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Mixed matrix membranes (MMMs) were developed by adding MIL-125(Ti) and the amine-functionalized counterpart as fillers to Matrimid® polyimide. Through a well-optimized synthesis, strong performing MMMs with loadings up to 30 wt% could be prepared. SEM images of the synthesized MMMs confirmed the good adhesion to and dispersion of the fillers within the polymer matrix. Significantly improved CO 2 mixed gas selectivities and permeabilities for (50:50) CO 2 :N 2 and CO 2 :CH 4 gas mixtures at 9 bar and 308 K were achieved. The separation results demonstrated that the overall separation efficiency is increased by the addition of both MIL-125 and NH 2 -MIL-125 fillers but that the NH 2 -functionalized filler is preferred as it leads to higher selectivities and permeabilities. The performance of the membranes was compared to previously reported literature data for (CO 2 :CH 4 ) separation which shows that carefully tuned membrane synthesis procedure along with right selection of polymer and filler are crucial factors to get a highly selective and permeable membrane. Among non-fluorinated polymers forming the membrane matrix, present data outperform all previously reported MMM separation. MMMs based on fluorinated polyimide showed slightly higher selectivities, but much lower permeabilities.

Mixed matrix membranes (MMMs) have a potential to improve the separation performance of polymeric membranes while maintaining their advantages of easy processing and lower costs. In this work, series of MMMs were developed via solution casting by adding porous carbon-silica nanocomposite (CSM) fillers to a readily available Matrimid (R) membrane. CSMs were prepared by a hard template synthesis technique to get a tuneable porosity and surface chemistry which is controlled by the optimization of the filler porosity using carbon deposition, the pyrolysis conditions, and the maximization of polarity via oxygen functional groups. SEM images of the synthesized MMMs confirmed the good adhesion and dispersion of the fillers within the polymer matrix. The separation results demonstrate that the overall separation efficiency is increased by the addition of a carbon phase, providing an increased affinity for the CO2 gas molecules next to the creation of extra porosity and free volume. It was showed that significantly improved CO2 mixed gas selectivity and permeability for CO2:N-2 and CO2:CH4 gas mixtures at 9 bar and 308 K was achieved. For gas mixtures with a 50:50 (CO2:N-2) feed composition, a 2-fold and 6-fold increase of the mixed gas selectivity (up to 42.5) and permeability (up to 27 Barrer) compared to unfilled PI was achieved, respectively. The performance of the membranes was compared to the existing literature data. (C) 2015 Elsevier B.V. All rights reserved.

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.