A Polyethersulfone/sulfonated Polysulfone Blend Ultrafiltration Membrane Was Prepared By A Non-solvent-induced Gel Phase Inversion Method

Membrane fouling is a serious problem for the pressure driven membrane filtration.Polymer blend is an important method to improve the hydrophilic and antifouling property of membranes.This study reported the preparation of hydrophilic polyethersulfone(PES)/sulfonated polysulfone(SPSf)blend ultrafiltration membrane by non-solvent-H2O induced gelation phase separation through the interaction between H2O and SPSf.Firstly,the PES/SPSf blend flat ultrafiltration membrane was prepared by non-solvent induce gelation separation,using N,N-dimethylacetamide(DMAc)as solvent,polyethylene glycol(PEG)as additive and H2O as non-solvent additive and coagulation bath.The concentration of PSE/SPSf casting solution was 18 wt%.The results indicated that the viscosity of the casting solutions increased with the increase of H2O concentration,which leaded to the changes of membrane structure from macrovoid to sponge-like.Ultrasonic measurements demonstrated that the membrane formation behavior transformed from instantaneous phase separation to delay phase separation with the increase H2O concentration.The PES/SPSf blend membrane with sponge-like structure was obtained from the casting solution with 9 wt%H2O.A simple method was used to predict the demixing behavior of instantaneous phase separation and delay phase separation by introducing the approach ratio.Secondly,the PES/SPSf blend seven-bore hollow fiber ultrafiltration membranes were prepared via non-solvent H2O induced phase separation under the optimum composition condition.The results indicated that the pore size and porosity of the membrane gradually increased with the increase of coagulation bath temperature from 30? to 50?.Besides,the pure water flux of the resultant membranes also increased from 242 L/m2h to 302 L/m2h and the BSA rejection was over 95%.Further,the DMAc-H2O was used as first coagulation bath and H2O as second coagulation bath.The results showed that the pUrewater flux of the resultant membranes increased from 320 L/m2h to 545 L/m2h,and the BSA rejection reduced from 98.6%to 80.87%with the increase of DMAc concentration in the coagulation bath from 0 wt%to 60 wt%.In addition,the pure water flux of the membranes increased from 248 L/m2h to 307 L/m2h and the BSA rejection reduced from 95%to 89.8%with the increase of DMAc concentration in bore fluid from Owt%to 60%.Moreover,the pure water flux of the resultant membrane increased at first,and then declined with the increase of air gap from 10mm to 160mm.The optimum air gap w.as 40 mm.Finally,the PES/SPSf blend outside-in hollow fiber ultrafiltration membranes were prepared via non-solvent H2O induced phase separation.The PES/SPSf blend hollow fiber membrane with the pure water flux of 221 L/m2h and the BSA rejection of 96%was obtained under the conditions of coagulation bath temperature 50 ?,the air gap 40 mm,the bore solution-60 wt%DMAc solution.