Polyvinylidene fluoride (PVDF)-perfluorosulphonic acid (PFSA) hollow fibre ultrafiltration (UF) blend membranes were prepared by wet-spinning method. Polyvinylpyrrolidone (PVP) and ethanol aqueous solutions were employed as additive and coagulants, respectively. The effect of PVP concentration in the dopes and ethanol concentration in the coagulants on morphology and performance of PVDF- PFSA hollow fibre UF blend membranes were investigated. Blend membranes were characterized in terms of precipitation kinetics, morphology, thermal property and separation performance. The results showed that the increments of PVP concentration in the dopes and ethanol concentration in coagulants both resulted in higher pure water permeation flux (PWP) and worse rejection (R) of bovine serum albumin (with the increment of PVP concentration from 0 to 5 wt% in the dopes, PWP increased from 41.7 L.m-2.h-1 to 134 L.m-2.h-1 and R decreased from 99.8% to 84.4% as well as with the increase in ethanol concentration in coagulants from 0 to 40 wt%, PWP increased from 33.5 L.m-2.h-1 to 123 L.m -2.h-1 and R decreased from 97.7% to 88.7%). However, the proportion of sponge-like structure in the cross-section of membranes decreased with the increasing PVP concentration in the dopes and the proportion increased with the increased ethanol concentration in the coagulations. In addition, the location of the sponge-like structure in the cross-section of membranes was significantly influenced by ethanol concentrations in the coagulants and DSC results revealed that the crystallinity (Xc) of the blend membrane was in accordance with the proportion of sponge-like structure. These behaviours were attributed to the different roles of PVP in the dopes and ethanol in the coagulants, respectively. PVDF-PFSA hollow fibre membranes with different morphologies and performances were prepared by these two different routes. Meanwhile, the range of PVDF-PFSA hollow fibre blend membranes was extended.
|Journal||Iranian Polymer Journal|
|Publication status||Published - 2009|
- Body fluids
- Concentration (process)
- Precipitation (chemical)
- Thermodynamic properties
- Membrane structures