Study On Preparation And Separation Performance Of Polyimide Nanofiltration Membrane

In this study, solvent-resistant nano-filtration polyimide (PI) membrane wasprepared from polyamic acid (PA) solution via immersion precipitation phaseinversion process. Polyimide precursor was obtained from pyromellitic dianhidride(PMDA) and 4,4-oxydianiline (ODA). By performing the reactants pretreatment,adjusting reaction time, the characteristic viscosity of PA could be stabilized at 0.99.The separation performance of the synthesized membrane was evaluated by usingPEG300. The membrane prepared by 15% PA, evaporation for 30 min and thegel-bath of 30% ethanol aqueous solution showed a good PEG300 rejection rate up to91% with a flux of 5.75 L/m2.h. And the rejection rate for toluene/acetone/ lubricatingoil solution is 66% with a flux of 4.256 L/m2.h. The prepared PI membrane will havepromising applications in separations of organic solvent systems.