Polysulfone-sulfonated poly(ether ether) ketone blend membranes: systematic synthesis and characterisation

The effect of sulfonated poly(ether ether ketone) (SPEEK) in membrane forma tion and separation properties has been investigated in polysulfone(PSU)/SP EEK/N-methyl-2-pyrrolidinone (NMP) systems. Charged ultrafiltration/nanofil tration membranes were obtained reliably in the range of 0.5-5 wt.% SPEEK i n the polymer blend. All PSU/SPEEK blend membranes had substantially higher water flux, salt rejection, porosity and greatly reduced particle adhesion compared to the PSU base membrane, Further, all of these properties varied systematically with variation of SPEEK content. Reproducibility and stabil ity of the membrane properties was excellent. Port: sizes determined from d extran retention data and AFM measurements showed reasonable agreement. Mem branes with 5 wt.% SPEEK demonstrated excellent overall properties. Such me mbranes had very high permeability, 22.6 +/- 1.6 x 10(-11) m(3) s(-1) N-1, 0.999 fractional rejection of 4000 Da dextran, 0.65 rejection of 0.001 M Na Cl, and only 0.75 mN m(-1) adhesion of a 4 mum silica particle. Such membra nes are very promising for scale-up of production and testing on real proce ss streams. (C) 2001 Elsevier Science B.V. All rights reserved.