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.

UiO66–NH2 AS A NEW PHOTOCATALYST FOR THE DEGRADATION OF p–XYLENE IN GASEOUS PHASE

“…Apparently, the crystals of UiO66-NH 2 were formed in a ball shape and particle size was about 200 nm. These features were also discussed by Luu Cam Loc et al [25] and Anjum et al [26]. Figure 1c displayed the thermogravimetric analysis (TGA) result of the obtained UiO66-NH 2 .…”

Enhancement of Oxidative Desulfurization Performance over UiO‐66(Zr) by Titanium Ion Exchange

“…To better understand why Ti–UiO‐66‐H and Ti–UiO‐66‐D exhibited enhanced catalytic activity in the ODS reaction of DBT, a model for the structure of UiO‐66(Zr) before and after Ti ion exchange was proposed (Scheme ). It is known that most of Zr sites in the structure of high‐crystallinity UiO‐66‐H are well coordinated by O and Cl ions . As a result, UiO‐66‐H exhibited low ODS activity (5.6 % yield of DBTO 2 ), which can be attributed to the lack of active sites.…”

“…It is known that most of Zr sites in the structure of high-crystallinity UiO-66-H are well coordinated by Oa nd Cl ions. [37,38] As ar esult, UiO-66-H exhibited low ODS activity (5.6 %y ield of DBTO 2 ), whichc an be attributedt ot he lack of active sites.…”

Mixed‐Matrix Membranes

“…The results showed that the combination of the amine‐functionalized modulator and linker in UiO‐66‐NH 2 ‐ABA gave the best performance among the MMMs with different filler/modulator combinations. The MMMs with 30 wt % filler loading (CO 2 permeability: 38 Barrer, CO 2 /CH 4 selectivity: 48) were over 50 % more selective and 540 % more permeable than the reference Matrimid membrane (CO 2 permeability: 6 Barrer, CO 2 /CH 4 selectivity: 31) as well as 30 % and 140 % more selective and permeable, respectively, than MMMs based on the reference UiO‐66 (CO 2 permeability: 16 Barrer, CO 2 /CH 4 selectivity: 36) …”