POLYCARBONATE (DMF METAL SALT) COMPLEX MEMBRANE PREPARED VIA A WET PHASE INVERSION METHOD FOR OXYGEN ENRICHMENT FROM AIR

Asymmetric polycarbonate (PC)/metal salt complex membranes were prepar ed by a wet phase inversion method utilizing the complex structure to improve ps separation performance. The effects of PC content in the ca sting solution, kind of added metal salts, coagulation medium on membr ane formation, morphology, and gas separation performances of the comp lex membranes are reported. The PC/DMF/metal salt complex structure is characterized by FTIR and elemental analysis (EA). The rate of liquid -liquid phase separation decreases with increasing alcohol molar volum e of the coagulation medium. The gas separation performance for metal salt added polycarbonate membranes was better than that of the membran e without additive with pressure-normalized oxygen fluxes of 0.034 x 1 0(-6) cm3 (STP)/cm2 . sec . cmHg and O2/N2 selectivity of 6.46. For ex ample: the pressure-normalized oxygen flux and the selectivity of the PC/DMF/CoCl2 . 6H2O complex membrane are 4.62 x 10(-6) cm3 (STP)/cm2 . s . cmHg and 3.53, respectively with the CH3OH coagulation medium. Th e pressure-normalized fluxes for PC/DMF/FeCl3 . 6H2O complex membrane were 20 times higher than that of the pure PC membrane with an O2/N2 s electivity of 6.83 obtained by the CH3OH coagulation medium.