition temperature ( T g ) of the polymer (590 K) to prevent the transition into a rubbery-state. [ 19 ] . The thickness of the resulting membranes was evaluated using a digital micrometer (Mitutoyo, Quickmike Series).…”

“…As an alternative, the possibility of incorporating certain functional groups, i.e., amino functions, on the surface of MOF crystals could result in enhanced interactions with the functions existing in the polymer chains, e.g., amide, sulfone groups, as reported for MMM comprising NH 2 -MIL-53 (Al) and polysulfone that was attributed to hydrogen bonding between the amine and sulfone groups of both constituents at their interface. [ 19 ] In addition, such enhanced fi ller-matrix contact is expected to result in better fi ller dispersions within the membrane and to minimize the formation of interfacial voids between both phases, which would represent non-selective bypasses for the permeating gases. However, although fi ller distribution and fi ller-matrix contact are considered key parameters for the MMMs, they are also notoriously diffi cult to assess experimentally.…”

Zeolite membranes – a review and comparison with MOFs

“…15 -is reported. [341][342][343][344][345] In principle, the lab-scale fabrication procedure of MOF-based MMMs is similar to the one applied for the synthesis of other MMMs. This involves the phase-inversion and solution-casting methods.…”

High performance mixed matrix membranes (MMMs) composed of ZIF-94 filler and 6FDA-DAM polymer

“…Permeation experiments were performed for pure gases and CO 2 /N 2 gas mixtures in the gas permeation setup described elsewhere [48]. Circular samples of 3.14 cm 2 were cut and placed in the permeation cell over a macroporous stainless steel SS 316 L support with 20 µm nominal pore size.…”