Preparation and characterization of novel PES/SPES blend ultrafiltration membranes

Novel polyethersulfone/sulfonated polyethersulfone(PES/SPES) blend ultrafiltration membranes were prepared via phase inversion,and the effect of SPES/PES ratio and the degree of sulfonation(DS) of SPES solution on morphology and properties of membranes were investigated.The results showed an excellent compatibility between PES and SPES.The sulfonic acid groups of SPES accumulated onto the membrane surface during phase separation process.All membranes presented asymmetric structure consisting of a dense skin layer and a porous sub-layer.With increasing DS of SPES solution,the finger-like structure of membrane tended to change into sponge-like structure.With 11.5% DS of SPES and 0.36 of SPES/PES ratio,the pure water flux of blend membrane was 211.9 L/(m2.h),and the rejection rate for PEG20000,PEG10000 and PEG6000 were 96.6%,88.5% and 58.3%,respectively.The rejection rate of Na2SO4 for blend membranes decreased with increasing of salts concentration.The hydrophilicity of blend membrane was improved obviously through hydrophilic modification.