Gas permeation and sorption properties of ZIF-8 filled polymeric membranes prepared by infrared and incandescent light induced liquid and vapor phase inversion

Thesis Type: Doctorate

Institution Of The Thesis: Middle East Technical University, Faculty of Engineering, Department of Chemical Engineering, Turkey

Approval Date: 2017

Thesis Language: English


Principal Supervisor (For Co-Supervisor Theses): Halil Kalıpçılar

Co-Supervisor: Levent Yılmaz


The asymmetric PES membranes were produced by wet phase inversion method. Observations show that 10% loading of ZIF-8 with 65 nm crystal size into PES membranes, increasing solvent and non-solvent content of the IPA coagulation bath improved the permeance of PES membranes. The PI membranes were prepared by light induced dry-wet phase inversion method which is a new method and is not used in literature yet. The maximum permeance was observed when the IR exposure took less than 10 seconds. The permeance was about 8.51 GPU, 2.44 GPU and 0.13 GPU for H2, CO2 and CH4, respectively. Solvent ratio THF/DMF was the other parameter whose effect was studied. CO2 permeance of PI membranes was measured 0.81 GPU, 2.55 GPU and 6.65 GPU corresponding to the 0.80, 0.42, 0.17 THF/DMF ratio of casting solution, respectively. For PI membranes, ZIF-8 loading resulted in thicker skin layer and lower permeance. The asymmetric PI membranes were produced by light induced dry-vapor phase inversion method. The two important opportunities of this method were fixing the ZIF-8 crystals in the skin layer and contributing pNA in the membrane. For mixed matrix-pNA membranes produced by this method, the maximum selectivity was about 3.24, 132.68, and 40.9 for H2/CO2, H2/CH4 and CO2/CH4, respectively. The effect of ZIF-8 loading on sorption capacity of dense PI mixed matrix membrane (MMM) was investigated. CO2 sorption capacity increased by 22% and 40% at 10 bar corresponding to ZIF-8 loading by 10% and 20 %. The enhancement in CH4 sorption capacity was 20% and 60% at 10 bar corresponding to 10% and 20% of ZIF-8 addition. In the multicomponent sorption in glassy polymers the solubility of all gases depressed with different extents due to a competitive effect.