Formation kinetics and characterization of polyphthalazinone ether ketone hollow fiber ultrafiltration membranes

This paper reports an evaluation of the effect of both organic and inorganic additives on the gelation kinetics, morphology and separation properties of asymmetric poly(phthalazine ether ketone) (PPEK) hollow fiber ultrafiltration membranes. Using an online optical microscope-CCD camera for observation of precipitation front movement (X), a good linear relationship between X2 and time was observed for the whole gelation process with the correlation coefficient (R2) higher than 0.98. It was found that the pure water flux of membranes with additives were lower than neat PPEK membranes. This observation might be attributed to the decrease in the face gelation velocity caused by the extra organic additives. The water flux of PEG600 was higher than that of Tween80 at the same additive concentration. When OA concentration increased from 3.5 to 5.0 wt.%, the pure water flux increased from 332 to 367 L/m2 h and the rejection decreased from 98.6 to 96.8%. The PPEK hollow fiber membranes exhibited finger-like macro-voids structure and a skin layer at the outer-most region of the hollow fiber. Evaluation of the membrane chemical resistance with various chemical solutions indicated that PPEK membranes had good chemical resistance against HCl, H2SO4, HNO3, CH3COOH, OA, NaOH and H2O2, while the NaClO solution can greatly damage the membrane mechanical strength. Static sorption tests of PPEK membrane revealed that PPEK membrane adsorbed more bacitracin than BSA due to the smaller size of bacitracin.