TY - JOUR
T1 - Performance and plasticization behavior of polymer–MOF membranes for gas separation at elevated pressures
AU - Shahid, S.
AU - Nijmeijer, Dorothea C.
PY - 2014
Y1 - 2014
N2 - Mixed matrix membranes (MMMs) based on three distinctively different MOFs (MIL-53(Al) (breathing MOF), ZIF-8 (flexible MOF) and Cu3BTC2 (rigid MOF)) dispersed in Matrimid®-PI have been investigated. MOF loading was varied between 0 wt% and 30 wt%. The fabricated MOF-MMMs were characterized for pure and binary gas mixture separations at low and high pressures and their performance in terms of CO2 permeability and CO2/CH4 selectivity was evaluated. The use of a less volatile co-solvent, optimized priming protocol to prepare the MMMs and thermal annealing resulted in a good dispersion of MOF particles in the Matrimid®-PI matrix. Incorporation of MOFs resulted in increased density, Tg and improved degradation behavior of the membranes confirming a good compatibility between the polymer and the MOFs. Low pressure gas separation showed moderate enhancement in CO2 permeability and CO2/CH4 selectivity of MOF-MMMs compared to native polymer membranes, but the improvement becomes pronounced at high pressures. At high pressures, the native Matrimid®-PI membrane showed typical plasticization behavior, while in MMMs, MOF particles limit the mobility of polymer chains thus suppressing CO2 induced plasticization and maintain large separation factors over a wide pressure range investigated. The respective increase in performance of MMMs is very much dependent on MOF crystal structure and its interactions with CO2 gas molecules. Among the three MOF-MMMs, membranes based on Cu3BTC2 showed highest selectivity while ZIF-8 based membranes showed highest permeability. In general it can be concluded that the high CO2 permeability and CO2/CH4 selectivity of MMMs is the combined effect of an increased sorption and diffusion selectivity and reduced plasticization. Overall, this work reveals that MOF-MMMs delay CO2 induced plasticization and show good separation performance even at high pressures, showing their potential to a wide range of newly emerging high pressure energy applications
AB - Mixed matrix membranes (MMMs) based on three distinctively different MOFs (MIL-53(Al) (breathing MOF), ZIF-8 (flexible MOF) and Cu3BTC2 (rigid MOF)) dispersed in Matrimid®-PI have been investigated. MOF loading was varied between 0 wt% and 30 wt%. The fabricated MOF-MMMs were characterized for pure and binary gas mixture separations at low and high pressures and their performance in terms of CO2 permeability and CO2/CH4 selectivity was evaluated. The use of a less volatile co-solvent, optimized priming protocol to prepare the MMMs and thermal annealing resulted in a good dispersion of MOF particles in the Matrimid®-PI matrix. Incorporation of MOFs resulted in increased density, Tg and improved degradation behavior of the membranes confirming a good compatibility between the polymer and the MOFs. Low pressure gas separation showed moderate enhancement in CO2 permeability and CO2/CH4 selectivity of MOF-MMMs compared to native polymer membranes, but the improvement becomes pronounced at high pressures. At high pressures, the native Matrimid®-PI membrane showed typical plasticization behavior, while in MMMs, MOF particles limit the mobility of polymer chains thus suppressing CO2 induced plasticization and maintain large separation factors over a wide pressure range investigated. The respective increase in performance of MMMs is very much dependent on MOF crystal structure and its interactions with CO2 gas molecules. Among the three MOF-MMMs, membranes based on Cu3BTC2 showed highest selectivity while ZIF-8 based membranes showed highest permeability. In general it can be concluded that the high CO2 permeability and CO2/CH4 selectivity of MMMs is the combined effect of an increased sorption and diffusion selectivity and reduced plasticization. Overall, this work reveals that MOF-MMMs delay CO2 induced plasticization and show good separation performance even at high pressures, showing their potential to a wide range of newly emerging high pressure energy applications
KW - METIS-307338
KW - IR-95017
U2 - 10.1016/j.memsci.2014.07.034
DO - 10.1016/j.memsci.2014.07.034
M3 - Article
SN - 0376-7388
VL - 470
SP - 166
EP - 177
JO - Journal of membrane science
JF - Journal of membrane science
ER -