Abstract:
The fabrication of mixed matrix membranes (MMMs), which contain metal-organic
frameworks (MOFs) of Ni and Cu-MOF-74 with rubbery polydimethylsiloxane (PDMS)
polymer matrix, is a response to the growing concern about carbon dioxide (CO2)
emissions. These membranes have a lot of potential to separate gases because of the
hydrophobicity, high gas permeability, and flexibility of PDMS, as well as the substantial
effective areas and distinctive characteristics to adsorb gas by MOFs. In order to maximize
CO2 separation and CO2/N2 and O2/N2 selectivities, this work describes the manufacturing
procedure of MMMs with different concentrations of Ni and Cu-MOF-74 (0.5%, 1%,
1.5%, and 2%). To get understanding of the behavior of the MOFs and MMMs, the
characterization using XRD, SEM, FTIR, and mechanical strength testing was conducted.
Following analysis, it was determined that 1wt%Ni-MOF-74@PDMS and 1wt%CuMOF-74@PDMS were the best MMMs because of their uniform MOF dispersion into the
polymer matrix, which was determined by SEM-EDX mapping, high tensile strength, and
increased CO2 permeation to 4288 Barrer (34% increase) and 4432 Barrer (40% increase),
respectively. Moreover, 1wt%Cu-MOF@PDMS demonstrated an increase in CO2/N2 and
O2/N2 selectivity to 94.7 (428% increase) and 6.47 (150% increase), respectively, whereas
1wt%Ni-MOF@PDMS showed an increase in CO2/N2 and O2/N2 selectivity to 36.2
(125% increase) and 3.2 (25% increase). The Lewis acidic sites of MOF-74-NCs for CO2
and O2 as well as the presence of porous fillers are both credited with this increase in
selectivity. In conclusion, this work offers insightful information on how MOF chemistry
affects membrane permeability and selectivity, which may have important ramifications
for the advancement of gas separation technologies
