(519a) Effect of Co Ions in Cross-Linked Poly(ethylene oxide) on O2 Transport Characteristics | AIChE

(519a) Effect of Co Ions in Cross-Linked Poly(ethylene oxide) on O2 Transport Characteristics


Alebrahim, T. - Presenter, University At Buffalo
Esmaeili, N., University at Buffalo, The State University of New York
Tran, T., University At Buffalo
Lin, H., University of Buffalo, State University of New Yor
Cobalt (Co)-based complexes are considered as attractive O2-binding elements, which can reversibly and selectively interact with O2 and affect O2 gas transport properties. Herein, we investigate the effect of Co ions dissociated in amorphous cross-linked poly(ethylene oxide) (XLPEO) on physical properties and gas transport characteristics. Polymeric films containing Co salts were prepared by photo-polymerization of solutions containing poly(ethylene glycol) diacrylate (PEGDA), poly(ethylene glycol) methyl ether acrylate (PEGMEA), and different salts such as Co(ClO4)2, and Co(BF4)2. The salts can be fully dissociated, and the Co2+ ions form conjugations with the ethylene oxide in XLPEO, as validated by FTIR and XRD. Increasing the Co content increases the density (following the additive model) and glass transition temperature of XLPEO. For instance, adding 17 wt.% Co(ClO4)2 to XLPEO increases the Tg and density from -65 ºC and 1.149 g/cm3 to -26 ºC and 1.304 g/cm3, respectively. The O2 and N2 permeability are significantly impacted by adding high concentration of Co salts. Specifically, O2 and N2 permeability decreases from 26 and 10 to 0.24 and 0.14 Barrer, respectively, by adding 17 wt.% of Co(BF4)2. Interestingly, the CO2/O2 selectivity increases from 20 to 60 by addition of 17 wt.% of Co(BF4)2 presumably due to the retarded O2 diffusion. Additionally, we found that O2 solubility increases with increasing Co(BF4)2 content due to high affinity between Co ions and oxygen. For example, O2 solubility increases from 0.2 to 6.4 cm3(STP)/cm3 atm at 35°C by addition of 6.4 wt.% Co(BF4)2 to XLPEO. Understanding the effect of Co ions-O2 interactions on gas transport properties may provide guidance in designing advanced polymeric membranes with high CO2/O2 selectivity.